Pericoronary adipose tissue imaging biomarkers (PCAT, FAI) in normal-weight, overweight, and obese patients with CAD-RADS 0

Introduction Vascular inflammation is a key driver of atherosclerosis and plaque instability, leading to major adverse cardiac events (MACE). Although a coronary artery calcium (CAC) score of zero indicates a very low likelihood of obstructive CAD on coronary computed tomography angiography (CCTA), low-attenuation noncalcified coronary plaque remains a strong predictor of myocardial infarction. Pericoronary adipose tissue (PCAT) attenuation, quantified as the Fat Attenuation Index (FAI), reflects local coronary inflammation and may improve risk stratification. Purpose We aimed to assess the association between body mass index (BMI) categories and PCAT attenuation in patients without atherosclerosis in CCTA (Coronary Artery Disease – Reporting and Data System [CAD-RADS] = 0). Methods We studied 119 patients with a CAD-RADS=0 (mean age, 49 years), who underwent CCTA as part of routine CAD diagnostics. Participants were stratified into three cohorts according to BMI categories. PCAT attenuation was assessed within 40-mm proximal segments of the three major epicardial coronary arteries (right coronary artery [RCA], left anterior descending artery [LAD], and left circumflex artery [LCx]), with the RCA analyzed from 10 to 50 mm distal to the ostium. Results Patients with overweight and obesity had higher (less negative) FAI values in the RCA, LAD, and LCx arteries compared to normal-weight individuals (all p < 0.001). Compared to normal-weight individuals, FAI values were elevated by 3.1% and 7.0% in the RCA for overweight and obese patients, respectively. Similarly, LAD FAI values were higher by 5.0% in overweight and 5.3% in obese groups, while LCx FAI values showed increases of 4.2% and 8.6%, respectively. Conclusions We demonstrated that higher BMI was associated with increased PCAT radiomic density in patients with CAD-RADS=0, indicating enhanced local coronary inflammation despite no visible atherosclerosis process. These findings suggest that increased body weight may promote early perivascular inflammatory activity and that FAI could provide incremental risk stratification beyond classical arterial lumen stenosis during CCTA assessment.