Magnetic resonance imaging appearances of fatigue fractures of the long bones of the lower limb.

Fatigue fractures may be confused with malignant bone lesions on radiography and hence are periodically referred for further imaging assessment with computed tomography (CT) and magnetic resonance imaging (MRI). The appearances on MRI are characteristic although not pathognomonic. Typical findings include: intramedullary bands of low signal intensity, continuous at some point with the cortex, indicative of a fracture line; intramedullary areas of high signal on both T2-weighted and short-tau inversion recovery (STIR) images representing marrow oedema or haemorrhage, together with evidence of periosteal oedema. We present seven cases of fatigue fractures of the long bones of the lower limb and discuss the MRI findings and compare CT and MRI in imaging these lesions.