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Aim: This study aimed to compare the apparent diffusion coefficient (ADC) values of the masticatory muscles between patients with and without temporomandibular joint osteoarthritis (TMJ‐OA) on diffusion‐weighted magnetic resonance imaging. Methods: This prospective study included 120 patients with temporomandibular disorders (TMD), including 60 patients with TMJ‐OA and 60 without TMJ‐OA, and 60 without TMD patients. All patients underwent magnetic resonance imaging of the TMJs at our hospital between November 2011 and January 2017. The regions of interest included the right and left lateral pterygoid muscles, medial pterygoid muscles, and masseter muscles on axial slices. Magnetic resonance images from the TMJ‐OA and control groups were independently evaluated by two oral and maxillofacial radiologists. ADC values were compared between the two groups using Mann–Whitney U tests. Results: The respective mean ADC values of the lateral pterygoid muscles in patients with TMJ‐OA and controls were 1.18 × 10−3 and 1.33 × 10−3 mm2/s, respectively. Those for the medial pterygoid muscles were 1.14 × 10−3 and 1.25 × 10−3 mm2/s, while those for the masseter muscles were 1.20 × 10−3 and 1.28 × 10−3 mm2/s, respectively. The mean ADC values of the normal lateral pterygoid, normal medial pterygoid, and normal masseter muscles were 1.29 × 10−3, 1.09 × 10−3, and 1.08 × 10−3 mm2/s, respectively. Conclusion: Among patients with TMDs, the ADC values of the masticatory muscles were significantly higher in patients without TMJ‐OA than in those with TMJ‐OA. [ABSTRACT FROM AUTHOR]

Objective: This retrospective study aimed to assess the parotid glands in diabetes mellitus (DM) using diffusion‐weighted magnetic resonance imaging (DW‐MRI). Methods: We investigated 54 patients aged between 38 and 83 years, with DM (DM group) and without DM (control group), who underwent magnetic resonance imaging (MRI) in the facility between November 2006 and January 2021. We calculated the median apparent diffusion coefficients (ADCs) of the parotid glands in the control group and DM group. These groups were compared using the Mann–Whitney U tests. A receiver operating characteristic (ROC) curve analysis was performed to assess the ability of the ADC to predict DM. Statistical significance was set at p < 0.05. Results: The median ADCs of parotid grands in the control group and DM group were 0.83 × 10−3 mm2/s and 0.74 × 10−3 mm2/s, respectively (p < 0.01). ROC analysis revealed a cut‐off ADC value of 0.81 to distinguish between the control and DM group. Sensitivity, specificity, accuracy, and area under the ROC curve were 0.7, 0.67, 0.69, and 0.71, respectively. Conclusion: The ADC was significantly higher in DM groups than in the control group. This suggests that DW‐MRI may be able to quantitatively distinguish parotid glands between normal and DM patients. [ABSTRACT FROM AUTHOR]

Purpose: Magnetic resonance imaging (MRI) is frequently used to diagnose temporomandibular joint disease. However, very few studies have assessed the relationship between the mandibular gonial angle and temporomandibular joint (TMJ) disorders using panoramic radiography and MRI. The aim of this study was to assess the relationship between the gonial angle and articular disk position of the TMJs using panoramic radiography and MRI. Material and method: The patients underwent panoramic radiography and MRI simultaneously at a university hospital between April 2017 and March 2018. We analyzed the records of 109 patients with and without disc displacement. Among these, 88 patients had disc displacement of the TMJ, while 21 patients were normal. The variable "mean mandibular gonial angle" was evaluated as a predictor. The primary outcome was the presence or absence of disc displacement in the TMJs. The other variables included sex and age. Data were analyzed using Spearman's rank correlation coefficient, the Mann–Whitney U test, and receiver operating characteristic (ROC) curves. Statistical significance was set at P < 0.05. Results: There was no significant difference between men and women in mean gonial angle, and there was no correlation with age (P > 0.05). Moreover, the mean mandibular gonial angle in the disc displacement group was significantly higher than that in the nondisc displacement group (P < 0.01). ROC analysis revealed a cutoff mandibular gonial angle of 120.23° for predicting the development of disc displacement. Conclusions: Mandibular gonial angle is a useful parameter for predicting disc displacement of the TMJs. [ABSTRACT FROM AUTHOR]

Purpose: Computed tomography (CT) is frequently used in the diagnosis of oral and maxillofacial diseases. However, very few studies have assessed the association between osteoarthritis (OA) of the temporomandibular joint (TMJ) and mandibular cortical width (MCW), which is used to assess bone quality using CT. The present study sought to assess the correlation between MCW and presence or absence OA of the TMJ using CT. Materials and methods: This was a retrospective cohort study in which a total of 101 women with a mean age of 53.72 years (range: 20–90 years) underwent CT at our university hospital between April 2019 and July 2019. The variable "mean MCW" was evaluated as a predictor. The primary outcome comprised the presence or absence of OA in the TMJ. The other variable was age. Data were analyzed using Spearman's rank correlation coefficient, the Mann–Whitney U test, and receiver operating characteristic (ROC) curves. Statistical significance was set at P < 0.05. Results: The mean MCW values in the OA group were significantly lower than that in the non‐OA group (P < 0.01). In addition, there was a significant negative correlation between age and mean MCW values (P < 0.05). Moreover, ROC analysis revealed a cutoff MCW value of 3.3 mm for predicting the association of OA. Conclusions: These results suggest that MCW may be a useful parameter for predicting the association of OA in the TMJ. [ABSTRACT FROM AUTHOR]