Abstract 2785: Anatomical versus Functional Assessment of Coronary Artery Disease: A Comparative Regional Analysis of Non Invasive Coronary Angiography and Coronary Calcium Scoring by MSCT with Myocardial Perfusion Imaging by SPECT
Background: For the non-invasive evaluation of coronary artery disease (CAD), both MSCT and gated SPECT are available. How these 2 modalities relate however is yet unclear. The purpose of the study was to perform a head-to-head comparison between MSCT and gated SPECT results on a regional basis (per vessel distribution territory) in patients with known or suspected CAD.
Methods: 140 patients (84 male, average age 59 ± 11 years) underwent both MSCT (n=109: 64-MSCT, n=31: 16-MSCT) for coronary calcium scoring and coronary angiography and gated SPECT for myocardial perfusion imaging. Coronary calcium score was determined for each coronary artery. Coronary arteries on MSCT were classified as having no CAD, non-significant stenosis (<50% luminal narrowing), significant stenosis, or total or subtotal occlusion (≥90% luminal narrowing). Gated SPECT examinations were classified as normal or abnormal (reversible and/or fixed defects) and allocated to one of the territories of the different coronary arteries.
Results: In coronary arteries with a calcium score ≤10, corresponding myocardial perfusion was normal in 87% (n=194 of 224). In coronary arteries with extensive calcifications (>400), percentage vascular territories with normal myocardial perfusion was lower, but still 54% (n=13 of 24). Similarly, in the majority of the normal coronary arteries on MSCT, corresponding myocardial perfusion on SPECT normal as well (156 of 175, 89%). In contrast, percentage normal SPECT was significantly lower in coronary arteries with obstructive lesions (59%) and total or subtotal occlusions (8%) (P<0.01). Nonetheless, only 48% of vascular territories with normal perfusion corresponded to normal coronary arteries on MSCT, whereas non-significant and significant stenoses were present in respectively 40% and 12% of corresponding coronary arteries.
Conclusion: Although a relation exists between the severity of CAD on MSCT and corresponding myocardial perfusion, the observed agreement between atherosclerosis and abnormal perfusion was only moderate. Accordingly, MSCT and SPECT provide complementary rather than overlapping information, namely the presence of (subclinical) atherosclerosis versus the presence of ischemia.