Association between plaque quantification from coronary CTA and myocardial flow reserve derived from CT myocardial perfusion imaging

Although the relationship between coronary stenosis and myocardial perfusion is well established, the association between quantitative plaque parameters and myocardial perfusion remains poorly understood. This study investigated the association between quantified plaque parameters from coronary computed tomography angiography (CCTA) and myocardial flow reserve (MFR) derived from CT myocardial perfusion imaging (CT MPI). From April 2019 to October 2023, consecutive patients with suspicion of stable coronary artery disease (CAD) underwent CCTA and CT MPI. CCTA and CT MPI were performed with a third-generation dual-source CT scanner. Of the 399 patients, the median (interquartile range) age was 59.0 (53.0, 65.5) years, and 295 (73.9%) were male. Impaired global MFR (< 1.84) was detected in 278 (69.7%) patients. The vessel-based obstructive CAD ( β = 0.761, P < 0.001), calcified plaque burden ( β = 0.209, P = 0.040), and low-attenuation plaque burden ( β = 0.219, P = 0.019) were independently associated with impaired regional MFR. The vessel-based obstructive CAD and low-attenuation plaque burden were also inversely associated with regional MFR as a continuous variable. After adjusting for confounding factors, the patient-based obstructive CAD ( β = 0.685, P = 0.014) and low-attenuation plaque burden ( β = 0.339, P = 0.008) remained associated with impaired global MFR. Low-attenuation plaque burden from CCTA was independently associated with impaired MFR derived from CT MPI. This suggests that low-attenuation plaque burden can provide complementary information regarding MFR status and may serve as a marker for refining risk stratification in patients with CAD.