MR imaging of the osteomyelitis of the extremities

To evaluate the characteristics of MR findings in osteomyelitis, retrospective MR image interpretations were made in 18 patients with osteomyelitis proved either by surgery(n=17) or clinical course(n=1). Osteomyelitis was acute in five patients, subacute in five, chronic in seven, and healed in one. Area of active inflammation had low marrow signal intensity on T1-weighted images, high signal intensity on T2-weighted images inhomogeneously. It has been said that morphologic characteristics of osteomyelitis in MR improved the accuracy in diagnosis of osteomyelitis and that gadolinium enhanced MR images further assisted in the planning of surgery. Our study was performed to observe the signal intensity change or morphologic change of bone marrow, cortex, periosteal reaction, and soft tissue which are specific for osteomyelitis. Multiple inhomogeneous round marrow lesions were noted with central high signal intensity and peripheral low signal intensity on T1-weighted images, and central low signal intensity and peripheral high signal intensity on T2-weighted images in two patients. Intra and extraosseous abscesses showed rim enhancement after gadopentetate dimeglumine injection. The signal intensity of the rim was relatively higher than the internal area of the abscess on T1-weighted images. Cortical bone destruction showed high signal intensities T2-weighted images with destruction patterns of fine radial, circumferential, vertical or wedge shaped. MR imaging, by displaying specific signal intensities and morphological changes of bone marrow, cortex, periosteal reaction and soft tissue, would be an aid in early diagnosis and in planning for appropriate conservative and operative therapeutic procedures for osteomyelitis