Abstract
(1) Background: Our aim was to evaluate the diagnostic performance of combined coronary computed tomography angiography (CCTA) and dynamic CT myocardial perfusion imaging (CT-MPI) for detecting hemodynamically significant coronary artery disease (CAD) in patients with intermediate pretest probability. (2) Methods: Patients with an intermediate pretest probability of CAD were retrospectively enrolled. All patients underwent CCTA and dynamic CT-MPI using a third-generation dual-source CT scanner prior to invasive coronary angiography (ICA). Anatomically significant stenosis was defined as ≥50% luminal narrowing on both CCTA and ICA. Fractional flow reserve (FFR) was performed during ICA in selected cases. Hemodynamically significant CAD was defined per vessel as FFR ≤ 0.80, angiographic stenosis ≥70%, or having undergone revascularization. The diagnostic performance of CCTA alone and CCTA combined with CT-MPI was compared against this reference standard. (3) Results: Seventy-four patients (mean age, 66.8 ± 11.1 years; 59 men) were included. The median coronary calcium score was 508.5 Agatston units (interquartile range: 147-1173). ICA and CCTA detected anatomically significant stenoses in 137 (61.7%) and 146 (65.8%) coronary vessels, respectively, and in 62 (83.8%) and 71 (95.9%) patients, respectively. Hemodynamically significant stenosis was present in 56 patients (76%) and 99 vessels (45%). On a per-vessel basis, CCTA alone yielded a sensitivity of 96.7%, specificity of 60.3%, positive predictive value (PPV) of 64.4%, and negative predictive value (NPV) of 96.1%. Combined CCTA and CT-MPI demonstrated a sensitivity of 90.1%, specificity of 84.3%, PPV of 82.7%, and NPV of 91.1%. The area under the receiver operating characteristic curve improved from 0.787 (95% confidence interval: 0.73-0.84) for CCTA to 0.872 (95% confidence interval: 0.82-0.91) for the combined approach (p < 0.05). The median total radiation dose for both CCTA and CT-MPI was 8.05 mSv (interquartile range: 6.71-11.0). (4) Conclusions: In patients with intermediate pretest probability of CAD, combining CCTA with dynamic CT-MPI significantly enhances the diagnostic performance for identifying hemodynamically significant coronary stenosis compared to CCTA alone.