Standardized <scp>MRI</scp> ‐Based Quantification of Epicardial Adipose Tissue Volume: Reproducibility and Agreement With Cardiac Computed Tomography

BACKGROUND: Epicardial adipose tissue volume (EATV) is increasingly recognized as a cardiometabolic risk marker associated with adverse outcomes. The most established approach for EATV quantification is cardiac computed tomography (CT). MRI offers a radiation-free alternative allowing simultaneous assessment of myocardial function and tissue characteristics; however, standardization and validation are limited. PURPOSE: To evaluate a standardized MRI-based method for EATV quantification and determine its agreement with CT. STUDY TYPE: Retrospective. POPULATION: 127 patients with aortic stenosis (AS) (78 ± 6 years; 38% female) who underwent paired CT and MRI and 11 volunteers (74 ± 7 years, 45% female) who underwent repeat MRI after ≥ 6 weeks. FIELD STRENGTH/SEQUENCE: Short-axis balanced steady-state free precession cine sequence at 3T (AS patients) and 1.5T (volunteers). ASSESSMENT: On CT, EATV was quantified by manual delineation of the visceral pericardium and voxel-thresholding (-190 to -30 HU). MRI-based EATV quantification used manual volumetry with delineation of the visceral pericardium and epicardium on end-diastolic short-axis cine stacks. STATISTICAL TESTS: Inter-modality agreement was assessed by Spearman correlation and Bland-Altman analysis. Reproducibility was evaluated in 20 patients using intraclass correlation coefficient (ICC) and coefficient of variation (CoV). Scan-rescan reproducibility for MRI-derived EATV quantification was assessed using ICC and linear regression. p < 0.05 was considered significant. RESULTS: ), with a significant moderate correlation (ρ = 0.627) between measures. Inter- and intra-observer analyses showed excellent reproducibility for both modalities (CT: intra-observer ICC: 0.983, inter-observer ICC: 0.994; MRI: intra-observer ICC: 0.955, inter-observer ICC: 0.970). MRI-derived EATV quantification also showed excellent scan-rescan reproducibility (ICC: 0.985). DATA CONCLUSION: The standardized MRI-based approach enabled highly reproducible EATV measurements with excellent repeatability. Agreement with CT was moderate, with systematically higher values on MRI, limiting direct comparability. EVIDENCE LEVEL: 3. STAGE OF TECHNICAL EFFICACY: 2.