Evaluating Epicardial Fat Density Using ROI-Based Analysis: A Feasibility Study

Epicardial fat density (EFD) is implicated in cardiovascular diseases. This study aimed to assess the regional variability of epicardial fat density (EFD) using coronary computed tomography (CCT) and evaluate the feasibility of ROI-based measurements as an alternative to full segmentation. A retrospective analysis was conducted on 171 patients undergoing coronary CCT. EFD was measured on non-contrast scans acquired globally and in three predefined regions of interest (ROIs) for coronary calcium scoring: the aortic bulb, right posterolateral wall, and cardiac apex. Global EFD was quantified using semi-automated segmentation software (3D Slicer 5.6.2), while regional EFD values were manually determined. Statistical analyses were performed to compare global and regional EFD measurements. Global EFD averaged -83.92 ± 5.19 HU, while regional EFD showed significant variability. The aortic bulb had lower EFD values (-97.54 ± 12.80 HU) compared to the apex (-93.42 ± 18.94 HU) and right posterolateral wall (-94.99 ± 12.16 HU). Paired t-tests confirmed statistically significant differences between global and regional EFD values (p < 0.000). This study highlights significant regional variability in EFD across specific cardiac regions, suggesting that ROI-based assessments may not reliably reflect global EFD characteristics.