Margit Bristela1, Astrid Skolka2, Jaryna Eder3, Pavol Szomolanyi4, Michael Weber5, Eva Piehslinger6, Martina Schmid-Schwap7, Siegfried Trattnig8. 1. University Clinic of Dentistry, Department of Prosthodontics, Medical University of Vienna, Sensengasse 2a, 1090 Vienna, Austria. Electronic address: margit.bristela@meduniwien.ac.at. 2. University Clinic of Dentistry, Department of Prosthodontics, Medical University of Vienna, Sensengasse 2a, 1090 Vienna, Austria. Electronic address: astrid.skolka@meduniwien.ac.at. 3. University Clinic of Dentistry, Department of Prosthodontics, Medical University of Vienna, Sensengasse 2a, 1090 Vienna, Austria. Electronic address: jaryna.eder@meduniwien.ac.at. 4. High-Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna, Austria; Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Dubravska cesta 9, 84104 Bratislava, Slovakia. Electronic address: pavol.szomolanyi@meduniwien.ac.at. 5. Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria. Electronic address: michael.weber@meduniwien.ac.at. 6. University Clinic of Dentistry, Department of Prosthodontics, Medical University of Vienna, Sensengasse 2a, 1090 Vienna, Austria. Electronic address: eva.piehslinger@meduniwien.ac.at. 7. University Clinic of Dentistry, Department of Prosthodontics, Medical University of Vienna, Sensengasse 2a, 1090 Vienna, Austria. Electronic address: martina.schmid-schwap@meduniwien.ac.at. 8. High-Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna, Austria; CD Laboratory for Clinical Molecular MR Imaging, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Vienna, Austria. Electronic address: siegfried.trattnig@meduniwien.ac.at.
Abstract
INTRODUCTION: T2 mapping, as a quantitative biochemical MRI-technique that provides information on water and collagen fiber content and composition, was shown to be clinically feasible for the evaluation of healthy temporomandibular joints. OBJECTIVES: The aim of our study was to compare the T2 values of whole discs in patients with and without disc dislocation, to evaluate the possible influence of morphological findings on T2 values and to assess the interrater agreement. METHODS: Sixty-six patients were included in the study. Three experienced examiners assessed the perceptibility of the morphological parameters and the position of the articular disc on the morphological MR images. On the T2 maps, the T2 values of the region-of-interest (ROI) were assessed. RESULTS: The ICC (Intraclass Correlation Coefficient) for the reproducibility of the T2 values was 0.717. The assessment of the morphologic parameters was excellent or good in most of the discs. There was no significant difference in the T2 values based on disc position or signal intensity. But, a statistically significant moderation effect (p = .014) could be identified, indicating that the effect of disc position differs for different signal intensities. Condyle position, effusion, and degenerative changes showed pronounced moderation effects on the T2 values. CONCLUSION: Due to the high sensitivity to effusion, T2 mapping currently seems to be unsuitable as a diagnostic tool for routine use in the temporomandibular joint. The moderation effect clearly shows the influence of factors such as signal intensity, effusion, arthrosis, and condyle position. Perhaps a solution for these problems could be the development of dedicated TMJ coils for higher field strengths at 7.0 T.
INTRODUCTION: T2 mapping, as a quantitative biochemical MRI-technique that provides information on water and collagen fiber content and composition, was shown to be clinically feasible for the evaluation of healthy temporomandibular joints. OBJECTIVES: The aim of our study was to compare the T2 values of whole discs in patients with and without disc dislocation, to evaluate the possible influence of morphological findings on T2 values and to assess the interrater agreement. METHODS: Sixty-six patients were included in the study. Three experienced examiners assessed the perceptibility of the morphological parameters and the position of the articular disc on the morphological MR images. On the T2 maps, the T2 values of the region-of-interest (ROI) were assessed. RESULTS: The ICC (Intraclass Correlation Coefficient) for the reproducibility of the T2 values was 0.717. The assessment of the morphologic parameters was excellent or good in most of the discs. There was no significant difference in the T2 values based on disc position or signal intensity. But, a statistically significant moderation effect (p = .014) could be identified, indicating that the effect of disc position differs for different signal intensities. Condyle position, effusion, and degenerative changes showed pronounced moderation effects on the T2 values. CONCLUSION: Due to the high sensitivity to effusion, T2 mapping currently seems to be unsuitable as a diagnostic tool for routine use in the temporomandibular joint. The moderation effect clearly shows the influence of factors such as signal intensity, effusion, arthrosis, and condyle position. Perhaps a solution for these problems could be the development of dedicated TMJ coils for higher field strengths at 7.0 T.