Fig. 1

a Example MRI used to calculate fat signal fraction. Blue circles indicate approximate location where biopsies were taken from and fat signal fraction measurements were made. b Fat signal fraction map of MRI in (a). Red indicates voxels classified as muscle, yellow indicates voxels classified as fat. c Histogram of pixel intensities in (a) across a spectrum of fat (yellow) and muscle (red). Thresholds were defined on a patient-by-patient basis as the intersection between the Gaussian distribution of fat and water