Conference News Update—Radiological Society of North America 2015

DTI Reveals Changes in Brain Connections in Early Alzheimer’s Disease
Changes in brain connections visible on MRI could represent an imaging biomarker of Alzheimer’s disease, according to a study presented at the meeting.

As many as five million Americans have Alzheimer’s disease, and this number is expected to increase to 14 million by 2050, according to the Centers for Disease Control and Prevention. Preventive treatments may be most effective before Alzheimer’s disease is diagnosed, such as when a person is experiencing mild cognitive impairment.

Previous efforts at early detection have focused on beta amyloid. For the current study, researchers looked at the brain’s structural connectome, a map of white matter tracts that carry signals between various areas of the brain.

“The structural connectome provides us with a way to characterize and measure these connections and how they change through disease or age,” said Jeffrey W. Prescott, MD, PhD, a radiology resident at Duke University Medical Center in Durham, North Carolina, and a coauthor of the study.

Dr. Prescott and colleagues analyzed data for 102 patients enrolled in a national study called the Alzheimer’s Disease Neuroimaging Initiative 2. The patients had undergone diffusion tensor imaging (DTI), which assesses the integrity of white matter tracts in the brain by measuring how easy it is for water to move along them. “Water prefers moving along the defined physical connections between regions in the brain, which makes DTI a great tool for evaluating the structural connectome,” said Dr. Prescott.

The researchers compared changes in the structural connectome with results from florbetapir PET imaging, a technique that measures the amount of beta amyloid plaque in the brain. The results showed a strong association between florbetapir uptake and decreases in the strength of the structural connectome in each of the five areas of the brain studied.

“This study ties together two of the major changes in the Alzheimer’s brain—structural tissue changes and pathologic amyloid plaque deposition—and suggests a promising role for DTI as a possible diagnostic adjunct,” said Dr. Prescott.

Based on these findings, DTI may have a role in assessing brain damage in early Alzheimer’s disease and in monitoring the effect of new therapies.

“Traditionally, Alzheimer’s disease is believed to exert its effects on thinking via damage to the brain’s gray matter, where most of the nerve cells are concentrated,” said Jeffrey R. Petrella, MD, Professor of Radiology at Duke University and senior author of the research. “This study suggests that amyloid deposition in the gray matter affects the associated white matter connections, which are essential for conducting messages across the billions of nerve cells in the brain, allowing for all aspects of mental function.”

“We suspect that as amyloid plaque load in the gray matter increases, the brain’s white matter starts to break down or malfunction and lose its ability to move water and neurochemicals efficiently,” added Dr. Prescott.

The researchers plan to continue studying this cohort of patients over time to gain a better understanding of how the disease evolves in individual patients. They also intend to incorporate functional imaging into their research to learn about how the relationship between function and structure changes with increasing amyloid burden.

Asymptomatic Atherosclerosis May Be Associated With Cognitive Impairment
A buildup of plaque in the body’s major arteries is associated with mild cognitive impairment, according to a study of approximately 2,000 adults conducted at the University of Texas (UT) Southwestern Medical Center.

“It is well established that plaque buildup in the arteries is a predictor of heart disease, but the relationship between atherosclerosis and brain health is less clear,” said Christopher D. Maroules, MD, a radiology resident at UT Southwestern Medical Center in Dallas. “Our findings suggest that atherosclerosis not only affects the heart, but also brain health.”

Researchers analyzed the test results of 1,903 participants (mean age, 44) in the Dallas Heart Study, a multiethnic population-based study of adults from Dallas County, Texas. The participants included men and women who had no symptoms of cardiovascular disease.

Study participants completed the Montreal Cognitive Assessment (MoCA), a 30-point standardized test for detecting mild cognitive impairment, and underwent MRI of the brain to measure white matter hyperintensity volume. Bright white spots known as high signal intensity areas on a brain MRI indicate abnormal changes within the white matter.

“Increased white matter hyperintensity volume is part of the normal aging process,” explained Dr. Maroules. “But excessive white matter hyperintensity volume is a marker for cognitive impairment.”

Study participants also underwent imaging exams to measure the buildup of plaque in the arteries in three distinct vascular areas of the body. They underwent MRI to measure wall thickness in the carotid arteries and in the abdominal aorta, and received CT to measure coronary artery calcium.

Using the results, researchers performed a statistical regression to understand the relationship between the incidence of atherosclerosis and mild cognitive impairment. After adjusting for traditional risk factors for atherosclerosis, including age, ethnicity, male sex, diabetes, hypertension, smoking, and BMI, the investigators found independent relationships between atherosclerosis in all three vascular areas of the body and cognitive health, as measured by MoCA scores, and white matter hyperintensity volume on MRI.

Individuals in the highest quartile of internal carotid wall thickness were 21% more likely to have cognitive impairment, as indicated by a low MoCA score. An increasing coronary artery calcium score was predictive of large white matter intensity volume on MRI.

“These results underscore the importance of identifying atherosclerosis in its early stages, not just to help preserve heart function, but also to preserve cognition and brain health,” said Dr. Maroules. The MRI and CT imaging techniques provide valuable prognostic information about an individual’s downstream health risks, he added.

“Plaque buildup in blood vessels throughout the body offers us a window into brain health. Imaging with CT and MRI has an important role in identifying patients who are at a higher risk for cognitive impairment.”

A Season of High School Football Without Concussion May Cause Brain Changes
Some high school football players exhibit measurable brain changes after a single season of play, even in the absence of concussion, according to a study presented at the meeting.

“This study adds to the growing body of evidence that a season of play in a contact sport can affect the brain in the absence of clinical findings,” said Christopher T. Whitlow, MD, PhD, MHA, Associate Professor of Radiology at Wake Forest School of Medicine and radiologist at Wake Forest Baptist Medical Center in Winston-Salem, North Carolina.

In recent years, various reports have suggested the potential effects that participation in youth sports may have on the developing brain. Most of these studies have looked at brain changes as a result of concussion, however. Dr. Whitlow and colleagues set out to determine whether head impacts withstood in the course of a season of high school football produce white matter changes in the brain in the absence of clinically diagnosed concussion.

The researchers studied 24 high school football players between the ages of 16 and 18. For all games and practices, players were monitored with Head Impact Telemetry System (HITs) helmet-mounted accelerometers, which are used in youth and collegiate football to assess the frequency and severity of helmet impacts.

Risk-weighted cumulative exposure was computed from the HITs data and represented the risk of concussion over the course of the season. These data, along with the total number of impacts, were used to categorize the players as heavy hitters or light hitters. The researchers identified nine of the 24 participants as heavy hitters and 15 as light hitters. None of the players had concussion during the season.

All players underwent pre- and post-season evaluation with diffusion tensor imaging (DTI) of the brain. Diffusion tensor imaging measures fractional anisotropy, which indicates the movement of water molecules along axons. In healthy white matter, the direction of water movement is fairly uniform, and fractional anisotropy is high. When water movement is more random, fractional anisotropy values decrease, thus suggesting microstructural abnormalities.

The results showed that both groups demonstrated global increases of fractional anisotropy over time, likely reflecting the effects of brain development. However, the heavy-hitter group showed statistically significant areas of decreased fractional anisotropy post-season in specific areas of the brain, including the splenium of the corpus callosum and deep white matter tracts.

“Our study found that players experiencing greater levels of head impacts have more fractional anisotropy loss, compared with players with lower impact exposure,” said Dr. Whitlow. “Similar brain MRI changes have been previously associated with mild traumatic brain injury. However, it is unclear whether or not these effects will be associated with any negative long-term consequences.” These findings are preliminary, and more study needs to be performed, concluded Dr. Whitlow.

Mild Coronary Artery Disease Increases Risk of Cardiovascular Events
Patients with diabetes and mild coronary artery disease have the same relative risk for a heart attack or other major adverse heart event as patients with diabetes and serious single-vessel obstructive disease, according to a long-term study.

Researchers at the University of British Columbia and St. Paul’s Hospital in Vancouver analyzed data from the Coronary CT Angiography Evaluation For Clinical Outcomes: An International Multicenter (CONFIRM) Registry, which was developed to examine the prognostic value of cardiac computed tomography angiography (CCTA) for predicting adverse cardiac events related to coronary artery disease. The registry, which has CCTA data for 40,000 patients from 17 centers around the world, now has five-year follow-up data for 14,000 patients.

“The CONFIRM Registry is the largest long-term data set available and allowed us to evaluate the long-term prognostic value of CCTA in diabetic patients,” said Jonathan Leipsic, MD, vice chairman of the Department of Radiology at the University of British Columbia and study coauthor.

The researchers analyzed data for 1,823 patients with diabetes who underwent CCTA to detect and determine the extent of coronary artery disease. Men and women (median age, 61.7) in the study were categorized as having no coronary artery disease, mild disease (ie, coronary artery narrowed by less than 50%), or obstructive disease (ie, obstruction of more than 50% of the artery). Over a 5.2-year follow-up period, 246 deaths occurred, representing 13.5% of the total study group.

Major adverse cardiovascular event (MACE) data were available for 973 patients. During the follow-up period, 295 (30.3%) of the patients had a MACE, such as heart attack or a coronary revascularization.

The researchers found that both obstructive and mild, or nonobstructive, coronary artery disease, as determined by CCTA, were associated with patient deaths and MACE. Most importantly, the researchers found that the relative risk for death or MACE for a patient with mild coronary artery disease was comparable to that of patients with single vessel obstructive disease.

“Until now, two-year follow-up studies suggested that a diabetic patient with mild or nonobstructive coronary artery disease had a lower risk of major adverse cardiovascular events and death than patients with obstructive disease,” said Philipp Blanke, MD, a radiologist at the University of British Columbia and St. Paul’s Hospital and a coauthor of the study. “Our five-year follow-up data suggest that nonobstructive and obstructive coronary artery disease, as detected by cardiac CTA in diabetic patients, are both associated with higher rates of mortality.”

Researchers need a better understanding of the evolution of plaque in the arteries and of patient response to therapies, said Dr. Leipsic. “Cardiac CT angiography is helpful for identifying diabetic patients who are at higher risk for heart events and who may benefit from more aggressive therapy to help modify that risk,” he added.

Patients Prefer Direct Access to Imaging Records
Patients value direct, independent access to their medical exams, researchers reported.

Giampaolo Greco, PhD, MPH, Assistant Professor in the Department of Population Health Science and Policy at the Mount Sinai School of Medicine in New York City, and colleagues set out to evaluate patient and provider satisfaction with RSNA Image Share, an Internet-based interoperable image exchange system that gives patients ownership of their imaging exams and control over access to their imaging records. The network enables radiology sites to make results of imaging exams available for patients to incorporate in personal health record (PHR) accounts they can use to securely store, manage, and share their imaging records. Sites also can use the network to send patient imaging records to other participating sites to support better informed care.

For the study, patients undergoing radiologic exams at four academic centers were eligible to establish online PHR accounts using the RSNA Image Share network. Patients could then use their PHR accounts to maintain and share their images with selected providers, creating a detailed medical history accessible through any secure Internet connection.

Between July 2012 and August 2013, the study enrolled 2,562 patients, mean age 50.4, including a significant representation of older individuals. Older individuals have the highest healthcare utilization and often experience or perceive a significant barrier in using information technology.

The median number of exams uploaded per patient was six. Study participants were provided a brief survey to assess patient and physician experience with the exchange of images, and 502 patients completed and returned their surveys. Of these respondents, 448 patients identified the method used at the visit to share images: Internet, CDs, both Internet and CDs, or other, and 165 included a section completed by their physician.

Nearly all (96%) of the patients responded positively to having direct access to their medical images, and 78% viewed their images independently. There was no difference between Internet and CD users in satisfaction with privacy and security and timeliness of access to medical images. A greater percentage of Internet users reported being able to access their images without difficulty, compared with CD users (88.3% vs 77.5%).

DTI Reveals Changes in Brain Connections in Early Alzheimer’s Disease
Changes in brain connections visible on MRI could represent an imaging biomarker of Alzheimer’s disease, according to a study presented at the meeting.

As many as five million Americans have Alzheimer’s disease, and this number is expected to increase to 14 million by 2050, according to the Centers for Disease Control and Prevention. Preventive treatments may be most effective before Alzheimer’s disease is diagnosed, such as when a person is experiencing mild cognitive impairment.

Previous efforts at early detection have focused on beta amyloid. For the current study, researchers looked at the brain’s structural connectome, a map of white matter tracts that carry signals between various areas of the brain.

“The structural connectome provides us with a way to characterize and measure these connections and how they change through disease or age,” said Jeffrey W. Prescott, MD, PhD, a radiology resident at Duke University Medical Center in Durham, North Carolina, and a coauthor of the study.

Dr. Prescott and colleagues analyzed data for 102 patients enrolled in a national study called the Alzheimer’s Disease Neuroimaging Initiative 2. The patients had undergone diffusion tensor imaging (DTI), which assesses the integrity of white matter tracts in the brain by measuring how easy it is for water to move along them. “Water prefers moving along the defined physical connections between regions in the brain, which makes DTI a great tool for evaluating the structural connectome,” said Dr. Prescott.

The researchers compared changes in the structural connectome with results from florbetapir PET imaging, a technique that measures the amount of beta amyloid plaque in the brain. The results showed a strong association between florbetapir uptake and decreases in the strength of the structural connectome in each of the five areas of the brain studied.

“This study ties together two of the major changes in the Alzheimer’s brain—structural tissue changes and pathologic amyloid plaque deposition—and suggests a promising role for DTI as a possible diagnostic adjunct,” said Dr. Prescott.

Based on these findings, DTI may have a role in assessing brain damage in early Alzheimer’s disease and in monitoring the effect of new therapies.

“Traditionally, Alzheimer’s disease is believed to exert its effects on thinking via damage to the brain’s gray matter, where most of the nerve cells are concentrated,” said Jeffrey R. Petrella, MD, Professor of Radiology at Duke University and senior author of the research. “This study suggests that amyloid deposition in the gray matter affects the associated white matter connections, which are essential for conducting messages across the billions of nerve cells in the brain, allowing for all aspects of mental function.”

“We suspect that as amyloid plaque load in the gray matter increases, the brain’s white matter starts to break down or malfunction and lose its ability to move water and neurochemicals efficiently,” added Dr. Prescott.

The researchers plan to continue studying this cohort of patients over time to gain a better understanding of how the disease evolves in individual patients. They also intend to incorporate functional imaging into their research to learn about how the relationship between function and structure changes with increasing amyloid burden.

Asymptomatic Atherosclerosis May Be Associated With Cognitive Impairment
A buildup of plaque in the body’s major arteries is associated with mild cognitive impairment, according to a study of approximately 2,000 adults conducted at the University of Texas (UT) Southwestern Medical Center.

“It is well established that plaque buildup in the arteries is a predictor of heart disease, but the relationship between atherosclerosis and brain health is less clear,” said Christopher D. Maroules, MD, a radiology resident at UT Southwestern Medical Center in Dallas. “Our findings suggest that atherosclerosis not only affects the heart, but also brain health.”

Researchers analyzed the test results of 1,903 participants (mean age, 44) in the Dallas Heart Study, a multiethnic population-based study of adults from Dallas County, Texas. The participants included men and women who had no symptoms of cardiovascular disease.

Study participants completed the Montreal Cognitive Assessment (MoCA), a 30-point standardized test for detecting mild cognitive impairment, and underwent MRI of the brain to measure white matter hyperintensity volume. Bright white spots known as high signal intensity areas on a brain MRI indicate abnormal changes within the white matter.

“Increased white matter hyperintensity volume is part of the normal aging process,” explained Dr. Maroules. “But excessive white matter hyperintensity volume is a marker for cognitive impairment.”

Study participants also underwent imaging exams to measure the buildup of plaque in the arteries in three distinct vascular areas of the body. They underwent MRI to measure wall thickness in the carotid arteries and in the abdominal aorta, and received CT to measure coronary artery calcium.

Using the results, researchers performed a statistical regression to understand the relationship between the incidence of atherosclerosis and mild cognitive impairment. After adjusting for traditional risk factors for atherosclerosis, including age, ethnicity, male sex, diabetes, hypertension, smoking, and BMI, the investigators found independent relationships between atherosclerosis in all three vascular areas of the body and cognitive health, as measured by MoCA scores, and white matter hyperintensity volume on MRI.

Individuals in the highest quartile of internal carotid wall thickness were 21% more likely to have cognitive impairment, as indicated by a low MoCA score. An increasing coronary artery calcium score was predictive of large white matter intensity volume on MRI.

“These results underscore the importance of identifying atherosclerosis in its early stages, not just to help preserve heart function, but also to preserve cognition and brain health,” said Dr. Maroules. The MRI and CT imaging techniques provide valuable prognostic information about an individual’s downstream health risks, he added.

“Plaque buildup in blood vessels throughout the body offers us a window into brain health. Imaging with CT and MRI has an important role in identifying patients who are at a higher risk for cognitive impairment.”

A Season of High School Football Without Concussion May Cause Brain Changes
Some high school football players exhibit measurable brain changes after a single season of play, even in the absence of concussion, according to a study presented at the meeting.

“This study adds to the growing body of evidence that a season of play in a contact sport can affect the brain in the absence of clinical findings,” said Christopher T. Whitlow, MD, PhD, MHA, Associate Professor of Radiology at Wake Forest School of Medicine and radiologist at Wake Forest Baptist Medical Center in Winston-Salem, North Carolina.

In recent years, various reports have suggested the potential effects that participation in youth sports may have on the developing brain. Most of these studies have looked at brain changes as a result of concussion, however. Dr. Whitlow and colleagues set out to determine whether head impacts withstood in the course of a season of high school football produce white matter changes in the brain in the absence of clinically diagnosed concussion.

The researchers studied 24 high school football players between the ages of 16 and 18. For all games and practices, players were monitored with Head Impact Telemetry System (HITs) helmet-mounted accelerometers, which are used in youth and collegiate football to assess the frequency and severity of helmet impacts.

Risk-weighted cumulative exposure was computed from the HITs data and represented the risk of concussion over the course of the season. These data, along with the total number of impacts, were used to categorize the players as heavy hitters or light hitters. The researchers identified nine of the 24 participants as heavy hitters and 15 as light hitters. None of the players had concussion during the season.

All players underwent pre- and post-season evaluation with diffusion tensor imaging (DTI) of the brain. Diffusion tensor imaging measures fractional anisotropy, which indicates the movement of water molecules along axons. In healthy white matter, the direction of water movement is fairly uniform, and fractional anisotropy is high. When water movement is more random, fractional anisotropy values decrease, thus suggesting microstructural abnormalities.

The results showed that both groups demonstrated global increases of fractional anisotropy over time, likely reflecting the effects of brain development. However, the heavy-hitter group showed statistically significant areas of decreased fractional anisotropy post-season in specific areas of the brain, including the splenium of the corpus callosum and deep white matter tracts.

“Our study found that players experiencing greater levels of head impacts have more fractional anisotropy loss, compared with players with lower impact exposure,” said Dr. Whitlow. “Similar brain MRI changes have been previously associated with mild traumatic brain injury. However, it is unclear whether or not these effects will be associated with any negative long-term consequences.” These findings are preliminary, and more study needs to be performed, concluded Dr. Whitlow.

Mild Coronary Artery Disease Increases Risk of Cardiovascular Events
Patients with diabetes and mild coronary artery disease have the same relative risk for a heart attack or other major adverse heart event as patients with diabetes and serious single-vessel obstructive disease, according to a long-term study.

Researchers at the University of British Columbia and St. Paul’s Hospital in Vancouver analyzed data from the Coronary CT Angiography Evaluation For Clinical Outcomes: An International Multicenter (CONFIRM) Registry, which was developed to examine the prognostic value of cardiac computed tomography angiography (CCTA) for predicting adverse cardiac events related to coronary artery disease. The registry, which has CCTA data for 40,000 patients from 17 centers around the world, now has five-year follow-up data for 14,000 patients.

“The CONFIRM Registry is the largest long-term data set available and allowed us to evaluate the long-term prognostic value of CCTA in diabetic patients,” said Jonathan Leipsic, MD, vice chairman of the Department of Radiology at the University of British Columbia and study coauthor.

The researchers analyzed data for 1,823 patients with diabetes who underwent CCTA to detect and determine the extent of coronary artery disease. Men and women (median age, 61.7) in the study were categorized as having no coronary artery disease, mild disease (ie, coronary artery narrowed by less than 50%), or obstructive disease (ie, obstruction of more than 50% of the artery). Over a 5.2-year follow-up period, 246 deaths occurred, representing 13.5% of the total study group.

Major adverse cardiovascular event (MACE) data were available for 973 patients. During the follow-up period, 295 (30.3%) of the patients had a MACE, such as heart attack or a coronary revascularization.

The researchers found that both obstructive and mild, or nonobstructive, coronary artery disease, as determined by CCTA, were associated with patient deaths and MACE. Most importantly, the researchers found that the relative risk for death or MACE for a patient with mild coronary artery disease was comparable to that of patients with single vessel obstructive disease.

“Until now, two-year follow-up studies suggested that a diabetic patient with mild or nonobstructive coronary artery disease had a lower risk of major adverse cardiovascular events and death than patients with obstructive disease,” said Philipp Blanke, MD, a radiologist at the University of British Columbia and St. Paul’s Hospital and a coauthor of the study. “Our five-year follow-up data suggest that nonobstructive and obstructive coronary artery disease, as detected by cardiac CTA in diabetic patients, are both associated with higher rates of mortality.”

Researchers need a better understanding of the evolution of plaque in the arteries and of patient response to therapies, said Dr. Leipsic. “Cardiac CT angiography is helpful for identifying diabetic patients who are at higher risk for heart events and who may benefit from more aggressive therapy to help modify that risk,” he added.

Patients Prefer Direct Access to Imaging Records
Patients value direct, independent access to their medical exams, researchers reported.

Giampaolo Greco, PhD, MPH, Assistant Professor in the Department of Population Health Science and Policy at the Mount Sinai School of Medicine in New York City, and colleagues set out to evaluate patient and provider satisfaction with RSNA Image Share, an Internet-based interoperable image exchange system that gives patients ownership of their imaging exams and control over access to their imaging records. The network enables radiology sites to make results of imaging exams available for patients to incorporate in personal health record (PHR) accounts they can use to securely store, manage, and share their imaging records. Sites also can use the network to send patient imaging records to other participating sites to support better informed care.

For the study, patients undergoing radiologic exams at four academic centers were eligible to establish online PHR accounts using the RSNA Image Share network. Patients could then use their PHR accounts to maintain and share their images with selected providers, creating a detailed medical history accessible through any secure Internet connection.

Between July 2012 and August 2013, the study enrolled 2,562 patients, mean age 50.4, including a significant representation of older individuals. Older individuals have the highest healthcare utilization and often experience or perceive a significant barrier in using information technology.

The median number of exams uploaded per patient was six. Study participants were provided a brief survey to assess patient and physician experience with the exchange of images, and 502 patients completed and returned their surveys. Of these respondents, 448 patients identified the method used at the visit to share images: Internet, CDs, both Internet and CDs, or other, and 165 included a section completed by their physician.

Nearly all (96%) of the patients responded positively to having direct access to their medical images, and 78% viewed their images independently. There was no difference between Internet and CD users in satisfaction with privacy and security and timeliness of access to medical images. A greater percentage of Internet users reported being able to access their images without difficulty, compared with CD users (88.3% vs 77.5%).

DTI Reveals Changes in Brain Connections in Early Alzheimer’s Disease
Changes in brain connections visible on MRI could represent an imaging biomarker of Alzheimer’s disease, according to a study presented at the meeting.

As many as five million Americans have Alzheimer’s disease, and this number is expected to increase to 14 million by 2050, according to the Centers for Disease Control and Prevention. Preventive treatments may be most effective before Alzheimer’s disease is diagnosed, such as when a person is experiencing mild cognitive impairment.

Previous efforts at early detection have focused on beta amyloid. For the current study, researchers looked at the brain’s structural connectome, a map of white matter tracts that carry signals between various areas of the brain.

“The structural connectome provides us with a way to characterize and measure these connections and how they change through disease or age,” said Jeffrey W. Prescott, MD, PhD, a radiology resident at Duke University Medical Center in Durham, North Carolina, and a coauthor of the study.

Dr. Prescott and colleagues analyzed data for 102 patients enrolled in a national study called the Alzheimer’s Disease Neuroimaging Initiative 2. The patients had undergone diffusion tensor imaging (DTI), which assesses the integrity of white matter tracts in the brain by measuring how easy it is for water to move along them. “Water prefers moving along the defined physical connections between regions in the brain, which makes DTI a great tool for evaluating the structural connectome,” said Dr. Prescott.

The researchers compared changes in the structural connectome with results from florbetapir PET imaging, a technique that measures the amount of beta amyloid plaque in the brain. The results showed a strong association between florbetapir uptake and decreases in the strength of the structural connectome in each of the five areas of the brain studied.

“This study ties together two of the major changes in the Alzheimer’s brain—structural tissue changes and pathologic amyloid plaque deposition—and suggests a promising role for DTI as a possible diagnostic adjunct,” said Dr. Prescott.

Based on these findings, DTI may have a role in assessing brain damage in early Alzheimer’s disease and in monitoring the effect of new therapies.

“Traditionally, Alzheimer’s disease is believed to exert its effects on thinking via damage to the brain’s gray matter, where most of the nerve cells are concentrated,” said Jeffrey R. Petrella, MD, Professor of Radiology at Duke University and senior author of the research. “This study suggests that amyloid deposition in the gray matter affects the associated white matter connections, which are essential for conducting messages across the billions of nerve cells in the brain, allowing for all aspects of mental function.”

“We suspect that as amyloid plaque load in the gray matter increases, the brain’s white matter starts to break down or malfunction and lose its ability to move water and neurochemicals efficiently,” added Dr. Prescott.

The researchers plan to continue studying this cohort of patients over time to gain a better understanding of how the disease evolves in individual patients. They also intend to incorporate functional imaging into their research to learn about how the relationship between function and structure changes with increasing amyloid burden.

Asymptomatic Atherosclerosis May Be Associated With Cognitive Impairment
A buildup of plaque in the body’s major arteries is associated with mild cognitive impairment, according to a study of approximately 2,000 adults conducted at the University of Texas (UT) Southwestern Medical Center.

“It is well established that plaque buildup in the arteries is a predictor of heart disease, but the relationship between atherosclerosis and brain health is less clear,” said Christopher D. Maroules, MD, a radiology resident at UT Southwestern Medical Center in Dallas. “Our findings suggest that atherosclerosis not only affects the heart, but also brain health.”

Researchers analyzed the test results of 1,903 participants (mean age, 44) in the Dallas Heart Study, a multiethnic population-based study of adults from Dallas County, Texas. The participants included men and women who had no symptoms of cardiovascular disease.

Study participants completed the Montreal Cognitive Assessment (MoCA), a 30-point standardized test for detecting mild cognitive impairment, and underwent MRI of the brain to measure white matter hyperintensity volume. Bright white spots known as high signal intensity areas on a brain MRI indicate abnormal changes within the white matter.

“Increased white matter hyperintensity volume is part of the normal aging process,” explained Dr. Maroules. “But excessive white matter hyperintensity volume is a marker for cognitive impairment.”

Study participants also underwent imaging exams to measure the buildup of plaque in the arteries in three distinct vascular areas of the body. They underwent MRI to measure wall thickness in the carotid arteries and in the abdominal aorta, and received CT to measure coronary artery calcium.

Using the results, researchers performed a statistical regression to understand the relationship between the incidence of atherosclerosis and mild cognitive impairment. After adjusting for traditional risk factors for atherosclerosis, including age, ethnicity, male sex, diabetes, hypertension, smoking, and BMI, the investigators found independent relationships between atherosclerosis in all three vascular areas of the body and cognitive health, as measured by MoCA scores, and white matter hyperintensity volume on MRI.

Individuals in the highest quartile of internal carotid wall thickness were 21% more likely to have cognitive impairment, as indicated by a low MoCA score. An increasing coronary artery calcium score was predictive of large white matter intensity volume on MRI.

“These results underscore the importance of identifying atherosclerosis in its early stages, not just to help preserve heart function, but also to preserve cognition and brain health,” said Dr. Maroules. The MRI and CT imaging techniques provide valuable prognostic information about an individual’s downstream health risks, he added.

“Plaque buildup in blood vessels throughout the body offers us a window into brain health. Imaging with CT and MRI has an important role in identifying patients who are at a higher risk for cognitive impairment.”

A Season of High School Football Without Concussion May Cause Brain Changes
Some high school football players exhibit measurable brain changes after a single season of play, even in the absence of concussion, according to a study presented at the meeting.

“This study adds to the growing body of evidence that a season of play in a contact sport can affect the brain in the absence of clinical findings,” said Christopher T. Whitlow, MD, PhD, MHA, Associate Professor of Radiology at Wake Forest School of Medicine and radiologist at Wake Forest Baptist Medical Center in Winston-Salem, North Carolina.

In recent years, various reports have suggested the potential effects that participation in youth sports may have on the developing brain. Most of these studies have looked at brain changes as a result of concussion, however. Dr. Whitlow and colleagues set out to determine whether head impacts withstood in the course of a season of high school football produce white matter changes in the brain in the absence of clinically diagnosed concussion.

The researchers studied 24 high school football players between the ages of 16 and 18. For all games and practices, players were monitored with Head Impact Telemetry System (HITs) helmet-mounted accelerometers, which are used in youth and collegiate football to assess the frequency and severity of helmet impacts.

Risk-weighted cumulative exposure was computed from the HITs data and represented the risk of concussion over the course of the season. These data, along with the total number of impacts, were used to categorize the players as heavy hitters or light hitters. The researchers identified nine of the 24 participants as heavy hitters and 15 as light hitters. None of the players had concussion during the season.

All players underwent pre- and post-season evaluation with diffusion tensor imaging (DTI) of the brain. Diffusion tensor imaging measures fractional anisotropy, which indicates the movement of water molecules along axons. In healthy white matter, the direction of water movement is fairly uniform, and fractional anisotropy is high. When water movement is more random, fractional anisotropy values decrease, thus suggesting microstructural abnormalities.

The results showed that both groups demonstrated global increases of fractional anisotropy over time, likely reflecting the effects of brain development. However, the heavy-hitter group showed statistically significant areas of decreased fractional anisotropy post-season in specific areas of the brain, including the splenium of the corpus callosum and deep white matter tracts.

“Our study found that players experiencing greater levels of head impacts have more fractional anisotropy loss, compared with players with lower impact exposure,” said Dr. Whitlow. “Similar brain MRI changes have been previously associated with mild traumatic brain injury. However, it is unclear whether or not these effects will be associated with any negative long-term consequences.” These findings are preliminary, and more study needs to be performed, concluded Dr. Whitlow.

Mild Coronary Artery Disease Increases Risk of Cardiovascular Events
Patients with diabetes and mild coronary artery disease have the same relative risk for a heart attack or other major adverse heart event as patients with diabetes and serious single-vessel obstructive disease, according to a long-term study.

Researchers at the University of British Columbia and St. Paul’s Hospital in Vancouver analyzed data from the Coronary CT Angiography Evaluation For Clinical Outcomes: An International Multicenter (CONFIRM) Registry, which was developed to examine the prognostic value of cardiac computed tomography angiography (CCTA) for predicting adverse cardiac events related to coronary artery disease. The registry, which has CCTA data for 40,000 patients from 17 centers around the world, now has five-year follow-up data for 14,000 patients.

“The CONFIRM Registry is the largest long-term data set available and allowed us to evaluate the long-term prognostic value of CCTA in diabetic patients,” said Jonathan Leipsic, MD, vice chairman of the Department of Radiology at the University of British Columbia and study coauthor.

The researchers analyzed data for 1,823 patients with diabetes who underwent CCTA to detect and determine the extent of coronary artery disease. Men and women (median age, 61.7) in the study were categorized as having no coronary artery disease, mild disease (ie, coronary artery narrowed by less than 50%), or obstructive disease (ie, obstruction of more than 50% of the artery). Over a 5.2-year follow-up period, 246 deaths occurred, representing 13.5% of the total study group.

Major adverse cardiovascular event (MACE) data were available for 973 patients. During the follow-up period, 295 (30.3%) of the patients had a MACE, such as heart attack or a coronary revascularization.

The researchers found that both obstructive and mild, or nonobstructive, coronary artery disease, as determined by CCTA, were associated with patient deaths and MACE. Most importantly, the researchers found that the relative risk for death or MACE for a patient with mild coronary artery disease was comparable to that of patients with single vessel obstructive disease.

“Until now, two-year follow-up studies suggested that a diabetic patient with mild or nonobstructive coronary artery disease had a lower risk of major adverse cardiovascular events and death than patients with obstructive disease,” said Philipp Blanke, MD, a radiologist at the University of British Columbia and St. Paul’s Hospital and a coauthor of the study. “Our five-year follow-up data suggest that nonobstructive and obstructive coronary artery disease, as detected by cardiac CTA in diabetic patients, are both associated with higher rates of mortality.”

Researchers need a better understanding of the evolution of plaque in the arteries and of patient response to therapies, said Dr. Leipsic. “Cardiac CT angiography is helpful for identifying diabetic patients who are at higher risk for heart events and who may benefit from more aggressive therapy to help modify that risk,” he added.

Patients Prefer Direct Access to Imaging Records
Patients value direct, independent access to their medical exams, researchers reported.

Giampaolo Greco, PhD, MPH, Assistant Professor in the Department of Population Health Science and Policy at the Mount Sinai School of Medicine in New York City, and colleagues set out to evaluate patient and provider satisfaction with RSNA Image Share, an Internet-based interoperable image exchange system that gives patients ownership of their imaging exams and control over access to their imaging records. The network enables radiology sites to make results of imaging exams available for patients to incorporate in personal health record (PHR) accounts they can use to securely store, manage, and share their imaging records. Sites also can use the network to send patient imaging records to other participating sites to support better informed care.

For the study, patients undergoing radiologic exams at four academic centers were eligible to establish online PHR accounts using the RSNA Image Share network. Patients could then use their PHR accounts to maintain and share their images with selected providers, creating a detailed medical history accessible through any secure Internet connection.

Between July 2012 and August 2013, the study enrolled 2,562 patients, mean age 50.4, including a significant representation of older individuals. Older individuals have the highest healthcare utilization and often experience or perceive a significant barrier in using information technology.

The median number of exams uploaded per patient was six. Study participants were provided a brief survey to assess patient and physician experience with the exchange of images, and 502 patients completed and returned their surveys. Of these respondents, 448 patients identified the method used at the visit to share images: Internet, CDs, both Internet and CDs, or other, and 165 included a section completed by their physician.

Nearly all (96%) of the patients responded positively to having direct access to their medical images, and 78% viewed their images independently. There was no difference between Internet and CD users in satisfaction with privacy and security and timeliness of access to medical images. A greater percentage of Internet users reported being able to access their images without difficulty, compared with CD users (88.3% vs 77.5%).