Do we need Real-time MRI for Diagnosis of Temporomandibular Joint Disorders?

Introduction: Magnetic resonance imaging (MRI) has been approved as an appropriate radiological modality for temporomandibular joint (TMJ) diagnosis, whereas the results of international multicenter studies impressively show the limitations of static three-dimensional MRI. The state of the art for dynamic imaging of the TMJ in real-time are TrueFISP sequences in one sagittal plane. In order to support the diagnostics, a computer-assisted visualization procedure has been developed by the authors for both the static and dynamic MRI. Methods: A number of validated sequences are available for the static 3D-MRI within the clinical routine. For dynamic MRI in real-time, True-FISP sequences in one sagittal plane with a slice thickness of 5-10 mm and 1.3 mm × 1.3 mm spatial resolution were applied. Both the dynamic and static MRI datasets are animated and visualized using the computer- assisted procedure. Results: The computer-assisted procedure reliably supported the clinical diagnosis, especially the visibility of the articular disc was enhanced. On the basis of the static MRI, a 60-year-old patient was diagnosed with anterior disc displacement without reduction. In contrast, by the dynamic MRI, it was recognized how the articular disc was firstly somehow stretched and flattened before the mandibular condyle again glided under the disc, thus resulting in an anterior disc displacement with reduction. Conclusion: These results endorse the relevance of realtime diagnosis for the TMJ. The computer-assisted visualization has been approved as a reliable help for clinical diagnosis. Keywords: temporomandibular joint, articular disc, anterior disc displacement with reduction, anterior disc displacement without reduction, MRI, dynamic MRI, real-time imaging, computer-assisted visualization, direct volume rendering