Magnetic resonance imaging of osteomyelitis in the mandible. Comparative study with other radiologic modalities.

Magnetic resonance imaging of 14 histopathologically confirmed cases of osteomyelitis of the mandible was retrospectively reviewed. The findings of magnetic resonance imaging were compared with conventional radiography, computed tomography, bone scintigraphy, and histopathologic examinations. All lesions in bone marrow were shown as areas of low (64%) or low-to-intermediate (36%) signal intensity on T1-weighted images, and areas of high (29%), mixed (high and low, 21%; high and intermediate, 36%) or low (14%) signal intensity on T2-weighted images. Histopathologically, high T2-weighted signal intensity areas that showed enhancement after contrast injection corresponded to active infection. These were not collections of pus but were predominantly areas of granulation tissue. Magnetic resonance imaging showed larger areas of abnormality than plain radiography or computed tomography. Bone scintigraphy did not accurately reveal the locations of lesions but showed heterogeneous increased uptake in all patients. MRI was an extremely useful technique for assessing osteomyelitis of the mandible.