RÉSUMÉ
The biomechanical studies on the temporomandibular Joint（TMJ）are of great importance to understand the origin and progression of TMD disorders. The finite element method can be used to analyze stress/strain distribution patterns in the TMJ tissues after application of force or deformation. However, due to the delicate and complicated anatomical structures of TMJ, modeling research were always time-consuming, expensive and non-repeatable. To explore a more rapid and accurate method for establishment of 3D finite element model of TMJ, the relevant factors such as geometric similarity, biomechanical environment simulation for improving the accuracy of TMJ finite element modeling were summarized.
RÉSUMÉ
<p><b>OBJECTIVE</b>To investigate the manifestation of oral squamous cell carcinoma with metastatic lymph nodes in whole-body diffusion weighted imaging (WB-DWI) and its clinical significance.</p><p><b>METHODS</b>Twenty-one cases of oral squamous cell carcinoma with metastatic lymph nodes were examined by WB-DWI, of which 19 were scanned with routine MRI, 9 cases examined by positron-emission tomography (PET). All cases were confirmed by pathology. MRI scan covered whole body and built whole body diffusion image after reconstruction with GE HDe 1.5T MRI scanner.</p><p><b>RESULTS</b>There were 139 metastatic lymph nodes, 11 normal lymph nodes, and 21 inflammatory lymph nodes exhibited by WB-DWI in 21 cases. Metastatic lymph nodes showed higher signal and lower value of apparent diffusion coefficient (ADC). The mean ADC value of metastatic lymph nodes (0.78 +/- 0.07) was significantly lower than that of inflammatory (1.18 +/- 0.15) and normal nodes (1.78 +/- 0.16), and normal nodes showed even higher levels of ADC value.</p><p><b>CONCLUSIONS</b>STIR-EPI-DWI is a new promising technique for differentiating normal, inflammatory, and metastatic lymph nodes and can provide more useful information on lymph node metastasis.</p>