High-resolution ultrasonography of the TMJ: helpful diagnostic approach for patients with TMJ disorders ? Siegfried Jank, 1 Ansgar Rudisch, 2 Gerd Bodner, 2 Iris Brandlmaier, 1 Stefan Gerhard, 1 Ru¨diger Emshoff 1 1 Department of Oral and Maxillofacial Surgery (Head: Univ. Prof. Dr. E. Waldhart); 2 Department of Radiology (Head Univ. Prof. Dr. W. Jaschke), University of Innsbruck, Innsbruck, Austria SUMMARY. Purpose: The purpose of this study was to investigate patients with a clinical diagnosis of internal derangement to determine the diagnostic value of static high resolution ultrasonography (HR-US) when compared with magnetic resonance imaging (MRI). Patients: Sixty-six patients (132 temporomandibular joints [TMJs]) with a clinical diagnosis of internal derangement were investigated by HR-US and MRI. Methods: MRI and HR-US investigations were performed by experienced radiologists. The sonograms were done with a real-time 12-Mhz linear-array scanner. The HR-US interpretation errors were re-evaluated retrospectively by the same radiologist knowing the MRI results by comparing these with the ‘prospective’ and ‘retrospective’ diagnoses. The prospective and retrospective diagnoses were also compared with each other. Results: Eighty-seven of the 132 TMJs had a disc displacement proved by MRI in the closed-mouth position. At maximum mouth opening, 54 TMJs had a disc displacement. The prospective interpretations showed a sensitivity and specificity of 78% each, accounting for an accuracy of 78%. At maximum mouth opening, HR-US resulted in a sensitivity of 61%, a specificity of 88% and an accuracy of 77%. The retrospective interpretations yielded a sensitivity of 90%, a specificity of 84% and an accuracy of 88% in the closed-mouth position. At maximum mouth opening, HR-US showed a sensitivity of 73%, a specificity of 95% and an accuracy of 86%. Conclusion: HR-US is suitable for the detection of disc displacements in the TMJ. However, further studies may be warranted to reduce the proportion of false-positive interpretations, thereby avoiding the application of unnecessary treatment. r 2001 European Association for Cranio-Maxillofacial Surgery INTRODUCTION Internal derangements of the temporomandibular joint (TMJ) are described as one of the most common causes of orofacial pain and temporomandibular joint disorders. The term ‘internal derangement’ is generally used to describe an abnormal relationship between the articular disc, the mandibular condyle and the fossa including the articular eminence. TMJ disorders are associated with the following main clinical findings: pain, joint sounds such as crepita- tion, clicking, and dysfunction (American Dental Association, 1988; Eversole and Machade, 1985; Dworkin and LeResche, 1992; Truelove et al., 1992). TMJ imaging techniques revealed, that a displaced disc is often associated with these disorders (Lundh et al., 1988; Westesson and Lund, 1988; Lundh and Westesson, 1989). Arthrography and magnetic reso- nance imaging (MRI) are the most common methods to determine the disc position. Arthrography in combination with videofluoroscopy (Westesson and Bronstein, 1987) is said to have a diagnostic accuracy of 83%, while MRI has an accuracy of 95% when sagittal plus coronal slices are evaluated (Tasaki and Westesson, 1993). The disadvantages of MRI are non-availability in some centres and high cost. Arthrography is an invasive method with occasional complications such as allergic reactions, pain and disc perforation (Katzberg, 1989). Since 1992 ultrasonography has been suggested for diagnosis of TMJ disorders (Stefanoff et al., 1992; Sader et al., 1995). However, it has not been critically studied yet for disc displacement. Emshoff et al. (1997) achieved a diagnostic accuracy of 55% for ultrasonography using MRI as the ‘gold standard’. This figure differed with varying degrees of mouth opening. In this study, the diagnostic value of static high resolution ultrasonography (HR-US) was investigated in patients with a clinical dia- gnosis of internal derangement, using MRI for comparison. MATERIAL AND METHODS From April 1999 to May 2000, 66 patients (132 TMJs) with a clinical diagnosis of internal derange- ment have been investigated with HR-US and MRI (51 female, 15 male, aged 13–78 years, mean 38.2 years). These patients underwent MRI investigation immediately after the sonography. MRI and HR-US- investigation were performed by experienced radiol- ogists. The HR-US interpretation errors were then re-evaluated retrospectively by the same radiologist after learning the MRI results, by comparing the latter with the ‘prospective’ and ‘retrospective’ diagnoses. The prospective and retrospective diag- noses were compared with each other as well. 366 Journal of Cranio-Maxillofacial Surgery (2001) 29, 366–371 r 2001 European Association for Cranio-Maxillofacial Surgery doi:10.1054/jcms.2001.0252, available online at http://www.idealibrary.com on