Imaging

SAN FRANCISCO – With radiology assistance often taking hours, more physicians should know the basics of reading a trauma CT to identify injuries that require immediate action, Dr. Andrew D. Perron said.

"At 3 a.m., I have to know without calling someone whether I need to get moving," said Dr. Perron, an emergency physician at Maine Medical Center, Portland. It is crucial to be able to identify which diagnoses could kill a patient within an hour, so focus on detecting a handful of potentially life-threatening injuries in the head, chest, abdomen, and pelvis, he said at the Scientific Assembly of the American College of Emergency Physicians.

For trauma victims, CT scans have become almost automatic. Currently in the United States, 60-70 million CT scans are conducted each year, compared with only 3 million in 1980, Dr. Perron said. A quarter of the scans are of the head.

When reading a CT of the head, look for epidural hematoma, subdural hematoma, skull fracture, contusions, head pressure and shift, and neck injuries. An epidural hematoma will be lens shaped and does not cross the sutures. A clot will appear as bright white on the scan; if an area is on its way to clotting, it will be gray. Epidural hematomas have low mortality if the patient is treated before he or she loses consciousness.

Subdural hematomas are sickle-shaped and do cross the sutures but not the midline. Subdurals have an 80% mortality rate. Even if a neurosurgeon suctions out the clot, the brain may not recover, Dr. Perron said.

Any area of the skull can sustain a fracture, but skull fractures sometimes aren’t readily visible on plain film or CT. The give-away on imaging is if there is blood instead of air in the mastoid cells, he said.

Although brain contusions are not readily treatable, it is important to know they are there, Dr. Perron said. A contusion will appear as a high-density area on the scan. They commonly result from a sudden deceleration, as in a motor vehicle collision. CT scans can be used to show high pressure within the skull, but there is divergence in the literature about CT’s true utility for these cases, Dr. Perron said.

In the neck, look for fracture and dislocation. CT is 98% sensitive for neck fractures and is especially good for diagnosing fractures located either high or low in the neck. Vertebral body fractures are the most common and account for about a third of neck fractures. Axial views provide the most data on the state of the spinal canal, but a coronal view is easier to read if the physician is more experienced with plain x-rays.

Dislocation is most common, but easier to miss, at C5-6 and C6-7. Dislocations are usually accompanied by torn ligaments. The injury comes from a rotational deceleration in most cases. Vascular injury can occur with dislocation or subluxation, with an attendant risk for dissection. An angiogram should be considered for patients with a C1-3 fracture and subluxation or fracture of the foramen transversarium.

In the chest, the main concerns are aortic injury, pneumothorax, and hemothorax. Like contusions, aortic injuries often are caused by sudden deceleration. Most patients with an aortic injury die in the field. If they survive to the hospital and are scanned, leaking contrast material seen on imaging indicates a ruptured aorta, Dr. Perron said.

A chest x-ray can miss a small pneumothorax, but they are easy to see on CT, with a black space demonstrating where air is outside the lung. A hemothorax cannot be detected by x-ray until at least 250 cc of blood has accumulated, but CT is more sensitive for these as well.

The spleen, liver, kidneys, pancreas, and blood in the abdomen are the areas of greatest concern in abdominal trauma. When scanning the abdomen, Dr. Perron generally uses intravenous contrast because it helps identify the major blood vessels and shows active bleeding. He starts with a supine and coronal view, as axial orientations are more difficult to read.

There should never be blood visible in the middle of the spleen. The liver has more vascularity on a normal view. Lacerations are the most common injury in the liver, and lacerations to the kidneys are also often seen. CT may detect an absence of blood flow to the liver or kidney, indicating severe injury. The main issue with these organs is to be sure they are in one piece and functioning.

The sensitivity of CT is only 68% for pancreatic injuries. This pancreas can be damaged when it is compressed against the spine, which may occur in a bicycle- or sports-related impact. CT can be used to spot active bleeding; the active extravasation of IV contrast is the hallmark, but it may be subtle.

In the pelvis, fractures and other bony injuries and free fluid are the biggest concerns. Pelvic fractures, which are generally easy to see on imaging, suggest that the body sustained a large amount of force. Free fluid in the pelvis can indicate a solid organ injury, a mesenteric injury, a bowel injury, or even a preexisting condition such as ascites.

Dr. Perron reported no conflicts of interest.

SAN FRANCISCO – With radiology assistance often taking hours, more physicians should know the basics of reading a trauma CT to identify injuries that require immediate action, Dr. Andrew D. Perron said.

"At 3 a.m., I have to know without calling someone whether I need to get moving," said Dr. Perron, an emergency physician at Maine Medical Center, Portland. It is crucial to be able to identify which diagnoses could kill a patient within an hour, so focus on detecting a handful of potentially life-threatening injuries in the head, chest, abdomen, and pelvis, he said at the Scientific Assembly of the American College of Emergency Physicians.

For trauma victims, CT scans have become almost automatic. Currently in the United States, 60-70 million CT scans are conducted each year, compared with only 3 million in 1980, Dr. Perron said. A quarter of the scans are of the head.

When reading a CT of the head, look for epidural hematoma, subdural hematoma, skull fracture, contusions, head pressure and shift, and neck injuries. An epidural hematoma will be lens shaped and does not cross the sutures. A clot will appear as bright white on the scan; if an area is on its way to clotting, it will be gray. Epidural hematomas have low mortality if the patient is treated before he or she loses consciousness.

Subdural hematomas are sickle-shaped and do cross the sutures but not the midline. Subdurals have an 80% mortality rate. Even if a neurosurgeon suctions out the clot, the brain may not recover, Dr. Perron said.

Any area of the skull can sustain a fracture, but skull fractures sometimes aren’t readily visible on plain film or CT. The give-away on imaging is if there is blood instead of air in the mastoid cells, he said.

Although brain contusions are not readily treatable, it is important to know they are there, Dr. Perron said. A contusion will appear as a high-density area on the scan. They commonly result from a sudden deceleration, as in a motor vehicle collision. CT scans can be used to show high pressure within the skull, but there is divergence in the literature about CT’s true utility for these cases, Dr. Perron said.

In the neck, look for fracture and dislocation. CT is 98% sensitive for neck fractures and is especially good for diagnosing fractures located either high or low in the neck. Vertebral body fractures are the most common and account for about a third of neck fractures. Axial views provide the most data on the state of the spinal canal, but a coronal view is easier to read if the physician is more experienced with plain x-rays.

Dislocation is most common, but easier to miss, at C5-6 and C6-7. Dislocations are usually accompanied by torn ligaments. The injury comes from a rotational deceleration in most cases. Vascular injury can occur with dislocation or subluxation, with an attendant risk for dissection. An angiogram should be considered for patients with a C1-3 fracture and subluxation or fracture of the foramen transversarium.

In the chest, the main concerns are aortic injury, pneumothorax, and hemothorax. Like contusions, aortic injuries often are caused by sudden deceleration. Most patients with an aortic injury die in the field. If they survive to the hospital and are scanned, leaking contrast material seen on imaging indicates a ruptured aorta, Dr. Perron said.

A chest x-ray can miss a small pneumothorax, but they are easy to see on CT, with a black space demonstrating where air is outside the lung. A hemothorax cannot be detected by x-ray until at least 250 cc of blood has accumulated, but CT is more sensitive for these as well.

The spleen, liver, kidneys, pancreas, and blood in the abdomen are the areas of greatest concern in abdominal trauma. When scanning the abdomen, Dr. Perron generally uses intravenous contrast because it helps identify the major blood vessels and shows active bleeding. He starts with a supine and coronal view, as axial orientations are more difficult to read.

There should never be blood visible in the middle of the spleen. The liver has more vascularity on a normal view. Lacerations are the most common injury in the liver, and lacerations to the kidneys are also often seen. CT may detect an absence of blood flow to the liver or kidney, indicating severe injury. The main issue with these organs is to be sure they are in one piece and functioning.

The sensitivity of CT is only 68% for pancreatic injuries. This pancreas can be damaged when it is compressed against the spine, which may occur in a bicycle- or sports-related impact. CT can be used to spot active bleeding; the active extravasation of IV contrast is the hallmark, but it may be subtle.

In the pelvis, fractures and other bony injuries and free fluid are the biggest concerns. Pelvic fractures, which are generally easy to see on imaging, suggest that the body sustained a large amount of force. Free fluid in the pelvis can indicate a solid organ injury, a mesenteric injury, a bowel injury, or even a preexisting condition such as ascites.

Dr. Perron reported no conflicts of interest.

SAN FRANCISCO – With radiology assistance often taking hours, more physicians should know the basics of reading a trauma CT to identify injuries that require immediate action, Dr. Andrew D. Perron said.

"At 3 a.m., I have to know without calling someone whether I need to get moving," said Dr. Perron, an emergency physician at Maine Medical Center, Portland. It is crucial to be able to identify which diagnoses could kill a patient within an hour, so focus on detecting a handful of potentially life-threatening injuries in the head, chest, abdomen, and pelvis, he said at the Scientific Assembly of the American College of Emergency Physicians.

For trauma victims, CT scans have become almost automatic. Currently in the United States, 60-70 million CT scans are conducted each year, compared with only 3 million in 1980, Dr. Perron said. A quarter of the scans are of the head.

When reading a CT of the head, look for epidural hematoma, subdural hematoma, skull fracture, contusions, head pressure and shift, and neck injuries. An epidural hematoma will be lens shaped and does not cross the sutures. A clot will appear as bright white on the scan; if an area is on its way to clotting, it will be gray. Epidural hematomas have low mortality if the patient is treated before he or she loses consciousness.

Subdural hematomas are sickle-shaped and do cross the sutures but not the midline. Subdurals have an 80% mortality rate. Even if a neurosurgeon suctions out the clot, the brain may not recover, Dr. Perron said.

Any area of the skull can sustain a fracture, but skull fractures sometimes aren’t readily visible on plain film or CT. The give-away on imaging is if there is blood instead of air in the mastoid cells, he said.

Although brain contusions are not readily treatable, it is important to know they are there, Dr. Perron said. A contusion will appear as a high-density area on the scan. They commonly result from a sudden deceleration, as in a motor vehicle collision. CT scans can be used to show high pressure within the skull, but there is divergence in the literature about CT’s true utility for these cases, Dr. Perron said.

In the neck, look for fracture and dislocation. CT is 98% sensitive for neck fractures and is especially good for diagnosing fractures located either high or low in the neck. Vertebral body fractures are the most common and account for about a third of neck fractures. Axial views provide the most data on the state of the spinal canal, but a coronal view is easier to read if the physician is more experienced with plain x-rays.

Dislocation is most common, but easier to miss, at C5-6 and C6-7. Dislocations are usually accompanied by torn ligaments. The injury comes from a rotational deceleration in most cases. Vascular injury can occur with dislocation or subluxation, with an attendant risk for dissection. An angiogram should be considered for patients with a C1-3 fracture and subluxation or fracture of the foramen transversarium.

In the chest, the main concerns are aortic injury, pneumothorax, and hemothorax. Like contusions, aortic injuries often are caused by sudden deceleration. Most patients with an aortic injury die in the field. If they survive to the hospital and are scanned, leaking contrast material seen on imaging indicates a ruptured aorta, Dr. Perron said.

A chest x-ray can miss a small pneumothorax, but they are easy to see on CT, with a black space demonstrating where air is outside the lung. A hemothorax cannot be detected by x-ray until at least 250 cc of blood has accumulated, but CT is more sensitive for these as well.

The spleen, liver, kidneys, pancreas, and blood in the abdomen are the areas of greatest concern in abdominal trauma. When scanning the abdomen, Dr. Perron generally uses intravenous contrast because it helps identify the major blood vessels and shows active bleeding. He starts with a supine and coronal view, as axial orientations are more difficult to read.

There should never be blood visible in the middle of the spleen. The liver has more vascularity on a normal view. Lacerations are the most common injury in the liver, and lacerations to the kidneys are also often seen. CT may detect an absence of blood flow to the liver or kidney, indicating severe injury. The main issue with these organs is to be sure they are in one piece and functioning.

The sensitivity of CT is only 68% for pancreatic injuries. This pancreas can be damaged when it is compressed against the spine, which may occur in a bicycle- or sports-related impact. CT can be used to spot active bleeding; the active extravasation of IV contrast is the hallmark, but it may be subtle.

In the pelvis, fractures and other bony injuries and free fluid are the biggest concerns. Pelvic fractures, which are generally easy to see on imaging, suggest that the body sustained a large amount of force. Free fluid in the pelvis can indicate a solid organ injury, a mesenteric injury, a bowel injury, or even a preexisting condition such as ascites.

Dr. Perron reported no conflicts of interest.

Researchers have developed an inexpensive technique that, they say, can detect covert awareness in people diagnosed as vegetative.

The researchers used electroencephalography (EEG), instead of functional MRI (fMRI), a technology previously shown to detect minimal consciousness in people thought to be vegetative based on an evaluation of their behavioral symptoms (N. Engl. J. Med. 2010;362:579-89).

FMRI works by detecting a patient’s ability to modulate a blood oxygen–level dependent (BOLD) response to mental imagery tasks. Barriers to its wider use include its expense; the difficulty of transporting patients to MRI-equipped facilities; imaging problems when patients cannot remain still; and the technology’s inappropriateness for patients with metal implants in their bodies.

EEG, which measures the activity of groups of cortical neurons from scalp electrodes, can be used at the bedside and is inexpensive, widely available, and unaffected by metal.

For their research, published online Nov. 10 in The Lancet (doi:10.1016/S0140-6736(11)61224-5), Damian Cruse, Ph.D., of the University of Western Ontario, London, and his colleagues in the United Kingdom and Belgium recruited 16 patients diagnosed by behavioral indicators as vegetative according to established criteria. The patients varied in age, gender, cause of injury, and time since injury. Of the 16 patients, 5 had traumatic brain injuries, 2 had had a stroke, and the rest had experienced anoxia. The researchers also recruited a group of 12 healthy individuals to serve as controls.

All of the study participants – people diagnosed as vegetative and healthy controls – were repeatedly asked to imagine the action of squeezing their right hands or wiggling all their toes at the prompt of a beep. EEG responses to the commands were measured.

Dr. Cruse and colleagues found that 3 of 16 patients diagnosed as vegetative were able to repeatedly and reliably generate EEG responses to the two different commands. All 3 responding patients were male, between the ages of 29 and 45; 2 had been diagnosed with traumatic brain injuries and 1 with injury caused by anoxia.

Of the controls, nine produced EEG responses that could be classified as significantly above chance; the researchers could not say definitively why three controls did not. However, they noted, the lack of appropriate response underscored the importance of interpreting only positive results in patients, "because this finding shows unequivocally that a null EEG outcome does not necessarily indicate an absence of awareness."

Dr. Cruse and colleagues called it "extremely unlikely" that the response patterns they detected could have been involuntary or automatic, based on the design of the study and the outcomes recorded. "Successful completion of these EEG tasks represents a substantial cognitive feat, not only for patients who were presumed to be vegetative, but also for control participants," they wrote, noting that one patient’s responses were consistent in over 100 repeated trials, better than the vast majority of controls.

While the median age for subjects with traumatic brain injuries was younger than those with non-traumatic injuries (29 years vs. 44 years), the researchers found no significant relationships between the patients’ ages or clinical histories and their ability to respond.

Dr. Cruse and colleagues wrote in their analysis that their study shows that "this EEG method can identify covert awareness in patients diagnosed in the vegetative state with a similar degree of accuracy to other methods of detection."

The Medical Research Council, James S. McDonnell Foundation, Canada Excellence Research Chairs Program, the European Commission, Fonds de la Recherche Scientifique, the Mind Science Foundation, Belgian French-Speaking Community Concerted Research Action, University Hospital of Liège, and University of Liège all contributed funding to the study. Dr. Cruse and his colleagues disclosed no conflicts of interest.

Researchers have developed an inexpensive technique that, they say, can detect covert awareness in people diagnosed as vegetative.

The researchers used electroencephalography (EEG), instead of functional MRI (fMRI), a technology previously shown to detect minimal consciousness in people thought to be vegetative based on an evaluation of their behavioral symptoms (N. Engl. J. Med. 2010;362:579-89).

FMRI works by detecting a patient’s ability to modulate a blood oxygen–level dependent (BOLD) response to mental imagery tasks. Barriers to its wider use include its expense; the difficulty of transporting patients to MRI-equipped facilities; imaging problems when patients cannot remain still; and the technology’s inappropriateness for patients with metal implants in their bodies.

EEG, which measures the activity of groups of cortical neurons from scalp electrodes, can be used at the bedside and is inexpensive, widely available, and unaffected by metal.

For their research, published online Nov. 10 in The Lancet (doi:10.1016/S0140-6736(11)61224-5), Damian Cruse, Ph.D., of the University of Western Ontario, London, and his colleagues in the United Kingdom and Belgium recruited 16 patients diagnosed by behavioral indicators as vegetative according to established criteria. The patients varied in age, gender, cause of injury, and time since injury. Of the 16 patients, 5 had traumatic brain injuries, 2 had had a stroke, and the rest had experienced anoxia. The researchers also recruited a group of 12 healthy individuals to serve as controls.

All of the study participants – people diagnosed as vegetative and healthy controls – were repeatedly asked to imagine the action of squeezing their right hands or wiggling all their toes at the prompt of a beep. EEG responses to the commands were measured.

Dr. Cruse and colleagues found that 3 of 16 patients diagnosed as vegetative were able to repeatedly and reliably generate EEG responses to the two different commands. All 3 responding patients were male, between the ages of 29 and 45; 2 had been diagnosed with traumatic brain injuries and 1 with injury caused by anoxia.

Of the controls, nine produced EEG responses that could be classified as significantly above chance; the researchers could not say definitively why three controls did not. However, they noted, the lack of appropriate response underscored the importance of interpreting only positive results in patients, "because this finding shows unequivocally that a null EEG outcome does not necessarily indicate an absence of awareness."

Dr. Cruse and colleagues called it "extremely unlikely" that the response patterns they detected could have been involuntary or automatic, based on the design of the study and the outcomes recorded. "Successful completion of these EEG tasks represents a substantial cognitive feat, not only for patients who were presumed to be vegetative, but also for control participants," they wrote, noting that one patient’s responses were consistent in over 100 repeated trials, better than the vast majority of controls.

While the median age for subjects with traumatic brain injuries was younger than those with non-traumatic injuries (29 years vs. 44 years), the researchers found no significant relationships between the patients’ ages or clinical histories and their ability to respond.

Dr. Cruse and colleagues wrote in their analysis that their study shows that "this EEG method can identify covert awareness in patients diagnosed in the vegetative state with a similar degree of accuracy to other methods of detection."

The Medical Research Council, James S. McDonnell Foundation, Canada Excellence Research Chairs Program, the European Commission, Fonds de la Recherche Scientifique, the Mind Science Foundation, Belgian French-Speaking Community Concerted Research Action, University Hospital of Liège, and University of Liège all contributed funding to the study. Dr. Cruse and his colleagues disclosed no conflicts of interest.

Researchers have developed an inexpensive technique that, they say, can detect covert awareness in people diagnosed as vegetative.

The researchers used electroencephalography (EEG), instead of functional MRI (fMRI), a technology previously shown to detect minimal consciousness in people thought to be vegetative based on an evaluation of their behavioral symptoms (N. Engl. J. Med. 2010;362:579-89).

FMRI works by detecting a patient’s ability to modulate a blood oxygen–level dependent (BOLD) response to mental imagery tasks. Barriers to its wider use include its expense; the difficulty of transporting patients to MRI-equipped facilities; imaging problems when patients cannot remain still; and the technology’s inappropriateness for patients with metal implants in their bodies.

EEG, which measures the activity of groups of cortical neurons from scalp electrodes, can be used at the bedside and is inexpensive, widely available, and unaffected by metal.

For their research, published online Nov. 10 in The Lancet (doi:10.1016/S0140-6736(11)61224-5), Damian Cruse, Ph.D., of the University of Western Ontario, London, and his colleagues in the United Kingdom and Belgium recruited 16 patients diagnosed by behavioral indicators as vegetative according to established criteria. The patients varied in age, gender, cause of injury, and time since injury. Of the 16 patients, 5 had traumatic brain injuries, 2 had had a stroke, and the rest had experienced anoxia. The researchers also recruited a group of 12 healthy individuals to serve as controls.

All of the study participants – people diagnosed as vegetative and healthy controls – were repeatedly asked to imagine the action of squeezing their right hands or wiggling all their toes at the prompt of a beep. EEG responses to the commands were measured.

Dr. Cruse and colleagues found that 3 of 16 patients diagnosed as vegetative were able to repeatedly and reliably generate EEG responses to the two different commands. All 3 responding patients were male, between the ages of 29 and 45; 2 had been diagnosed with traumatic brain injuries and 1 with injury caused by anoxia.

Of the controls, nine produced EEG responses that could be classified as significantly above chance; the researchers could not say definitively why three controls did not. However, they noted, the lack of appropriate response underscored the importance of interpreting only positive results in patients, "because this finding shows unequivocally that a null EEG outcome does not necessarily indicate an absence of awareness."

Dr. Cruse and colleagues called it "extremely unlikely" that the response patterns they detected could have been involuntary or automatic, based on the design of the study and the outcomes recorded. "Successful completion of these EEG tasks represents a substantial cognitive feat, not only for patients who were presumed to be vegetative, but also for control participants," they wrote, noting that one patient’s responses were consistent in over 100 repeated trials, better than the vast majority of controls.

While the median age for subjects with traumatic brain injuries was younger than those with non-traumatic injuries (29 years vs. 44 years), the researchers found no significant relationships between the patients’ ages or clinical histories and their ability to respond.

Dr. Cruse and colleagues wrote in their analysis that their study shows that "this EEG method can identify covert awareness in patients diagnosed in the vegetative state with a similar degree of accuracy to other methods of detection."

The Medical Research Council, James S. McDonnell Foundation, Canada Excellence Research Chairs Program, the European Commission, Fonds de la Recherche Scientifique, the Mind Science Foundation, Belgian French-Speaking Community Concerted Research Action, University Hospital of Liège, and University of Liège all contributed funding to the study. Dr. Cruse and his colleagues disclosed no conflicts of interest.

Physicians who bill for both technical and professional services with nuclear stress imaging and stress echocardiography order such testing at double the rate of those who do not bill for such services, according to a study published online Nov. 8 in JAMA.

Overall, 12.2% of studied patients had a nuclear stress or echocardiography test within 30 days of a postrevascularization outpatient visit. Cardiologists were more likely than primary care physicians to conduct stress tests, at about 12%, compared with 5%, said Dr. Bimal R. Shah of Duke University, Durham, N.C., and colleagues.

The more physicians stood to receive from imaging, the more often they ordered the tests. Physicians who billed for both professional and technical fees ordered stress or echo tests about 13% of the time, compared to a 9% incidence among those who only billed for professional fees, and 5% for those who billed for neither.

According to Dr. Shah, 80% of the nuclear imaging studies would be considered self-referrals by physicians who billed for both technical and professional fees; 63% were self-referrals by those who billed for professional fees only. Rates were similar for echo tests, with 85% considered self-referrals by physicians who billed for both technical and professional fees, and 67% considered self-referrals by those who billed for professional fees only.

"The association between physician billing status for stress tests and testing frequency persisted after adjusting to the extent possible for patient and physician factors that influence testing," Dr. Shah and his colleagues said.

The authors focused on testing that was ordered following coronary revascularization. According to American College of Cardiology Foundation appropriateness utilization criteria, neither nuclear stress testing nor echocardiography is recommended following percutaneous coronary intervention or coronary artery bypass graft. Thus, stress testing in these cases is likely to be more discretionary based on the criteria.

The researchers analyzed United Healthcare data on enrollees aged 18-64 years during the period of 2004-2007. They excluded testing and outpatient visits during the first 90 days after revascularization, as those could be potentially deemed necessary. To determine how many tests might be self-referrals, the authors looked at the proportion of stress tests for which the testing physician’s tax identification number matched the outpatient visit tax ID; the final study population was 17,847 patients (JAMA 2011;306:1993-2000).

Only 14% had symptoms that were given as the indication for that index outpatient visit; 86% had no billing diagnosis code.

Among the physicians studied, 70% (2,111) of cardiologists billed for both technical and professional fees for nuclear stress imaging studies. In all, 14% (416) billed for professional fees only, and 16% (486) did not bill for either. The proportions were similar for cardiology practices, with 50% billing for both professional and technical services, and 19% for professional fees. A total of 31% did not bill for the services.

Of primary care physicians who conducted both nuclear stress testing and echocardiography, 5% (162) billed for both professional and technical fees for stress testing, and 3% (88) billed both fees for echocardiography. In all, 2% (44) and 1% (28) billed for professional fees only. More than 90% did not bill at all for stress testing or echocardiography.

Additionally, analysis determined that nuclear perfusion imaging in cardiologists’ offices increased 215% from 1998 to 2006, and increased by 181% in other physician offices during the same period, the authors said.

"Discretionary stress testing after revascularization has potential financial and clinical disadvantages for patients, including the costs of the tests, the exposure to ionizing radiation as well as potential downstream costs, and consequences from following up false-positive test results," they wrote.

The authors acknowledged that the study period was before, and contemporaneous to, the publication of the American College of Cardiology Foundation appropriateness criteria. Thus, they could not say whether those guidelines might have had any impact on patterns of testing.

The authors noted that they could not analyze the appropriateness of physicians’ decision-making in ordering tests, since it was based largely on administrative data. But they said that previous studies have shown that using ICD-9 coding, as they did, accurately reflects diagnoses.

But this absence of data "prevents understanding physician intent for performing the imaging study," Dr. Brent K. Hollenbeck and Dr. Brahmajee K. Nallamothu of the University of Michigan, Ann Arbor, said in an accompanying editorial (JAMA 2011;306:2028-30).

They also note that the data was observational, and that it is possible that the study could be founded by selective referral, for example, that the patients who needed imaging were referred to physicians who specialized in such testing.

"Collectively, these limitations might explain much of the differences in use according to physician billing status," wrote Dr. Hollenbeck and Dr. Nallamothu.

They acknowledge that the findings are "robust," but they also say that "It is uncertain whether the observed increase in imaging utilization is entirely a bad thing."

A shift from the inpatient to the outpatient setting over the last decade or so has been linked to a dramatic decline in mortality from cardiac disease, they said. Office-based imaging might improve quality of care by leading to potentially earlier diagnosis, and keeping referrals close by may also increase the coordination of care, said Dr. Hollenbeck and Nallamothu.

But they also note that cardiology has been shifting back to the hospital, and that government regulators are creating policies that will likely encourage that move. That could lead to higher costs again, they said.

"Moving forward in the current era of health care reform, the focus should be less about eliminating incentives altogether, and more about getting the price right in the first place," wrote Dr. Hollenbeck and Dr. Nallamothu.

The study was funded by United Healthcare, and one study author was a United Healthcare employee. Dr. Nallamothu reported no conflicts. Dr. Shah and Dr. Hollenbeck both received grants from the Agency for Health Care Research and Quality.

Physicians who bill for both technical and professional services with nuclear stress imaging and stress echocardiography order such testing at double the rate of those who do not bill for such services, according to a study published online Nov. 8 in JAMA.

Overall, 12.2% of studied patients had a nuclear stress or echocardiography test within 30 days of a postrevascularization outpatient visit. Cardiologists were more likely than primary care physicians to conduct stress tests, at about 12%, compared with 5%, said Dr. Bimal R. Shah of Duke University, Durham, N.C., and colleagues.

The more physicians stood to receive from imaging, the more often they ordered the tests. Physicians who billed for both professional and technical fees ordered stress or echo tests about 13% of the time, compared to a 9% incidence among those who only billed for professional fees, and 5% for those who billed for neither.

According to Dr. Shah, 80% of the nuclear imaging studies would be considered self-referrals by physicians who billed for both technical and professional fees; 63% were self-referrals by those who billed for professional fees only. Rates were similar for echo tests, with 85% considered self-referrals by physicians who billed for both technical and professional fees, and 67% considered self-referrals by those who billed for professional fees only.

"The association between physician billing status for stress tests and testing frequency persisted after adjusting to the extent possible for patient and physician factors that influence testing," Dr. Shah and his colleagues said.

The authors focused on testing that was ordered following coronary revascularization. According to American College of Cardiology Foundation appropriateness utilization criteria, neither nuclear stress testing nor echocardiography is recommended following percutaneous coronary intervention or coronary artery bypass graft. Thus, stress testing in these cases is likely to be more discretionary based on the criteria.

The researchers analyzed United Healthcare data on enrollees aged 18-64 years during the period of 2004-2007. They excluded testing and outpatient visits during the first 90 days after revascularization, as those could be potentially deemed necessary. To determine how many tests might be self-referrals, the authors looked at the proportion of stress tests for which the testing physician’s tax identification number matched the outpatient visit tax ID; the final study population was 17,847 patients (JAMA 2011;306:1993-2000).

Only 14% had symptoms that were given as the indication for that index outpatient visit; 86% had no billing diagnosis code.

Among the physicians studied, 70% (2,111) of cardiologists billed for both technical and professional fees for nuclear stress imaging studies. In all, 14% (416) billed for professional fees only, and 16% (486) did not bill for either. The proportions were similar for cardiology practices, with 50% billing for both professional and technical services, and 19% for professional fees. A total of 31% did not bill for the services.

Of primary care physicians who conducted both nuclear stress testing and echocardiography, 5% (162) billed for both professional and technical fees for stress testing, and 3% (88) billed both fees for echocardiography. In all, 2% (44) and 1% (28) billed for professional fees only. More than 90% did not bill at all for stress testing or echocardiography.

Additionally, analysis determined that nuclear perfusion imaging in cardiologists’ offices increased 215% from 1998 to 2006, and increased by 181% in other physician offices during the same period, the authors said.

"Discretionary stress testing after revascularization has potential financial and clinical disadvantages for patients, including the costs of the tests, the exposure to ionizing radiation as well as potential downstream costs, and consequences from following up false-positive test results," they wrote.

The authors acknowledged that the study period was before, and contemporaneous to, the publication of the American College of Cardiology Foundation appropriateness criteria. Thus, they could not say whether those guidelines might have had any impact on patterns of testing.

The authors noted that they could not analyze the appropriateness of physicians’ decision-making in ordering tests, since it was based largely on administrative data. But they said that previous studies have shown that using ICD-9 coding, as they did, accurately reflects diagnoses.

But this absence of data "prevents understanding physician intent for performing the imaging study," Dr. Brent K. Hollenbeck and Dr. Brahmajee K. Nallamothu of the University of Michigan, Ann Arbor, said in an accompanying editorial (JAMA 2011;306:2028-30).

They also note that the data was observational, and that it is possible that the study could be founded by selective referral, for example, that the patients who needed imaging were referred to physicians who specialized in such testing.

"Collectively, these limitations might explain much of the differences in use according to physician billing status," wrote Dr. Hollenbeck and Dr. Nallamothu.

They acknowledge that the findings are "robust," but they also say that "It is uncertain whether the observed increase in imaging utilization is entirely a bad thing."

A shift from the inpatient to the outpatient setting over the last decade or so has been linked to a dramatic decline in mortality from cardiac disease, they said. Office-based imaging might improve quality of care by leading to potentially earlier diagnosis, and keeping referrals close by may also increase the coordination of care, said Dr. Hollenbeck and Nallamothu.

But they also note that cardiology has been shifting back to the hospital, and that government regulators are creating policies that will likely encourage that move. That could lead to higher costs again, they said.

"Moving forward in the current era of health care reform, the focus should be less about eliminating incentives altogether, and more about getting the price right in the first place," wrote Dr. Hollenbeck and Dr. Nallamothu.

The study was funded by United Healthcare, and one study author was a United Healthcare employee. Dr. Nallamothu reported no conflicts. Dr. Shah and Dr. Hollenbeck both received grants from the Agency for Health Care Research and Quality.

Physicians who bill for both technical and professional services with nuclear stress imaging and stress echocardiography order such testing at double the rate of those who do not bill for such services, according to a study published online Nov. 8 in JAMA.

Overall, 12.2% of studied patients had a nuclear stress or echocardiography test within 30 days of a postrevascularization outpatient visit. Cardiologists were more likely than primary care physicians to conduct stress tests, at about 12%, compared with 5%, said Dr. Bimal R. Shah of Duke University, Durham, N.C., and colleagues.

The more physicians stood to receive from imaging, the more often they ordered the tests. Physicians who billed for both professional and technical fees ordered stress or echo tests about 13% of the time, compared to a 9% incidence among those who only billed for professional fees, and 5% for those who billed for neither.

According to Dr. Shah, 80% of the nuclear imaging studies would be considered self-referrals by physicians who billed for both technical and professional fees; 63% were self-referrals by those who billed for professional fees only. Rates were similar for echo tests, with 85% considered self-referrals by physicians who billed for both technical and professional fees, and 67% considered self-referrals by those who billed for professional fees only.

"The association between physician billing status for stress tests and testing frequency persisted after adjusting to the extent possible for patient and physician factors that influence testing," Dr. Shah and his colleagues said.

The authors focused on testing that was ordered following coronary revascularization. According to American College of Cardiology Foundation appropriateness utilization criteria, neither nuclear stress testing nor echocardiography is recommended following percutaneous coronary intervention or coronary artery bypass graft. Thus, stress testing in these cases is likely to be more discretionary based on the criteria.

The researchers analyzed United Healthcare data on enrollees aged 18-64 years during the period of 2004-2007. They excluded testing and outpatient visits during the first 90 days after revascularization, as those could be potentially deemed necessary. To determine how many tests might be self-referrals, the authors looked at the proportion of stress tests for which the testing physician’s tax identification number matched the outpatient visit tax ID; the final study population was 17,847 patients (JAMA 2011;306:1993-2000).

Only 14% had symptoms that were given as the indication for that index outpatient visit; 86% had no billing diagnosis code.

Among the physicians studied, 70% (2,111) of cardiologists billed for both technical and professional fees for nuclear stress imaging studies. In all, 14% (416) billed for professional fees only, and 16% (486) did not bill for either. The proportions were similar for cardiology practices, with 50% billing for both professional and technical services, and 19% for professional fees. A total of 31% did not bill for the services.

Of primary care physicians who conducted both nuclear stress testing and echocardiography, 5% (162) billed for both professional and technical fees for stress testing, and 3% (88) billed both fees for echocardiography. In all, 2% (44) and 1% (28) billed for professional fees only. More than 90% did not bill at all for stress testing or echocardiography.

Additionally, analysis determined that nuclear perfusion imaging in cardiologists’ offices increased 215% from 1998 to 2006, and increased by 181% in other physician offices during the same period, the authors said.

"Discretionary stress testing after revascularization has potential financial and clinical disadvantages for patients, including the costs of the tests, the exposure to ionizing radiation as well as potential downstream costs, and consequences from following up false-positive test results," they wrote.

The authors acknowledged that the study period was before, and contemporaneous to, the publication of the American College of Cardiology Foundation appropriateness criteria. Thus, they could not say whether those guidelines might have had any impact on patterns of testing.

The authors noted that they could not analyze the appropriateness of physicians’ decision-making in ordering tests, since it was based largely on administrative data. But they said that previous studies have shown that using ICD-9 coding, as they did, accurately reflects diagnoses.

But this absence of data "prevents understanding physician intent for performing the imaging study," Dr. Brent K. Hollenbeck and Dr. Brahmajee K. Nallamothu of the University of Michigan, Ann Arbor, said in an accompanying editorial (JAMA 2011;306:2028-30).

They also note that the data was observational, and that it is possible that the study could be founded by selective referral, for example, that the patients who needed imaging were referred to physicians who specialized in such testing.

"Collectively, these limitations might explain much of the differences in use according to physician billing status," wrote Dr. Hollenbeck and Dr. Nallamothu.

They acknowledge that the findings are "robust," but they also say that "It is uncertain whether the observed increase in imaging utilization is entirely a bad thing."

A shift from the inpatient to the outpatient setting over the last decade or so has been linked to a dramatic decline in mortality from cardiac disease, they said. Office-based imaging might improve quality of care by leading to potentially earlier diagnosis, and keeping referrals close by may also increase the coordination of care, said Dr. Hollenbeck and Nallamothu.

But they also note that cardiology has been shifting back to the hospital, and that government regulators are creating policies that will likely encourage that move. That could lead to higher costs again, they said.

"Moving forward in the current era of health care reform, the focus should be less about eliminating incentives altogether, and more about getting the price right in the first place," wrote Dr. Hollenbeck and Dr. Nallamothu.

The study was funded by United Healthcare, and one study author was a United Healthcare employee. Dr. Nallamothu reported no conflicts. Dr. Shah and Dr. Hollenbeck both received grants from the Agency for Health Care Research and Quality.

DENVER – A cascade of data generated recently by the CONFIRM registry is turning heads and winning converts to coronary CT angiography as a reasonable first-line test to diagnose or exclude coronary artery disease in many symptomatic patients with no history of the disease.

"The CONFIRM information about the need to rethink people’s pretest likelihood of CAD is enormously important. It shows that if we think a patient’s likelihood is intermediate, it’s actually low. So CT angiography might be the least expensive way to exclude CAD," Dr. James E. Udelson observed during a panel discussion at the annual meeting of the American Society of Nuclear Cardiology.

In addition to being less expensive than SPECT (single-photon emission CT) myocardial perfusion imaging for this purpose, CTA also confers less radiation exposure, which is a particularly important consideration given that that the majority of patients undergoing evaluation for symptoms suggestive of CAD turn out not to have it, added Dr. Udelson, chief of cardiology and director of the nuclear cardiology laboratory at Tufts Medical Center, Boston.

Dr. Udelson is not a CT angiographer and is not involved with CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry). Neither is fellow panelist Dr. John J. Mahmarian. But he too finds CONFIRM compelling.

"I’m really intrigued by the CONFIRM data on nonobstructive plaque. These individuals with nonobstructive atherosclerotic plaque have a good short-term risk but may not have a good long-term risk. With the armamentarium we have today, it’s important to know that so we can treat people more aggressively and impact the disease process," said Dr. Mahmarian, ASNC president-elect and director of nuclear cardiology and CT services at the Methodist DeBakey Heart and Vascular Institute, Houston.

Their comments came in reaction to a wide-ranging update on the registry by CONFIRM investigator Dr. James K. Min of Cedars-Sinai Medical Center in Los Angeles.

Dr. Min explained that CONFIRM is a prospective, multinational registry including more than 32,000 consecutive patients who have undergone CTA at 18 participating sites. The registry was created to answer three questions of fundamental importance regarding the noninvasive imaging procedure: Does it have the ability to diagnose or exclude CAD as well as does invasive coronary angiography? Does it reduce the need for percutaneous angiography? And does it improve health outcomes for patients with acute chest pain who present to emergency departments and other settings?

The answer on all three counts is ‘yes,’ although some of the data are preliminary, Dr. Min said. The registry is being expanded, with follow-up to be extended to a median of 5 years, along with the possible addition of another 12,000-15,000 patients in order to strengthen the findings.

The power of CTA as a risk stratification tool was highlighted in a recent CONFIRM publication (J. Am. Coll. Cardiol. 2011;58:849-60). Dr. Min and his coworkers reported on nearly 24,000 consecutive patients without known pretest CAD who were prospectively followed for a mean of 2.3 years after undergoing CTA for assessment of suspected CAD. These were mainly middle-aged patients with a high prevalence of cardiovascular risk factors. In all, 71% had an intermediate or high pretest likelihood of obstructive CAD.

In this study population, a normal CTA study (found in 43% of patients) was associated with a highly favorable prognosis – namely, an all-cause mortality rate of just 0.28% per year. Moreover, a normal CTA result carried a 4-year "warranty."

Another key finding was that nonobstructive CAD (that is, a 1%-49% stenosis) was associated with a 1.6-fold increased risk of mortality in a multivariate risk-adjusted analysis. Nonobstructive CAD was detected in 34% of subjects.

Mortality risk climbed stepwise with the number of coronary vessels showing obstructive CAD on CTA: a doubling of risk in patients with single-vessel obstructive disease relative to the risk in those with a normal study; a 2.92-fold increased risk in those with two-vessel obstructive CAD; and a 3.7-fold increased risk in patients with triple-vessel or left anterior descending obstructive disease.

The mortality risk associated with obstructive CAD varied by age and sex. Patients younger than age 65 had a significantly greater mortality risk for two-vessel disease than did those aged 65 years or older. The younger patients with two-vessel obstructive disease had a fourfold greater death rate than did young patients with a normal CTA study, whereas older patients with double-vessel disease had a 2.46-fold increased risk. Similarly, triple-vessel obstructive disease in patients younger than age 65 was associated with a 6.2-fold increased risk of death, compared with those who had a normal CTA, a risk twice that conferred by three-vessel obstructive disease in older patients.

The relative hazards for single- and double-vessel obstructive CAD were not significantly different for men vs. women. However, women with three-vessel disease had a 4.2-fold increased mortality risk, significantly greater than the 3.3-fold risk associated with triple-vessel disease in men.

In another CONFIRM analysis, this one involving roughly 8,100 patients with an average pretest likelihood of obstructive CAD of 50% by the widely used Diamond Forrester clinical risk score, investigators found that the actual prevalence of obstructive CAD on CTA was only 18%. The take-home lesson here is that cardiologists severely overestimate the likelihood of significant disease when they rely on clinical risk scores that were developed in an earlier era, Dr. Min emphasized.

Another CONFIRM analysis involved 15,223 patients, 7.2% of whom underwent coronary revascularization following CTA. Among the subgroup with high-risk CAD as defined by the Duke severity categorization criteria – for example, three vessels having moderate stenoses or two with severe stenoses – the mortality rate during an average 2.3 years of follow-up was 2.3% in those who were revascularized, significantly better than the 5.3% rate with medical management.

Thus, it appears that using CTA to identify patients with high-risk CAD results in a therapeutic benefit when such patients undergo revascularization, according to Dr. Min. In contrast, in patients with CTA findings indicative of non–high-risk CAD, mortality rates weren’t significantly different between those who had revascularization and those who had medical management only.

CONFIRM has also showed that CTA reduces the need for invasive coronary angiography. Patients with a normal CTA had a 3-year rate of invasive coronary angiography of 2.5%, and a 0.3% revascularization rate. These rates rose in graded fashion to a 44% invasive angiography rate and a 28% revascularization rate in patients with obstructive single-vessel disease on CTA; a 53% invasive coronary angiography rate and 44% revascularization for those identified as having obstructive two-vessel disease; and a 69% coronary angiography rate and 67% revascularization among patients found on CTA to have obstructive three-vessel or left anterior descending disease.

Dr. Min said that at present there is no evidence-based role for CTA in the evaluation of patients without chest pain or other symptoms suggestive of CAD. And there are better prognostic tests for those with known CAD, he added.

"I must say, looking at it from the outside, it’s really breathtaking how fast the data have grown over the last few years for CT angiography," Dr. Udelson commented. "You in the CT world have, in just a few short years, developed enormous databases it took those of us in nuclear imaging much longer to develop, and you can look at things nuclear can’t, like nonobstructive plaque, where the outcome is different than in people with normal coronary arteries."

Dr. Min has received research grants and is on the speakers bureau for GE Healthcare.

DENVER – A cascade of data generated recently by the CONFIRM registry is turning heads and winning converts to coronary CT angiography as a reasonable first-line test to diagnose or exclude coronary artery disease in many symptomatic patients with no history of the disease.

"The CONFIRM information about the need to rethink people’s pretest likelihood of CAD is enormously important. It shows that if we think a patient’s likelihood is intermediate, it’s actually low. So CT angiography might be the least expensive way to exclude CAD," Dr. James E. Udelson observed during a panel discussion at the annual meeting of the American Society of Nuclear Cardiology.

In addition to being less expensive than SPECT (single-photon emission CT) myocardial perfusion imaging for this purpose, CTA also confers less radiation exposure, which is a particularly important consideration given that that the majority of patients undergoing evaluation for symptoms suggestive of CAD turn out not to have it, added Dr. Udelson, chief of cardiology and director of the nuclear cardiology laboratory at Tufts Medical Center, Boston.

Dr. Udelson is not a CT angiographer and is not involved with CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry). Neither is fellow panelist Dr. John J. Mahmarian. But he too finds CONFIRM compelling.

"I’m really intrigued by the CONFIRM data on nonobstructive plaque. These individuals with nonobstructive atherosclerotic plaque have a good short-term risk but may not have a good long-term risk. With the armamentarium we have today, it’s important to know that so we can treat people more aggressively and impact the disease process," said Dr. Mahmarian, ASNC president-elect and director of nuclear cardiology and CT services at the Methodist DeBakey Heart and Vascular Institute, Houston.

Their comments came in reaction to a wide-ranging update on the registry by CONFIRM investigator Dr. James K. Min of Cedars-Sinai Medical Center in Los Angeles.

Dr. Min explained that CONFIRM is a prospective, multinational registry including more than 32,000 consecutive patients who have undergone CTA at 18 participating sites. The registry was created to answer three questions of fundamental importance regarding the noninvasive imaging procedure: Does it have the ability to diagnose or exclude CAD as well as does invasive coronary angiography? Does it reduce the need for percutaneous angiography? And does it improve health outcomes for patients with acute chest pain who present to emergency departments and other settings?

The answer on all three counts is ‘yes,’ although some of the data are preliminary, Dr. Min said. The registry is being expanded, with follow-up to be extended to a median of 5 years, along with the possible addition of another 12,000-15,000 patients in order to strengthen the findings.

The power of CTA as a risk stratification tool was highlighted in a recent CONFIRM publication (J. Am. Coll. Cardiol. 2011;58:849-60). Dr. Min and his coworkers reported on nearly 24,000 consecutive patients without known pretest CAD who were prospectively followed for a mean of 2.3 years after undergoing CTA for assessment of suspected CAD. These were mainly middle-aged patients with a high prevalence of cardiovascular risk factors. In all, 71% had an intermediate or high pretest likelihood of obstructive CAD.

In this study population, a normal CTA study (found in 43% of patients) was associated with a highly favorable prognosis – namely, an all-cause mortality rate of just 0.28% per year. Moreover, a normal CTA result carried a 4-year "warranty."

Another key finding was that nonobstructive CAD (that is, a 1%-49% stenosis) was associated with a 1.6-fold increased risk of mortality in a multivariate risk-adjusted analysis. Nonobstructive CAD was detected in 34% of subjects.

Mortality risk climbed stepwise with the number of coronary vessels showing obstructive CAD on CTA: a doubling of risk in patients with single-vessel obstructive disease relative to the risk in those with a normal study; a 2.92-fold increased risk in those with two-vessel obstructive CAD; and a 3.7-fold increased risk in patients with triple-vessel or left anterior descending obstructive disease.

The mortality risk associated with obstructive CAD varied by age and sex. Patients younger than age 65 had a significantly greater mortality risk for two-vessel disease than did those aged 65 years or older. The younger patients with two-vessel obstructive disease had a fourfold greater death rate than did young patients with a normal CTA study, whereas older patients with double-vessel disease had a 2.46-fold increased risk. Similarly, triple-vessel obstructive disease in patients younger than age 65 was associated with a 6.2-fold increased risk of death, compared with those who had a normal CTA, a risk twice that conferred by three-vessel obstructive disease in older patients.

The relative hazards for single- and double-vessel obstructive CAD were not significantly different for men vs. women. However, women with three-vessel disease had a 4.2-fold increased mortality risk, significantly greater than the 3.3-fold risk associated with triple-vessel disease in men.

In another CONFIRM analysis, this one involving roughly 8,100 patients with an average pretest likelihood of obstructive CAD of 50% by the widely used Diamond Forrester clinical risk score, investigators found that the actual prevalence of obstructive CAD on CTA was only 18%. The take-home lesson here is that cardiologists severely overestimate the likelihood of significant disease when they rely on clinical risk scores that were developed in an earlier era, Dr. Min emphasized.

Another CONFIRM analysis involved 15,223 patients, 7.2% of whom underwent coronary revascularization following CTA. Among the subgroup with high-risk CAD as defined by the Duke severity categorization criteria – for example, three vessels having moderate stenoses or two with severe stenoses – the mortality rate during an average 2.3 years of follow-up was 2.3% in those who were revascularized, significantly better than the 5.3% rate with medical management.

Thus, it appears that using CTA to identify patients with high-risk CAD results in a therapeutic benefit when such patients undergo revascularization, according to Dr. Min. In contrast, in patients with CTA findings indicative of non–high-risk CAD, mortality rates weren’t significantly different between those who had revascularization and those who had medical management only.

CONFIRM has also showed that CTA reduces the need for invasive coronary angiography. Patients with a normal CTA had a 3-year rate of invasive coronary angiography of 2.5%, and a 0.3% revascularization rate. These rates rose in graded fashion to a 44% invasive angiography rate and a 28% revascularization rate in patients with obstructive single-vessel disease on CTA; a 53% invasive coronary angiography rate and 44% revascularization for those identified as having obstructive two-vessel disease; and a 69% coronary angiography rate and 67% revascularization among patients found on CTA to have obstructive three-vessel or left anterior descending disease.

Dr. Min said that at present there is no evidence-based role for CTA in the evaluation of patients without chest pain or other symptoms suggestive of CAD. And there are better prognostic tests for those with known CAD, he added.

"I must say, looking at it from the outside, it’s really breathtaking how fast the data have grown over the last few years for CT angiography," Dr. Udelson commented. "You in the CT world have, in just a few short years, developed enormous databases it took those of us in nuclear imaging much longer to develop, and you can look at things nuclear can’t, like nonobstructive plaque, where the outcome is different than in people with normal coronary arteries."

Dr. Min has received research grants and is on the speakers bureau for GE Healthcare.

DENVER – A cascade of data generated recently by the CONFIRM registry is turning heads and winning converts to coronary CT angiography as a reasonable first-line test to diagnose or exclude coronary artery disease in many symptomatic patients with no history of the disease.

"The CONFIRM information about the need to rethink people’s pretest likelihood of CAD is enormously important. It shows that if we think a patient’s likelihood is intermediate, it’s actually low. So CT angiography might be the least expensive way to exclude CAD," Dr. James E. Udelson observed during a panel discussion at the annual meeting of the American Society of Nuclear Cardiology.

In addition to being less expensive than SPECT (single-photon emission CT) myocardial perfusion imaging for this purpose, CTA also confers less radiation exposure, which is a particularly important consideration given that that the majority of patients undergoing evaluation for symptoms suggestive of CAD turn out not to have it, added Dr. Udelson, chief of cardiology and director of the nuclear cardiology laboratory at Tufts Medical Center, Boston.

Dr. Udelson is not a CT angiographer and is not involved with CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry). Neither is fellow panelist Dr. John J. Mahmarian. But he too finds CONFIRM compelling.

"I’m really intrigued by the CONFIRM data on nonobstructive plaque. These individuals with nonobstructive atherosclerotic plaque have a good short-term risk but may not have a good long-term risk. With the armamentarium we have today, it’s important to know that so we can treat people more aggressively and impact the disease process," said Dr. Mahmarian, ASNC president-elect and director of nuclear cardiology and CT services at the Methodist DeBakey Heart and Vascular Institute, Houston.

Their comments came in reaction to a wide-ranging update on the registry by CONFIRM investigator Dr. James K. Min of Cedars-Sinai Medical Center in Los Angeles.

Dr. Min explained that CONFIRM is a prospective, multinational registry including more than 32,000 consecutive patients who have undergone CTA at 18 participating sites. The registry was created to answer three questions of fundamental importance regarding the noninvasive imaging procedure: Does it have the ability to diagnose or exclude CAD as well as does invasive coronary angiography? Does it reduce the need for percutaneous angiography? And does it improve health outcomes for patients with acute chest pain who present to emergency departments and other settings?

The answer on all three counts is ‘yes,’ although some of the data are preliminary, Dr. Min said. The registry is being expanded, with follow-up to be extended to a median of 5 years, along with the possible addition of another 12,000-15,000 patients in order to strengthen the findings.

The power of CTA as a risk stratification tool was highlighted in a recent CONFIRM publication (J. Am. Coll. Cardiol. 2011;58:849-60). Dr. Min and his coworkers reported on nearly 24,000 consecutive patients without known pretest CAD who were prospectively followed for a mean of 2.3 years after undergoing CTA for assessment of suspected CAD. These were mainly middle-aged patients with a high prevalence of cardiovascular risk factors. In all, 71% had an intermediate or high pretest likelihood of obstructive CAD.

In this study population, a normal CTA study (found in 43% of patients) was associated with a highly favorable prognosis – namely, an all-cause mortality rate of just 0.28% per year. Moreover, a normal CTA result carried a 4-year "warranty."

Another key finding was that nonobstructive CAD (that is, a 1%-49% stenosis) was associated with a 1.6-fold increased risk of mortality in a multivariate risk-adjusted analysis. Nonobstructive CAD was detected in 34% of subjects.

Mortality risk climbed stepwise with the number of coronary vessels showing obstructive CAD on CTA: a doubling of risk in patients with single-vessel obstructive disease relative to the risk in those with a normal study; a 2.92-fold increased risk in those with two-vessel obstructive CAD; and a 3.7-fold increased risk in patients with triple-vessel or left anterior descending obstructive disease.

The mortality risk associated with obstructive CAD varied by age and sex. Patients younger than age 65 had a significantly greater mortality risk for two-vessel disease than did those aged 65 years or older. The younger patients with two-vessel obstructive disease had a fourfold greater death rate than did young patients with a normal CTA study, whereas older patients with double-vessel disease had a 2.46-fold increased risk. Similarly, triple-vessel obstructive disease in patients younger than age 65 was associated with a 6.2-fold increased risk of death, compared with those who had a normal CTA, a risk twice that conferred by three-vessel obstructive disease in older patients.

The relative hazards for single- and double-vessel obstructive CAD were not significantly different for men vs. women. However, women with three-vessel disease had a 4.2-fold increased mortality risk, significantly greater than the 3.3-fold risk associated with triple-vessel disease in men.

In another CONFIRM analysis, this one involving roughly 8,100 patients with an average pretest likelihood of obstructive CAD of 50% by the widely used Diamond Forrester clinical risk score, investigators found that the actual prevalence of obstructive CAD on CTA was only 18%. The take-home lesson here is that cardiologists severely overestimate the likelihood of significant disease when they rely on clinical risk scores that were developed in an earlier era, Dr. Min emphasized.

Another CONFIRM analysis involved 15,223 patients, 7.2% of whom underwent coronary revascularization following CTA. Among the subgroup with high-risk CAD as defined by the Duke severity categorization criteria – for example, three vessels having moderate stenoses or two with severe stenoses – the mortality rate during an average 2.3 years of follow-up was 2.3% in those who were revascularized, significantly better than the 5.3% rate with medical management.

Thus, it appears that using CTA to identify patients with high-risk CAD results in a therapeutic benefit when such patients undergo revascularization, according to Dr. Min. In contrast, in patients with CTA findings indicative of non–high-risk CAD, mortality rates weren’t significantly different between those who had revascularization and those who had medical management only.

CONFIRM has also showed that CTA reduces the need for invasive coronary angiography. Patients with a normal CTA had a 3-year rate of invasive coronary angiography of 2.5%, and a 0.3% revascularization rate. These rates rose in graded fashion to a 44% invasive angiography rate and a 28% revascularization rate in patients with obstructive single-vessel disease on CTA; a 53% invasive coronary angiography rate and 44% revascularization for those identified as having obstructive two-vessel disease; and a 69% coronary angiography rate and 67% revascularization among patients found on CTA to have obstructive three-vessel or left anterior descending disease.

Dr. Min said that at present there is no evidence-based role for CTA in the evaluation of patients without chest pain or other symptoms suggestive of CAD. And there are better prognostic tests for those with known CAD, he added.

"I must say, looking at it from the outside, it’s really breathtaking how fast the data have grown over the last few years for CT angiography," Dr. Udelson commented. "You in the CT world have, in just a few short years, developed enormous databases it took those of us in nuclear imaging much longer to develop, and you can look at things nuclear can’t, like nonobstructive plaque, where the outcome is different than in people with normal coronary arteries."

Dr. Min has received research grants and is on the speakers bureau for GE Healthcare.

DENVER – The historically shaky evidence base for cardiac imaging strategies is in the midst of being shored up by a strong new foundation.

Just a couple of years ago, analysts concluded that cardiac imaging guidelines have among the weakest supporting evidence bases of any of the 53 American College of Cardiology/American Heart Association practice guidelines they looked at. The investigators found that only 2.4% of the evidence supporting the imaging guidelines had a level of evidence of A, meaning supported by multiple randomized trials. Thirty-seven percent of the evidence was level B, coming from multiple observational studies. Another 17% was based on expert opinion, and the rest of the imaging guideline recommendations were not supported by any conclusive evidence (JAMA 2009;301:831-41).

All that is clearly in the process of changing, and in a big way, Dr. James E. Udelson observed at the annual meeting of the American Society of Nuclear Cardiology.

An unprecedented raft of multicenter randomized trials is underway in patients with chest pain. The government-supported studies range in size from 4,300 to 10,000 patients. They are variously aimed at determining whether anatomic imaging via coronary CT angiography (CTA) or functional imaging by SPECT myocardial perfusion imaging stress ECG, or stress echocardiography is the best initial strategy for the diagnosis of coronary artery disease, and at using imaging results to identify optimal management strategies, explained Dr. Udelson, chief of cardiology and director of the nuclear cardiology laboratory at Tufts Medical Center, Boston.

Here’s what’s underway:

• PROMISE. The PROspective Multicenter Imaging Study for Evaluation of chest pain), funded by the National Heart, Lung, and Blood Institute, involves 10,000 patients with symptoms suggestive of CAD and low to intermediate pretest probability of CAD. They’ll be randomized to CTA or functional imaging by SPECT myocardial perfusion imaging, stress ECG, or stress echo, with the study results immediately available to the care team for use in management decisions.

The primary end point is the 30-month composite of death, MI, major complications due to cardiac catheterization, or hospitalization for unstable angina. The study hypothesis is that noninvasive anatomic imaging via CTA will result in superior long-term outcomes.

Enrollment is progressing quickly, with 2,800 randomized patients, according to Dr. Udelson, who is a PROMISE investigator.

• RESCUE. In the Randomized Evaluation of patients with Stable angina Comparing Utilization of diagnostic Examinations, 4,300 symptomatic outpatients are being randomized to SPECT myocardial perfusion imaging or CTA, with their subsequent management being driven by an algorithm based on their test results. The hypothesis here is that CTA will be associated with no increase in adverse events, similar outcomes, lower cost, less radiation exposure, and resultant superior cost-effectiveness. Dr. Udelson is an investigator in RESCUE, which is supported by the Agency for Healthcare Research and Quality and the American College of Radiology Imaging Network.

• ISCHEMIA. The most ambitious of the studies is the International Study of Comparative Health Effectiveness with Medical and Invasive Approaches.

The National Institutes of Health has awarded an $84 million grant to conduct ISCHEMIA, a study of an early invasive versus conservative strategy in patients with stable CAD and moderate to severe ischemia.

The trial involves 8,000 patients with a left ventricular ejection fraction of 35% or more and at least 10% cardiac ischemia. They will undergo blinded CTA to rule out high-risk left main disease or normal coronary arteries. Then they will be randomized to catheterization and revascularization plus optimal medical therapy or to optimal medical management alone with revascularization reserved for worsening symptoms. Follow-up will be for 3-6 years.

ISCHEMIA is designed to provide answers to questions left open by the COURAGE and BARI 2D trials. The key design difference is that ISCHEMIA participants will be randomized to the invasive or conservative strategy before cardiac catheterization. The study hypothesis is that the invasive strategy will prove superior in terms of the primary composite end point of cardiovascular death, MI, or adjudicated hospitalization for unstable angina, heart failure, or cardiac arrest. Secondary end points will include cost-effectiveness and quality of life measures.

Dr. Udelson declared having no financial conflicts.

DENVER – The historically shaky evidence base for cardiac imaging strategies is in the midst of being shored up by a strong new foundation.

Just a couple of years ago, analysts concluded that cardiac imaging guidelines have among the weakest supporting evidence bases of any of the 53 American College of Cardiology/American Heart Association practice guidelines they looked at. The investigators found that only 2.4% of the evidence supporting the imaging guidelines had a level of evidence of A, meaning supported by multiple randomized trials. Thirty-seven percent of the evidence was level B, coming from multiple observational studies. Another 17% was based on expert opinion, and the rest of the imaging guideline recommendations were not supported by any conclusive evidence (JAMA 2009;301:831-41).

All that is clearly in the process of changing, and in a big way, Dr. James E. Udelson observed at the annual meeting of the American Society of Nuclear Cardiology.

An unprecedented raft of multicenter randomized trials is underway in patients with chest pain. The government-supported studies range in size from 4,300 to 10,000 patients. They are variously aimed at determining whether anatomic imaging via coronary CT angiography (CTA) or functional imaging by SPECT myocardial perfusion imaging stress ECG, or stress echocardiography is the best initial strategy for the diagnosis of coronary artery disease, and at using imaging results to identify optimal management strategies, explained Dr. Udelson, chief of cardiology and director of the nuclear cardiology laboratory at Tufts Medical Center, Boston.

Here’s what’s underway:

• PROMISE. The PROspective Multicenter Imaging Study for Evaluation of chest pain), funded by the National Heart, Lung, and Blood Institute, involves 10,000 patients with symptoms suggestive of CAD and low to intermediate pretest probability of CAD. They’ll be randomized to CTA or functional imaging by SPECT myocardial perfusion imaging, stress ECG, or stress echo, with the study results immediately available to the care team for use in management decisions.

The primary end point is the 30-month composite of death, MI, major complications due to cardiac catheterization, or hospitalization for unstable angina. The study hypothesis is that noninvasive anatomic imaging via CTA will result in superior long-term outcomes.

Enrollment is progressing quickly, with 2,800 randomized patients, according to Dr. Udelson, who is a PROMISE investigator.

• RESCUE. In the Randomized Evaluation of patients with Stable angina Comparing Utilization of diagnostic Examinations, 4,300 symptomatic outpatients are being randomized to SPECT myocardial perfusion imaging or CTA, with their subsequent management being driven by an algorithm based on their test results. The hypothesis here is that CTA will be associated with no increase in adverse events, similar outcomes, lower cost, less radiation exposure, and resultant superior cost-effectiveness. Dr. Udelson is an investigator in RESCUE, which is supported by the Agency for Healthcare Research and Quality and the American College of Radiology Imaging Network.

• ISCHEMIA. The most ambitious of the studies is the International Study of Comparative Health Effectiveness with Medical and Invasive Approaches.

The National Institutes of Health has awarded an $84 million grant to conduct ISCHEMIA, a study of an early invasive versus conservative strategy in patients with stable CAD and moderate to severe ischemia.

The trial involves 8,000 patients with a left ventricular ejection fraction of 35% or more and at least 10% cardiac ischemia. They will undergo blinded CTA to rule out high-risk left main disease or normal coronary arteries. Then they will be randomized to catheterization and revascularization plus optimal medical therapy or to optimal medical management alone with revascularization reserved for worsening symptoms. Follow-up will be for 3-6 years.

ISCHEMIA is designed to provide answers to questions left open by the COURAGE and BARI 2D trials. The key design difference is that ISCHEMIA participants will be randomized to the invasive or conservative strategy before cardiac catheterization. The study hypothesis is that the invasive strategy will prove superior in terms of the primary composite end point of cardiovascular death, MI, or adjudicated hospitalization for unstable angina, heart failure, or cardiac arrest. Secondary end points will include cost-effectiveness and quality of life measures.

Dr. Udelson declared having no financial conflicts.

DENVER – The historically shaky evidence base for cardiac imaging strategies is in the midst of being shored up by a strong new foundation.

Just a couple of years ago, analysts concluded that cardiac imaging guidelines have among the weakest supporting evidence bases of any of the 53 American College of Cardiology/American Heart Association practice guidelines they looked at. The investigators found that only 2.4% of the evidence supporting the imaging guidelines had a level of evidence of A, meaning supported by multiple randomized trials. Thirty-seven percent of the evidence was level B, coming from multiple observational studies. Another 17% was based on expert opinion, and the rest of the imaging guideline recommendations were not supported by any conclusive evidence (JAMA 2009;301:831-41).

All that is clearly in the process of changing, and in a big way, Dr. James E. Udelson observed at the annual meeting of the American Society of Nuclear Cardiology.

An unprecedented raft of multicenter randomized trials is underway in patients with chest pain. The government-supported studies range in size from 4,300 to 10,000 patients. They are variously aimed at determining whether anatomic imaging via coronary CT angiography (CTA) or functional imaging by SPECT myocardial perfusion imaging stress ECG, or stress echocardiography is the best initial strategy for the diagnosis of coronary artery disease, and at using imaging results to identify optimal management strategies, explained Dr. Udelson, chief of cardiology and director of the nuclear cardiology laboratory at Tufts Medical Center, Boston.

Here’s what’s underway:

• PROMISE. The PROspective Multicenter Imaging Study for Evaluation of chest pain), funded by the National Heart, Lung, and Blood Institute, involves 10,000 patients with symptoms suggestive of CAD and low to intermediate pretest probability of CAD. They’ll be randomized to CTA or functional imaging by SPECT myocardial perfusion imaging, stress ECG, or stress echo, with the study results immediately available to the care team for use in management decisions.

The primary end point is the 30-month composite of death, MI, major complications due to cardiac catheterization, or hospitalization for unstable angina. The study hypothesis is that noninvasive anatomic imaging via CTA will result in superior long-term outcomes.

Enrollment is progressing quickly, with 2,800 randomized patients, according to Dr. Udelson, who is a PROMISE investigator.

• RESCUE. In the Randomized Evaluation of patients with Stable angina Comparing Utilization of diagnostic Examinations, 4,300 symptomatic outpatients are being randomized to SPECT myocardial perfusion imaging or CTA, with their subsequent management being driven by an algorithm based on their test results. The hypothesis here is that CTA will be associated with no increase in adverse events, similar outcomes, lower cost, less radiation exposure, and resultant superior cost-effectiveness. Dr. Udelson is an investigator in RESCUE, which is supported by the Agency for Healthcare Research and Quality and the American College of Radiology Imaging Network.

• ISCHEMIA. The most ambitious of the studies is the International Study of Comparative Health Effectiveness with Medical and Invasive Approaches.

The National Institutes of Health has awarded an $84 million grant to conduct ISCHEMIA, a study of an early invasive versus conservative strategy in patients with stable CAD and moderate to severe ischemia.

The trial involves 8,000 patients with a left ventricular ejection fraction of 35% or more and at least 10% cardiac ischemia. They will undergo blinded CTA to rule out high-risk left main disease or normal coronary arteries. Then they will be randomized to catheterization and revascularization plus optimal medical therapy or to optimal medical management alone with revascularization reserved for worsening symptoms. Follow-up will be for 3-6 years.

ISCHEMIA is designed to provide answers to questions left open by the COURAGE and BARI 2D trials. The key design difference is that ISCHEMIA participants will be randomized to the invasive or conservative strategy before cardiac catheterization. The study hypothesis is that the invasive strategy will prove superior in terms of the primary composite end point of cardiovascular death, MI, or adjudicated hospitalization for unstable angina, heart failure, or cardiac arrest. Secondary end points will include cost-effectiveness and quality of life measures.

Dr. Udelson declared having no financial conflicts.

DENVER – The added prognostic value gained by measuring coronary flow reserve in addition to myocardial perfusion for predicting the risk of cardiac events is a major emerging theme in cardiac nuclear imaging.

The impetus for developing PET quantitation of coronary flow reserve as a tool for evaluating cardiac event risk in patients with known or suspected CAD lies in the relatively recent recognition that a normal or low-risk conventional single-photon emission computed tomography (SPECT) myocardial perfusion imaging study is no guarantee of a low event risk, Dr. George A. Beller noted at the annual meeting of the American Society of Nuclear Cardiology.

"In order to identify those patients with normal or low-risk perfusion scans who really are high risk, we need to do more than just look at relative perfusion," he explained. "Myocardial flow reserve as assessed by PET is emerging now as a really good adjunct to just looking at relative uptake."

Italian investigators recently utilized dynamic SPECT imaging to assess coronary flow reserve in 58 patients with a normal myocardial perfusion study. In the 20 patients with normal coronary flow reserve as well as normal perfusion, the cardiac event rate was just 0.7% per year. In the 38 with normal perfusion along with an abnormally low coronary flow reserve, however, the event rate was 5.2% per year (J. Nucl. Cardiol. 2011;18:612-9).

"This is a substantial sevenfold increase in event rate in those with what we would consider a normal scan with normal perfusion," commented Dr. Beller of the University of Virginia, Charlottesville.

PET offers several key advantages over SPECT for assessment of coronary flow reserve, the most important being that it provides accurate quantification of the extent of abnormal regional myocardial blood flow reserve. In addition, it readily detects microvascular dysfunction, and it also picks up balanced ischemia, which often results in a false-negative SPECT myocardial perfusion imaging study, he continued.

"Myocardial flow reserve as assessed by PET is emerging now as a really good adjunct to just looking at relative uptake."

A recent study by investigators at the University of Ottawa Heart Institute National Cardiac PET Center showed that quantitation of coronary flow reserve using rubidium-82 PET predicted hard cardiac events independently of summed stress scores for myocardial ischemia.

In 704 consecutive patients prospectively followed for a median of 387 days after testing, those with a summed symptom score of less than 4, indicative of normal myocardial perfusion, plus normal coronary flow reserve had a 1.3% incidence of cardiac death or MI. In contrast, patients with a summed symptom score below 4 and abnormally low coronary flow reserve had a significantly higher 2.0% event rate, while those with a summed symptom score of 4 or higher plus abnormal coronary flow reserve had an 11.1% cardiac event rate. Patients with abnormal myocardial perfusion and normal coronary flow reserve had a 1.1% incidence of cardiac events (J. Am. Coll. Cardiol. 2011;58:740-8).

Similarly, investigators at Johns Hopkins University, Baltimore, recently demonstrated that a finding of globally impaired myocardial flow reserve was a potent independent predictor of near-term cardiovascular events.

They utilized rubidium-82 PET to quantify global myocardial flow reserve in 275 patients referred for perfusion imaging and subsequently followed for an average of 1 year. In an age-adjusted multivariate analysis, a finding of regional perfusion defects was independently associated with a 2.5-fold increased risk of cardiac events, confirming a long-established relationship. But in addition, a global myocardial flow reserve below the median value was also an independent predictor of cardiac events, with an associated 2.9-fold increased risk (J. Nucl. Med. 2011;52:726-32).

On the basis of these and other compelling studies reported in the last year or two, Dr. Beller offered the following algorithm for noninvasive testing to predict the risk of cardiac events in patients with stable CAD: Those who can perform more than 10 METs (metabolic equivalents) of exercise on the treadmill are at very low risk and warrant being placed on optimal medical therapy, with crossover to an invasive strategy only if symptoms worsen. Patients less than 5% left ventricular ischemia and normal coronary flow reserve also belong in this low-risk category.

A high-risk test is defined by 10%-15% left ventricular ischemia or markedly reduced coronary flow reserve, even in the presence of only a mild perfusion defect. These are patients for whom consideration should be given to an invasive strategy coupled with optimal medical therapy.

For patients with mild ischemia – that is, 5%-9% – a normal ejection fraction, and either a normal or only a small focal area of diminished coronary flow reserve, optimal medical therapy and follow-up stress imaging is an appropriate approach, Dr. Beller added.

He declared having no financial conflicts.

DENVER – The added prognostic value gained by measuring coronary flow reserve in addition to myocardial perfusion for predicting the risk of cardiac events is a major emerging theme in cardiac nuclear imaging.

The impetus for developing PET quantitation of coronary flow reserve as a tool for evaluating cardiac event risk in patients with known or suspected CAD lies in the relatively recent recognition that a normal or low-risk conventional single-photon emission computed tomography (SPECT) myocardial perfusion imaging study is no guarantee of a low event risk, Dr. George A. Beller noted at the annual meeting of the American Society of Nuclear Cardiology.

"In order to identify those patients with normal or low-risk perfusion scans who really are high risk, we need to do more than just look at relative perfusion," he explained. "Myocardial flow reserve as assessed by PET is emerging now as a really good adjunct to just looking at relative uptake."

Italian investigators recently utilized dynamic SPECT imaging to assess coronary flow reserve in 58 patients with a normal myocardial perfusion study. In the 20 patients with normal coronary flow reserve as well as normal perfusion, the cardiac event rate was just 0.7% per year. In the 38 with normal perfusion along with an abnormally low coronary flow reserve, however, the event rate was 5.2% per year (J. Nucl. Cardiol. 2011;18:612-9).

"This is a substantial sevenfold increase in event rate in those with what we would consider a normal scan with normal perfusion," commented Dr. Beller of the University of Virginia, Charlottesville.

PET offers several key advantages over SPECT for assessment of coronary flow reserve, the most important being that it provides accurate quantification of the extent of abnormal regional myocardial blood flow reserve. In addition, it readily detects microvascular dysfunction, and it also picks up balanced ischemia, which often results in a false-negative SPECT myocardial perfusion imaging study, he continued.

"Myocardial flow reserve as assessed by PET is emerging now as a really good adjunct to just looking at relative uptake."

A recent study by investigators at the University of Ottawa Heart Institute National Cardiac PET Center showed that quantitation of coronary flow reserve using rubidium-82 PET predicted hard cardiac events independently of summed stress scores for myocardial ischemia.

In 704 consecutive patients prospectively followed for a median of 387 days after testing, those with a summed symptom score of less than 4, indicative of normal myocardial perfusion, plus normal coronary flow reserve had a 1.3% incidence of cardiac death or MI. In contrast, patients with a summed symptom score below 4 and abnormally low coronary flow reserve had a significantly higher 2.0% event rate, while those with a summed symptom score of 4 or higher plus abnormal coronary flow reserve had an 11.1% cardiac event rate. Patients with abnormal myocardial perfusion and normal coronary flow reserve had a 1.1% incidence of cardiac events (J. Am. Coll. Cardiol. 2011;58:740-8).

Similarly, investigators at Johns Hopkins University, Baltimore, recently demonstrated that a finding of globally impaired myocardial flow reserve was a potent independent predictor of near-term cardiovascular events.

They utilized rubidium-82 PET to quantify global myocardial flow reserve in 275 patients referred for perfusion imaging and subsequently followed for an average of 1 year. In an age-adjusted multivariate analysis, a finding of regional perfusion defects was independently associated with a 2.5-fold increased risk of cardiac events, confirming a long-established relationship. But in addition, a global myocardial flow reserve below the median value was also an independent predictor of cardiac events, with an associated 2.9-fold increased risk (J. Nucl. Med. 2011;52:726-32).

On the basis of these and other compelling studies reported in the last year or two, Dr. Beller offered the following algorithm for noninvasive testing to predict the risk of cardiac events in patients with stable CAD: Those who can perform more than 10 METs (metabolic equivalents) of exercise on the treadmill are at very low risk and warrant being placed on optimal medical therapy, with crossover to an invasive strategy only if symptoms worsen. Patients less than 5% left ventricular ischemia and normal coronary flow reserve also belong in this low-risk category.

A high-risk test is defined by 10%-15% left ventricular ischemia or markedly reduced coronary flow reserve, even in the presence of only a mild perfusion defect. These are patients for whom consideration should be given to an invasive strategy coupled with optimal medical therapy.

For patients with mild ischemia – that is, 5%-9% – a normal ejection fraction, and either a normal or only a small focal area of diminished coronary flow reserve, optimal medical therapy and follow-up stress imaging is an appropriate approach, Dr. Beller added.

He declared having no financial conflicts.

DENVER – The added prognostic value gained by measuring coronary flow reserve in addition to myocardial perfusion for predicting the risk of cardiac events is a major emerging theme in cardiac nuclear imaging.

The impetus for developing PET quantitation of coronary flow reserve as a tool for evaluating cardiac event risk in patients with known or suspected CAD lies in the relatively recent recognition that a normal or low-risk conventional single-photon emission computed tomography (SPECT) myocardial perfusion imaging study is no guarantee of a low event risk, Dr. George A. Beller noted at the annual meeting of the American Society of Nuclear Cardiology.

"In order to identify those patients with normal or low-risk perfusion scans who really are high risk, we need to do more than just look at relative perfusion," he explained. "Myocardial flow reserve as assessed by PET is emerging now as a really good adjunct to just looking at relative uptake."

Italian investigators recently utilized dynamic SPECT imaging to assess coronary flow reserve in 58 patients with a normal myocardial perfusion study. In the 20 patients with normal coronary flow reserve as well as normal perfusion, the cardiac event rate was just 0.7% per year. In the 38 with normal perfusion along with an abnormally low coronary flow reserve, however, the event rate was 5.2% per year (J. Nucl. Cardiol. 2011;18:612-9).

"This is a substantial sevenfold increase in event rate in those with what we would consider a normal scan with normal perfusion," commented Dr. Beller of the University of Virginia, Charlottesville.

PET offers several key advantages over SPECT for assessment of coronary flow reserve, the most important being that it provides accurate quantification of the extent of abnormal regional myocardial blood flow reserve. In addition, it readily detects microvascular dysfunction, and it also picks up balanced ischemia, which often results in a false-negative SPECT myocardial perfusion imaging study, he continued.

"Myocardial flow reserve as assessed by PET is emerging now as a really good adjunct to just looking at relative uptake."

A recent study by investigators at the University of Ottawa Heart Institute National Cardiac PET Center showed that quantitation of coronary flow reserve using rubidium-82 PET predicted hard cardiac events independently of summed stress scores for myocardial ischemia.

In 704 consecutive patients prospectively followed for a median of 387 days after testing, those with a summed symptom score of less than 4, indicative of normal myocardial perfusion, plus normal coronary flow reserve had a 1.3% incidence of cardiac death or MI. In contrast, patients with a summed symptom score below 4 and abnormally low coronary flow reserve had a significantly higher 2.0% event rate, while those with a summed symptom score of 4 or higher plus abnormal coronary flow reserve had an 11.1% cardiac event rate. Patients with abnormal myocardial perfusion and normal coronary flow reserve had a 1.1% incidence of cardiac events (J. Am. Coll. Cardiol. 2011;58:740-8).

Similarly, investigators at Johns Hopkins University, Baltimore, recently demonstrated that a finding of globally impaired myocardial flow reserve was a potent independent predictor of near-term cardiovascular events.

They utilized rubidium-82 PET to quantify global myocardial flow reserve in 275 patients referred for perfusion imaging and subsequently followed for an average of 1 year. In an age-adjusted multivariate analysis, a finding of regional perfusion defects was independently associated with a 2.5-fold increased risk of cardiac events, confirming a long-established relationship. But in addition, a global myocardial flow reserve below the median value was also an independent predictor of cardiac events, with an associated 2.9-fold increased risk (J. Nucl. Med. 2011;52:726-32).

On the basis of these and other compelling studies reported in the last year or two, Dr. Beller offered the following algorithm for noninvasive testing to predict the risk of cardiac events in patients with stable CAD: Those who can perform more than 10 METs (metabolic equivalents) of exercise on the treadmill are at very low risk and warrant being placed on optimal medical therapy, with crossover to an invasive strategy only if symptoms worsen. Patients less than 5% left ventricular ischemia and normal coronary flow reserve also belong in this low-risk category.

A high-risk test is defined by 10%-15% left ventricular ischemia or markedly reduced coronary flow reserve, even in the presence of only a mild perfusion defect. These are patients for whom consideration should be given to an invasive strategy coupled with optimal medical therapy.

For patients with mild ischemia – that is, 5%-9% – a normal ejection fraction, and either a normal or only a small focal area of diminished coronary flow reserve, optimal medical therapy and follow-up stress imaging is an appropriate approach, Dr. Beller added.

He declared having no financial conflicts.

DENVER – Nuclear medicine specialists are feeling the brunt of increased public anxiety and regulatory concern regarding patient radiation exposures.

Nuclear cardiologists, in particular, find themselves in the crosshairs as a result of recent evidence of inappropriate overutilization of myocardial perfusion imaging. The profession has responded with a campaign aimed at defining appropriate use scenarios for practitioners and encouraging adoption of newer techniques that reduce radiation exposure while retaining high image quality.

"Based on these recommendations, we expect that for the population of patients referred for SPECT or PET myocardial perfusion imaging, on average a total radiation exposure of 9 mSv or less can be achieved in 50% of studies by 2014," Dr. Manuel D. Cerqueira said at the annual meeting of the American Society of Nuclear Cardiology.

Meeting that goal will require, for example, doing fewer separate-day, stress/rest technetium-99 myocardial perfusion imaging tests, which typically entail 13-16 mSv of radiation exposure. Also, the American Society of Nuclear Cardiology (ASNC) recommendations urge consideration of stress echocardiography as an alternative to nuclear imaging in younger patients because the diagnostic accuracy may be comparable and they can avoid radiation exposure altogether. In addition, the ASNC report discourages thallium-201–based imaging protocols, which involve 22-31 mSv of radiation exposure, noted Dr. Cerqueira, who was first author of the recommendations (J. Nucl. Cardiol. 2010;17:709-18), and is professor of radiology and medicine at Case Western Reserve University, Cleveland.

Something that has nuclear medicine specialists and interventional radiologists greatly concerned, according to Robert W. Atcher, Ph.D., is a proposed Nuclear Regulatory Commission (NRC) policy change that would lower the occupational radiation exposure limit from 5 to 2 rem (Roentgen equivalent man).

"The most affected groups in our field are technologists with a heavy PET [positron emission tomography] patient flow, cyclotron engineers, maintenance personnel, and radiochemists synthesizing PET tracers and therapeutic compounds. This is potentially devastating to us, because if we lower the limit then we have to double the number of people who are responsible for doing the same number of imaging studies, with no way to collect any more reimbursement to handle that task. In essence, they’re threatening to devastate our ability to do imaging," said Dr. Atcher, director of the National Isotope Development Center at the U.S. Department of Energy.

The NRC got an earful from concerned physicians and nonphysician scientists at hearings on the proposed changes held last year in Los Angeles, Houston, and Washington. The agency has not yet announced whether it plans to go ahead.

Another instance of what Dr. Atcher characterized as "regulatory overreacting" involves congressional interest in requiring hospitalization for patients who have received iodine-131. He and others have testified that there is no scientific evidence of risk to patients’ families or the general public if current guidelines for I-131 use are followed. Congressional representatives were also told that hospitalizing I-131 recipients would cost in excess of $600 million annually. In addition, critics of the idea pointed out that the risk of acquiring a serious methicillin-resistant Staphylococcus aureus infection during a hospital stay is quite real, said Dr. Atcher, a former president of the Society for Nuclear Medicine.

The new mantra at ASNC is "patient-centered imaging." The group’s recommendations for reducing radiation exposure from myocardial perfusion imaging emphasize appropriate patient selection, the use of standardized imaging protocols, radiotracers with shorter half-lives, weight-based dosing, and improved imaging systems.

Dr. E. Gordon DePuey highlighted the many new methods of optimizing image quality that have reached the market. These include resolution recovery and noise modeling software that provides superior image quality with shortened radiation exposure time. "All vendors now offer software that does this," he pointed out.

Also, hardware enhancements such as cardiofocal collimation are making a big difference. This particular technology allows half-time SPECT (single-photon emission computed tomography) with 100% myocardial radiation count density, explained Dr. DePuey of Columbia University, New York.

"All these new hardware and software methods out there are major advancements in nuclear cardiology. They need to be very seriously considered and incorporated in your practice, because they are really the keys to allowing you to decrease the radiation dose to your patients," he said.

Dr. Cerqueira drew attention to a large study that concluded myocardial perfusion imaging accounts for 22% of the total effective radiation dose accumulated from all nuclear medicine imaging procedures. Abdominal CT was the second biggest contributor, at 18% (N. Engl. J. Med. 2009;361:849-57).

Also concerning was a recent study using the very large UnitedHealthcare patient database. It showed that myocardial perfusion imaging accounted for 80% of the cumulative effective radiation dose from all cardiac imaging procedures in women age 18-34 years (J. Am. Coll. Cardiol. 2010;56:702-11).

"That’s a young population of women of childbearing age where you really wouldn’t expect a great many of these myocardial perfusion imaging studies to be done," Dr. Cerqueira commented.

He noted that the ASNC recommendations urge reserving myocardial perfusion imaging for patients in whom it has the greatest clinical utility: those at intermediate risk of coronary artery disease, patients requiring prognostic or management information, and those with persistent unexplained symptoms.

Dr. DePuey disclosed that he serves as an adviser to UltraSPECT and Dogwood Pharmaceuticals. The other speakers declared having no relevant financial interests.

DENVER – Nuclear medicine specialists are feeling the brunt of increased public anxiety and regulatory concern regarding patient radiation exposures.

Nuclear cardiologists, in particular, find themselves in the crosshairs as a result of recent evidence of inappropriate overutilization of myocardial perfusion imaging. The profession has responded with a campaign aimed at defining appropriate use scenarios for practitioners and encouraging adoption of newer techniques that reduce radiation exposure while retaining high image quality.

"Based on these recommendations, we expect that for the population of patients referred for SPECT or PET myocardial perfusion imaging, on average a total radiation exposure of 9 mSv or less can be achieved in 50% of studies by 2014," Dr. Manuel D. Cerqueira said at the annual meeting of the American Society of Nuclear Cardiology.

Meeting that goal will require, for example, doing fewer separate-day, stress/rest technetium-99 myocardial perfusion imaging tests, which typically entail 13-16 mSv of radiation exposure. Also, the American Society of Nuclear Cardiology (ASNC) recommendations urge consideration of stress echocardiography as an alternative to nuclear imaging in younger patients because the diagnostic accuracy may be comparable and they can avoid radiation exposure altogether. In addition, the ASNC report discourages thallium-201–based imaging protocols, which involve 22-31 mSv of radiation exposure, noted Dr. Cerqueira, who was first author of the recommendations (J. Nucl. Cardiol. 2010;17:709-18), and is professor of radiology and medicine at Case Western Reserve University, Cleveland.

Something that has nuclear medicine specialists and interventional radiologists greatly concerned, according to Robert W. Atcher, Ph.D., is a proposed Nuclear Regulatory Commission (NRC) policy change that would lower the occupational radiation exposure limit from 5 to 2 rem (Roentgen equivalent man).

"The most affected groups in our field are technologists with a heavy PET [positron emission tomography] patient flow, cyclotron engineers, maintenance personnel, and radiochemists synthesizing PET tracers and therapeutic compounds. This is potentially devastating to us, because if we lower the limit then we have to double the number of people who are responsible for doing the same number of imaging studies, with no way to collect any more reimbursement to handle that task. In essence, they’re threatening to devastate our ability to do imaging," said Dr. Atcher, director of the National Isotope Development Center at the U.S. Department of Energy.

The NRC got an earful from concerned physicians and nonphysician scientists at hearings on the proposed changes held last year in Los Angeles, Houston, and Washington. The agency has not yet announced whether it plans to go ahead.

Another instance of what Dr. Atcher characterized as "regulatory overreacting" involves congressional interest in requiring hospitalization for patients who have received iodine-131. He and others have testified that there is no scientific evidence of risk to patients’ families or the general public if current guidelines for I-131 use are followed. Congressional representatives were also told that hospitalizing I-131 recipients would cost in excess of $600 million annually. In addition, critics of the idea pointed out that the risk of acquiring a serious methicillin-resistant Staphylococcus aureus infection during a hospital stay is quite real, said Dr. Atcher, a former president of the Society for Nuclear Medicine.

The new mantra at ASNC is "patient-centered imaging." The group’s recommendations for reducing radiation exposure from myocardial perfusion imaging emphasize appropriate patient selection, the use of standardized imaging protocols, radiotracers with shorter half-lives, weight-based dosing, and improved imaging systems.

Dr. E. Gordon DePuey highlighted the many new methods of optimizing image quality that have reached the market. These include resolution recovery and noise modeling software that provides superior image quality with shortened radiation exposure time. "All vendors now offer software that does this," he pointed out.

Also, hardware enhancements such as cardiofocal collimation are making a big difference. This particular technology allows half-time SPECT (single-photon emission computed tomography) with 100% myocardial radiation count density, explained Dr. DePuey of Columbia University, New York.

"All these new hardware and software methods out there are major advancements in nuclear cardiology. They need to be very seriously considered and incorporated in your practice, because they are really the keys to allowing you to decrease the radiation dose to your patients," he said.

Dr. Cerqueira drew attention to a large study that concluded myocardial perfusion imaging accounts for 22% of the total effective radiation dose accumulated from all nuclear medicine imaging procedures. Abdominal CT was the second biggest contributor, at 18% (N. Engl. J. Med. 2009;361:849-57).

Also concerning was a recent study using the very large UnitedHealthcare patient database. It showed that myocardial perfusion imaging accounted for 80% of the cumulative effective radiation dose from all cardiac imaging procedures in women age 18-34 years (J. Am. Coll. Cardiol. 2010;56:702-11).

"That’s a young population of women of childbearing age where you really wouldn’t expect a great many of these myocardial perfusion imaging studies to be done," Dr. Cerqueira commented.

He noted that the ASNC recommendations urge reserving myocardial perfusion imaging for patients in whom it has the greatest clinical utility: those at intermediate risk of coronary artery disease, patients requiring prognostic or management information, and those with persistent unexplained symptoms.

Dr. DePuey disclosed that he serves as an adviser to UltraSPECT and Dogwood Pharmaceuticals. The other speakers declared having no relevant financial interests.

DENVER – Nuclear medicine specialists are feeling the brunt of increased public anxiety and regulatory concern regarding patient radiation exposures.

Nuclear cardiologists, in particular, find themselves in the crosshairs as a result of recent evidence of inappropriate overutilization of myocardial perfusion imaging. The profession has responded with a campaign aimed at defining appropriate use scenarios for practitioners and encouraging adoption of newer techniques that reduce radiation exposure while retaining high image quality.

"Based on these recommendations, we expect that for the population of patients referred for SPECT or PET myocardial perfusion imaging, on average a total radiation exposure of 9 mSv or less can be achieved in 50% of studies by 2014," Dr. Manuel D. Cerqueira said at the annual meeting of the American Society of Nuclear Cardiology.

Meeting that goal will require, for example, doing fewer separate-day, stress/rest technetium-99 myocardial perfusion imaging tests, which typically entail 13-16 mSv of radiation exposure. Also, the American Society of Nuclear Cardiology (ASNC) recommendations urge consideration of stress echocardiography as an alternative to nuclear imaging in younger patients because the diagnostic accuracy may be comparable and they can avoid radiation exposure altogether. In addition, the ASNC report discourages thallium-201–based imaging protocols, which involve 22-31 mSv of radiation exposure, noted Dr. Cerqueira, who was first author of the recommendations (J. Nucl. Cardiol. 2010;17:709-18), and is professor of radiology and medicine at Case Western Reserve University, Cleveland.

Something that has nuclear medicine specialists and interventional radiologists greatly concerned, according to Robert W. Atcher, Ph.D., is a proposed Nuclear Regulatory Commission (NRC) policy change that would lower the occupational radiation exposure limit from 5 to 2 rem (Roentgen equivalent man).

"The most affected groups in our field are technologists with a heavy PET [positron emission tomography] patient flow, cyclotron engineers, maintenance personnel, and radiochemists synthesizing PET tracers and therapeutic compounds. This is potentially devastating to us, because if we lower the limit then we have to double the number of people who are responsible for doing the same number of imaging studies, with no way to collect any more reimbursement to handle that task. In essence, they’re threatening to devastate our ability to do imaging," said Dr. Atcher, director of the National Isotope Development Center at the U.S. Department of Energy.

The NRC got an earful from concerned physicians and nonphysician scientists at hearings on the proposed changes held last year in Los Angeles, Houston, and Washington. The agency has not yet announced whether it plans to go ahead.

Another instance of what Dr. Atcher characterized as "regulatory overreacting" involves congressional interest in requiring hospitalization for patients who have received iodine-131. He and others have testified that there is no scientific evidence of risk to patients’ families or the general public if current guidelines for I-131 use are followed. Congressional representatives were also told that hospitalizing I-131 recipients would cost in excess of $600 million annually. In addition, critics of the idea pointed out that the risk of acquiring a serious methicillin-resistant Staphylococcus aureus infection during a hospital stay is quite real, said Dr. Atcher, a former president of the Society for Nuclear Medicine.

The new mantra at ASNC is "patient-centered imaging." The group’s recommendations for reducing radiation exposure from myocardial perfusion imaging emphasize appropriate patient selection, the use of standardized imaging protocols, radiotracers with shorter half-lives, weight-based dosing, and improved imaging systems.

Dr. E. Gordon DePuey highlighted the many new methods of optimizing image quality that have reached the market. These include resolution recovery and noise modeling software that provides superior image quality with shortened radiation exposure time. "All vendors now offer software that does this," he pointed out.

Also, hardware enhancements such as cardiofocal collimation are making a big difference. This particular technology allows half-time SPECT (single-photon emission computed tomography) with 100% myocardial radiation count density, explained Dr. DePuey of Columbia University, New York.

"All these new hardware and software methods out there are major advancements in nuclear cardiology. They need to be very seriously considered and incorporated in your practice, because they are really the keys to allowing you to decrease the radiation dose to your patients," he said.

Dr. Cerqueira drew attention to a large study that concluded myocardial perfusion imaging accounts for 22% of the total effective radiation dose accumulated from all nuclear medicine imaging procedures. Abdominal CT was the second biggest contributor, at 18% (N. Engl. J. Med. 2009;361:849-57).

Also concerning was a recent study using the very large UnitedHealthcare patient database. It showed that myocardial perfusion imaging accounted for 80% of the cumulative effective radiation dose from all cardiac imaging procedures in women age 18-34 years (J. Am. Coll. Cardiol. 2010;56:702-11).

"That’s a young population of women of childbearing age where you really wouldn’t expect a great many of these myocardial perfusion imaging studies to be done," Dr. Cerqueira commented.

He noted that the ASNC recommendations urge reserving myocardial perfusion imaging for patients in whom it has the greatest clinical utility: those at intermediate risk of coronary artery disease, patients requiring prognostic or management information, and those with persistent unexplained symptoms.

Dr. DePuey disclosed that he serves as an adviser to UltraSPECT and Dogwood Pharmaceuticals. The other speakers declared having no relevant financial interests.

SAN DIEGO – What if 3-6 million Americans had an asymptomatic condition that was easily, but coincidentally, detected on CT and MRI scans?

What if a number of excellent, but expensive, options existed to treat this condition, potentially preventing a catastrophic event in 0%-53% of cases, depending on the size, location, and duration of the problematic entity?

Obviously, you would look to well-designed, prospective, randomized, controlled trials intended to determine which patients should be referred for treatment, which patients should be watched, and which should be reassured.

But such trials don’t exist.

This real-life scenario describes asymptomatic, saccular, unruptured intracranial aneurysms (UIAs), which pose a management conundrum for virtually every neurologist in practice today.

"These are extremely common. About 2% of the population has a UIA," including perhaps 14 of the 700 attendees of the annual meeting of the American Neurological Association, noted Dr. Robert D. Brown during a symposium at the meeting.

"Not to fret," Dr. Brown assured the audience after personalizing his statistics. "That doesn’t necessary mean [14 attendees possess] a ticking time bomb."

Aneurysmal subarachnoid hemorrhages affect 6-10 per 100,000 U.S. population annually, with a case fatality rate of 30%-40%.

Still, "most aneurysms do not rupture," said Dr. Brown, chair of neurology at the Mayo Clinic in Rochester, Minn.

The predominance of natural history studies point to size as being of critical importance in the assessment of rupture risk, "no matter where the location or what the age of the patient," he said.

Secondarily, location and age matter, with posterior aneurysms and those in older patients being at seemingly greater risk of rupture.

But with smaller and smaller aneurysms becoming increasingly easy to see on scans, "we’re in the situation right now where the question is not ‘Can we do anything [with incidentally discovered aneurysms in younger patients],’ but should we?" he remarked.

Beyond patient age and aneurysm size and position, the hypothesized risk factors for rupture include smoking, hypertension, alcohol consumption (with risk associated with no alcohol or high alcohol use), and perhaps family history, as well as morphological characteristics and growth of the aneurysm itself over time.

Epidemiologic cohort studies can help to direct management in the absence of a well-designed, randomized trial, Dr. Brown said.

For example, data on unoperated patients who were enrolled in the 5,500-patient ISUIA (International Study of Unruptured Intracranial Aneurysms) suggest that smaller aneurysms located in the anterior circulation of the circle of Willis and the cavernous segment of the internal carotid artery are quite unlikely to hemorrhage when they are followed conservatively for 5 years.

Available data from the trial also suggest that even very small (less than 7 mm) aneurysms have a potential for hemorrhage that is "noteworthy and certainly far from zero" if they are located in the posterior communicating artery or posterior circulation.

Current and future research is exploring whether more precise analysis of the features of such aneurysms – including their undulation and elliptical indices and nonspherical shape – may be more predictive of rupture risk.

Computational fluid dynamics, drawn from engineering principles, may also provide better guidance, Dr. Brown said.

In the meantime, he cited a "huge variation" in clinical practice when it comes to management of smaller, unruptured aneurysms, with some centers opting to treat 90% with coils or clips and others treating fewer than 10% of such cases.

His own practice, guided by the literature, is to advise treatment in the following situations:

• In younger patients in otherwise good health whose aneurysms measure 7 mm or greater.

• In younger patients in otherwise good health whose aneurysms measure less than 7 mm but are in the posterior circulation.

• Possibly, in older patients with aneurysms measuring 7-12 mm in the posterior circulation.

• In older patients with aneurysms greater than 12 mm in which a reasonable treatment option exists.

Dr. Brown advised aggressive treatment of hypertension and smoking-cessation management in all patients with unruptured aneurysms, as well as careful, imaging-based follow-up of conservatively managed patients based on limited data showing growth in moderate and large lesions over time.

Even 1 in 12 small (measuring less than 8 mm) aneurysms demonstrated "clear, definitive growth" over 4 years in a study of 165 patients (Stroke 2009;40:406-11), he noted.

Aspirin therapy may be beneficial, based on soon-to-be-released data from the ISUIA study showing a "strong and significant" trend toward lower rupture risk in patients taking the highest aspirin doses, he said.

Dr. Brown disclosed no conflicts of interest relative to his talk.

SAN DIEGO – What if 3-6 million Americans had an asymptomatic condition that was easily, but coincidentally, detected on CT and MRI scans?

What if a number of excellent, but expensive, options existed to treat this condition, potentially preventing a catastrophic event in 0%-53% of cases, depending on the size, location, and duration of the problematic entity?

Obviously, you would look to well-designed, prospective, randomized, controlled trials intended to determine which patients should be referred for treatment, which patients should be watched, and which should be reassured.

But such trials don’t exist.

This real-life scenario describes asymptomatic, saccular, unruptured intracranial aneurysms (UIAs), which pose a management conundrum for virtually every neurologist in practice today.

"These are extremely common. About 2% of the population has a UIA," including perhaps 14 of the 700 attendees of the annual meeting of the American Neurological Association, noted Dr. Robert D. Brown during a symposium at the meeting.

"Not to fret," Dr. Brown assured the audience after personalizing his statistics. "That doesn’t necessary mean [14 attendees possess] a ticking time bomb."

Aneurysmal subarachnoid hemorrhages affect 6-10 per 100,000 U.S. population annually, with a case fatality rate of 30%-40%.

Still, "most aneurysms do not rupture," said Dr. Brown, chair of neurology at the Mayo Clinic in Rochester, Minn.

The predominance of natural history studies point to size as being of critical importance in the assessment of rupture risk, "no matter where the location or what the age of the patient," he said.

Secondarily, location and age matter, with posterior aneurysms and those in older patients being at seemingly greater risk of rupture.

But with smaller and smaller aneurysms becoming increasingly easy to see on scans, "we’re in the situation right now where the question is not ‘Can we do anything [with incidentally discovered aneurysms in younger patients],’ but should we?" he remarked.

Beyond patient age and aneurysm size and position, the hypothesized risk factors for rupture include smoking, hypertension, alcohol consumption (with risk associated with no alcohol or high alcohol use), and perhaps family history, as well as morphological characteristics and growth of the aneurysm itself over time.

Epidemiologic cohort studies can help to direct management in the absence of a well-designed, randomized trial, Dr. Brown said.

For example, data on unoperated patients who were enrolled in the 5,500-patient ISUIA (International Study of Unruptured Intracranial Aneurysms) suggest that smaller aneurysms located in the anterior circulation of the circle of Willis and the cavernous segment of the internal carotid artery are quite unlikely to hemorrhage when they are followed conservatively for 5 years.

Available data from the trial also suggest that even very small (less than 7 mm) aneurysms have a potential for hemorrhage that is "noteworthy and certainly far from zero" if they are located in the posterior communicating artery or posterior circulation.

Current and future research is exploring whether more precise analysis of the features of such aneurysms – including their undulation and elliptical indices and nonspherical shape – may be more predictive of rupture risk.

Computational fluid dynamics, drawn from engineering principles, may also provide better guidance, Dr. Brown said.

In the meantime, he cited a "huge variation" in clinical practice when it comes to management of smaller, unruptured aneurysms, with some centers opting to treat 90% with coils or clips and others treating fewer than 10% of such cases.

His own practice, guided by the literature, is to advise treatment in the following situations:

• In younger patients in otherwise good health whose aneurysms measure 7 mm or greater.

• In younger patients in otherwise good health whose aneurysms measure less than 7 mm but are in the posterior circulation.

• Possibly, in older patients with aneurysms measuring 7-12 mm in the posterior circulation.

• In older patients with aneurysms greater than 12 mm in which a reasonable treatment option exists.

Dr. Brown advised aggressive treatment of hypertension and smoking-cessation management in all patients with unruptured aneurysms, as well as careful, imaging-based follow-up of conservatively managed patients based on limited data showing growth in moderate and large lesions over time.

Even 1 in 12 small (measuring less than 8 mm) aneurysms demonstrated "clear, definitive growth" over 4 years in a study of 165 patients (Stroke 2009;40:406-11), he noted.

Aspirin therapy may be beneficial, based on soon-to-be-released data from the ISUIA study showing a "strong and significant" trend toward lower rupture risk in patients taking the highest aspirin doses, he said.

Dr. Brown disclosed no conflicts of interest relative to his talk.

SAN DIEGO – What if 3-6 million Americans had an asymptomatic condition that was easily, but coincidentally, detected on CT and MRI scans?

What if a number of excellent, but expensive, options existed to treat this condition, potentially preventing a catastrophic event in 0%-53% of cases, depending on the size, location, and duration of the problematic entity?

Obviously, you would look to well-designed, prospective, randomized, controlled trials intended to determine which patients should be referred for treatment, which patients should be watched, and which should be reassured.

But such trials don’t exist.

This real-life scenario describes asymptomatic, saccular, unruptured intracranial aneurysms (UIAs), which pose a management conundrum for virtually every neurologist in practice today.

"These are extremely common. About 2% of the population has a UIA," including perhaps 14 of the 700 attendees of the annual meeting of the American Neurological Association, noted Dr. Robert D. Brown during a symposium at the meeting.

"Not to fret," Dr. Brown assured the audience after personalizing his statistics. "That doesn’t necessary mean [14 attendees possess] a ticking time bomb."

Aneurysmal subarachnoid hemorrhages affect 6-10 per 100,000 U.S. population annually, with a case fatality rate of 30%-40%.

Still, "most aneurysms do not rupture," said Dr. Brown, chair of neurology at the Mayo Clinic in Rochester, Minn.

The predominance of natural history studies point to size as being of critical importance in the assessment of rupture risk, "no matter where the location or what the age of the patient," he said.

Secondarily, location and age matter, with posterior aneurysms and those in older patients being at seemingly greater risk of rupture.

But with smaller and smaller aneurysms becoming increasingly easy to see on scans, "we’re in the situation right now where the question is not ‘Can we do anything [with incidentally discovered aneurysms in younger patients],’ but should we?" he remarked.

Beyond patient age and aneurysm size and position, the hypothesized risk factors for rupture include smoking, hypertension, alcohol consumption (with risk associated with no alcohol or high alcohol use), and perhaps family history, as well as morphological characteristics and growth of the aneurysm itself over time.

Epidemiologic cohort studies can help to direct management in the absence of a well-designed, randomized trial, Dr. Brown said.

For example, data on unoperated patients who were enrolled in the 5,500-patient ISUIA (International Study of Unruptured Intracranial Aneurysms) suggest that smaller aneurysms located in the anterior circulation of the circle of Willis and the cavernous segment of the internal carotid artery are quite unlikely to hemorrhage when they are followed conservatively for 5 years.

Available data from the trial also suggest that even very small (less than 7 mm) aneurysms have a potential for hemorrhage that is "noteworthy and certainly far from zero" if they are located in the posterior communicating artery or posterior circulation.

Current and future research is exploring whether more precise analysis of the features of such aneurysms – including their undulation and elliptical indices and nonspherical shape – may be more predictive of rupture risk.

Computational fluid dynamics, drawn from engineering principles, may also provide better guidance, Dr. Brown said.

In the meantime, he cited a "huge variation" in clinical practice when it comes to management of smaller, unruptured aneurysms, with some centers opting to treat 90% with coils or clips and others treating fewer than 10% of such cases.

His own practice, guided by the literature, is to advise treatment in the following situations:

• In younger patients in otherwise good health whose aneurysms measure 7 mm or greater.

• In younger patients in otherwise good health whose aneurysms measure less than 7 mm but are in the posterior circulation.

• Possibly, in older patients with aneurysms measuring 7-12 mm in the posterior circulation.

• In older patients with aneurysms greater than 12 mm in which a reasonable treatment option exists.

Dr. Brown advised aggressive treatment of hypertension and smoking-cessation management in all patients with unruptured aneurysms, as well as careful, imaging-based follow-up of conservatively managed patients based on limited data showing growth in moderate and large lesions over time.

Even 1 in 12 small (measuring less than 8 mm) aneurysms demonstrated "clear, definitive growth" over 4 years in a study of 165 patients (Stroke 2009;40:406-11), he noted.

Aspirin therapy may be beneficial, based on soon-to-be-released data from the ISUIA study showing a "strong and significant" trend toward lower rupture risk in patients taking the highest aspirin doses, he said.

Dr. Brown disclosed no conflicts of interest relative to his talk.

DENVER – Physicians making referrals for cardiac stress testing often underestimate their patients’ ability to exercise to target heart rate, according to Dr. Michael Ross.

Here’s what can happen as a result: In a prospective series of 120 consecutive patients referred for pharmacologic myocardial perfusion imaging stress testing by primary care physicians, surgeons, and cardiologists, 60% of the patients were able to mount the treadmill and exercise to 85% of their estimated maximum heart rate, he reported at the annual meeting of American Society of Nuclear Cardiology.

Primary care physicians were significantly more likely than were cardiologists or surgeons to order a pharmacologic stress test in patients who did not need one because they were able to complete the less costly exercise stress test.

Is that because primary care physicians don’t know their patients and their physical capacities as well as other physicians do? Highly unlikely. Instead, it appears they are more concerned that if they order an exercise stress test and a patient can’t complete it, they’ll have to reorder the test – this time using pharmacologic stress – with the attendant inconvenience and delay, according to Dr. Ross of Northwestern University, Chicago.

In a multivariate logistic regression analysis, the only independent predictors of failure to reach target heart rate were being on a beta-blocker and having diabetes.

Dr. Ross said he had no relevant financial disclosures.

DENVER – Physicians making referrals for cardiac stress testing often underestimate their patients’ ability to exercise to target heart rate, according to Dr. Michael Ross.

Here’s what can happen as a result: In a prospective series of 120 consecutive patients referred for pharmacologic myocardial perfusion imaging stress testing by primary care physicians, surgeons, and cardiologists, 60% of the patients were able to mount the treadmill and exercise to 85% of their estimated maximum heart rate, he reported at the annual meeting of American Society of Nuclear Cardiology.

Primary care physicians were significantly more likely than were cardiologists or surgeons to order a pharmacologic stress test in patients who did not need one because they were able to complete the less costly exercise stress test.

Is that because primary care physicians don’t know their patients and their physical capacities as well as other physicians do? Highly unlikely. Instead, it appears they are more concerned that if they order an exercise stress test and a patient can’t complete it, they’ll have to reorder the test – this time using pharmacologic stress – with the attendant inconvenience and delay, according to Dr. Ross of Northwestern University, Chicago.

In a multivariate logistic regression analysis, the only independent predictors of failure to reach target heart rate were being on a beta-blocker and having diabetes.

Dr. Ross said he had no relevant financial disclosures.

DENVER – Physicians making referrals for cardiac stress testing often underestimate their patients’ ability to exercise to target heart rate, according to Dr. Michael Ross.

Here’s what can happen as a result: In a prospective series of 120 consecutive patients referred for pharmacologic myocardial perfusion imaging stress testing by primary care physicians, surgeons, and cardiologists, 60% of the patients were able to mount the treadmill and exercise to 85% of their estimated maximum heart rate, he reported at the annual meeting of American Society of Nuclear Cardiology.

Primary care physicians were significantly more likely than were cardiologists or surgeons to order a pharmacologic stress test in patients who did not need one because they were able to complete the less costly exercise stress test.

Is that because primary care physicians don’t know their patients and their physical capacities as well as other physicians do? Highly unlikely. Instead, it appears they are more concerned that if they order an exercise stress test and a patient can’t complete it, they’ll have to reorder the test – this time using pharmacologic stress – with the attendant inconvenience and delay, according to Dr. Ross of Northwestern University, Chicago.

In a multivariate logistic regression analysis, the only independent predictors of failure to reach target heart rate were being on a beta-blocker and having diabetes.

Dr. Ross said he had no relevant financial disclosures.