Predictive Value of Multislice Computed Tomography Variables of Atherosclerosis for Ischemia on Stress-Rest Single Photon Emission Computed Tomography (SPECT)

BACKGROUND: -Previous studies have shown that the presence of stenosis alone on multislice computed tomography (MSCT) has a limited positive predictive value for the presence of ischemia on myocardial perfusion imaging (MPI). The purpose of this study was to assess which variables of atherosclerosis on MSCT angiography are related to ischemia on MPI. METHODS AND RESULTS: -Both MSCT and MPI were performed in 514 patients. On MSCT, the calcium score, degree of stenosis (>/=50% and >/=70% stenosis), plaque extent and location were determined. Plaque composition was classified as non-calcified, mixed or calcified. Ischemia was defined as a summed difference score >/=2 on a per patient basis. Ischemia was observed in 137 patients (27%). On a patient basis, multivariate analysis showed that the degree of stenosis (presence of >/=70% stenosis, OR 3.5), plaque extent and composition (mixed plaques >/=3, OR 1.7 and calcified plaques >/=3, OR 2.0) and location (atherosclerotic disease in left main coronary artery and/or proximal left anterior descending coronary artery, OR 1.6) were independent predictors for ischemia on MPI. In addition, MSCT variables of atherosclerosis such as plaque extent, composition and location had significant incremental value for the prediction of ischemia over the presence of >/=70% stenosis. CONCLUSIONS: -In addition to the degree of stenosis, MSCT variables of atherosclerosis describing plaque extent, composition and location are predictive of the presence of ischemia on MPI