Tsukasa Sano

The Association of Temporomandibular Joint Pain With Abnormal Bone Marrow in the Mandibular Condyle

PURPOSE This study investigated the association between temporomandibular joint pain and bone marrow alterations in the mandibular condyle seen on magnetic resonance (MR) images. PATIENTS AND METHODS The study was based on 112 temporomandibular joints in 112 patients with disc displacement without reduction. Thirty-four patients with abnormal bone marrow on MR images were compared with a control group of 78 patients with normal bone marrow. The analysis was based on proton density and T2-weighted MR images in the oblique sagittal and coronal planes. The degree of pain was correlated to the status of the bone marrow using statistical methods. RESULTS The degree of pain in joints with abnormal bone marrow was higher than in joints with normal bone marrow signal on MR images (P = .0045). CONCLUSION Because the stage of internal derangement was similar in both groups, more intensive pain appears to be associated with bone marrow alterations.

Comparison of accuracy of intravoxel incoherent motion and apparent diffusion coefficient techniques for predicting malignancy of head and neck tumors using half-Fourier single-shot turbo spin-echo diffusion-weighted imaging.

PURPOSE To evaluate the use of the intravoxel incoherent motion (IVIM) technique in half-Fourier single-shot turbo spin-echo (HASTE) diffusion-weighted imaging (DWI), and to compare its accuracy to that of apparent diffusion coefficient (ADC) to predict malignancy in head and neck tumors. PATIENTS AND METHODS HASTE DW images of 33 patients with head and neck tumors (10 benign and 23 malignant) were evaluated. Using the IVIM technique, parameters (D, true diffusion coefficient; f, perfusion fraction; D*, pseudodiffusion coefficient) were calculated for each tumor. ADC values were measured over a range of b values from 0 to 1000s/mm(2). IVIM parameters and ADC values in benign and malignant tumors were compared using Students t test, receiver operating characteristics (ROC) analysis, and multivariate logistic regression modeling. RESULTS Mean ADC and D values of malignant tumors were significantly lower than those of benign tumors (P<0.05). Mean D* values of malignant tumors were significantly higher than those of benign tumors (P<0.05). There was no significant difference in mean f values between malignant and benign tumors (P>0.05). The technique of combining D and D* was the best for predicting malignancy; accuracy for this model was higher than that for ADC. CONCLUSIONS The IVIM technique may be applied in HASTE DWI as a diagnostic tool to predict malignancy in head and neck masses. The use of D and D* in combination increases the diagnostic accuracy in comparison with ADC.

A longitudinal study of magnetic resonance (MR) evidence of temporomandibular joint (TMJ) fluid in patients with TMJ disorders.

Abstract It has been reported that joint effusion, the excessive accumulation of joint fluid in and around the joint, is related to temporomandibular joint (TMJ) disorders such as pain and disk displacement. However, there have been no longitudinal studies of this phenomenon. We performed a longitudinal study on the relationship between joint fluid and various pathological disk conditions. The subjects were 17 patients who visited our facility for orthodontic treatment and were diagnosed using MRI as having internal derangement of one or both TMJs (three males and 14 females; age 12-31 years; mean age 20.5 years). MRI was performed before, during, or after treatment for their disorders. We evaluated the relationship between changes in joint fluid in the joint space and the state of the disk, as well as the presence or absence of pain. Joint fluid was evaluated by classifying the extent of high-signal areas in the upper and lower articular cavities on T2-weighted images. The extent of high-signal areas was classified into five levels. Disk displacement and the extent of displacement were evaluated using proton density-weighted images. Statistical analysis was performed using the chi-square test, and differences in the distribution among the groups were examined. Effusion was noted on the first MRI in nine of the eleven joints (81.8%) in which joint fluid decreased on the second MRI (p<0.01). Displacement remained unchanged or worsened in 18 of the 21 joints (85.7%) that showed joint fluid on the first MRI (p<0.01). Pain was alleviated or absent in all joints in which the fluid decreased. These results suggest that joint fluid may be a factor in the outcome of disk recapture treatment as well as in the evaluation of pain.

Magnetic resonance evidence of joint fluid with temporomandibular joint disorders.

Objectives The relationship between temporomandibular joint (TMJ) effusion and TMJ disorders is controversial. The frequency of TMJ effusion has varied as shown in previous studies. Furthermore, though some authors have suggested a correlation between TMJ effusion and pain, others question the relationship. In order to clarify the relationship, it is necessary to quantify the degree of effusion and thoroughly investigate its relationship to other factors. The purpose of this study was to analyze the amount of TMJ fluid present in joints with TMJ disorders and to see how TMJ effusion is related to TMJ status and pain. Methods We studied 577 joints in 293 patients referred to us for magnetic resonance imaging. The joints were divided into painful and nonpainful categories and also classified according to Westessons criteria for the status of the TMJ. The grading system of Larheim et al was used for categorizing the amount of fluid. Statistical methods were used for analyzing the relationship between TMJ fluid and TMJ status and pain. Results TMJs with disk displacement without reduction showed the largest amount of fluid while TMJs with normal superior disk position showed the least fluid (Kruskal-Wallis test, P < 0.001; Scheffe test, P < 0.001). There was a significant difference in the amount of the fluid between painful and nonpainful joints in the group of disk displacement without reduction (Wilcoxon rank sum test, P < 0.001). No significant differences were found between other groups. Conclusions Joint effusion is likely to appear in painful TMJs with disk displacement without reduction. Joint effusion may be an abnormal entity just suited to joints with disk displacement without reduction.

Temporomandibular joint: MR imaging

Diagnostic imaging of TMJ has improved remarkably in the last 20 years. Various abnormalities related patient symptoms. Further studies using the latest imaging techniques will allow a better understanding of the sources of joint pain and the discrepancy between imaging findings and patient symptoms. For clinical practice, appropriate clinical examinations are needed to determine exactly which imaging findings are significant.

Differences in temporomandibular joint pain and age distribution between marrow edema and osteonecrosis in the mandibular condyle.

Abstract This study investigated the differences of age distribution and temporomandibular joint (TMJ) pain between marrow edema and osteonecrosis in the mandibular condyle. Subjects consisted of 35 TMJs in 35 patients with abnormal bone marrow on MR images who were selected from a consecutive series of 527 patients with TMJ disorders. Proton density and T2-weighted MR images taken in the oblique sagittal and coronal planes were used to diagnose condylar marrow abnormalities and divide them into either edema or osteonecrosis. The differences in TMJ pain and age distribution for these two abnormalities were assessed with the one-sided Wilcoxon rank sum test with 0.05 alpha level.The degree of pain was higher in joints with marrow edema than in joints with osteonecrosis (p=0.033). The mean age was higher in joints with osteonecrosis (p<0.001). Our results suggest that there is more severe pain in TMJs with marrow edema of the mandibular condyle than in those with osteonecrosis. Since the patients with marrow edema have lower age, it also appears that marrow edema may be a precursor condition for osteonecrosis of the TMJ.

Magnetic Resonance Evidence of Joint Effusion of the Temporomandibular Joint After Fractures of the Mandibular Condyle: A Preliminary Report

Abstract To investigate the clinical significance of magnetic resonance (MR) evidence of joint effusion of the temporomandibular joint after mandibular condylar fractures, magnetic resonance imaging (MRI) was performed on 18 joints in 15 patients with either unilateral or bilateral mandibular condylar fractures using a 1.5 Tesla MRI scanner (Signa, General Electric, Milwaukee, WI). MR evidence of joint effusion was evaluated and compared with the types and the positions of the fractures. MR evidence of joint effusion was observed in 11 of 18 TMJs, which was 61% of the condylar fractures. It appeared more frequently after fractures with dislocation than those without dislocation (p<0.05). In addition, MR evidence of effusion appeared more frequently in TMJs after high condylar fractures (head to upper neck) than low condylar fractures (lower neck to subcondylar) (p<0.05). These findings indicate that MR evidence of joint effusion may serve as a marker for the detection of severe intra-articular damage to the TMJ after mandibular condyle fractures.

Imaging of the mylohyoid muscle: separation of submandibular and sublingual spaces.

OBJECTIVE This article focuses on the anatomy of the mylohyoid muscle, a crucial landmark in imaging of the oral cavity and upper neck, showing dissected specimens and CT and MR images. CONCLUSION Identification of the relationship of a lesion in the sublingual space to the mylohyoid muscle using MDCT and high-resolution MRI is a key part of the imaging assessment of the oral cavity and upper neck.

Usefulness of proton density and T2-weighted vs. T1-weighted MRI in diagnoses of TMJ disk status.

ABSTRACT The aim of this study was to test the hypothesis that proton density and T2-weighted magnetic resonance (MR) images are more useful than T1-weighted MR images in the diagnoses of disk displacement, disk reduction, and disk shape. The subject group consisted of 92 patients referred for bilateral MRI imaging because of diagnosed signs of temporomandibular disorders (TMD). In the experimental group (52 patients), both T2-weighted and proton density images were made. In the control group (40 patients), only T1-weighted images were taken. The images were evaluated by two oral radiologists relative to their usefulness as a diagnostic aid and rated as either good or fair in each diagnostic category. The percentages of ratings that were good were higher (p<0.01) for T2-weighted and proton density images than for T1-weighted images in all three types of diagnoses (Fishers Exact test). In conclusion, T2-weighted and proton density-weighted images were found to be more useful than T1-weighted images in the diagnoses of disk status.

Angiography of the temporomandibular joint: Description of an experimental technique with initial results

The vascular supply to the temporomandibular joint is not completely understood. To form a base for advancement in this area we developed a method for experimental angiography of the temporomandibular joint that was applied to fresh temporomandibular joint autopsy specimens. Via the external carotid artery the vessels were infused with a mixture of barium and an acrylic resin. The specimens were sectioned and contact radiographs were obtained. These showed the vascularity of the joint and the surrounding structures with great detail. Most of the vascular supply appears to come from the lateral and medial aspects of the condyle head and from the anterior and posterior disk attachments. The method was applied to both normal and abnormal joints and the results suggest that this method could be used to gather further understanding of the vascularity of the temporomandibular joint relative to disease.