37-year-old man with 1-year history of prednisone use in 2013 who presented with right groin pain.
A and B, Dynamic contrast-enhanced MR images of right femoral head (A) and acetabulum (B) are presented with slice and ROIs (white outlines) delineated on left and time history for enhancement shown on right. Control study of right acetabulum (B) shows rapid increase in contrast enhancement with slope of 0.859 and normal washout, whereas ischemic right femoral head enhancement curve (A) shows rate of increase of 0.858 with delayed washout, reflective of associated reparative response. Diamonds in graphs denote average enhancement of all voxels in ROI at indicated time point. Lines in graph denote estimate of rate of enhancement. Curves are fit of time history of enhancement. Kep, kel, and Akep are pharmacokinetic parameters of model used by code to describe various parameters of uptake and elimination of gadolinium contrast material.