Search

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]

Objectives: Warthin's tumors (WT) and pleomorphic adenomas (PA) are the commonest parotid gland tumors; however, their differentiation remains difficult. This study aimed to investigate the utility of the apparent diffusion coefficient (ADC) value, texture features, and their combination for the differential diagnosis of parotid gland tumors. Methods: Patients who underwent magnetic resonance imaging (MRI) between April 2008 and March 2021 for parotid gland tumors were included and divided into two groups according to the tumor type: WT and PA. The tumor types were used as predictor variables, while the ADC value, texture features, and their combination were the outcome variables. Texture features were measured on short tau inversion recovery (STIR) images and selected using the Fisher's coefficient method and probability of error, and average correlation coefficients. The Mann‐Whitney U‐test was used to analyze bivariate statistics. Receiver operating characteristic curve analysis was used to assess the ability of the ADC value, texture features, and their combination to distinguishing between the two tumor types. Results: A total of 22 patients were included, 11 in each group. The ADC value, 10 texture features, and their combination were significantly different between the two groups (p <.001). Moreover, all three variables had high area under the curve values of 0.93–0.96. Conclusion: The ADC value, texture features, and their combination demonstrated good diagnostic ability to distinguish between WTs and PAs. This method may be used to aid the differential diagnosis of parotid gland tumors, thereby promoting timely and adequate treatment. [ABSTRACT FROM AUTHOR]

Purpose: Medication-related osteonecrosis of the jaw (MRONJ) is a serious complication of treatment with bisphosphonates or antiangiogenic inhibitors. MRONJ has four stages (0-3); however, stage 0 MRONJ is difficult to detect using computed tomography (CT). This study aimed to quantitatively assess the mandibular bone marrow using texture analysis to detect stage 0 MRONJ from CT images.Methods: This retrospective study included 25 patients with stage 0 MRONJ who had a history of treatment with bisphosphonates and underwent CT and magnetic resonance imaging (MRI). The mandibular bone marrow with abnormal signals (T1-weighted imaging: low, T2-weighted imaging: low or high, short-tau inversion recovery: high) on MRI, and no qualitative characteristic CT and oral findings indicative of osteonecrosis (exposed bone, sequestrum, periosteal reaction, and osteolysis) was identified as 0 MRONJ. Texture features of the bone marrow of the mandible with MRONJ and the contralateral, normal mandibular bone marrow were extracted using an open-access software, namely, LIFEx. The volumes of interest (VOIs) were manually placed on CT images by tracing the bilateral mandibular bone marrow regions, excluding the teeth, mandibular canal, and cortical bone. Thirty-seven texture features were extracted from each VOI.Results: Six gray-level run length matrix features and four gray-level zone length matrix features exhibited significant differences between mandibular bone marrow with and without MRONJ.Conclusions: CT was able to quantitatively assess texture features of normal mandibular bone marrow and that with MRONJ. Texture analysis may be useful as a new method for detecting stage 0 MRONJ using CT. [ABSTRACT FROM AUTHOR]

Purpose: Chronic diffuse sclerosing osteomyelitis (CDSO) is a non-suppurative inflammatory bone disease diagnosed based on combined clinical, histopathological, and radiological findings. Accurate diagnosis is important since CDSO is more refractory to treatment than suppurative osteomyelitis. The purpose of this study was to determine the diagnostic efficacy of diffusion-weighted imaging (DWI) in the quantitative assessment of CDSO to distinguish it from acute suppurative osteomyelitis (ASO) and chronic suppurative osteomyelitis (CSO) of the mandible., Methods: Using a retrospective cohort study design, we analyzed MRI data of 6 patients with CDSO and 34 patients with ASO and CSO. The mean apparent diffusion coefficient (ADC) values of the three groups (CDSO, ASO, and CSO groups) were calculated, and differences were analyzed using Kruskal-Wallis and post-hoc Mann-Whitney tests with Bonferroni adjustments. We performed a receiver operating characteristic (ROC) curve analysis to evaluate the ability of the ADC to predict CDSO. P < 0.05 was considered statistically significant., Results: The mean ADCs in the CDSO, ASO, and CSO groups were 1.22 ± 0.04 × 10 -3 mm 2 /s, 1.28 ± 0.08 × 10 -3 mm 2 /s, and 1.06 ± 0.09 × 10 -3 mm 2 /s, respectively. Significant differences were observed between the ASO and CSO groups (P < 0.001) and CSO and CDSO groups (P < 0.01). However, there was no significant difference between the ASO and CDSO groups (P = 0.21). The ROC analysis revealed a cut-off ADC value of 1.19 for distinguishing the CSO group from the CDSO group. Sensitivity, specificity, accuracy, and area under the ROC curve were 1.0, 0.92, 0, 95, and 0.94, respectively., Conclusion: The results suggest that ADC may be useful in distinguishing CDSO from mandibular suppurative osteomyelitis.

Objectives: Warthin's tumors (WT) and pleomorphic adenomas (PA) are the commonest parotid gland tumors; however, their differentiation remains difficult. This study aimed to investigate the utility of the apparent diffusion coefficient (ADC) value, texture features, and their combination for the differential diagnosis of parotid gland tumors., Methods: Patients who underwent magnetic resonance imaging (MRI) between April 2008 and March 2021 for parotid gland tumors were included and divided into two groups according to the tumor type: WT and PA. The tumor types were used as predictor variables, while the ADC value, texture features, and their combination were the outcome variables. Texture features were measured on short tau inversion recovery (STIR) images and selected using the Fisher's coefficient method and probability of error, and average correlation coefficients. The Mann-Whitney U-test was used to analyze bivariate statistics. Receiver operating characteristic curve analysis was used to assess the ability of the ADC value, texture features, and their combination to distinguishing between the two tumor types., Results: A total of 22 patients were included, 11 in each group. The ADC value, 10 texture features, and their combination were significantly different between the two groups ( p < .001). Moreover, all three variables had high area under the curve values of 0.93-0.96., Conclusion: The ADC value, texture features, and their combination demonstrated good diagnostic ability to distinguish between WTs and PAs. This method may be used to aid the differential diagnosis of parotid gland tumors, thereby promoting timely and adequate treatment.

Objectives: The aim of this study was to assess whether magnetic resonance imaging (MRI) texture features of the lateral pterygoid muscle can distinguish between rheumatoid arthritis (RA) and osteoarthritis (OA) of the temporomandibular joint (TMJ)., Methods: The authors extracted 279 texture features from 36 patients with RA and OA from the region of interest set for the lateral pterygoid muscle on short tau inversion recovery (STIR) images using MaZda Ver.3.3. A total of 10 texture features were selected using Fisher's coefficients, as well as probability of error and average correlation coefficients. Data observed to have a non-normal distribution using the Kolmogorov-Smirnov test were compared using the Mann-Whitney U-test. Receiver operating characteristic (ROC) curves were used to assess the ability of the 10 texture features to distinguish RA and OA of the TMJ., Results: A total of 10 features (5 Correlation, 3 Run Length Nonuniformity, 1 Sigma, and 1 Teta) were selected from 279 texture features. These texture features revealed significant differences between the RA and OA groups ( p < 0.01). The sensitivity, specificity, accuracy, and area under the ROC curve of the texture features for distinguishing RA from OA were 0.78-0.94, 0.89-1.0, 0.86-0.92, and 0.89-0.95, respectively., Conclusion: MRI texture analysis of the lateral pterygoid muscle may be useful for distinguishing between RA and OA of the TMJ.

Purpose: This study aimed to evaluate whether lacunar infarcts can be predicted from occlusal support and periodontal stage on images., Methods: Seventy patients with lacunar infarcts and 300 participants without lacunar infarcts who underwent cerebral checkups at our university hospital were retrospectively reviewed. Lacunar infarcts were assessed using magnetic resonance images by a neuroradiologist. The number of teeth, occlusal support, and severity of radiographic bone loss (RBL) were evaluated using computed tomography. Occlusal support was classified according to the Eichner classification. Additionally, patient characteristics were investigated using medical charts and blood test reports. Records of clinical periodontal parameters, such as clinical attachment loss and bleeding on probing, were also evaluated., Results: The severity of RBL and Eichner classification in patients with lacunar infarcts was significantly higher than that in individuals without lacunar infarcts (P<.01). Receiver operating characteristic analysis revealed that the cut-off values for predicting lacunar infarct were ≥ III in the severity of RBL and ≥B1 in the Eichner classification. The corresponding areas under the curve were 0.75 and 0.70, respectively. In multivariate analysis, the factors affecting the severity of RBL (≥ III) (odds ratio [OR], 8.1; 95% confidence interval [CI], 4.1-16.3; P<.001), and Eichner classification (≥B1) (OR, 1.9; 95% CI, 0.86-4.1; P<.05) were significantly associated with the occurrence of lacunar infarcts., Conclusion: The severity of RBL and the Eichner classification may be helpful in predicting lacunar infarcts. Therefore, proper periodontal treatment and prosthodontic rehabilitation of missing teeth may prevent lacunar infarcts.

A normal variant is defined as an incidental, often asymptomatic, imaging finding that mimics a true pathologic condition. Given the complex anatomy and wide variety of normal variants in the oral and maxillofacial region, a thorough understanding of commonly encountered normal variants in this region is essential to avoid misinterpretation and unnecessary further imaging or interventions. Moreover, familiarity with normal variants that are known to become symptomatic at times is necessary to facilitate further workup and guide the treatment plan. Intraoral radiography and panoramic radiography, which are unique to oral and maxillofacial radiology, provide two-dimensional (2D) images. Hence, the overlapping of structures or the displacement of the tomographic layer on images can confuse radiologists. It is crucial to understand the principle of 2D imaging to avoid being confused by ghost images or optical illusions. In addition, understanding the normal development of the maxillofacial region is essential when interpreting maxillofacial images in children or young adults because the anatomy may be quite different from that of mature adults. Knowledge of changes in the jaw bone marrow and each tissue's growth rate is essential. It is also necessary to know when the tooth germ begins to calcify and the tooth erupts for diagnostic imaging of the maxillofacial region. The authors describe imaging findings and clinical manifestations of common normal variants in the oral and maxillofacial region, divided into four parts: the maxilla, mandible, tooth, and temporomandibular joint, and discuss the imaging approach used to differentiate normal variants from true pathologic conditions. Online supplemental material is available for this article. © RSNA, 2022.