Abstract 2234: Value of Multi-Detector Computed Tomography Evaluation of Myocardial Perfusion in the Assessment of Ischemic Heart Disease: Comparison with Nuclear Perfusion Imaging

While CT coronary angiography (CTCA) is gaining acceptance as a diagnostic technique, MDCT derived myocardial perfusion has not been validated against an accepted reference standard. We sought to develop a technique for quantitative assessment of myocardial perfusion from MDCT images, and investigate the diagnostic value of resting MDCT perfusion in comparison with SPECT myocardial perfusion imaging (MPI). We studied 98 consecutive patients undergoing CTCA who also had MPI. 20 patients with normal MPI were used as controls. MDCT perfusion was measured in 16 segments in terms of x-ray attenuation. Abnormal resting perfusion was detected by comparison against normal values obtained in the control group. Accuracy of detection was determined against resting MPI on a segment, vascular territory and patient basis. To determine the causes of resting perfusion defects detected by MDCT but not confirmed by resting MPI, stress MPI data were used. Perfusion abnormalities were detected by resting MPI in 36/78 patients in 58 vascular territories. MDCT detected these abnormalities in 31/36 patients (sensitivity 0.86). Abnormalities found in additional 28/78 patients were not confirmed by resting MPI (specificity 0.33). However, 23 of these 28 apparently false positive resting MDCT perfusion tests (82%) were associated with abnormal stress MPI. In the majority of these 23 patients (16 or 70%), the quality of MDCT images was optimal, while in the remaining 5/28 patients with resting MDCT perfusion abnormalities that were not confirmed by stress MPI, 4 (80%) had suboptimal images. Resting MDCT can accurately detect perfusion abnormalities in agreement with resting MPI. Moreover, the majority of abnormalities not confirmed by resting MPI were associated with stress-induced ischemia. Therefore, myocardial perfusion assessment, even at rest, is a potentially valuable addition to MDCT tools for noninvasive evaluation of coronary artery disease without additional radiation or contrast load, which promises not only to improve the diagnostic accuracy of cardiac CT, but is also likely to prove as a cost-effective, single-stop alternative to costly serial testing.