Feasibility of dual gradient-echo in-phase and opposed-phase magnetic resonance imaging for the evaluation of epicardial fat

Background: Dual gradient-echo in-phase (IP) and opposed-phase (OP) magnetic resonance imaging (MRI) can evaluate small amounts of fat, and is widely used for imaging abdominal organs. Epicardial fat has recently been revealed as having an important role in the development of heart disease, but IPOP-MRI has not been widely applied in this field, probably because of cardiac motion artifacts. Purpose: To demonstrate the feasibility of IPOP-MRI with electrocardiography (ECG)-gating for evaluation of epicardial fat in the normal human heart, compared to black-blood T1-weighted imaging (T1WI). Material and Methods: Ten healthy volunteers were studied. Epicardial fat volume was quantitatively evaluated on OP-from-IP subtraction images and T1-weighted images. Results: Epicardial fat was clearly visualized on the subtraction images as hyperintense areas that corresponded to regions identified as epicardial fat on the T1-weighted images. Epicardial fat volume correlated well between the two methods (r = 0.93, P < 0.0001), and tended to be larger on the subtraction images than on the T1-weighted images (91.4 +/- 30.1 vs. 84.1 +/- 30.5 mL, P = 0.07). Conclusion: IPOP-MRI with ECG-gating may be a useful alternative method to black-blood T1WI for evaluation of epicardial fat.