Comparison of Coronary Computed Tomography Angiography, Fractional Flow Reserve, and Perfusion Imaging for Ischemia Diagnosis

Abstract Background Fractional flow reserve (FFR) computation from coronary computed tomography angiography (CTA) datasets (FFR CT ) has emerged as a promising noninvasive test to assess hemodynamic severity of coronary artery disease (CAD), but has not yet been compared with traditional functional imaging. Objectives The purpose of this study was to evaluate the diagnostic performance of FFR CT and compare it with coronary CTA, single-photon emission computed tomography (SPECT), and positron emission tomography (PET) for ischemia diagnosis. Methods This subanalysis involved 208 prospectively included patients with suspected stable CAD, who underwent 256-slice coronary CTA, 99mTc-tetrofosmin SPECT, [ 15 O]H 2 O PET, and routine 3-vessel invasive FFR measurements. FFR CT values were retrospectively derived from the coronary CTA images. Images from each modality were interpreted by core laboratories, and their diagnostic performances were compared using invasively measured FFR ≤0.80 as the reference standard. Results In total, 505 of 612 (83%) vessels could be evaluated with FFR CT . FFR CT showed a diagnostic accuracy, sensitivity, and specificity of 87%, 90%, and 86% on a per-vessel basis and 78%, 96%, and 63% on a per-patient basis, respectively. Area under the receiver-operating characteristic curve (AUC) for identification of ischemia-causing lesions was significantly greater for FFR CT (0.94 and 0.92) in comparison with coronary CTA (0.83 and 0.81; p  CT also outperformed PET on a per-vessel basis (AUC 0.87; p  CT (0.86 vs. 0.83; p = 0.157; and 0.90 vs. 0.79; p = 0.005, respectively). Conclusions In this study, FFR CT showed higher diagnostic performance than standard coronary CTA, SPECT, and PET for vessel-specific ischemia, provided coronary CTA images were evaluable by FFR CT , whereas PET had a favorable performance in per-patient and intention-to-diagnose analysis. Still, in patients in whom 3-vessel FFR CT could be analyzed, FFR CT holds clinical potential to provide anatomic and hemodynamic significance of coronary lesions.