Imaging

NEW ORLEANS — The fat that surrounds the heart is associated with cardiac abnormalities, including low stroke volume and cardiac output, that are independent of body mass index, a study has found.

The finding casts doubt on the widespread practice of using body mass index (BMI) as an indicator of cardiovascular disease risk, Dr. Zhongjing Chen, of Boston University, said at the annual meeting of NAASO, the Obesity Society.

Dr. Chen and colleagues assessed 13 obese women with metabolic syndrome—but no recognized atherosclerosis—using magnetic resonance imaging. The patients' average age was 47 years (range 30–59).

The women had a BMI of 30 kg/m

“The limit for weight was 275 pounds, and for waist circumference 50 inches, because of the table weight and size limits of our scanner,” Dr. Chen said.

The researchers used special software developed by Boston University's Center for Biomedical Imaging to calculate epicardial and periaortic fat and then analyzed stroke volume, end diastolic wall mass, and ejection fraction, as well as flow volume and peak blood velocity.

Both stroke volume and cardiac output were negatively correlated with epicardial and periaortic fat, and this negative correlation was statistically significant. Ascending aorta compliance also worsened in the presence of epicardial and periaortic fat.

However, there were no correlations between stroke volume, cardiac output, or ascending aorta compliance and the subjects' BMI, Dr. Chen said.

“The major morbidities associated with metabolic syndrome are myocardial infarction and stroke. People have been correlating body mass index with these risks, but our results indicate that it's the fat stores around the heart that are important risk factors,” she said in an interview.

Dr. Chen added that MRI is noninvasive and therefore provides an excellent way of measuring epicardial fat and cardiovascular disease risk.

“Epicardial and periaortic fat can be directly detected and quantified with MRI to give us a good reading of cardiac function and vessel wall properties. We would like to see whether reducing those fat depots is associated with improvements in cardiac or vascular function. More studies are needed to answer this question,” she said.

MRI images show epicardial fat (bright ring) in a woman with a BMI of 44 kg/m

NEW ORLEANS — The fat that surrounds the heart is associated with cardiac abnormalities, including low stroke volume and cardiac output, that are independent of body mass index, a study has found.

The finding casts doubt on the widespread practice of using body mass index (BMI) as an indicator of cardiovascular disease risk, Dr. Zhongjing Chen, of Boston University, said at the annual meeting of NAASO, the Obesity Society.

Dr. Chen and colleagues assessed 13 obese women with metabolic syndrome—but no recognized atherosclerosis—using magnetic resonance imaging. The patients' average age was 47 years (range 30–59).

The women had a BMI of 30 kg/m

“The limit for weight was 275 pounds, and for waist circumference 50 inches, because of the table weight and size limits of our scanner,” Dr. Chen said.

The researchers used special software developed by Boston University's Center for Biomedical Imaging to calculate epicardial and periaortic fat and then analyzed stroke volume, end diastolic wall mass, and ejection fraction, as well as flow volume and peak blood velocity.

Both stroke volume and cardiac output were negatively correlated with epicardial and periaortic fat, and this negative correlation was statistically significant. Ascending aorta compliance also worsened in the presence of epicardial and periaortic fat.

However, there were no correlations between stroke volume, cardiac output, or ascending aorta compliance and the subjects' BMI, Dr. Chen said.

“The major morbidities associated with metabolic syndrome are myocardial infarction and stroke. People have been correlating body mass index with these risks, but our results indicate that it's the fat stores around the heart that are important risk factors,” she said in an interview.

Dr. Chen added that MRI is noninvasive and therefore provides an excellent way of measuring epicardial fat and cardiovascular disease risk.

“Epicardial and periaortic fat can be directly detected and quantified with MRI to give us a good reading of cardiac function and vessel wall properties. We would like to see whether reducing those fat depots is associated with improvements in cardiac or vascular function. More studies are needed to answer this question,” she said.

MRI images show epicardial fat (bright ring) in a woman with a BMI of 44 kg/m

NEW ORLEANS — The fat that surrounds the heart is associated with cardiac abnormalities, including low stroke volume and cardiac output, that are independent of body mass index, a study has found.

The finding casts doubt on the widespread practice of using body mass index (BMI) as an indicator of cardiovascular disease risk, Dr. Zhongjing Chen, of Boston University, said at the annual meeting of NAASO, the Obesity Society.

Dr. Chen and colleagues assessed 13 obese women with metabolic syndrome—but no recognized atherosclerosis—using magnetic resonance imaging. The patients' average age was 47 years (range 30–59).

The women had a BMI of 30 kg/m

“The limit for weight was 275 pounds, and for waist circumference 50 inches, because of the table weight and size limits of our scanner,” Dr. Chen said.

The researchers used special software developed by Boston University's Center for Biomedical Imaging to calculate epicardial and periaortic fat and then analyzed stroke volume, end diastolic wall mass, and ejection fraction, as well as flow volume and peak blood velocity.

Both stroke volume and cardiac output were negatively correlated with epicardial and periaortic fat, and this negative correlation was statistically significant. Ascending aorta compliance also worsened in the presence of epicardial and periaortic fat.

However, there were no correlations between stroke volume, cardiac output, or ascending aorta compliance and the subjects' BMI, Dr. Chen said.

“The major morbidities associated with metabolic syndrome are myocardial infarction and stroke. People have been correlating body mass index with these risks, but our results indicate that it's the fat stores around the heart that are important risk factors,” she said in an interview.

Dr. Chen added that MRI is noninvasive and therefore provides an excellent way of measuring epicardial fat and cardiovascular disease risk.

“Epicardial and periaortic fat can be directly detected and quantified with MRI to give us a good reading of cardiac function and vessel wall properties. We would like to see whether reducing those fat depots is associated with improvements in cardiac or vascular function. More studies are needed to answer this question,” she said.

MRI images show epicardial fat (bright ring) in a woman with a BMI of 44 kg/m

SAN DIEGO — Postacquisition processing using Astonish software technology results in improved image quality and similar diagnostic accuracy to conventional 64-frame filtered back-projection processing, even at a 32-frame SPECT acquisition, results from a multicenter study showed.

“These findings confirm the value of half-acquisition Astonish, which may lead to important improvement in laboratory efficiency,” Dr. Gary V. Heller said at the annual meeting of the American Society of Nuclear Cardiology.

Manufactured by Philips Medical Systems, Astonish is a program that includes depth-dependent collimator resolution and scatter correction to permit reduced angular or shortened acquisition times.

Dr. Heller and his associates evaluated 221 patients who presented to three nuclear cardiology laboratories for clinically indicated rest/stress technetium-99m sestamibi or tetrofosmin single-photon emission computed tomography (SPECT) imaging. The purpose was to compare conventional 64-frame filtered back-projection processing with 64-frame (full-time) and 32-frame (half-time) Astonish processing. The researchers measured image quality of both stress and rest perfusion, image quality of rest and stress ECG-gated, diagnostic certainty of perfusion, diagnostic accuracy of the perfusion, and the size of the perfusion abnormalities. Comparison of the three imaging methods was made in blinded fashion by consensus interpretation.

The mean age of the 221 patients was 65 years, and 36% were women. Their average body mass index was 30 kg/m

The stress and rest perfusion image quality was “quite good” in all three groups, Dr. Heller said, although there were significantly higher rates of fair- or poor-quality images in the conventional 64-frame filtered back-projection group compared with the full-time and half-time Astonish groups.

There were also significantly higher rates of fair or poor stress functional image quality in the conventional group compared with the full-time and half-time Astonish groups. However, the rate of fair or poor rest functional image quality was the same between patients in the conventional group and the full-time Astonish group, but was slightly higher among patients in the half-time Astonish group.

Dr. Heller, director of nuclear cardiology at Hartford (Conn.) Hospital, reported that there were no differences in interpretive certainty of stress myocardial perfusion imaging between the three groups of patients. There also were no differences between the groups in the diagnostic accuracy of 50% stenosis, “although there was a trend toward reduced specificity with regard to patients in the half-time Astonish processing group,” he said.

The researchers observed significantly higher summed stress scores among patients in the half-time and full-time Astonish groups, compared with those in the conventional 64-frame filtered back-projection group (10.7, 9.7, and 8.8, respectively), but there were no statistically significant differences in the summed rest score between the three groups (2.7, 2.4, and 2.6, respectively).

There were no differences between the groups in poststress ejection fraction between the three groups (a rate of 57% for all). The ejection fraction at rest was similar between the three groups (61% for the half-time Astonish group, 63% for the full-time Astonish group, and 62% for the conventional 64-frame filtered back-projection group).

“If labs use Astonish without changing acquisition times, it will result in higher-quality images, easier to interpret,” Dr. Heller concluded in a later interview. “If labs choose to improve efficiency by using half acquisition, the image quality is actually superior to filtered back projection.”

The study was funded with an unrestricted research grant from Philips Medical Systems. The company was not involved in the development of the study or in the interpretation of the results.

Dr. Heller disclosed that he has received grants from Philips Medical Systems and that he is a member of the company's speakers' bureau.

In these perfusion images of normal stress, the top three rows show processing with 64-frame (full-time) Astonish. The middle three rows show processing with conventional 64-frame filtered back projection. The bottom three rows show processing with 32-frame (half-time) Astonish. Courtesy Dr. Gary V. Heller

SAN DIEGO — Postacquisition processing using Astonish software technology results in improved image quality and similar diagnostic accuracy to conventional 64-frame filtered back-projection processing, even at a 32-frame SPECT acquisition, results from a multicenter study showed.

“These findings confirm the value of half-acquisition Astonish, which may lead to important improvement in laboratory efficiency,” Dr. Gary V. Heller said at the annual meeting of the American Society of Nuclear Cardiology.

Manufactured by Philips Medical Systems, Astonish is a program that includes depth-dependent collimator resolution and scatter correction to permit reduced angular or shortened acquisition times.

Dr. Heller and his associates evaluated 221 patients who presented to three nuclear cardiology laboratories for clinically indicated rest/stress technetium-99m sestamibi or tetrofosmin single-photon emission computed tomography (SPECT) imaging. The purpose was to compare conventional 64-frame filtered back-projection processing with 64-frame (full-time) and 32-frame (half-time) Astonish processing. The researchers measured image quality of both stress and rest perfusion, image quality of rest and stress ECG-gated, diagnostic certainty of perfusion, diagnostic accuracy of the perfusion, and the size of the perfusion abnormalities. Comparison of the three imaging methods was made in blinded fashion by consensus interpretation.

The mean age of the 221 patients was 65 years, and 36% were women. Their average body mass index was 30 kg/m

The stress and rest perfusion image quality was “quite good” in all three groups, Dr. Heller said, although there were significantly higher rates of fair- or poor-quality images in the conventional 64-frame filtered back-projection group compared with the full-time and half-time Astonish groups.

There were also significantly higher rates of fair or poor stress functional image quality in the conventional group compared with the full-time and half-time Astonish groups. However, the rate of fair or poor rest functional image quality was the same between patients in the conventional group and the full-time Astonish group, but was slightly higher among patients in the half-time Astonish group.

Dr. Heller, director of nuclear cardiology at Hartford (Conn.) Hospital, reported that there were no differences in interpretive certainty of stress myocardial perfusion imaging between the three groups of patients. There also were no differences between the groups in the diagnostic accuracy of 50% stenosis, “although there was a trend toward reduced specificity with regard to patients in the half-time Astonish processing group,” he said.

The researchers observed significantly higher summed stress scores among patients in the half-time and full-time Astonish groups, compared with those in the conventional 64-frame filtered back-projection group (10.7, 9.7, and 8.8, respectively), but there were no statistically significant differences in the summed rest score between the three groups (2.7, 2.4, and 2.6, respectively).

There were no differences between the groups in poststress ejection fraction between the three groups (a rate of 57% for all). The ejection fraction at rest was similar between the three groups (61% for the half-time Astonish group, 63% for the full-time Astonish group, and 62% for the conventional 64-frame filtered back-projection group).

“If labs use Astonish without changing acquisition times, it will result in higher-quality images, easier to interpret,” Dr. Heller concluded in a later interview. “If labs choose to improve efficiency by using half acquisition, the image quality is actually superior to filtered back projection.”

The study was funded with an unrestricted research grant from Philips Medical Systems. The company was not involved in the development of the study or in the interpretation of the results.

Dr. Heller disclosed that he has received grants from Philips Medical Systems and that he is a member of the company's speakers' bureau.

In these perfusion images of normal stress, the top three rows show processing with 64-frame (full-time) Astonish. The middle three rows show processing with conventional 64-frame filtered back projection. The bottom three rows show processing with 32-frame (half-time) Astonish. Courtesy Dr. Gary V. Heller

SAN DIEGO — Postacquisition processing using Astonish software technology results in improved image quality and similar diagnostic accuracy to conventional 64-frame filtered back-projection processing, even at a 32-frame SPECT acquisition, results from a multicenter study showed.

“These findings confirm the value of half-acquisition Astonish, which may lead to important improvement in laboratory efficiency,” Dr. Gary V. Heller said at the annual meeting of the American Society of Nuclear Cardiology.

Manufactured by Philips Medical Systems, Astonish is a program that includes depth-dependent collimator resolution and scatter correction to permit reduced angular or shortened acquisition times.

Dr. Heller and his associates evaluated 221 patients who presented to three nuclear cardiology laboratories for clinically indicated rest/stress technetium-99m sestamibi or tetrofosmin single-photon emission computed tomography (SPECT) imaging. The purpose was to compare conventional 64-frame filtered back-projection processing with 64-frame (full-time) and 32-frame (half-time) Astonish processing. The researchers measured image quality of both stress and rest perfusion, image quality of rest and stress ECG-gated, diagnostic certainty of perfusion, diagnostic accuracy of the perfusion, and the size of the perfusion abnormalities. Comparison of the three imaging methods was made in blinded fashion by consensus interpretation.

The mean age of the 221 patients was 65 years, and 36% were women. Their average body mass index was 30 kg/m

The stress and rest perfusion image quality was “quite good” in all three groups, Dr. Heller said, although there were significantly higher rates of fair- or poor-quality images in the conventional 64-frame filtered back-projection group compared with the full-time and half-time Astonish groups.

There were also significantly higher rates of fair or poor stress functional image quality in the conventional group compared with the full-time and half-time Astonish groups. However, the rate of fair or poor rest functional image quality was the same between patients in the conventional group and the full-time Astonish group, but was slightly higher among patients in the half-time Astonish group.

Dr. Heller, director of nuclear cardiology at Hartford (Conn.) Hospital, reported that there were no differences in interpretive certainty of stress myocardial perfusion imaging between the three groups of patients. There also were no differences between the groups in the diagnostic accuracy of 50% stenosis, “although there was a trend toward reduced specificity with regard to patients in the half-time Astonish processing group,” he said.

The researchers observed significantly higher summed stress scores among patients in the half-time and full-time Astonish groups, compared with those in the conventional 64-frame filtered back-projection group (10.7, 9.7, and 8.8, respectively), but there were no statistically significant differences in the summed rest score between the three groups (2.7, 2.4, and 2.6, respectively).

There were no differences between the groups in poststress ejection fraction between the three groups (a rate of 57% for all). The ejection fraction at rest was similar between the three groups (61% for the half-time Astonish group, 63% for the full-time Astonish group, and 62% for the conventional 64-frame filtered back-projection group).

“If labs use Astonish without changing acquisition times, it will result in higher-quality images, easier to interpret,” Dr. Heller concluded in a later interview. “If labs choose to improve efficiency by using half acquisition, the image quality is actually superior to filtered back projection.”

The study was funded with an unrestricted research grant from Philips Medical Systems. The company was not involved in the development of the study or in the interpretation of the results.

Dr. Heller disclosed that he has received grants from Philips Medical Systems and that he is a member of the company's speakers' bureau.

In these perfusion images of normal stress, the top three rows show processing with 64-frame (full-time) Astonish. The middle three rows show processing with conventional 64-frame filtered back projection. The bottom three rows show processing with 32-frame (half-time) Astonish. Courtesy Dr. Gary V. Heller

SAN DIEGO — The way Dr. Raymond J. Gibbons sees it, the best way to practice appropriate single-photon emission computed tomography myocardial perfusion imaging is to apply the appropriateness criteria established by the American College of Cardiology Foundation and the American Society of Nuclear Cardiology.

These criteria grade clinical scenarios with respect to whether they are appropriate or inappropriate uses of SPECT myocardial perfusion imaging (J. Am. Coll. Cardiol. 2005;46:1587–605). When Dr. Gibbons and his associates at the Mayo Clinic Nuclear Cardiology Laboratory in Rochester, Minn., applied the criteria to several hundred patients in their nuclear cardiology laboratory, they discovered that 64% of the SPECT myocardial perfusion imaging studies they did were appropriate, 11% could not be classified, 11% were of uncertain appropriateness, and about 14% were inappropriate.

“We need to reduce this number of inappropriate tests,” Dr. Gibbons said at the annual meeting of the American Society of Nuclear Cardiology. “I would urge all of you to do this same study in your own laboratory. The goal should be to educate ordering physicians to reduce this segment of the pie.”

In Dr. Gibbon's study, four inappropriate indications for SPECT myocardial perfusion imaging accounted for almost all of the inappropriate studies. These included studies in asymptomatic low-risk patients; preoperative studies in patients who were undergoing intermediate-risk surgery and had good exercise capacity; studies in symptomatic patients with a low pretest likelihood of coronary artery disease, an interpretable ECG; and who are able to exercise, and studies conducted as preoperative testing in patients undergoing low-risk surgery.

“Together, these four indications accounted for 88% of the inappropriate studies,” said Dr. Gibbons, who is a codirector of Mayo's Nuclear Cardiology Laboratory. “We have initiated a program to try to educate our physicians and nurses to reduce these inappropriate studies.”

Dr. Gibbons, a former president of the American Heart Association, expressed concern about the future of health care and imaging in the United States. In the summer of 2007 the House of Representatives passed State Children's Health Insurance Program and Medicare reform legislation that eliminated a 9.9% decrease in physician payment in 2008 and a 5% decrease in 2009. That's the good news. The bad news is that in 2010 the sustainable growth rate formula will be replaced with a new system with six separate targets, one of which is imaging.

“Growth in those targets will be limited to the growth in gross domestic product,” Dr. Gibbons said. “Given the interest in CT and MR, and the dramatic growth in cardiac imaging, this will have a draconian effect if it goes into law.”

'We have initiated a program to try to educate our physicians and nurses to reduce these inappropriate studies.' DR. GIBBONS

SAN DIEGO — The way Dr. Raymond J. Gibbons sees it, the best way to practice appropriate single-photon emission computed tomography myocardial perfusion imaging is to apply the appropriateness criteria established by the American College of Cardiology Foundation and the American Society of Nuclear Cardiology.

These criteria grade clinical scenarios with respect to whether they are appropriate or inappropriate uses of SPECT myocardial perfusion imaging (J. Am. Coll. Cardiol. 2005;46:1587–605). When Dr. Gibbons and his associates at the Mayo Clinic Nuclear Cardiology Laboratory in Rochester, Minn., applied the criteria to several hundred patients in their nuclear cardiology laboratory, they discovered that 64% of the SPECT myocardial perfusion imaging studies they did were appropriate, 11% could not be classified, 11% were of uncertain appropriateness, and about 14% were inappropriate.

“We need to reduce this number of inappropriate tests,” Dr. Gibbons said at the annual meeting of the American Society of Nuclear Cardiology. “I would urge all of you to do this same study in your own laboratory. The goal should be to educate ordering physicians to reduce this segment of the pie.”

In Dr. Gibbon's study, four inappropriate indications for SPECT myocardial perfusion imaging accounted for almost all of the inappropriate studies. These included studies in asymptomatic low-risk patients; preoperative studies in patients who were undergoing intermediate-risk surgery and had good exercise capacity; studies in symptomatic patients with a low pretest likelihood of coronary artery disease, an interpretable ECG; and who are able to exercise, and studies conducted as preoperative testing in patients undergoing low-risk surgery.

“Together, these four indications accounted for 88% of the inappropriate studies,” said Dr. Gibbons, who is a codirector of Mayo's Nuclear Cardiology Laboratory. “We have initiated a program to try to educate our physicians and nurses to reduce these inappropriate studies.”

Dr. Gibbons, a former president of the American Heart Association, expressed concern about the future of health care and imaging in the United States. In the summer of 2007 the House of Representatives passed State Children's Health Insurance Program and Medicare reform legislation that eliminated a 9.9% decrease in physician payment in 2008 and a 5% decrease in 2009. That's the good news. The bad news is that in 2010 the sustainable growth rate formula will be replaced with a new system with six separate targets, one of which is imaging.

“Growth in those targets will be limited to the growth in gross domestic product,” Dr. Gibbons said. “Given the interest in CT and MR, and the dramatic growth in cardiac imaging, this will have a draconian effect if it goes into law.”

'We have initiated a program to try to educate our physicians and nurses to reduce these inappropriate studies.' DR. GIBBONS

SAN DIEGO — The way Dr. Raymond J. Gibbons sees it, the best way to practice appropriate single-photon emission computed tomography myocardial perfusion imaging is to apply the appropriateness criteria established by the American College of Cardiology Foundation and the American Society of Nuclear Cardiology.

These criteria grade clinical scenarios with respect to whether they are appropriate or inappropriate uses of SPECT myocardial perfusion imaging (J. Am. Coll. Cardiol. 2005;46:1587–605). When Dr. Gibbons and his associates at the Mayo Clinic Nuclear Cardiology Laboratory in Rochester, Minn., applied the criteria to several hundred patients in their nuclear cardiology laboratory, they discovered that 64% of the SPECT myocardial perfusion imaging studies they did were appropriate, 11% could not be classified, 11% were of uncertain appropriateness, and about 14% were inappropriate.

“We need to reduce this number of inappropriate tests,” Dr. Gibbons said at the annual meeting of the American Society of Nuclear Cardiology. “I would urge all of you to do this same study in your own laboratory. The goal should be to educate ordering physicians to reduce this segment of the pie.”

In Dr. Gibbon's study, four inappropriate indications for SPECT myocardial perfusion imaging accounted for almost all of the inappropriate studies. These included studies in asymptomatic low-risk patients; preoperative studies in patients who were undergoing intermediate-risk surgery and had good exercise capacity; studies in symptomatic patients with a low pretest likelihood of coronary artery disease, an interpretable ECG; and who are able to exercise, and studies conducted as preoperative testing in patients undergoing low-risk surgery.

“Together, these four indications accounted for 88% of the inappropriate studies,” said Dr. Gibbons, who is a codirector of Mayo's Nuclear Cardiology Laboratory. “We have initiated a program to try to educate our physicians and nurses to reduce these inappropriate studies.”

Dr. Gibbons, a former president of the American Heart Association, expressed concern about the future of health care and imaging in the United States. In the summer of 2007 the House of Representatives passed State Children's Health Insurance Program and Medicare reform legislation that eliminated a 9.9% decrease in physician payment in 2008 and a 5% decrease in 2009. That's the good news. The bad news is that in 2010 the sustainable growth rate formula will be replaced with a new system with six separate targets, one of which is imaging.

“Growth in those targets will be limited to the growth in gross domestic product,” Dr. Gibbons said. “Given the interest in CT and MR, and the dramatic growth in cardiac imaging, this will have a draconian effect if it goes into law.”

'We have initiated a program to try to educate our physicians and nurses to reduce these inappropriate studies.' DR. GIBBONS

Microbubble ultrasound contrast agents used in patients with suboptimal echocardiograms have been linked to serious cardiopulmonary reactions and several deaths, according to the Food and Drug Administration.

In October, the agency issued a notice on its MedWatch site alerting health care professionals that the agency had received reports of deaths and cardiopulmonary reactions after ultrasound microbubble contrast agents had been administered to patients undergoing echocardiography. Of the 11 deaths reported, 4 were due to cardiac arrest during the infusion or within 30 minutes of administration, and most of the serious, nonfatal reactions also occurred during this time period.

The manufacturers of Definity (perflutren lipid microsphere) injectable suspension and Optison (perflutren protein-type A microspheres for Injection), the only microbubble ultrasound contrast agents approved in the United States, have agreed to add a black box warning and other warnings to the product labels describing these risks. A contraindication against their use in patients at a particular risk for cardiopulmonary reactions will also be added to the label. These patients include with those with known cardiac shunts, clinically unstable or recent worsening of heart failure, symptomatic arrhythmias, or those at high risk for arrhythmias due to QT prolongation, respiratory failure, severe emphysema, pulmonary emboli “or other conditions that compromise pulmonary arterial vasculature.”

These agents are a sterile suspension of perflutren gas microspheres that are indicated for use in patients with suboptimal echocardiograms, and are used to “opacify the left ventricular chamber and to improve the delineation of the left ventricular endocardial border,” according to the FDA.

Most of the reports have been associated with Definity, approved in 2001. There have been 10 postmarketing deaths reported with Definity and 1 following the administration of Optison, which was approved in 1997; marketing of Optison was temporarily suspended in 2005. In most of the deaths, the patient had a severe underlying condition: Some patients were on other medications the FDA statement said “could have contributed to their death.” Four of the deaths that followed cardiac arrest occurred during administration of Definity or within the 30 minutes that followed; two patients had severe heart failure and one was mechanically ventilated because of respiratory failure.

The FDA has also received 190 reports of serious nonfatal reactions following Definity administration and 9 such reports after Optison administration. In many of these cases, the patient had an “acute onset of symptoms suggestive of an anaphylactoid reaction.” Other cases described cardiopulmonary reactions with cardiac or respiratory arrest, loss of consciousness, convulsions, symptomatic arrhythmias, cardiac ischemia, hypotension, respiratory distress, and oxygen desaturation “without signs or symptoms of a typical allergic reaction.”

The boxed warning and warnings section also will recommend that vital signs, cardiac rhythm, and oxygen saturation be monitored in patients who receive these agents, and that resuscitation equipment and trained personnel be “readily available,” in patients who receive these agents, the FDA said.

The indications section will also point out that the safety and efficacy of Definity for use with exercise or pharmacologic stress testing has not been established. (One of the Definity-associated deaths was in a patient undergoing a cardiac stress test.)

The full summary is available at: www.fda.gov/medwatch/safety/2007/safety07.htm#bubblewww.fda.gov/medwatch/report.htm

Microbubble ultrasound contrast agents used in patients with suboptimal echocardiograms have been linked to serious cardiopulmonary reactions and several deaths, according to the Food and Drug Administration.

In October, the agency issued a notice on its MedWatch site alerting health care professionals that the agency had received reports of deaths and cardiopulmonary reactions after ultrasound microbubble contrast agents had been administered to patients undergoing echocardiography. Of the 11 deaths reported, 4 were due to cardiac arrest during the infusion or within 30 minutes of administration, and most of the serious, nonfatal reactions also occurred during this time period.

The manufacturers of Definity (perflutren lipid microsphere) injectable suspension and Optison (perflutren protein-type A microspheres for Injection), the only microbubble ultrasound contrast agents approved in the United States, have agreed to add a black box warning and other warnings to the product labels describing these risks. A contraindication against their use in patients at a particular risk for cardiopulmonary reactions will also be added to the label. These patients include with those with known cardiac shunts, clinically unstable or recent worsening of heart failure, symptomatic arrhythmias, or those at high risk for arrhythmias due to QT prolongation, respiratory failure, severe emphysema, pulmonary emboli “or other conditions that compromise pulmonary arterial vasculature.”

These agents are a sterile suspension of perflutren gas microspheres that are indicated for use in patients with suboptimal echocardiograms, and are used to “opacify the left ventricular chamber and to improve the delineation of the left ventricular endocardial border,” according to the FDA.

Most of the reports have been associated with Definity, approved in 2001. There have been 10 postmarketing deaths reported with Definity and 1 following the administration of Optison, which was approved in 1997; marketing of Optison was temporarily suspended in 2005. In most of the deaths, the patient had a severe underlying condition: Some patients were on other medications the FDA statement said “could have contributed to their death.” Four of the deaths that followed cardiac arrest occurred during administration of Definity or within the 30 minutes that followed; two patients had severe heart failure and one was mechanically ventilated because of respiratory failure.

The FDA has also received 190 reports of serious nonfatal reactions following Definity administration and 9 such reports after Optison administration. In many of these cases, the patient had an “acute onset of symptoms suggestive of an anaphylactoid reaction.” Other cases described cardiopulmonary reactions with cardiac or respiratory arrest, loss of consciousness, convulsions, symptomatic arrhythmias, cardiac ischemia, hypotension, respiratory distress, and oxygen desaturation “without signs or symptoms of a typical allergic reaction.”

The boxed warning and warnings section also will recommend that vital signs, cardiac rhythm, and oxygen saturation be monitored in patients who receive these agents, and that resuscitation equipment and trained personnel be “readily available,” in patients who receive these agents, the FDA said.

The indications section will also point out that the safety and efficacy of Definity for use with exercise or pharmacologic stress testing has not been established. (One of the Definity-associated deaths was in a patient undergoing a cardiac stress test.)

The full summary is available at: www.fda.gov/medwatch/safety/2007/safety07.htm#bubblewww.fda.gov/medwatch/report.htm

Microbubble ultrasound contrast agents used in patients with suboptimal echocardiograms have been linked to serious cardiopulmonary reactions and several deaths, according to the Food and Drug Administration.

In October, the agency issued a notice on its MedWatch site alerting health care professionals that the agency had received reports of deaths and cardiopulmonary reactions after ultrasound microbubble contrast agents had been administered to patients undergoing echocardiography. Of the 11 deaths reported, 4 were due to cardiac arrest during the infusion or within 30 minutes of administration, and most of the serious, nonfatal reactions also occurred during this time period.

The manufacturers of Definity (perflutren lipid microsphere) injectable suspension and Optison (perflutren protein-type A microspheres for Injection), the only microbubble ultrasound contrast agents approved in the United States, have agreed to add a black box warning and other warnings to the product labels describing these risks. A contraindication against their use in patients at a particular risk for cardiopulmonary reactions will also be added to the label. These patients include with those with known cardiac shunts, clinically unstable or recent worsening of heart failure, symptomatic arrhythmias, or those at high risk for arrhythmias due to QT prolongation, respiratory failure, severe emphysema, pulmonary emboli “or other conditions that compromise pulmonary arterial vasculature.”

These agents are a sterile suspension of perflutren gas microspheres that are indicated for use in patients with suboptimal echocardiograms, and are used to “opacify the left ventricular chamber and to improve the delineation of the left ventricular endocardial border,” according to the FDA.

Most of the reports have been associated with Definity, approved in 2001. There have been 10 postmarketing deaths reported with Definity and 1 following the administration of Optison, which was approved in 1997; marketing of Optison was temporarily suspended in 2005. In most of the deaths, the patient had a severe underlying condition: Some patients were on other medications the FDA statement said “could have contributed to their death.” Four of the deaths that followed cardiac arrest occurred during administration of Definity or within the 30 minutes that followed; two patients had severe heart failure and one was mechanically ventilated because of respiratory failure.

The FDA has also received 190 reports of serious nonfatal reactions following Definity administration and 9 such reports after Optison administration. In many of these cases, the patient had an “acute onset of symptoms suggestive of an anaphylactoid reaction.” Other cases described cardiopulmonary reactions with cardiac or respiratory arrest, loss of consciousness, convulsions, symptomatic arrhythmias, cardiac ischemia, hypotension, respiratory distress, and oxygen desaturation “without signs or symptoms of a typical allergic reaction.”

The boxed warning and warnings section also will recommend that vital signs, cardiac rhythm, and oxygen saturation be monitored in patients who receive these agents, and that resuscitation equipment and trained personnel be “readily available,” in patients who receive these agents, the FDA said.

The indications section will also point out that the safety and efficacy of Definity for use with exercise or pharmacologic stress testing has not been established. (One of the Definity-associated deaths was in a patient undergoing a cardiac stress test.)

The full summary is available at: www.fda.gov/medwatch/safety/2007/safety07.htm#bubblewww.fda.gov/medwatch/report.htm

SAN DIEGO — Nearly 80% of patients with type 2 diabetes who had silent myocardial ischemia revealed by stress myocardial perfusion imaging had a reversal of exercise-induced myocardial perfusion abnormalities 3 years later.

The unexpected finding suggests that a substantial proportion of patients with type 2 diabetes and silent myocardial ischemia have the potential for improvement of stress myocardial perfusion imaging abnormalities with medical management, Dr. Frans J.Th. Wackers said at the annual meeting of the American Society of Nuclear Cardiology.

“These results are consistent with the INSPIRE study and the COURAGE trial, which found that aggressive and optimal treatment can reverse myocardial perfusion abnormalities.” said Dr. Wackers, director of the cardiovascular nuclear imaging and stress laboratories at Yale University, New Haven.

The study was a follow-up to the Detection of Ischemia in Asymptomatic Diabetics (DIAD)-1 study, which documented a 22% prevalence of silent myocardial ischemia during adenosine stress testing with sestamibi SPECT myocardial perfusion imaging. In the current study, known as DIAD-2, Dr. Wackers and associates performed repeat stress myocardial perfusion imaging in DIAD-1 study participants after 3 years to evaluate for progression of silent myocardial ischemia. Initial myocardial perfusion imaging was performed in 2003, and repeat myocardial perfusion imaging was performed in 2006.

Of the initial 522 patients, 356 underwent repeat myocardial perfusion imaging, 70 of whom had previously documented silent myocardial ischemia in DIAD-1. The mean age of the 356 patients was 61 years, and 44% were women.

Repeat myocardial perfusion imaging could not be performed in 166 patients because of an intervening cardiovascular event or death, in 29 patients; severe comorbidity, in 10; refusal by 108 patients; loss to follow-up in 17; and uninterpretable study in 2. The initial and repeat DIAD studies were read by the same blinded panel of experts, said Dr. Wackers.

The overall prevalence of silent myocardial ischemia in DIAD-2 was 12%, which is 10% lower than the overall prevalence in DIAD-1.

In addition, of the 286 patients who had normal DIAD-1 studies, 90% remained normal in DIAD-2, whereas 10% developed new myocardial ischemia.

Of the 71 patients who had abnormal DIAD-1 studies, 56 (79%) showed resolution of inducible ischemia, and 15 (21%) remained abnormal.

When the researchers compared patients who had resolution of ischemia with those who developed new inducible ischemia, they observed no significant baseline differences in age, gender, BMI, duration of diabetes, family history, blood pressure, hemoglobin A_1c, LDL or HDL cholesterol, or C-reactive protein.

In another part of the analysis, the researchers observed a significant increase among all patients in the use of aspirin, statins, and ACE inhibitors between 2003 and 2006. Specifically, the use of aspirin rose from 42% to 69%, the use of statins rose from 38% to 59%, and the use of ACE inhibitors rose from 34% to 42%.

DIAD-2 patients who had resolution of ischemia were exposed to cardiac medications for a significantly longer period of time, compared with those who developed new ischemia (59 months vs. 45 months).

Dr. Wackers has received research honoraria from Bristol-Myers Squibb, Astellas, and General Electric, and is a scientific adviser for General Electric and King Pharmaceuticals.

In 2001 (left), a 59-year-old asymptomatic man had a small defect in the anterior wall (arrows) on sestamibi SPECT imaging. By 2004 (right), the defect had normalized. During the interval, the patient was treated with aspirin, a statin, and an ACE inhibitor. Courtesy Dr. Frans J.Th. Wackers

SAN DIEGO — Nearly 80% of patients with type 2 diabetes who had silent myocardial ischemia revealed by stress myocardial perfusion imaging had a reversal of exercise-induced myocardial perfusion abnormalities 3 years later.

The unexpected finding suggests that a substantial proportion of patients with type 2 diabetes and silent myocardial ischemia have the potential for improvement of stress myocardial perfusion imaging abnormalities with medical management, Dr. Frans J.Th. Wackers said at the annual meeting of the American Society of Nuclear Cardiology.

“These results are consistent with the INSPIRE study and the COURAGE trial, which found that aggressive and optimal treatment can reverse myocardial perfusion abnormalities.” said Dr. Wackers, director of the cardiovascular nuclear imaging and stress laboratories at Yale University, New Haven.

The study was a follow-up to the Detection of Ischemia in Asymptomatic Diabetics (DIAD)-1 study, which documented a 22% prevalence of silent myocardial ischemia during adenosine stress testing with sestamibi SPECT myocardial perfusion imaging. In the current study, known as DIAD-2, Dr. Wackers and associates performed repeat stress myocardial perfusion imaging in DIAD-1 study participants after 3 years to evaluate for progression of silent myocardial ischemia. Initial myocardial perfusion imaging was performed in 2003, and repeat myocardial perfusion imaging was performed in 2006.

Of the initial 522 patients, 356 underwent repeat myocardial perfusion imaging, 70 of whom had previously documented silent myocardial ischemia in DIAD-1. The mean age of the 356 patients was 61 years, and 44% were women.

Repeat myocardial perfusion imaging could not be performed in 166 patients because of an intervening cardiovascular event or death, in 29 patients; severe comorbidity, in 10; refusal by 108 patients; loss to follow-up in 17; and uninterpretable study in 2. The initial and repeat DIAD studies were read by the same blinded panel of experts, said Dr. Wackers.

The overall prevalence of silent myocardial ischemia in DIAD-2 was 12%, which is 10% lower than the overall prevalence in DIAD-1.

In addition, of the 286 patients who had normal DIAD-1 studies, 90% remained normal in DIAD-2, whereas 10% developed new myocardial ischemia.

Of the 71 patients who had abnormal DIAD-1 studies, 56 (79%) showed resolution of inducible ischemia, and 15 (21%) remained abnormal.

When the researchers compared patients who had resolution of ischemia with those who developed new inducible ischemia, they observed no significant baseline differences in age, gender, BMI, duration of diabetes, family history, blood pressure, hemoglobin A_1c, LDL or HDL cholesterol, or C-reactive protein.

In another part of the analysis, the researchers observed a significant increase among all patients in the use of aspirin, statins, and ACE inhibitors between 2003 and 2006. Specifically, the use of aspirin rose from 42% to 69%, the use of statins rose from 38% to 59%, and the use of ACE inhibitors rose from 34% to 42%.

DIAD-2 patients who had resolution of ischemia were exposed to cardiac medications for a significantly longer period of time, compared with those who developed new ischemia (59 months vs. 45 months).

Dr. Wackers has received research honoraria from Bristol-Myers Squibb, Astellas, and General Electric, and is a scientific adviser for General Electric and King Pharmaceuticals.

In 2001 (left), a 59-year-old asymptomatic man had a small defect in the anterior wall (arrows) on sestamibi SPECT imaging. By 2004 (right), the defect had normalized. During the interval, the patient was treated with aspirin, a statin, and an ACE inhibitor. Courtesy Dr. Frans J.Th. Wackers

SAN DIEGO — Nearly 80% of patients with type 2 diabetes who had silent myocardial ischemia revealed by stress myocardial perfusion imaging had a reversal of exercise-induced myocardial perfusion abnormalities 3 years later.

The unexpected finding suggests that a substantial proportion of patients with type 2 diabetes and silent myocardial ischemia have the potential for improvement of stress myocardial perfusion imaging abnormalities with medical management, Dr. Frans J.Th. Wackers said at the annual meeting of the American Society of Nuclear Cardiology.

“These results are consistent with the INSPIRE study and the COURAGE trial, which found that aggressive and optimal treatment can reverse myocardial perfusion abnormalities.” said Dr. Wackers, director of the cardiovascular nuclear imaging and stress laboratories at Yale University, New Haven.

The study was a follow-up to the Detection of Ischemia in Asymptomatic Diabetics (DIAD)-1 study, which documented a 22% prevalence of silent myocardial ischemia during adenosine stress testing with sestamibi SPECT myocardial perfusion imaging. In the current study, known as DIAD-2, Dr. Wackers and associates performed repeat stress myocardial perfusion imaging in DIAD-1 study participants after 3 years to evaluate for progression of silent myocardial ischemia. Initial myocardial perfusion imaging was performed in 2003, and repeat myocardial perfusion imaging was performed in 2006.

Of the initial 522 patients, 356 underwent repeat myocardial perfusion imaging, 70 of whom had previously documented silent myocardial ischemia in DIAD-1. The mean age of the 356 patients was 61 years, and 44% were women.

Repeat myocardial perfusion imaging could not be performed in 166 patients because of an intervening cardiovascular event or death, in 29 patients; severe comorbidity, in 10; refusal by 108 patients; loss to follow-up in 17; and uninterpretable study in 2. The initial and repeat DIAD studies were read by the same blinded panel of experts, said Dr. Wackers.

The overall prevalence of silent myocardial ischemia in DIAD-2 was 12%, which is 10% lower than the overall prevalence in DIAD-1.

In addition, of the 286 patients who had normal DIAD-1 studies, 90% remained normal in DIAD-2, whereas 10% developed new myocardial ischemia.

Of the 71 patients who had abnormal DIAD-1 studies, 56 (79%) showed resolution of inducible ischemia, and 15 (21%) remained abnormal.

When the researchers compared patients who had resolution of ischemia with those who developed new inducible ischemia, they observed no significant baseline differences in age, gender, BMI, duration of diabetes, family history, blood pressure, hemoglobin A_1c, LDL or HDL cholesterol, or C-reactive protein.

In another part of the analysis, the researchers observed a significant increase among all patients in the use of aspirin, statins, and ACE inhibitors between 2003 and 2006. Specifically, the use of aspirin rose from 42% to 69%, the use of statins rose from 38% to 59%, and the use of ACE inhibitors rose from 34% to 42%.

DIAD-2 patients who had resolution of ischemia were exposed to cardiac medications for a significantly longer period of time, compared with those who developed new ischemia (59 months vs. 45 months).

Dr. Wackers has received research honoraria from Bristol-Myers Squibb, Astellas, and General Electric, and is a scientific adviser for General Electric and King Pharmaceuticals.

In 2001 (left), a 59-year-old asymptomatic man had a small defect in the anterior wall (arrows) on sestamibi SPECT imaging. By 2004 (right), the defect had normalized. During the interval, the patient was treated with aspirin, a statin, and an ACE inhibitor. Courtesy Dr. Frans J.Th. Wackers

CHICAGO — Up to 20% of strokes begin in the heart, so cardiac imaging should be part of the work-up of many stroke patients, Dr. Gautham Reddy said at the annual meeting of the American Society of Neuroradiology.

Electrocardiographically gated multidetector CT can assess the brain, cerebral vessels, and carotid arteries as well as the heart simultaneously and expedite diagnosis, he said.

At the University of California, San Francisco, where Dr. Reddy is chief of cardiac and pulmonary imaging, stroke patients are routinely scanned from the head down to the heart. Other modalities such as transthoracic or transesophageal echocardiography or MRI may be superior for evaluating cardiac masses, cardiomyopathy, or ischemic heart disease, but the ability to obtain a comprehensive evaluation from one sitting using CT can be advantageous for both the patient and physician—especially in the emergency setting.

The most common cardiac source of stroke is emboli, Dr. Reddy said. One such patient, diagnosed using multidetector CT, who had a history of atrial fibrillation and had been on anticoagulation, decided to stop taking his medication, then developed a stroke caused by a thrombus originating in the left atrium. Mitral stenosis is another common source of cardiac thrombus from the atrium.

Coagulation disorders and aneurysms may cause cardiac thrombi that originate in the ventricles. Left ventricular aneurysms may follow myocardial infarction and can be categorized as either true or false aneurysms.

True aneurysms characteristically have an anteroapical location with a wide ostium (greater than 50% of the aneurysm diameter). In contrast, false aneurysms are postdiaphragmatic with narrow ostia. Accurate and rapid diagnosis can have an impact on treatment, because true aneurysms are generally managed medically while false aneurysms require resection.

Cardiac tumors can also embolize to the brain. According to Dr. Reddy, about 98% of cardiac tumors are metastases from another source. Of primary cardiac tumors, myxomas, which are benign, are the most common and most likely to produce brain emboli. In fact, avoiding brain emboli is one of the major reasons for myxoma resection. Primary malignant tumors of the heart, such as angiosarcomas, also have the potential to embolize and cause stroke, as can secondary tumors such as lymphoma.

Cardiac imaging also can reveal the presence of patent foramen ovale or other septal defects in patients with strokes. These openings allow a clot or tumor to pass from the right side to the left side of the heart, and then enter the arterial circulation as a paradoxical embolism. Repair of even small defects may be recommended to avoid subsequent strokes, Dr. Reddy said.

Reconstructed coronal imaging shows a thrombus in the left atrial appendage.

The arrow shows a thrombus in a true aneurysm of the left ventricle.

A false aneurysm in the postero-inferior aspect of the LV is reconstructed on CT. Photos courtesy Dr. Gautham Reddy

CHICAGO — Up to 20% of strokes begin in the heart, so cardiac imaging should be part of the work-up of many stroke patients, Dr. Gautham Reddy said at the annual meeting of the American Society of Neuroradiology.

Electrocardiographically gated multidetector CT can assess the brain, cerebral vessels, and carotid arteries as well as the heart simultaneously and expedite diagnosis, he said.

At the University of California, San Francisco, where Dr. Reddy is chief of cardiac and pulmonary imaging, stroke patients are routinely scanned from the head down to the heart. Other modalities such as transthoracic or transesophageal echocardiography or MRI may be superior for evaluating cardiac masses, cardiomyopathy, or ischemic heart disease, but the ability to obtain a comprehensive evaluation from one sitting using CT can be advantageous for both the patient and physician—especially in the emergency setting.

The most common cardiac source of stroke is emboli, Dr. Reddy said. One such patient, diagnosed using multidetector CT, who had a history of atrial fibrillation and had been on anticoagulation, decided to stop taking his medication, then developed a stroke caused by a thrombus originating in the left atrium. Mitral stenosis is another common source of cardiac thrombus from the atrium.

Coagulation disorders and aneurysms may cause cardiac thrombi that originate in the ventricles. Left ventricular aneurysms may follow myocardial infarction and can be categorized as either true or false aneurysms.

True aneurysms characteristically have an anteroapical location with a wide ostium (greater than 50% of the aneurysm diameter). In contrast, false aneurysms are postdiaphragmatic with narrow ostia. Accurate and rapid diagnosis can have an impact on treatment, because true aneurysms are generally managed medically while false aneurysms require resection.

Cardiac tumors can also embolize to the brain. According to Dr. Reddy, about 98% of cardiac tumors are metastases from another source. Of primary cardiac tumors, myxomas, which are benign, are the most common and most likely to produce brain emboli. In fact, avoiding brain emboli is one of the major reasons for myxoma resection. Primary malignant tumors of the heart, such as angiosarcomas, also have the potential to embolize and cause stroke, as can secondary tumors such as lymphoma.

Cardiac imaging also can reveal the presence of patent foramen ovale or other septal defects in patients with strokes. These openings allow a clot or tumor to pass from the right side to the left side of the heart, and then enter the arterial circulation as a paradoxical embolism. Repair of even small defects may be recommended to avoid subsequent strokes, Dr. Reddy said.

Reconstructed coronal imaging shows a thrombus in the left atrial appendage.

The arrow shows a thrombus in a true aneurysm of the left ventricle.

A false aneurysm in the postero-inferior aspect of the LV is reconstructed on CT. Photos courtesy Dr. Gautham Reddy

CHICAGO — Up to 20% of strokes begin in the heart, so cardiac imaging should be part of the work-up of many stroke patients, Dr. Gautham Reddy said at the annual meeting of the American Society of Neuroradiology.

Electrocardiographically gated multidetector CT can assess the brain, cerebral vessels, and carotid arteries as well as the heart simultaneously and expedite diagnosis, he said.

At the University of California, San Francisco, where Dr. Reddy is chief of cardiac and pulmonary imaging, stroke patients are routinely scanned from the head down to the heart. Other modalities such as transthoracic or transesophageal echocardiography or MRI may be superior for evaluating cardiac masses, cardiomyopathy, or ischemic heart disease, but the ability to obtain a comprehensive evaluation from one sitting using CT can be advantageous for both the patient and physician—especially in the emergency setting.

The most common cardiac source of stroke is emboli, Dr. Reddy said. One such patient, diagnosed using multidetector CT, who had a history of atrial fibrillation and had been on anticoagulation, decided to stop taking his medication, then developed a stroke caused by a thrombus originating in the left atrium. Mitral stenosis is another common source of cardiac thrombus from the atrium.

Coagulation disorders and aneurysms may cause cardiac thrombi that originate in the ventricles. Left ventricular aneurysms may follow myocardial infarction and can be categorized as either true or false aneurysms.

True aneurysms characteristically have an anteroapical location with a wide ostium (greater than 50% of the aneurysm diameter). In contrast, false aneurysms are postdiaphragmatic with narrow ostia. Accurate and rapid diagnosis can have an impact on treatment, because true aneurysms are generally managed medically while false aneurysms require resection.

Cardiac tumors can also embolize to the brain. According to Dr. Reddy, about 98% of cardiac tumors are metastases from another source. Of primary cardiac tumors, myxomas, which are benign, are the most common and most likely to produce brain emboli. In fact, avoiding brain emboli is one of the major reasons for myxoma resection. Primary malignant tumors of the heart, such as angiosarcomas, also have the potential to embolize and cause stroke, as can secondary tumors such as lymphoma.

Cardiac imaging also can reveal the presence of patent foramen ovale or other septal defects in patients with strokes. These openings allow a clot or tumor to pass from the right side to the left side of the heart, and then enter the arterial circulation as a paradoxical embolism. Repair of even small defects may be recommended to avoid subsequent strokes, Dr. Reddy said.

Reconstructed coronal imaging shows a thrombus in the left atrial appendage.

The arrow shows a thrombus in a true aneurysm of the left ventricle.

A false aneurysm in the postero-inferior aspect of the LV is reconstructed on CT. Photos courtesy Dr. Gautham Reddy

WASHINGTON — Multidetector CT angiography appears to be very accurate in diagnosing coronary artery disease even in less-than-ideal patients, according to data presented at the annual meeting of the Society of Cardiovascular Computed Tomography.

While published studies have shown impressive diagnostic sensitivity and specificity for 64-slice CT in the assessment of coronary artery disease (CAD), patients with irregular heartbeats or allergies to β-blockers have tended to be excluded. In addition, patients with histories of coronary disease or those with high calcium scores sometimes were excluded.

“MDCT studies that have been published … have been highly selective of all the patients they have picked in order to determine the diagnostic accuracy of CT,” said Dr. Amgad N. Makaryus, a cardiologist at North Shore University Hospital in Manhasset, New York.

Dr. Makaryus and his colleagues evaluated the accuracy of 64-detector scanning compared with coronary angiography in a real-world population, at North Shore University Hospital, a large tertiary care center.

The facility is a referral center for hospitals on Long Island. Roughly 10,000 cardiac catheterizations are performed there yearly. In addition, 4,000–5,000 single-photon emission computed tomography myocardial perfusion studies are performed annually.

The study involved 1,818 consecutive patients who underwent coronary CT (64-detector). β-Blockers were used as much as possible.

Calcium channel blockers were used in patients who had contraindications to β-blockers.

The imaging protocol involved an 8- to 10-second breath hold with a 5- to 7-second image-acquisition time.

Overall, 17% of patients had a history of coronary disease; 10% had a history of atrial fibrillation or flutter. The mean heart rate during CT studies was roughly 58 beats per minute. The two most common indications were chest pain and abnormal stress test.

Specifically, the researchers assessed those patients who underwent invasive angiography based on their MDCT results. A total of 41 patients were referred for coronary angiography for 164 coronary arteries (410 coronary segments).

The mean patient age was 62 years (range 39–85 years) and the population was almost three-quarters male (73%). Stenosis of greater than 50% was considered significant.

On a per-vessel basis, the sensitivity of MDCT was 86% and specificity was 84%. The positive predictive value was 65% and the negative predictive value was 85%.

“Still we have this very high negative predictive value as has been seen in many of the prior studies,” commented Dr. Makaryus. On a per-segment basis, the sensitivity of MDCT was 77% and specificity was 93%.

The positive predictive value was 61% and the negative predictive value was 97%.

Calcium is a particular problem in CT angiography. Calcified plaques appear enlarged (or bloomed) because of partial-volume averaging effects and obscure the adjacent coronary lumen. This effect can lead to false-positive results because the degree of stenosis is overestimated.

The mean calcium score in this group was 789. “More of the patients that had higher calcium scores actually had a disagreement between their CTA result and the invasive coronary angiogram,” said Dr. Makaryus. In other words, “our false positives tended to be those patients who had higher calcium scores, and this neared statistical significance [P = .059].”

Irregular heart rate and motion artifacts also can be problematic in CT angiography, he said.

Dr. Makaryus, who disclosed that he had no significant conflicts of interest, was a postdoctoral clinical cardiovascular imaging fellow at New York-Presbyterian Hospital, New York, during 2006–2007.

WASHINGTON — Multidetector CT angiography appears to be very accurate in diagnosing coronary artery disease even in less-than-ideal patients, according to data presented at the annual meeting of the Society of Cardiovascular Computed Tomography.

While published studies have shown impressive diagnostic sensitivity and specificity for 64-slice CT in the assessment of coronary artery disease (CAD), patients with irregular heartbeats or allergies to β-blockers have tended to be excluded. In addition, patients with histories of coronary disease or those with high calcium scores sometimes were excluded.

“MDCT studies that have been published … have been highly selective of all the patients they have picked in order to determine the diagnostic accuracy of CT,” said Dr. Amgad N. Makaryus, a cardiologist at North Shore University Hospital in Manhasset, New York.

Dr. Makaryus and his colleagues evaluated the accuracy of 64-detector scanning compared with coronary angiography in a real-world population, at North Shore University Hospital, a large tertiary care center.

The facility is a referral center for hospitals on Long Island. Roughly 10,000 cardiac catheterizations are performed there yearly. In addition, 4,000–5,000 single-photon emission computed tomography myocardial perfusion studies are performed annually.

The study involved 1,818 consecutive patients who underwent coronary CT (64-detector). β-Blockers were used as much as possible.

Calcium channel blockers were used in patients who had contraindications to β-blockers.

The imaging protocol involved an 8- to 10-second breath hold with a 5- to 7-second image-acquisition time.

Overall, 17% of patients had a history of coronary disease; 10% had a history of atrial fibrillation or flutter. The mean heart rate during CT studies was roughly 58 beats per minute. The two most common indications were chest pain and abnormal stress test.

Specifically, the researchers assessed those patients who underwent invasive angiography based on their MDCT results. A total of 41 patients were referred for coronary angiography for 164 coronary arteries (410 coronary segments).

The mean patient age was 62 years (range 39–85 years) and the population was almost three-quarters male (73%). Stenosis of greater than 50% was considered significant.

On a per-vessel basis, the sensitivity of MDCT was 86% and specificity was 84%. The positive predictive value was 65% and the negative predictive value was 85%.

“Still we have this very high negative predictive value as has been seen in many of the prior studies,” commented Dr. Makaryus. On a per-segment basis, the sensitivity of MDCT was 77% and specificity was 93%.

The positive predictive value was 61% and the negative predictive value was 97%.

Calcium is a particular problem in CT angiography. Calcified plaques appear enlarged (or bloomed) because of partial-volume averaging effects and obscure the adjacent coronary lumen. This effect can lead to false-positive results because the degree of stenosis is overestimated.

The mean calcium score in this group was 789. “More of the patients that had higher calcium scores actually had a disagreement between their CTA result and the invasive coronary angiogram,” said Dr. Makaryus. In other words, “our false positives tended to be those patients who had higher calcium scores, and this neared statistical significance [P = .059].”

Irregular heart rate and motion artifacts also can be problematic in CT angiography, he said.

Dr. Makaryus, who disclosed that he had no significant conflicts of interest, was a postdoctoral clinical cardiovascular imaging fellow at New York-Presbyterian Hospital, New York, during 2006–2007.

WASHINGTON — Multidetector CT angiography appears to be very accurate in diagnosing coronary artery disease even in less-than-ideal patients, according to data presented at the annual meeting of the Society of Cardiovascular Computed Tomography.

While published studies have shown impressive diagnostic sensitivity and specificity for 64-slice CT in the assessment of coronary artery disease (CAD), patients with irregular heartbeats or allergies to β-blockers have tended to be excluded. In addition, patients with histories of coronary disease or those with high calcium scores sometimes were excluded.

“MDCT studies that have been published … have been highly selective of all the patients they have picked in order to determine the diagnostic accuracy of CT,” said Dr. Amgad N. Makaryus, a cardiologist at North Shore University Hospital in Manhasset, New York.

Dr. Makaryus and his colleagues evaluated the accuracy of 64-detector scanning compared with coronary angiography in a real-world population, at North Shore University Hospital, a large tertiary care center.

The facility is a referral center for hospitals on Long Island. Roughly 10,000 cardiac catheterizations are performed there yearly. In addition, 4,000–5,000 single-photon emission computed tomography myocardial perfusion studies are performed annually.

The study involved 1,818 consecutive patients who underwent coronary CT (64-detector). β-Blockers were used as much as possible.

Calcium channel blockers were used in patients who had contraindications to β-blockers.

The imaging protocol involved an 8- to 10-second breath hold with a 5- to 7-second image-acquisition time.

Overall, 17% of patients had a history of coronary disease; 10% had a history of atrial fibrillation or flutter. The mean heart rate during CT studies was roughly 58 beats per minute. The two most common indications were chest pain and abnormal stress test.

Specifically, the researchers assessed those patients who underwent invasive angiography based on their MDCT results. A total of 41 patients were referred for coronary angiography for 164 coronary arteries (410 coronary segments).

The mean patient age was 62 years (range 39–85 years) and the population was almost three-quarters male (73%). Stenosis of greater than 50% was considered significant.

On a per-vessel basis, the sensitivity of MDCT was 86% and specificity was 84%. The positive predictive value was 65% and the negative predictive value was 85%.

“Still we have this very high negative predictive value as has been seen in many of the prior studies,” commented Dr. Makaryus. On a per-segment basis, the sensitivity of MDCT was 77% and specificity was 93%.

The positive predictive value was 61% and the negative predictive value was 97%.

Calcium is a particular problem in CT angiography. Calcified plaques appear enlarged (or bloomed) because of partial-volume averaging effects and obscure the adjacent coronary lumen. This effect can lead to false-positive results because the degree of stenosis is overestimated.

The mean calcium score in this group was 789. “More of the patients that had higher calcium scores actually had a disagreement between their CTA result and the invasive coronary angiogram,” said Dr. Makaryus. In other words, “our false positives tended to be those patients who had higher calcium scores, and this neared statistical significance [P = .059].”

Irregular heart rate and motion artifacts also can be problematic in CT angiography, he said.

Dr. Makaryus, who disclosed that he had no significant conflicts of interest, was a postdoctoral clinical cardiovascular imaging fellow at New York-Presbyterian Hospital, New York, during 2006–2007.