The temporomandibular joint constitutes a synovial connection between the mandible and the skull base and plays a pivotal role in functions such as jaw movement, chewing, and verbal and emotional expression. Temporomandibular joint dysfunction is observed in about 30% of the population, with a higher prevalence in young to middle-aged women. Interestingly, a majority of individuals affected do not report pain, and only 5%-10% of symptomatic cases necessitate therapeutic intervention. The most common temporomandibular joint disorder manifests as pain in the masticatory muscles and is referred to as myofascial syndrome. However, articular disorders are also very common, usually due to disk displacement and degenerative or inflammatory arthropathies. Less frequently, the temporomandibular joint may be affected by a range of congenital and acquired conditions such as trauma and neoplasms. Imaging becomes necessary for the small percentage of patients who do not respond to conservative management or when there is uncertainty in the diagnosis. A comprehensive understanding of the normal imaging appearance of the temporomandibular joint as well as the wide range of potential pathologic conditions is essential for conducting an accurate radiologic assessment. Moreover, collaboration among multidisciplinary teams and the correlation of imaging findings with arthroscopic observations are crucial to advancing the diagnosis and treatment of temporomandibular joint dysfunction. ©RSNA, 2024 Supplemental material is available for this article.

To study the feasibility of magnetic resonance cinematography of the fingers (MRCF) with comparison of image quality of different protocols for depicting the finger anatomy during motion.

MRCF was performed during a full flexion and extension movement in 14 healthy volunteers using a finger-gating device. Three real-time sequences (frame rates 17-59 images/min) and one proton density (PD) sequence (3 images/min) were acquired during incremental and continuous motion. Analyses were performed independently by three readers. Qualitative image analysis included Likert-scale grading from 0 (useless) to 5 (excellent) and specific visual analog scale (VAS) grading from 0 (insufficient) to 100 (excellent). Signal-to-noise calculation was performed. Overall percentage agreement and mean absolute disagreement were calculated.

Within the real-time sequences a high frame-rate true fast imaging with steady-state free precession (TRUFI) yielded the best image quality with Likert and overall VAS scores of 3.0 ± 0.2 and 60.4 ± 25.3, respectively. The best sequence regarding image quality was an incremental PD with mean values of 4.8 ± 0.2 and 91.2 ± 9.4, respectively. Overall percentage agreement and mean absolute disagreement were 47.9 and 0.7, respectively. No statistically significant SNR differences were found between continuous and incremental motion for the real-time protocols.

MRCF is feasible with appropriate image quality during continuous motion using a finger-gating device. Almost perfect image quality is achievable with incremental PD imaging, which represents a compromise for MRCF with the drawback of prolonged scanning time.

The aim of this study was to evaluate the efficacy of injection of plasma rich in growth factors (PRGF) after temporomandibular joint (TMJ) arthroscopy in patients with Wilkes stage IV internal derangement. Ninety-two patients were randomized to two experimental groups: group A (42 joints) received injections of PRGF, group B (50 joints) received saline injections. Pain intensity on a visual analogue scale (VAS) and maximum mouth opening (MMO, mm) were measured before and after surgery and compared by analysis of variance (ANOVA). The mean age of patients was 35.8 years (range 17-67 years); 86 were female. Significant reductions in pain were noted in both groups after surgery: VAS 7.9 preoperative and 1.4 at 24 months postoperative. Significantly better clinical results were achieved in group A than in group B only at 6 and 12 months postoperative; no significant difference was noted at 18 or 24 months after the surgical intervention. MMO increased after surgery in both groups: 26.2mm preoperative and 36.8mm at 24 months postoperative. No significant differences in MMO were found when the two groups of patients were compared. In conclusion, the injection of PRGF does not add any significant improvement to clinical outcomes at 2 years after surgery in patients with advanced internal derangement of the TMJ.

The purposes of this article are to report the imaging finding of inferior displacement of the lower belly of the lateral pterygoid muscle (LPM) in patients with lesions arising from the temporomandibular joint (TMJ) and to propose that this imaging finding is suggestive of the presence of a TMJ lesion.

We reviewed computed tomographic and magnetic resonance images of 9 patients with lesions involving the TMJ. Images were evaluated for identification of an inferiorly displaced lower belly of the LPM. Pathology reports were reviewed to determine the histopathologic diagnosis of the TMJ lesion.

Inferior displacement of the lower belly of the LPM was observed in all cases on magnetic resonance images, computed tomographic images, or both. In 2 cases, the diagnosis was calcium pyrophosphate deposition disease. The remaining cases were ganglion cyst, joint effusion due to dermatomyositis, septic arthritis, chondromyxoid fibroma, synovial chondromatosis, pigmented villonodular synovitis, and giant cell tumor of bone.

Inferior displacement of the lower belly of the LPM is a useful radiologic sign to suggest that a lesion arises from the TMJ.

As part of the Multisite Research Diagnostic Criteria For Temporomandibular Disorders (RDC/TMD) Validation Project, comprehensive temporomandibular joint diagnostic criteria were developed for image analysis using panoramic radiography, magnetic resonance imaging (MRI), and computerized tomography (CT).

Interexaminer reliability was estimated using the kappa (kappa) statistic, and agreement between rater pairs was characterized by overall, positive, and negative percent agreement. Computerized tomography was the reference standard for assessing validity of other imaging modalities for detecting osteoarthritis (OA).

For the radiologic diagnosis of OA, reliability of the 3 examiners was poor for panoramic radiography (kappa = 0.16), fair for MRI (kappa = 0.46), and close to the threshold for excellent for CT (kappa = 0.71). Using MRI, reliability was excellent for diagnosing disc displacements (DD) with reduction (kappa = 0.78) and for DD without reduction (kappa = 0.94) and good for effusion (kappa = 0.64). Overall percent agreement for pairwise ratings was >or=82% for all conditions. Positive percent agreement for diagnosing OA was 19% for panoramic radiography, 59% for MRI, and 84% for CT. Using MRI, positive percent agreement for diagnoses of any DD was 95% and of effusion was 81%. Negative percent agreement was >or=88% for all conditions. Compared with CT, panoramic radiography and MRI had poor and marginal sensitivity, respectively, but excellent specificity in detecting OA.

Comprehensive image analysis criteria for the RDC/TMD Validation Project were developed, which can reliably be used for assessing OA using CT and for disc position and effusion using MRI.

Disorders of the TMJ are best evaluated with MR. Anatomy and morphology of the meniscus are key features of the imaging evaluation conducted using coronal and sagittal views with open and closed mouth. There is no direct correlation between symptoms and MR imaging findings. Anterior or lateral meniscal displacement, permanent or reversible, are described. Arthroscopy or arthrography may help in diagnosis of meniscal adhesion or perforation. HRCT is an adjunct to study degenerative bone changes.