Introduction: The relationship between luminal stenosis measured by coronary CT angiography and stress-induced ischemia by SPECT myocardial perfusion imaging is not clearly defined. The aims of this study were to evaluate the relationship between stenosis severity by coronary CT angiography and abnormal SPECT finding and to explore the impact of clinical factors on this relationship.
Patients and methods: Seven hundred six consecutive patients with suspected coronary artery disease between January 2008 and October 2010 were prospectively enrolled.
Results: SPECT revealed 348 reversible and 58 fixed defects in 91 patients. Coronary CT angiography revealed that 339 patients had a maximal luminal stenosis 50% or greater. Total coronary artery calcium score was calculated in 428 patients, including 193 without calcification as well as 128 with mild, 59 with moderate, and 48 with severe-to-extensive calcification. Sensitivity, specificity, positive predictive value and negative predictive value (NPV) of coronary CT angiography for detecting abnormal SPECT finding were, respectively, 48.4%, 90.4%, 42.7%, and 92.2% on a patients' level and 40.2%, 95.6%, 33.6%, and 96.6% on vascular level when cutoff value of stenosis was set at 75%. Receiver operating characteristic analysis showed that the best cutoff value of stenosis for detecting abnormal SPECT finding was 55% on patients' level and 43% on vascular level. Patients with severe-to-extensive calcification had lowest specificity (56.3%) and NPV (69.2%). The sensitivity and positive predictive value of coronary CT angiography were not affected by any clinical factors (P = nonsignificant), whereas the specificity was higher in female patients, population younger than 60 years, and population without hypertension or family history of coronary artery disease (P < 0.05), and the NPV was higher among female patients and population without hypertension (P < 0.05).
Conclusions: Coronary CT angiography has good agreement with stress/rest myocardial perfusion SPECT imaging. Coronary calcification and several clinical factors could affect the specificity and NPV of coronary CT angiography for detecting abnormal SPECT finding.