Fig. 21.

MRI of a Charcot foot complicated with osteomyelitis. a Sagittal T1. b Sagittal STIR. c Sagittal T1 fat sat after contrast administration. Skin ulceration and sinus tract extending from the skin to the talar bone are present, showing a direct spread of infection (red arrow) (a). Diffuse bone marrow alteration is present within the talus. Note the disappearance of bony contours in the sagittal T1-weighted image (white arrows in b) and the reappearance of the bone structures after contrast administration (white arrows in c) demonstrating the “Ghost sign,” which is described in many reviews as pathognomonic for osteomyelitis in Charcot foot [20]. However, up to now, there is no study published evaluating the accuracy of this sign