Cardiac adipose tissue proton-density fat fraction quantification by free-running cardiac Dixon at 3T

Free-running cardiac Dixon-MRI has the potential for motion-resolved R2* and PDFF quantification to explore cardiac fat accumulation and alteration in metabolic diseases. This study combines a self-navigated 3D radial sequence with 13 echoes using fast bipolar signal-readouts, a k-space trajectory correction, a compressed sensing reconstruction, and IDEAL fat-water separation to obtain precise ( limits of agreement: ±1.2 % and 5.0 s-1) and highly spatially and motion-resolved quantitative PDFF and R2* maps of the whole heart. We report here the first in vivo characterization of metabolically-active epicardial fat (PDFF: 81.6±9.6 %), distinct from adjacent paracardial fat.