Abstract 674: Direct Comparison of Rest and Adenosine Stress Myocardial Perfusion CT With Rest and Stress SPECT
INTRODUCTION: We have recently described a technique for assessing myocardial perfusion using adenosine-mediated stress imaging (CTP) with Dual Source Computed Tomography (DSCT) that offers sub-millimeter spatial resolution and tomographic datasets. We have assessed the diagnostic accuracy of CTP for the detection of obstructive coronary artery disease by comparison with invasive angiography. However, comparison of a physiologic test with an anatomic gold standard is not ideal. The luminal narrowing of a stenosis does not always determine its hemodynamic significance, and patients with syndrome X may have ischemia in the absence of angiographic disease. SPECT myocardial perfusion imaging (MPI) is a widely utilized and extensively validated method for assessing perfusion. Thus, the aim of this study was to determine the level of agreement between CTP and MPI at rest and under stress on a per-segment, per-vessel, and per-patient basis.
METHODS: 30 consecutive patients underwent CTP and MPI. Perfusion images were interpreted using the 17 segment AHA model and were scored on a 0 (normal) to 3 (abnormal) scale. Summed rest and stress scores were calculated for each vascular territory and each patient by adding the corresponding segmental scores. Summed scores were divided into three categories of perfusion abnormality: 0 –3, 4 – 6, and >=7.
RESULTS: On a per-segment basis (n=510), CTP and MPI demonstrated an excellent correlation: Goodman-Kruskal y=0.70 (0.48 – 0.91) for stress and 0.83 (0.60 –1.1) for rest. On a per-vessel basis (n=90), CTP and MPI summed scores demonstrated a good correlation: Pearson r=0.53 (p<0.0001) for stress and 0.75 (p<0.0001) for rest. On a per-patient basis (n=30), CTP and MPI demonstrated a good correlation: Pearson r=0.48 (p=0.008) for stress and 0.78 (p<0.0001) for rest. Agreement between CTP and MPI to determine the severity of perfusion abnormalities using three categories was 70% for stress and 79% for rest.
CONCLUSIONS: This study demonstrates that CTP compares favorably with SPECT-MPI for detection, extent and severity of myocardial perfusion defects at rest and stress.