Visualization of the articular disk of the temporomandibular joint in near-real-time MRI: feasibility study

Abstract

While static MRI of the TMJ is the method of choice to evaluate the articular disk (AD), dynamic MRI so far has failed to display the AD. The capability of a modified True-FISP sequence to visualize the AD in dynamic near-real-time imaging (NRTI) was evaluated. Twelve healthy subjects and 17 patients were investigated. Besides static routine imaging, sagittal NRTI of both TMJs was performed with a True-FISP sequence at 1.5 T with TE/TR=1.84/3.68 ms. Two temporal resolutions (250/500 ms) were tested. The quality of the visualization of the AD was rated on a four-point scale (1= very good to 4= poor visualization) by two observers in consensus. ADs of the volunteers were visualized with high quality in all stages of movement (score: 1.69). In patients with internal derangement, disk-motion was clearly depicted, including fast reposition movements. Due to degenerative changes of the AD, the quality of the depiction in patients was slightly lower (score: 2.4). According to the preliminary results of this feasibility study, the suggested NRTI True-FISP sequence is capable of visualizing the entire motion of the AD of the TMJ in normal and pathologic stages with high quality. Further studies are needed to prove the clinical usefulness of this new technique.

Real-Time Magnetic Resonance Imaging of Temporomandibular Joint Dynamics

“…In comparison to previous studies of TMJ dynamics [7][8][9][10][11][12][13], the present results are superior in terms of spatial resolution, tissue contrast, and residual artefacts. A brief review and comparison with the present work is summarized in Table 3.…”

“…Alternatively, a number of fast pulse sequences have been proposed for dynamic MRI [7][8][9][10][11][12][13], but so far no generally accepted approach of sufficient quality has evolved. Typical problems comprise susceptibility-induced *Address correspondence to this author at the Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, 37070 Göttingen, Germany; Tel: +49-551-201-1735; E-mail: szhang1@gwdg.de signal losses (e.g., for echo-planar imaging), sensitivity to off-resonance effects (e.g., balanced steady-state free precession sequences), or limited spatial resolution.…”

Image Quality Using Dynamic MR Imaging of the Temporomandibular Joint with True-FISP Sequence

“…However, the present study used true dynamic MR images. 8 Detection of the mandibular condyle and articular eminence and interobserver variability were better without fat saturation because its use obscured the contour of the bone structure in the TMJ.…”

“…Abolmaali's group reported poor observation in a case of lateral displacement of the disk in the TMJ, but good detection of the articular disk in a case of anterior displacement. 8 They adopted a 7-mm slice thickness, which was thought to be comparatively thick. Optimal slice thickness needs to be resolved for future use.…”

“…8 Abolmaali and colleagues reported that dynamic MR imaging of the TMJ by truefast imaging in a steady state precession (true-FISP) sequence allowed the evaluation of the displacement of the articular disk. 8 Although static MR imaging is the primary imaging modality for diagnosing internal derangement, 4 additional dynamic MR imaging provides more information. Dynamic MR imaging complements static imaging by clarifying the disk-condyle relationship and its orbit during repeated motion at the respective open-mouth positions.…”