P2491Physiologic assessment for coronary artery disease with myocardial perfusion imaging is clinically more relevant when selecting diabetic with high risk features

Background Based on previously published data, routine myocardial perfusion imaging in diabetics is not recommended. Selecting patients with diabetes and high risk cardiovascular features could be important to improve the yield of physiologic assessment of the coronary arteries disease and subsequently patient outcome. Purpose We posed the question whether nuclear stress testing has a better yield by selecting diabetic individuals with known vascular disease. Methods We analyzed records for 15,392 diabetics from 1996 to 2009 with and without vascular disease. Vascular disease is defined as carotid vascular disease, abdominal aortic aneurysm, or peripheral arterial disease. There was 2457 myocardial perfusion studies performed within 2 years of the vascular evaluation. We studied the results of these stress testing in each group and evaluated for the presence of myocardial ischemia. Multivariate Cox proportional regression was used to calculate hazard ratios (HR) with 95% confidence intervals after adjusting for age, gender. Results Of those who underwent myocardial perfusion studies 1819 were diabetic with vascular disease group A (mean age 67.8, 70.5% female) and 638 were diabetic without vascular disease group B (mean age 64.5 years, 67.1% female). There was at least one reversible defect suggest myocardial ischemia in 225 and 758 studies in group A and B respectively. Comparing outcome based on the presence of myocardial ischemia in group A without vascular disease, those with vascular disease did have an increased risk of myocardial infarction (adjusted HR: 1.630, 95% CI: 1.281–2.074) and death (adjusted HR: 1.646, 95% CI: 1.413–1.918). Conclusion Myocardial perfusion imaging is a reasonable test in patients with diabetes and vascular disease. The presence of myocardial ischemia is more common and is associated with worse cardiovascular outcome. Acknowledgement/Funding None

Basic principles and technological state of the art: hybrid imaging

The core principle of hybrid imaging is based on the fact that it provides information beyond that achievable with either data set alone. This is attained through the combination and fusion of two datasets by which both modalities synergistically contribute to image information. Hybrid imaging is, thus, more powerful than the sum of its parts, yielding improved sensitivity and specificity. While datasets for integration may be obtained by a variety of imaging modalities, its merits are intuitively best exploited when combining anatomical and functional imaging, particularly in the setting of evaluation of coronary artery disease (CAD) as this combination allows a comprehensive assessment with regard to presence or absence of coronary atherosclerosis, the extent and severity of coronary plaques, and the haemodynamic relevance of stenosis. In clinical practice, the combination of CT coronary angiography (CCTA) with myocardial perfusion studies obtained by single-photon emission computed tomography (SPECT) and by positron emission tomography (PET) has been well established. Recent literature also reports on the feasibility of combining CCTA with cardiac magnetic resonance imaging. Finally, recent advances in CCTA and SPECT imaging have led to a substantial reduction of radiation exposure, now allowing for comprehensive morphological and functional diagnostic work-up by cardiac hybrid SPECT/CCTA imaging at low radiation dose exposures ranging below 5 mSv.

Basic principles and technological state of the art: hybrid imaging

The core principle of hybrid imaging is based on the fact that it provides information beyond that achievable with either data set alone. This is attained through the combination and fusion of two datasets by which both modalities synergistically contribute to image information. Hybrid imaging is, thus, more powerful than the sum of its parts, yielding improved sensitivity and specificity. While datasets for integration may be obtained by a variety of imaging modalities, its merits are intuitively best exploited when combining anatomical and functional imaging, particularly in the setting of evaluation of coronary artery disease (CAD) as this combination allows a comprehensive assessment with regard to presence or absence of coronary atherosclerosis, the extent and severity of coronary plaques, and the haemodynamic relevance of stenosis. In clinical practice, the combination of CT coronary angiography (CCTA) with myocardial perfusion studies obtained by single-photon emission computed tomography (SPECT) and by positron emission tomography (PET) has been well established. Recent literature also reports on the feasibility of combining CCTA with cardiac magnetic resonance imaging. Finally, recent advances in CCTA and SPECT imaging have led to a substantial reduction of radiation exposure, now allowing for comprehensive morphological and functional diagnostic work-up by cardiac hybrid SPECT/CCTA imaging at low radiation dose exposures ranging below 5 mSv.