[Comparative study of sagittal and coronal MRI of histological disk and temporomandibular joint specimen for examining an identity of anterior disk dislocation and anterior capsular connective tissue].
OBJECTIVE
Anterior dislocation of the articular disk of the temporomandibular joint (TMJ) found by MRI tomography often presents a problem. It may persist in MRI despite improvement of articular symptoms and even be found in healthy persons free of any symptoms. Can this be explained by the similarity in structure of the anterior connective tissue of the disk and capsule and their pathological changes? Is a second coronal plane required for MRI investigation?


METHODS
The preauricular regions of 72 patients of the TMJ clinic were examined by oblique-sagittal and oblique-coronal MRI. A Siemens-Vision MRI was used. It was also possible to prepare 10 articular disks of the TMJ with anterior capsular tissue as well as 20 complete TMJs of adults from autopsy material. Sagittal, transversal, and horizontal serial sections were examined histologically.


RESULTS
In 49 of the 72 cases examined, an anterior dislocation without reduction found in the sagittal MRI was not confirmed in the oblique-coronal MRI. In the sagittal MRI it was possible to differentiate three, in the coronal MRI six typical forms of magnetic resonance signals, which are represented in figures. They are compared with anatomical and histological connective tissue findings adjacent to the TMJ. The structural similarity of the disk and anterior capsular tissue of the TMJ is demonstrated. The close connection of the disk and connective tissue surrounding the TMJ makes differentiation of MRI findings difficult especially following regressive and adaptive reactions.


CONCLUSIONS
In MRI, anterior capsular tissue is able to simulate dislocation of the disk. Pathological tissue reactions may alter the MRI signal and lead to the wrong diagnosis of dislocation of the disk. Diagnosis of an anterior disk dislocation cannot be established solely on the basis of oblique-sagittal MRI findings.
Pinkert
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Klinik und Poliklinik für Mund-, Kiefer- und Gesichtschirurgie, Zentrum für Zahn-, Mund- und Kieferheilkunde, Universitätsklinikum Carl Gustav Carus, Technische Universität Dresden. MKG-Chirurgie@mailbox.tu-dresden.de
Wandelt
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Kittner
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D000328:Adult; D003238:Connective Tissue / Q000473:pathology; D006801:Humans; D004204:Joint Dislocations / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012680:Sensitivity and Specificity; D019224:Temporomandibular Joint Disc / Q000293:injuries* / Q000473:pathology; D013705:Temporomandibular Joint Disorders / Q000175:diagnosis* / Q000473:pathology