[Imaging of osteomedullary infarctions and their complications]

Radiographic, CT, bone scan and MR patterns of the infarcts of the metaphyses and diaphyses of tubular bones and their main complications are presented. Bone marrow infarcts are located in the medullary cavity of long bones. They most often involve the lower limbs. They are commonly associated with necrosis of the epiphyses and have common origin. In contrast to necrosis of the epiphyses, bone infarcts may present specific complications. They are most often detected incidentally, because of their clinical latency. Radiographic and CT changes appear late, showing localized areas of increased density with irregular rims, or sharply demarcated shells of calcification. Earlier changes are demonstrated by bone scan and MRI. MR pattern is characteristic, showing an area of hyposignal on T1- and T2-weighted sequences, with irregular rims, and sometimes small areas of fat signal. Their complications include cystic formation and malignant degeneration (sarcoma and particularly malignant fibrous histocytoma). An unusual complication, infection involving bone infarcts is also presented.