Comparison of tomography and midfield magnetic resonance imaging for osseous changes of the temporomandibular joint.

The purpose of this study was to compare midfield (0.3 Tesla) magnetic resonance imaging with conventional tomography for assessment of osseous changes of the temporomandibular joint. The material consisted of magnetic resonance images and tomograms of 66 temporomandibular joints. Each set of images was assessed for osseous changes without knowledge about patient symptoms or findings of the other imaging modality. The results showed that 30 joints were normal both by magnetic resonance imaging and tomography, 21 joints showed osseous changes with both techniques, and there were discrepancies between the two techniques in 15 joints. In 12 of these 15 joints magnetic resonance imaging was negative, but tomography showed osseous changes. In the other three joints tomography was normal, but magnetic resonance imaging showed osseous changes. Based on previous tomographic and midfield magnetic resonance imaging studies with correlation to cryosections and dissection and the quality of the depiction of the osseous changes in these images, it was apparent that tomography represented a more accurate representation of the osseous anatomy. The results therefore suggest that conventional tomography is superior to midfield magnetic resonance imaging for assessment of osseous changes of the temporomandibular joint.