Diagnostic Imaging of the Temporomandibular Joint: Recommendations for Use of the Various Techniques

The indications for an imaging study of the TMJ are the same for MR, CT, and arthrognaphy; only those for a plain film study differ. In general, an examination is warranted (1) when the diagnosis of an internal derangement is in doubt and must be established before therapy can be instituted; (2) if the diagnosis is not in doubt but confirmation or documentation is required, such as for third-party payers and in medicolegal cases; (3) pneoperatively for disk surgery; and (4) when therapy for a presumed internal derangement has failed and doubt about the diagnosis arises. Note that this set of indications excludes many patients with clicking, painful joints who will have conservative treatment. We believe it is impontant to emphasize that not every patient with an internal derangement needs to have an imaging study. An internal derangement of the TMJ is basically an anterionly displaced disk. Although joint dynamics, capsular tears, adhesions, and disk perforations also can be imaged, they are usually incidental findings that are not treated differently from the accompanying displaced disk. Only when it is decided that an imaging study should be performed is it necessary to decide which type of study is appropriate. Choosing the type of study that is appropriate will depend on what is available and what information the referring clinician desires. Each imaging technique has its strengths and weaknesses (Table 1); however, in most cases the only information required is the disk position.