Abstract 17548: Computed Tomography Stress Myocardial Perfusion for Diagnosing Myocardial Ischemia – A Comparison with Quantitative Coronary Angiography and Fractional Flow Reserve
Purpose: To determine the accuracy of 320 slice adenosine stress computed tomography myocardial perfusion imaging (CTP) for detection of significant myocardial ischemia using combined QCA on invasive angiography (IA) and fractional flow reserve (FFR) as the reference standard.
Methods: 87 vessel territories in 29 patients (19 male, 63 ± 8 years) with chest pain were investigated using CTA, CTP and IA within a two week interval. The CT protocol was 1) Stress CT: contrast enhanced scan during intravenous adenosine infusion; 2) Delayed scan 10 minutes after stress; 3) Rest CT contrast enhanced scan using prospective triggering. FFR was determined in 60 territories supplied by arteries with ≥50% stenosis on IA. Territories were defined as ischemic, if supplied by an artery with FFR ≤0.8, and non ischemic, if supplied by an artery with QCA <50% or FFR >0.8. Images for CTA and CTP were assessed by consensus between two independent blinded observers.
Results: All patients completed the CT protocol (radiation dose 11.7 ± 4mSV). CTP correctly identified 27/37 ischemic territories and 43/50 non ischemic territories. Ten false negative territories occurred in 8 patients, of whom 7 had at least 2 ischemic territories. There were no false positive or negative territories in 15 patients, 14 of whom had ischemia in ≤ 1 ischemic territories. Overall, CTP yielded a sensitivity of 0.73 (confidence interval = 0.56–0.86) and specificity of 0.86 (0.73–0.94) for detection of ischemia, with positive and negative predictive values of 0.79 (0.62–0.91) and 0.81 (0.68–0.90) respectively. When vessel territories which had not been interrogated with FFR were excluded, the positive predictive value increased to 0.87 (0.69–0.96) associated with a decrease in negative predictive value, 0.66 (0.46–0.81) with no significant change in sensitivity 0.73 (0.56–0.87) or specificity 0.83 (0.60–0.94).
Conclusions: 320 slice adenosine stress CT accurately identifies stress induced myocardial perfusion defects in comparison with fractional flow reserve. The accuracy is decreased in patients with multi- vessel territory ischemia.
- © 2010 by American Heart Association, Inc.