Evaluating the temporomandibular joint disc using calcium-suppressed technique in dual-layer detector computed tomography

OBJECTIVES: To investigate the application value of the calcium-suppressed (CaSupp) images of dual-layer detector computed tomography (DLCT) in the evaluation of the temporomandibular joint (TMJ) discs. METHODS: Thirty-three healthy subjects underwent DLCT and magnetic resonance imaging (MRI) examinations. CaSupp images were reconstructed from the spectral-based images using a calcium suppression algorithm. The location, morphology, and thickness of the posterior band of the TMJ discs were evaluated on the oblique sagittal proton-density weighted images and CaSupp images. RESULTS: Of the 66 TMJ discs, anterior displacement was observed on 9 TMJ discs on MR images and 6 TMJ discs on CaSupp images, and posterior displacement was present on 3 TMJ discs on MR and CaSupp images. No significant difference was observed in TMJ disc displacement between MR images and CaSupp images (P value = 0.730). The TMJ discs without displacement had no significant difference in the thickness of the posterior band between the MR and CaSupp images (P value = 0.401). CONCLUSIONS: The calcium-suppressed technique in DLCT may be a simple and preliminary way to evaluate the TMJ disc displacement and structure.