The fat attenuation index (FAI), a threshold-based method for assessing pericoronary adipose tissue (PCAT) density, provides strong evidence for patient-specific coronary inflammation assessment. However, the reliance on fat thresholds may result in the omission of some critical information. Thus, this study aimed to explore the diagnostic potential of a novel method, pericoronary adipose tissue mean attenuation (PCATMA), which is not constrained by fat threshold limitations, by investigating the relationships among PCATMA, the FAI, and coronary artery plaque types.This single-center observational study enrolled patients undergoing coronary computed tomography angiography (CCTA) between May 2021 and October 2022. In total, 75 patients with plaque and 63 patients without plaque were enrolled in the study. PCAT density was measured at various distances (0.50, 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00 mm) from the vascular wall in the non-plaque group to investigate the effect of varying distances from the coronary artery on PCAT density. A Bland-Altman analysis and intraclass correlation coefficients were used to assess the feasibility and reproducibility of the PCATMA measurements. PCATMA and the FAI were measured in all patients to compare the differences between PCATMA and the FAI in the assessment of coronary atherosclerotic lesions.As the distance from the lumen increased, the PCAT density gradually decreased, plateauing after a distance of 0.75 mm (P=0.907). There were no differences between PCATMA and the FAI of each vessel in the non-plaque group (P>0.05), but the proximal right coronary artery (RCA) had a higher FAI compared to the mid-RCA (P=0.03). Compared with the non-plaque group, significant differences in PCATMA were observed in coronary artery segments with non-calcified plaque (NCP) (P<0.001) and mixed plaque (MP) (P=0.047); however, no such significant differences were found for the FAI (all P>0.05). Nor were any significant differences found between PCATMA and the FAI in terms of the different types of plaque (all P>0.05).The novel PCATMA measurement method based on non-fat threshold limitations has good feasibility and repeatability. PCATMA may be more sensitive than the FAI in assessing changes in PCAT density resulting from early coronary artery inflammation, but it is not associated with plaque type.Copyright © 2025 AME Publishing Company. All rights reserved.