Assessment of Coronary Flow Reserve and CT Angiography By Hybrid PET/CT: Relation to Clinically Indicated SPECT Studies

Advances in Non-invasive Multislice CT Imaging: Multislice CT (MSCT) and PET imaging are becoming more widely available and more useful in cardiac assessment. MSCT provides quantification of coronary calcium as well as information about the structures of the coronary vessel walls and atherosclerotic plaques. Multiple studies have demonstrated that MSCT provides information on coronary artery stenosis comparable to that obtained from invasive coronary angiography. PET imaging provides functional data via the measurement of coronary flow reserve (CFR). CFR is a quantitative measure of the increase in coronary blood flow in response to vasodilation; normal coronary flow is able to augment by three- to four-fold; diseased coronary arteries show less ability to increase flow, i.e. less CFR. Assessment of CFR yields functional information about the significance of coronary disease and is often used clinically in conjunction with anatomic imaging to identify early atherosclerosis. There is no current data evaluating the incremental value of hybrid PET/CT assessment of CFR and coronary anatomy in relation to SPECT studies in the clinical setting.