[Magnetic Resonance Imaging (MRI) of the TMJ: Influence on therapy and inter-observer agreement of two radiologists].

AIM

To evaluate the influence of MRI of the temporomandibular joint on the therapeutic strategy in patients with craniomandibular disorders (internal derangement) and, furthermore, to analyze interobserver agreement for defined MRI criteria.

MATERIALS AND METHODS

Fifty-one unilateral and bilateral MRI examinations of 32 patients were enrolled. Therapeutic strategies before and after performance of the MRI were compared. Retrospectively, two radiologists independently analyzed the MR images for position of the disk, position of the condyle, signal intensity of the disk and bilaminar zone, osseous changes and several additional findings, using a check list. Agreement was tested by kappa statistics.

RESULTS

In 56% of the cases, changes of the therapeutic regimen were registered after MRI. Statistically significant agreement of the two observers was found for anterior position of the disk (kappa = 0.44), transverse position of the disk (kappa = 0.46) and position of the condyle (kappa = 0.45). No significant agreement was found for signal intensity of the disk (kappa = 0.14) or bilaminar zone (kappa = 0.24), osseous changes (kappa = 0.13) and the additional findings (kappa = 0.29).

DISCUSSION

MRI has a measurable impact on the therapeutic approach to the internal derangement of the TMJ. The position of the disk and condyle can be reproducibly judged, while the signal intensity of the disk and bilaminar zone and the osseous changes are subject to wide observer variations.