[Preoperative magnetic resonance tomography in chronic osteomyelitis of the extremities].

39 patients with bone and joint infections of the extremities were examined with magnetic resonance imaging (MRI) in view of an operative procedure. Patients with hip affections and patients with nonoperative treatment were excluded; therefore, 21 patients including 12 post-traumatic and 9 hematogenous cases of chronic osteomyelitis form the study group. MRI findings were verified at operation. Typical MRI findings were: intraosseous abscess (n = 15), extraosseous abscess (n = 9), communication of both (n = 7), edema of bone marrow (n = 9), soft tissues changes (n = 6) and fluid-surrounded sequestrum (n = 6). 83% of the post-traumatic cases had an intraosseous abscess, 67% of the hematogenous cases an edema of bone marrow. MRI improves preoperative planning considerably by sensitive depiction of pathological findings in three planes. To obtain information about activity of the process, scintigraphy is needed in addition. In some cases computer tomography (CT) is helpful to find small sequestra.