Evaluation of the usefulness of magnetic resonance imaging in the assessment of the thickness of the roof of the glenoid fossa of the temporomandibular joint

Objective: The aim of this study was to evaluate the usefulness of magnetic resonance imaging (MRI) in measuring thickness of the roof of the glenoid fossa (RGF) of the temporomandibular joint (TMJ). Study design: Minimum RGF thickness in 95 TMJs of 59 patients with temporomandibular disorders were measured and compared on both sagittal-section MRI and cone-beam computed tomography (CBCT). RGF thickness on MRI was also compared with MRI, CBCT, and arthrographic findings. Results: Minimum RGF thickness was greater on MRI (1.46 mm) than on CBCT (0.90 mm). Spearman's correlation coefficient by rank for these 2 types of measurements was 0.63. RGF thickness on MRI differed significantly between those with and without degenerative joint changes (1.69 vs 1.32 mm; P <.01) and between those with and without disk displacement (1.58 vs 1.35 mm; P =.04), but showed no associations with disk deformity, joint effusion, or disk perforation. Conclusions: MRI is useful in measuring RGF thickness from diagnostic as well as radiation protection standpoints.