Recently, magnetic resonance (MR) imaging is capable of producting high-quality diagnosic images of medical fields. It is known that MR imaging provides much greater softtissue contrast than conventional X-ray based methods.
With temporomandibular joint (TMJ) disorders, most X-ray based methods are useful for diagnosis of bony abnormalities, but their reduced soft-tissue contrast often make diagnostic evaluation difficult.
This paper, reports on MR images of the TMJ. Materials and Methods: The subjects were 8 healthy persons (20-to 40-year males and/or females) with normal occlusion. No disorders were found in the TMJ and radiological findings were normal. MR imaging was performed on a 0.5 Tesla imaging system (MAGNETON, Siemens Co. made in Germany) using a surface coil (10 cm in diamter) for signal detection. Sagittal images in open (degrees of open: 1, 2, 3, 4cm) and closed mouth positions' were obtained of each subject.
Results: The anatomy of the TMJ was well delineated on the MR images. Especially, important soft-tissue anatomy, including the articular disk with its anterior and posterior band, adjacent tissue, and its changes, etc., were readily appreciated: Namely low in signal (black) at the center of the articular disk, enhanced signal (dark gray) in its anterior and posterior edges and relatively hyperintense (bright) in the retrodiscal pad.
We believe, therefore, that the region of the TMJ can now take advantage of the highresolution MR imaging, and these images permit the diagnostic evaluation of TMJ abnormalities.
