Value of additional axial imaging in magnetic resonance imaging of the temporomandibular joint to identify extra-articular diseases

Objectives: The conventional magnetic resonance (MR) imaging protocol for the temporomandibular joint (TMJ) is typically performed with focused oblique, sagittal, and coronal imaging of each joint and can miss extra-articular diseases and conditions that may present with similar symptoms. The purpose of this study was to investigate the value of an additional axial short tau inversion recovery (STIR) sequence to identify conditions other than ordinal TMJ disorders. Methods: From September 2000 to April 2006, 601 patients with clinically diagnosed TMJ disorders underwent MR imaging at 0.5 T with a dedicated TMJ coil. In addition to the standard TMJ MR imaging protocol with oblique, sagittal, and coronal proton-density and T2-weighted images of each TMJ in the closed- and open-mouth positions, axial STIR images from the superior orbit to the thoracic inlet level were obtained. Results: Of 601 patients, 580 (96.5 %) had TMJ disorders without other imaging abnormalities. Extra-articular diseases outside the TMJ were found in 21 patients (3.5 %), with all abnormalities seen only on axial STIR images. These conditions comprised 13 infectious/inflammatory processes and 8 neoplasms including 7 malignancies. Six of these patients had coexistent TMJ disorders, and 15 had no TMJ abnormality. Conclusions: The addition of axial STIR images to the standard TMJ MR imaging protocol detected unexpected pathology in 3.5 % of patients, including malignancies (1.0 %). The addition of these images could potentially be used as an adjunct to the typical TMJ MR imaging protocol to improve detection of unexpected extra-articular disease.