Imaging

Erosive progression is arrested in rheumatoid arthritis patients who are treated with adalimumab and methotrexate combination therapy, judging from results of a novel longitudinal study comparing MRI, ultrasonography, CT, and radiography.

However, only MRI was sensitive enough to document repair of individual erosions. Both MRI and ultrasound could detect changes in bone edema, which "was predictive of subsequent erosive progression on CT, both at the individual bone/joint level and also for MRI bone edema at the patient level," reported lead author Dr. Uffe Møller Døhn of the department of rheumatology at the University of Copenhagen in the February 2011 edition of the Annals of the Rheumatic Diseases. "These data emphasize the predictive value of modern imaging, and especially highlight the importance of MRI bone edema for predicting erosive progression."

The findings also offer a different way of thinking about RA’s pathology. In an accompanying editorial, Dr. Fiona McQueen and Dr. Esperanza Naredo said that the study’s findings add to existing evidence suggesting that osteitis is more strongly predictive of bone erosion than is synovitis, which supports "the notion that there is a more direct connection between bone inflammation and bone damage than between synovial inflammation and bone damage" (Ann. Rheum. Dis. 2011;70:241-4). They described synovitis and osteitis as "cousins with a common ancestor, the process that ultimately drives both remaining obscure but possibly sited in the bone marrow."

Dr. Døhn and his associates used MRI, ultrasound, standard radiography, and high-resolution CT images of the wrist and metacarpophalangeal joints 2-5 to study response to adalimumab/methotrexate therapy in 52 RA patients naive to biological agents. All images were obtained before the first dose of adalimumab injection and were repeated after 6 and 12 months of treatment (Ann. Rheum. Dis. 2011;70:252-8).

The median age of patients was 61 years, and 67% were women. From baseline, the researchers did not observe any statistically significant changes in overall bone destruction or repair at 6 or 12 months, but differences were seen when researchers used the smallest-detectable-change cutoff. For example, after 6 and 12 months, the scores of MRI synovitis, grey-scale synovitis, and power Doppler ultrasonography decreased. So did scores as assessed by DAS28 (disease activity score in 28 joints), a health assessment questionnaire, and tender and swollen joint counts.

Study participants with disease progression on CT had higher baseline MRI bone edema scores. In fact, when baseline MRI bone edema was present, the risk ratio for erosive progression in the same bone on CT at 12 months was 3.8. In addition, time-integrated MRI bone edema, power Doppler, and grey-scale synovitis scores were higher in bones and joints with CT progression.

With CT as the reference method, the researchers determined that the sensitivity and specificity for the other imaging modalities were 68% and 92%, respectively, on MRI; 44% and 95% on ultrasonography; and 26% and 98% on radiography.

In their concluding remarks in the editorial, Dr. McQueen and Dr. Naredo emphasized that the reduction of both synovitis and osteitis "is clearly an important therapeutic goal" in treating RA. "The detection and monitoring of synovitis is often more feasible in clinical practice using [ultrasound] than MRI scanning, but the latter does afford the opportunity to detect and monitor bone edema at the same time."

Dr. McQueen is with the department of molecular medicine and pathology at the University of Auckland (New Zealand). Dr. Naredo is with the department of rheumatology at the Hospital Universitario Severo Ochoa in Madrid.

Funding for the study was provided by Abbott Denmark, the Danish Rheumatism Association, and the Aase and Ejner Danielsen Foundation. Dr. Døhn reported no relevant financial conflicts, but many of the study’s coauthors disclosed that they have received consulting fees, speaking fees, or research grants from Abbott, Centocor, Roche, Schering-Plough, UCB-Nordic, and Wyeth. Dr. McQueen and Dr. Naredo stated that they have no conflicts of interest.

Erosive progression is arrested in rheumatoid arthritis patients who are treated with adalimumab and methotrexate combination therapy, judging from results of a novel longitudinal study comparing MRI, ultrasonography, CT, and radiography.

However, only MRI was sensitive enough to document repair of individual erosions. Both MRI and ultrasound could detect changes in bone edema, which "was predictive of subsequent erosive progression on CT, both at the individual bone/joint level and also for MRI bone edema at the patient level," reported lead author Dr. Uffe Møller Døhn of the department of rheumatology at the University of Copenhagen in the February 2011 edition of the Annals of the Rheumatic Diseases. "These data emphasize the predictive value of modern imaging, and especially highlight the importance of MRI bone edema for predicting erosive progression."

The findings also offer a different way of thinking about RA’s pathology. In an accompanying editorial, Dr. Fiona McQueen and Dr. Esperanza Naredo said that the study’s findings add to existing evidence suggesting that osteitis is more strongly predictive of bone erosion than is synovitis, which supports "the notion that there is a more direct connection between bone inflammation and bone damage than between synovial inflammation and bone damage" (Ann. Rheum. Dis. 2011;70:241-4). They described synovitis and osteitis as "cousins with a common ancestor, the process that ultimately drives both remaining obscure but possibly sited in the bone marrow."

Dr. Døhn and his associates used MRI, ultrasound, standard radiography, and high-resolution CT images of the wrist and metacarpophalangeal joints 2-5 to study response to adalimumab/methotrexate therapy in 52 RA patients naive to biological agents. All images were obtained before the first dose of adalimumab injection and were repeated after 6 and 12 months of treatment (Ann. Rheum. Dis. 2011;70:252-8).

The median age of patients was 61 years, and 67% were women. From baseline, the researchers did not observe any statistically significant changes in overall bone destruction or repair at 6 or 12 months, but differences were seen when researchers used the smallest-detectable-change cutoff. For example, after 6 and 12 months, the scores of MRI synovitis, grey-scale synovitis, and power Doppler ultrasonography decreased. So did scores as assessed by DAS28 (disease activity score in 28 joints), a health assessment questionnaire, and tender and swollen joint counts.

Study participants with disease progression on CT had higher baseline MRI bone edema scores. In fact, when baseline MRI bone edema was present, the risk ratio for erosive progression in the same bone on CT at 12 months was 3.8. In addition, time-integrated MRI bone edema, power Doppler, and grey-scale synovitis scores were higher in bones and joints with CT progression.

With CT as the reference method, the researchers determined that the sensitivity and specificity for the other imaging modalities were 68% and 92%, respectively, on MRI; 44% and 95% on ultrasonography; and 26% and 98% on radiography.

In their concluding remarks in the editorial, Dr. McQueen and Dr. Naredo emphasized that the reduction of both synovitis and osteitis "is clearly an important therapeutic goal" in treating RA. "The detection and monitoring of synovitis is often more feasible in clinical practice using [ultrasound] than MRI scanning, but the latter does afford the opportunity to detect and monitor bone edema at the same time."

Dr. McQueen is with the department of molecular medicine and pathology at the University of Auckland (New Zealand). Dr. Naredo is with the department of rheumatology at the Hospital Universitario Severo Ochoa in Madrid.

Funding for the study was provided by Abbott Denmark, the Danish Rheumatism Association, and the Aase and Ejner Danielsen Foundation. Dr. Døhn reported no relevant financial conflicts, but many of the study’s coauthors disclosed that they have received consulting fees, speaking fees, or research grants from Abbott, Centocor, Roche, Schering-Plough, UCB-Nordic, and Wyeth. Dr. McQueen and Dr. Naredo stated that they have no conflicts of interest.

Erosive progression is arrested in rheumatoid arthritis patients who are treated with adalimumab and methotrexate combination therapy, judging from results of a novel longitudinal study comparing MRI, ultrasonography, CT, and radiography.

However, only MRI was sensitive enough to document repair of individual erosions. Both MRI and ultrasound could detect changes in bone edema, which "was predictive of subsequent erosive progression on CT, both at the individual bone/joint level and also for MRI bone edema at the patient level," reported lead author Dr. Uffe Møller Døhn of the department of rheumatology at the University of Copenhagen in the February 2011 edition of the Annals of the Rheumatic Diseases. "These data emphasize the predictive value of modern imaging, and especially highlight the importance of MRI bone edema for predicting erosive progression."

The findings also offer a different way of thinking about RA’s pathology. In an accompanying editorial, Dr. Fiona McQueen and Dr. Esperanza Naredo said that the study’s findings add to existing evidence suggesting that osteitis is more strongly predictive of bone erosion than is synovitis, which supports "the notion that there is a more direct connection between bone inflammation and bone damage than between synovial inflammation and bone damage" (Ann. Rheum. Dis. 2011;70:241-4). They described synovitis and osteitis as "cousins with a common ancestor, the process that ultimately drives both remaining obscure but possibly sited in the bone marrow."

Dr. Døhn and his associates used MRI, ultrasound, standard radiography, and high-resolution CT images of the wrist and metacarpophalangeal joints 2-5 to study response to adalimumab/methotrexate therapy in 52 RA patients naive to biological agents. All images were obtained before the first dose of adalimumab injection and were repeated after 6 and 12 months of treatment (Ann. Rheum. Dis. 2011;70:252-8).

The median age of patients was 61 years, and 67% were women. From baseline, the researchers did not observe any statistically significant changes in overall bone destruction or repair at 6 or 12 months, but differences were seen when researchers used the smallest-detectable-change cutoff. For example, after 6 and 12 months, the scores of MRI synovitis, grey-scale synovitis, and power Doppler ultrasonography decreased. So did scores as assessed by DAS28 (disease activity score in 28 joints), a health assessment questionnaire, and tender and swollen joint counts.

Study participants with disease progression on CT had higher baseline MRI bone edema scores. In fact, when baseline MRI bone edema was present, the risk ratio for erosive progression in the same bone on CT at 12 months was 3.8. In addition, time-integrated MRI bone edema, power Doppler, and grey-scale synovitis scores were higher in bones and joints with CT progression.

With CT as the reference method, the researchers determined that the sensitivity and specificity for the other imaging modalities were 68% and 92%, respectively, on MRI; 44% and 95% on ultrasonography; and 26% and 98% on radiography.

In their concluding remarks in the editorial, Dr. McQueen and Dr. Naredo emphasized that the reduction of both synovitis and osteitis "is clearly an important therapeutic goal" in treating RA. "The detection and monitoring of synovitis is often more feasible in clinical practice using [ultrasound] than MRI scanning, but the latter does afford the opportunity to detect and monitor bone edema at the same time."

Dr. McQueen is with the department of molecular medicine and pathology at the University of Auckland (New Zealand). Dr. Naredo is with the department of rheumatology at the Hospital Universitario Severo Ochoa in Madrid.

Funding for the study was provided by Abbott Denmark, the Danish Rheumatism Association, and the Aase and Ejner Danielsen Foundation. Dr. Døhn reported no relevant financial conflicts, but many of the study’s coauthors disclosed that they have received consulting fees, speaking fees, or research grants from Abbott, Centocor, Roche, Schering-Plough, UCB-Nordic, and Wyeth. Dr. McQueen and Dr. Naredo stated that they have no conflicts of interest.

Hologic’s Selenia Dimensions digital breast tomosynthesis system (Dimensions 3-D) is the first three-dimensional mammography system to reach the U.S. market following premarket approval by the Food and Drug Administration on Feb. 11. The low-dose x-ray device provides both 2-D and 3-D images of the breast for breast cancer screening and diagnosis.

Conventional 2-D mammography systems have limitations caused by overlapping tissue in the breast that may hide lesions or cause benign areas to appear suspicious, the company explained. Clinical trials of Dimensions 3-D showed significant gains in specificity and other benefits, including improved lesion and margin visibility and the ability to accurately localize structures in the breast, the firm noted.

The approval follows endorsement of the product’s safety and efficacy data by FDA’s Radiological Devices advisory panel last September.

This coverage is provided courtesy of "The Pink Sheet." "The Pink Sheet" and Internal Medicine News Digital Network are both owned by Elsevier.

Hologic’s Selenia Dimensions digital breast tomosynthesis system (Dimensions 3-D) is the first three-dimensional mammography system to reach the U.S. market following premarket approval by the Food and Drug Administration on Feb. 11. The low-dose x-ray device provides both 2-D and 3-D images of the breast for breast cancer screening and diagnosis.

Conventional 2-D mammography systems have limitations caused by overlapping tissue in the breast that may hide lesions or cause benign areas to appear suspicious, the company explained. Clinical trials of Dimensions 3-D showed significant gains in specificity and other benefits, including improved lesion and margin visibility and the ability to accurately localize structures in the breast, the firm noted.

The approval follows endorsement of the product’s safety and efficacy data by FDA’s Radiological Devices advisory panel last September.

This coverage is provided courtesy of "The Pink Sheet." "The Pink Sheet" and Internal Medicine News Digital Network are both owned by Elsevier.

Hologic’s Selenia Dimensions digital breast tomosynthesis system (Dimensions 3-D) is the first three-dimensional mammography system to reach the U.S. market following premarket approval by the Food and Drug Administration on Feb. 11. The low-dose x-ray device provides both 2-D and 3-D images of the breast for breast cancer screening and diagnosis.

Conventional 2-D mammography systems have limitations caused by overlapping tissue in the breast that may hide lesions or cause benign areas to appear suspicious, the company explained. Clinical trials of Dimensions 3-D showed significant gains in specificity and other benefits, including improved lesion and margin visibility and the ability to accurately localize structures in the breast, the firm noted.

The approval follows endorsement of the product’s safety and efficacy data by FDA’s Radiological Devices advisory panel last September.

This coverage is provided courtesy of "The Pink Sheet." "The Pink Sheet" and Internal Medicine News Digital Network are both owned by Elsevier.

Two imaging modalities independently predicted progressive joint erosion in patients with early rheumatoid arthritis as a group, but the tests performed only slightly better than did clinical and demographic variables for individual prognoses, judging from findings of a 1-year study published in Annals of the Rheumatic Diseases.

Among 79 patients who completed quarterly follow-ups with a battery of imaging and nonimaging measures, 53 (67%) showed erosive progression. On a group level, results of ultrasound grey-scale (USGS) findings of inflammation and magnetic resonance images showing bone marrow edema each were significant predictors that erosive disease progression would be detected by MRI.

Patients with USGS inflammation in the dominant wrist were twice as likely to develop erosive progression and patients with MRI bone marrow edema in the dominant wrist were 28% more likely to develop erosive progression compared with patients without these imaging findings, Dr. Pernille Bøyesen and associates reported (Ann. Rheum. Dis. 2011;70:176-9 [doi: 10.1136/ard.2009.126953]).

On an individual level, however, the imaging modalities were not dramatically better than clinical and demographic variables to predict erosive progression of early RA. USGS inflammation, synovitis on MRI, and bone marrow edema that was visible on MRI performed slightly better than using antibody to cyclic citrullinated protein, rheumatoid factor, and disease activity score based on a 28-joint count, reported Dr. Bøyesen of Diakonhjemmet Hospital, Oslo.

USGS inflammation was the best of 12 imaging modalities and measures of disease severity in identifying patients at risk of developing erosions on MRI, with a sensitivity of 78%, a specificity of 55%, a positive likelihood ration of 1.75, and accuracy of 70%.

Future studies are needed using composite indices of disease progression, including modern imaging modalities, to determine their value as predictors of an individual patient’s likelihood of disease progression, the investigators concluded.

The study appears to be the first to confirm previous data suggesting that measuring inflammation by ultrasound can help predict subsequent joint damage, they noted. The findings also confirmed previous data identifying bone marrow edema on MRI as an independent predictor of joint damage.

Other imaging modalities in the study included digital x-ray radiogrammetry (DXR) of cortical bone mineral density in the hand. Results showed only trends toward higher levels of synovitis on MRI and bone density loss on DXR in patients with erosive progression of disease at 1 year. The findings did not support previous studies that reported cortical hand bone mineral density to be independently predictive of erosive progression, perhaps due to the small size of the study, Dr. Bøyesen added.

Given the comprehensive comparison of imaging modalities in the study, however, 84 patients can be considered a large number, the investigators noted.

The multivariate analyses controlled for the effects of age, sex, and other independent variables.

The investigators declared having no conflicts of interest. The study was funded by the Eastern Norway Regional Health Authority, the Research Council of Norway, the Norwegian Rheumatism Association, the Norwegian Women Public Health Association, the Grethe Harbitz Legacy, and the Marie and Else Mustad Legacy.

Two imaging modalities independently predicted progressive joint erosion in patients with early rheumatoid arthritis as a group, but the tests performed only slightly better than did clinical and demographic variables for individual prognoses, judging from findings of a 1-year study published in Annals of the Rheumatic Diseases.

Among 79 patients who completed quarterly follow-ups with a battery of imaging and nonimaging measures, 53 (67%) showed erosive progression. On a group level, results of ultrasound grey-scale (USGS) findings of inflammation and magnetic resonance images showing bone marrow edema each were significant predictors that erosive disease progression would be detected by MRI.

Patients with USGS inflammation in the dominant wrist were twice as likely to develop erosive progression and patients with MRI bone marrow edema in the dominant wrist were 28% more likely to develop erosive progression compared with patients without these imaging findings, Dr. Pernille Bøyesen and associates reported (Ann. Rheum. Dis. 2011;70:176-9 [doi: 10.1136/ard.2009.126953]).

On an individual level, however, the imaging modalities were not dramatically better than clinical and demographic variables to predict erosive progression of early RA. USGS inflammation, synovitis on MRI, and bone marrow edema that was visible on MRI performed slightly better than using antibody to cyclic citrullinated protein, rheumatoid factor, and disease activity score based on a 28-joint count, reported Dr. Bøyesen of Diakonhjemmet Hospital, Oslo.

USGS inflammation was the best of 12 imaging modalities and measures of disease severity in identifying patients at risk of developing erosions on MRI, with a sensitivity of 78%, a specificity of 55%, a positive likelihood ration of 1.75, and accuracy of 70%.

Future studies are needed using composite indices of disease progression, including modern imaging modalities, to determine their value as predictors of an individual patient’s likelihood of disease progression, the investigators concluded.

The study appears to be the first to confirm previous data suggesting that measuring inflammation by ultrasound can help predict subsequent joint damage, they noted. The findings also confirmed previous data identifying bone marrow edema on MRI as an independent predictor of joint damage.

Other imaging modalities in the study included digital x-ray radiogrammetry (DXR) of cortical bone mineral density in the hand. Results showed only trends toward higher levels of synovitis on MRI and bone density loss on DXR in patients with erosive progression of disease at 1 year. The findings did not support previous studies that reported cortical hand bone mineral density to be independently predictive of erosive progression, perhaps due to the small size of the study, Dr. Bøyesen added.

Given the comprehensive comparison of imaging modalities in the study, however, 84 patients can be considered a large number, the investigators noted.

The multivariate analyses controlled for the effects of age, sex, and other independent variables.

The investigators declared having no conflicts of interest. The study was funded by the Eastern Norway Regional Health Authority, the Research Council of Norway, the Norwegian Rheumatism Association, the Norwegian Women Public Health Association, the Grethe Harbitz Legacy, and the Marie and Else Mustad Legacy.

Two imaging modalities independently predicted progressive joint erosion in patients with early rheumatoid arthritis as a group, but the tests performed only slightly better than did clinical and demographic variables for individual prognoses, judging from findings of a 1-year study published in Annals of the Rheumatic Diseases.

Among 79 patients who completed quarterly follow-ups with a battery of imaging and nonimaging measures, 53 (67%) showed erosive progression. On a group level, results of ultrasound grey-scale (USGS) findings of inflammation and magnetic resonance images showing bone marrow edema each were significant predictors that erosive disease progression would be detected by MRI.

Patients with USGS inflammation in the dominant wrist were twice as likely to develop erosive progression and patients with MRI bone marrow edema in the dominant wrist were 28% more likely to develop erosive progression compared with patients without these imaging findings, Dr. Pernille Bøyesen and associates reported (Ann. Rheum. Dis. 2011;70:176-9 [doi: 10.1136/ard.2009.126953]).

On an individual level, however, the imaging modalities were not dramatically better than clinical and demographic variables to predict erosive progression of early RA. USGS inflammation, synovitis on MRI, and bone marrow edema that was visible on MRI performed slightly better than using antibody to cyclic citrullinated protein, rheumatoid factor, and disease activity score based on a 28-joint count, reported Dr. Bøyesen of Diakonhjemmet Hospital, Oslo.

USGS inflammation was the best of 12 imaging modalities and measures of disease severity in identifying patients at risk of developing erosions on MRI, with a sensitivity of 78%, a specificity of 55%, a positive likelihood ration of 1.75, and accuracy of 70%.

Future studies are needed using composite indices of disease progression, including modern imaging modalities, to determine their value as predictors of an individual patient’s likelihood of disease progression, the investigators concluded.

The study appears to be the first to confirm previous data suggesting that measuring inflammation by ultrasound can help predict subsequent joint damage, they noted. The findings also confirmed previous data identifying bone marrow edema on MRI as an independent predictor of joint damage.

Other imaging modalities in the study included digital x-ray radiogrammetry (DXR) of cortical bone mineral density in the hand. Results showed only trends toward higher levels of synovitis on MRI and bone density loss on DXR in patients with erosive progression of disease at 1 year. The findings did not support previous studies that reported cortical hand bone mineral density to be independently predictive of erosive progression, perhaps due to the small size of the study, Dr. Bøyesen added.

Given the comprehensive comparison of imaging modalities in the study, however, 84 patients can be considered a large number, the investigators noted.

The multivariate analyses controlled for the effects of age, sex, and other independent variables.

The investigators declared having no conflicts of interest. The study was funded by the Eastern Norway Regional Health Authority, the Research Council of Norway, the Norwegian Rheumatism Association, the Norwegian Women Public Health Association, the Grethe Harbitz Legacy, and the Marie and Else Mustad Legacy.

CHICAGO — Repeated myocardial perfusion imaging is common and associated with high cumulative radiation doses that are well within the range believed to increase cancer risk, according to a large, single-center study.

This retrospective study of 1,097 consecutive patients who underwent MPI at Columbia University Medical Center, New York, in the first 100 days of 2006 showed that 39% of them received more than one MPI during the study period running from 1988 through June 2008; 18% had at least three MPIs, and 5% had five or more, Dr. Andrew J. Einstein reported at the annual scientific sessions of the American Heart Association.

Among patients with multiple MPIs, the median time between the imaging studies was just under 2 years. However, 56% of patients with multiple MPIs had two within 2 years, and 28% had two within 1 year.

Patients with more than one MPI had a median 121-mSv cumulative estimated effective radiation dose from all medical sources. That’s more than in Japanese atomic bomb survivors, as documented in the landmark Life Span Study. By comparison, 1 year’s background radiation exposure is about 3 mSv, noted Dr. Einstein, a cardiologist at Columbia.

The radiation burden accruing from CT scans has drawn much attention in recent years, but in fact MPI entails the highest radiation exposure of all imaging procedures. Moreover, MPI is booming in popularity: The volume in the United States rose from fewer than 3 million of the imaging procedures in 1990 to 9.3 million in 2002.

In the Columbia University series, men, whites, and patients with health insurance had significantly greater likelihood of undergoing multiple MPIs, compared with women, nonwhites, and the uninsured. They also received higher cumulative radiation doses over the 20-year study period. But whether this increased utilization resulted in improved cardiovascular outcomes requires further study.

The great majority of MPIs ordered in the Columbia study were medically justified as an aid to therapeutic decision making, given that more than 80% of initial MPIs and 90% of repeat procedures were performed in patients with known cardiac disease or symptoms consistent with it. But in ordering these imaging studies, physicians often don’t consider that patients with heart disease undergo numerous additional procedures involving radiation exposure, including cardiac catheterizations. Indeed, the 1,097 patients in this study had a median of 15 procedures involving radiation exposure, including 4 high-dose procedures, Dr. Einstein noted.

Alternative tests without radiation exposure include stress MRI, stress echocardiography, and exercise ECG. Lower radiation exposure alternatives to MPI for use in ruling out cardiac causes of atypical symptoms are CT angiography and percutaneous angiography, he said.

In addition to utilizing tests other than MPI when appropriate, another means of reducing cumulative radiation doses is to avoid the dual-isotope MPI imaging protocol, which typically entails more than twice as great a radiation dose than does technetium-99m MPI, the cardiologist added.

Although the high cumulative radiation doses documented in the Columbia study are "certainly a matter of concern and an important target for improvement," in Dr. Einstein’s view it is worth bearing in mind that solid tumors generally don’t develop until at least 5-10 years following radiation exposure. Patients undergoing MPI are typically older than the general population, and they have a shorter-than-average life expectancy for their age because of their cardiac disease. So the risk:benefit ratio of radiation exposure from MPIs isn’t the same as a similar exposure would be in healthy young adults.

The study was published simultaneously with his presentation at the American Heart Association meeting (JAMA 2010;304:2137-44).

Dr. Einstein’s study was supported by the National Institutes of Health and university research grants. He declared having served as a consultant to the International Atomic Energy Agency as well as GE Healthcare.

CHICAGO — Repeated myocardial perfusion imaging is common and associated with high cumulative radiation doses that are well within the range believed to increase cancer risk, according to a large, single-center study.

This retrospective study of 1,097 consecutive patients who underwent MPI at Columbia University Medical Center, New York, in the first 100 days of 2006 showed that 39% of them received more than one MPI during the study period running from 1988 through June 2008; 18% had at least three MPIs, and 5% had five or more, Dr. Andrew J. Einstein reported at the annual scientific sessions of the American Heart Association.

Among patients with multiple MPIs, the median time between the imaging studies was just under 2 years. However, 56% of patients with multiple MPIs had two within 2 years, and 28% had two within 1 year.

Patients with more than one MPI had a median 121-mSv cumulative estimated effective radiation dose from all medical sources. That’s more than in Japanese atomic bomb survivors, as documented in the landmark Life Span Study. By comparison, 1 year’s background radiation exposure is about 3 mSv, noted Dr. Einstein, a cardiologist at Columbia.

The radiation burden accruing from CT scans has drawn much attention in recent years, but in fact MPI entails the highest radiation exposure of all imaging procedures. Moreover, MPI is booming in popularity: The volume in the United States rose from fewer than 3 million of the imaging procedures in 1990 to 9.3 million in 2002.

In the Columbia University series, men, whites, and patients with health insurance had significantly greater likelihood of undergoing multiple MPIs, compared with women, nonwhites, and the uninsured. They also received higher cumulative radiation doses over the 20-year study period. But whether this increased utilization resulted in improved cardiovascular outcomes requires further study.

The great majority of MPIs ordered in the Columbia study were medically justified as an aid to therapeutic decision making, given that more than 80% of initial MPIs and 90% of repeat procedures were performed in patients with known cardiac disease or symptoms consistent with it. But in ordering these imaging studies, physicians often don’t consider that patients with heart disease undergo numerous additional procedures involving radiation exposure, including cardiac catheterizations. Indeed, the 1,097 patients in this study had a median of 15 procedures involving radiation exposure, including 4 high-dose procedures, Dr. Einstein noted.

Alternative tests without radiation exposure include stress MRI, stress echocardiography, and exercise ECG. Lower radiation exposure alternatives to MPI for use in ruling out cardiac causes of atypical symptoms are CT angiography and percutaneous angiography, he said.

In addition to utilizing tests other than MPI when appropriate, another means of reducing cumulative radiation doses is to avoid the dual-isotope MPI imaging protocol, which typically entails more than twice as great a radiation dose than does technetium-99m MPI, the cardiologist added.

Although the high cumulative radiation doses documented in the Columbia study are "certainly a matter of concern and an important target for improvement," in Dr. Einstein’s view it is worth bearing in mind that solid tumors generally don’t develop until at least 5-10 years following radiation exposure. Patients undergoing MPI are typically older than the general population, and they have a shorter-than-average life expectancy for their age because of their cardiac disease. So the risk:benefit ratio of radiation exposure from MPIs isn’t the same as a similar exposure would be in healthy young adults.

The study was published simultaneously with his presentation at the American Heart Association meeting (JAMA 2010;304:2137-44).

Dr. Einstein’s study was supported by the National Institutes of Health and university research grants. He declared having served as a consultant to the International Atomic Energy Agency as well as GE Healthcare.

CHICAGO — Repeated myocardial perfusion imaging is common and associated with high cumulative radiation doses that are well within the range believed to increase cancer risk, according to a large, single-center study.

This retrospective study of 1,097 consecutive patients who underwent MPI at Columbia University Medical Center, New York, in the first 100 days of 2006 showed that 39% of them received more than one MPI during the study period running from 1988 through June 2008; 18% had at least three MPIs, and 5% had five or more, Dr. Andrew J. Einstein reported at the annual scientific sessions of the American Heart Association.

Among patients with multiple MPIs, the median time between the imaging studies was just under 2 years. However, 56% of patients with multiple MPIs had two within 2 years, and 28% had two within 1 year.

Patients with more than one MPI had a median 121-mSv cumulative estimated effective radiation dose from all medical sources. That’s more than in Japanese atomic bomb survivors, as documented in the landmark Life Span Study. By comparison, 1 year’s background radiation exposure is about 3 mSv, noted Dr. Einstein, a cardiologist at Columbia.

The radiation burden accruing from CT scans has drawn much attention in recent years, but in fact MPI entails the highest radiation exposure of all imaging procedures. Moreover, MPI is booming in popularity: The volume in the United States rose from fewer than 3 million of the imaging procedures in 1990 to 9.3 million in 2002.

In the Columbia University series, men, whites, and patients with health insurance had significantly greater likelihood of undergoing multiple MPIs, compared with women, nonwhites, and the uninsured. They also received higher cumulative radiation doses over the 20-year study period. But whether this increased utilization resulted in improved cardiovascular outcomes requires further study.

The great majority of MPIs ordered in the Columbia study were medically justified as an aid to therapeutic decision making, given that more than 80% of initial MPIs and 90% of repeat procedures were performed in patients with known cardiac disease or symptoms consistent with it. But in ordering these imaging studies, physicians often don’t consider that patients with heart disease undergo numerous additional procedures involving radiation exposure, including cardiac catheterizations. Indeed, the 1,097 patients in this study had a median of 15 procedures involving radiation exposure, including 4 high-dose procedures, Dr. Einstein noted.

Alternative tests without radiation exposure include stress MRI, stress echocardiography, and exercise ECG. Lower radiation exposure alternatives to MPI for use in ruling out cardiac causes of atypical symptoms are CT angiography and percutaneous angiography, he said.

In addition to utilizing tests other than MPI when appropriate, another means of reducing cumulative radiation doses is to avoid the dual-isotope MPI imaging protocol, which typically entails more than twice as great a radiation dose than does technetium-99m MPI, the cardiologist added.

Although the high cumulative radiation doses documented in the Columbia study are "certainly a matter of concern and an important target for improvement," in Dr. Einstein’s view it is worth bearing in mind that solid tumors generally don’t develop until at least 5-10 years following radiation exposure. Patients undergoing MPI are typically older than the general population, and they have a shorter-than-average life expectancy for their age because of their cardiac disease. So the risk:benefit ratio of radiation exposure from MPIs isn’t the same as a similar exposure would be in healthy young adults.

The study was published simultaneously with his presentation at the American Heart Association meeting (JAMA 2010;304:2137-44).

Dr. Einstein’s study was supported by the National Institutes of Health and university research grants. He declared having served as a consultant to the International Atomic Energy Agency as well as GE Healthcare.

LONDON – Magnetic resonance imaging should be used as early as possible to scan the neonatal brain if there are any unexplained symptoms, or if hemorrhagic or thrombotic lesions are suspected.

In the case of thrombosis, it’s important to scan early to decide whether anticoagulation is required, neonatal imaging expert Dr. Mary A. Rutherford of Imperial College London said at the Excellence in Paediatrics annual meeting.

However, Dr. Rutherford, who trained as a pediatrician, noted that for acquired injuries, the use of conventional MRI should be delayed 1-4 weeks, as hypoxic-ischemic brain injury is easier to detect 7 days after the insult.

MRI can be used for a variety of diagnostic and prognostic reasons in full-term neonates; it can help to establish the cause of symptoms, identify brain abnormalities, and determine the likely timing of any injury to the developing brain, she said. Neonatal MRI can also help predict outcomes, provide information for risk management and, in these days of increased medicolegal vigilance, perhaps help clinicians avoid the threat of litigation.

Today, most clinical departments will have an MRI scanner that uses field strengths of 1.5-3 Tesla, which are fine for neonatal imaging, Dr. Rutherford said. "What you really need," she noted, "is an interested radiologist or radiographer." Myelination occurs during the first 2 years of life, so an experienced pediatric or radiology image interpreter is also required.

As access to MRI scanners may be limited, it’s important to be ready as soon as a scanner is free, Dr. Rutherford advised. This means that the neonate must be suitably prepared prior to the scan. Choral hydrate, given 15 minutes before the scan, may be used to keep the neonate sedated temporarily, and ear protection must be worn. The neonate’s head and body should then be "wrapped and fixed" as carefully as possibly into position inside the scanner, so there is little chance of any waking or movement during the scan.

Ventilation may be needed during the scan, and a pediatric staff member needs to be with the baby at all times. Pulse oximetry can be used to monitor the neonate while the scan is in progress.

"MRI is an expensive technology, and you really want to make sure that you get the best possible results from all the effort that is put in by trying to put a baby into an MRI scanner," Dr. Rutherford said.

A key element to successful scanning is ensuring that the MRI coil used fits as closely as possibly to the neonate’s head. "Poor coil choice or head positioning results in poor image quality," she warned.

Motion is another common reason for poor quality images, so motion-resistant sequences need to be considered. T1-weighted (transverse/sagittal), T2-weighted (transverse), and diffusion-weighted imaging may all be appropriate sequences to use. Magnetic resonance venography and angiography can provide useful information about thrombosis or stroke, respectively.

"In this day and age, all infants with a neonatal encephalopathy require – and deserve to have – the benefit of an MR scan," Dr. Rutherford said. Other candidates for MRI include neonates with seizures, severe jaundice, abnormal cranial ultrasound findings, unexplained neurologic signs, dysmorphic features, and where a co-twin has died in utero.

Neonates with unexplained symptoms or who are at risk of hemorrhagic/thrombotic lesions require prompt MRI, as soon as access to a scanner can be arranged.

"You will also want to image fairly quickly in cases of severe neonatal encephalopathy, especially if you are considering withdrawing active treatment," Dr. Rutherford said.

By contrast, for acquired injuries, she noted, "If we want to get the best possible detection of any acquired injury, then we should think about imaging probably between 1 and 4 weeks post insult." Diffusion-weighted imaging is best for identifying early ischemic lesions.

With regards to preterm neonates, routine MRI scanning is not recommended, but early scanning is perhaps advisable if there are unexplained symptoms or withdrawal of care is being considered.

Dr. Rutherford is the editor of "MRI of the Neonatal Brain," (Philadelphia: Saunders, Ltd., 2001). More information: MRI of the Neonatal Brain.

LONDON – Magnetic resonance imaging should be used as early as possible to scan the neonatal brain if there are any unexplained symptoms, or if hemorrhagic or thrombotic lesions are suspected.

In the case of thrombosis, it’s important to scan early to decide whether anticoagulation is required, neonatal imaging expert Dr. Mary A. Rutherford of Imperial College London said at the Excellence in Paediatrics annual meeting.

However, Dr. Rutherford, who trained as a pediatrician, noted that for acquired injuries, the use of conventional MRI should be delayed 1-4 weeks, as hypoxic-ischemic brain injury is easier to detect 7 days after the insult.

MRI can be used for a variety of diagnostic and prognostic reasons in full-term neonates; it can help to establish the cause of symptoms, identify brain abnormalities, and determine the likely timing of any injury to the developing brain, she said. Neonatal MRI can also help predict outcomes, provide information for risk management and, in these days of increased medicolegal vigilance, perhaps help clinicians avoid the threat of litigation.

Today, most clinical departments will have an MRI scanner that uses field strengths of 1.5-3 Tesla, which are fine for neonatal imaging, Dr. Rutherford said. "What you really need," she noted, "is an interested radiologist or radiographer." Myelination occurs during the first 2 years of life, so an experienced pediatric or radiology image interpreter is also required.

As access to MRI scanners may be limited, it’s important to be ready as soon as a scanner is free, Dr. Rutherford advised. This means that the neonate must be suitably prepared prior to the scan. Choral hydrate, given 15 minutes before the scan, may be used to keep the neonate sedated temporarily, and ear protection must be worn. The neonate’s head and body should then be "wrapped and fixed" as carefully as possibly into position inside the scanner, so there is little chance of any waking or movement during the scan.

Ventilation may be needed during the scan, and a pediatric staff member needs to be with the baby at all times. Pulse oximetry can be used to monitor the neonate while the scan is in progress.

"MRI is an expensive technology, and you really want to make sure that you get the best possible results from all the effort that is put in by trying to put a baby into an MRI scanner," Dr. Rutherford said.

A key element to successful scanning is ensuring that the MRI coil used fits as closely as possibly to the neonate’s head. "Poor coil choice or head positioning results in poor image quality," she warned.

Motion is another common reason for poor quality images, so motion-resistant sequences need to be considered. T1-weighted (transverse/sagittal), T2-weighted (transverse), and diffusion-weighted imaging may all be appropriate sequences to use. Magnetic resonance venography and angiography can provide useful information about thrombosis or stroke, respectively.

"In this day and age, all infants with a neonatal encephalopathy require – and deserve to have – the benefit of an MR scan," Dr. Rutherford said. Other candidates for MRI include neonates with seizures, severe jaundice, abnormal cranial ultrasound findings, unexplained neurologic signs, dysmorphic features, and where a co-twin has died in utero.

Neonates with unexplained symptoms or who are at risk of hemorrhagic/thrombotic lesions require prompt MRI, as soon as access to a scanner can be arranged.

"You will also want to image fairly quickly in cases of severe neonatal encephalopathy, especially if you are considering withdrawing active treatment," Dr. Rutherford said.

By contrast, for acquired injuries, she noted, "If we want to get the best possible detection of any acquired injury, then we should think about imaging probably between 1 and 4 weeks post insult." Diffusion-weighted imaging is best for identifying early ischemic lesions.

With regards to preterm neonates, routine MRI scanning is not recommended, but early scanning is perhaps advisable if there are unexplained symptoms or withdrawal of care is being considered.

Dr. Rutherford is the editor of "MRI of the Neonatal Brain," (Philadelphia: Saunders, Ltd., 2001). More information: MRI of the Neonatal Brain.

LONDON – Magnetic resonance imaging should be used as early as possible to scan the neonatal brain if there are any unexplained symptoms, or if hemorrhagic or thrombotic lesions are suspected.

In the case of thrombosis, it’s important to scan early to decide whether anticoagulation is required, neonatal imaging expert Dr. Mary A. Rutherford of Imperial College London said at the Excellence in Paediatrics annual meeting.

However, Dr. Rutherford, who trained as a pediatrician, noted that for acquired injuries, the use of conventional MRI should be delayed 1-4 weeks, as hypoxic-ischemic brain injury is easier to detect 7 days after the insult.

MRI can be used for a variety of diagnostic and prognostic reasons in full-term neonates; it can help to establish the cause of symptoms, identify brain abnormalities, and determine the likely timing of any injury to the developing brain, she said. Neonatal MRI can also help predict outcomes, provide information for risk management and, in these days of increased medicolegal vigilance, perhaps help clinicians avoid the threat of litigation.

Today, most clinical departments will have an MRI scanner that uses field strengths of 1.5-3 Tesla, which are fine for neonatal imaging, Dr. Rutherford said. "What you really need," she noted, "is an interested radiologist or radiographer." Myelination occurs during the first 2 years of life, so an experienced pediatric or radiology image interpreter is also required.

As access to MRI scanners may be limited, it’s important to be ready as soon as a scanner is free, Dr. Rutherford advised. This means that the neonate must be suitably prepared prior to the scan. Choral hydrate, given 15 minutes before the scan, may be used to keep the neonate sedated temporarily, and ear protection must be worn. The neonate’s head and body should then be "wrapped and fixed" as carefully as possibly into position inside the scanner, so there is little chance of any waking or movement during the scan.

Ventilation may be needed during the scan, and a pediatric staff member needs to be with the baby at all times. Pulse oximetry can be used to monitor the neonate while the scan is in progress.

"MRI is an expensive technology, and you really want to make sure that you get the best possible results from all the effort that is put in by trying to put a baby into an MRI scanner," Dr. Rutherford said.

A key element to successful scanning is ensuring that the MRI coil used fits as closely as possibly to the neonate’s head. "Poor coil choice or head positioning results in poor image quality," she warned.

Motion is another common reason for poor quality images, so motion-resistant sequences need to be considered. T1-weighted (transverse/sagittal), T2-weighted (transverse), and diffusion-weighted imaging may all be appropriate sequences to use. Magnetic resonance venography and angiography can provide useful information about thrombosis or stroke, respectively.

"In this day and age, all infants with a neonatal encephalopathy require – and deserve to have – the benefit of an MR scan," Dr. Rutherford said. Other candidates for MRI include neonates with seizures, severe jaundice, abnormal cranial ultrasound findings, unexplained neurologic signs, dysmorphic features, and where a co-twin has died in utero.

Neonates with unexplained symptoms or who are at risk of hemorrhagic/thrombotic lesions require prompt MRI, as soon as access to a scanner can be arranged.

"You will also want to image fairly quickly in cases of severe neonatal encephalopathy, especially if you are considering withdrawing active treatment," Dr. Rutherford said.

By contrast, for acquired injuries, she noted, "If we want to get the best possible detection of any acquired injury, then we should think about imaging probably between 1 and 4 weeks post insult." Diffusion-weighted imaging is best for identifying early ischemic lesions.

With regards to preterm neonates, routine MRI scanning is not recommended, but early scanning is perhaps advisable if there are unexplained symptoms or withdrawal of care is being considered.

Dr. Rutherford is the editor of "MRI of the Neonatal Brain," (Philadelphia: Saunders, Ltd., 2001). More information: MRI of the Neonatal Brain.