Association Between Pericoronary Fat Attenuation Index and High-Risk Plaque Features Assessed by Photon-Counting CT

To evaluate the correlation between pericoronary fat attenuation index (pFAI) and the presence, characteristics, and number of high-risk plaque (HRP) features identified using photon-counting computed tomography coronary computed tomography angiography (PCCT-CCTA) in patients with suspected coronary artery disease (CAD).

This was a single-center prospective cross-sectional study. We prospectively enrolled 119 consecutive patients with suspected CAD who underwent PCCT-CCTA at a local hospital between August and September, 2025. pFAI was measured from coronary computed tomography angiography (CCTA) images, and its correlation with individual HRP features and their cumulative number was investigated.

A total of 119 patients with suspected CAD were prospectively enrolled (mean age: 58.9±11.3 years; 62.1% male). pFAI was significantly higher in the HRP group than in the non-HRP group (-90.1±7.5 HU vs. -98.4±6.7 HU, P<0.001). Patients with ≥2 high-risk features exhibited significantly higher pFAI scores than those without HRP features. The pFAI was not significantly increased in patients with only one HRP feature (P=0.408). Furthermore, pFAI was significantly higher in patients with spotty calcification (SC), positive remodeling (PR), or napkin-ring sign (NRS) (all P<0.05), but no significant increase in pFAI was found in patients with low-attenuation plaque (LAP). Multivariable analysis identified non-calcified plaque (NCP) volume, SC, and PR as independent factors associated with pFAI (all P < 0.05).

The pFAI was significantly elevated in patients with HRP. Coronary arterial inflammation plays a pivotal role in HRP formation. The PCCT is a powerful tool for detecting HRP and assessing coronary arterial inflammation.