Fig. 4

Typical stress lesion of the left midfemoral shaft in a middle-aged female. This is difficult to appreciate on the coronal images (a, short tau inversion recovery, STIR, image) and is just visible as subtle medial high fluid signal at the midshaft (black arrow). It is best seen on an axial proton density fat saturation (PD-FS) sequence (b) as a medial periosteal reaction and intracortical high fluid signal (white arrow). This was not visible on a radiograph taken at the same time but became radiographically visible 2 months later (c) as a subtle periosteal reaction medially (black arrow). Typical femoral stress fractures are located on the medial femoral shaft and have a broad-based bone reaction