Magnetic resonance imaging of the temporomandibular joint: Value of axial images

The purpose of this study was to determine the value of axial images for diagnosis of disk displacement and osseous changes of the temporomandibular joint. Sagittal, coronal, and axial magnetic resonance images were obtained of 35 fresh temporomandibular joint autopsy specimens. The sagittal and coronal images were interpreted for position of the disk and osseous changes. The value of the axial images for diagnosis of the disk and osseous components was classified into one of four categories: 1) did not add diagnostic information, 2) confirmed findings of sagittal and coronal images, 3) added diagnostic information but did not change the diagnosis, 4) changed the diagnosis. The results showed that the axial images did not add diagnostic information concerning position of the disk in 5 joints, confirmed the diagnosis in 29 joints, and added information but did not change the diagnosis in 1 joint. Concerning osseous abnormalities, the axial images did not add any diagnostic information in 5 joints, confirmed findings of the sagittal and coronal images in 26 joints, added information but did not change the diagnosis in 3 joints and changed the diagnosis in 1 joint. On the basis of these results, it is concluded that the axial plane of imaging of the temporomandibular joint is of relatively little value for assessment of disk displacement and osseous changes. Axial imaging is therefore not recommended for diagnosis of disk position and osseous abnormalities.     

Functional magnetic resonance imaging of temporomandibular joint disorders

Fifty-eight temporomandibular joints (TMJs) from 40 patients with TMJ-related symptoms were examined by means of magnetic resonance scans with modified gradient echo sequences and a special double coil. This technique yielded a good spatial resolution of the intra-articular soft tissues, especially the articular disc and the bone structure of the TMJ. In combination with an incremental jaw opener, the disc-condyle complex was analysed in various closed and open mouth positions, depending on the clinical examination. Open mouth movement with differentiation of disc-condyle rotational and translation movement was demonstrated. Disturbances of TMJ motion showed interrupted condylar translation combined with mandibular deviation during open mouth movement (n = 8/58). Early phases of internal derangement of the TMJ with partial anterior disc displacement with (n = 12/58) or without (n = 2/58) reduction, total anterior disc displacement without reduction (n = 10/58), disc deformation (n = 10/58), disc adhesion (n = 2/58), condylar hypermobility (n = 6/58), condylar displacement (n = 8/58), and late phases of internal derangement of the TMJ with osteoarthrosis (n = 14/58) were clearly identified. Bilateral TMJ disorder was found in 72.5 per cent of the patients. By using motion-adapted, semi-dynamic magnetic resonance imaging (MRI), it is possible to improve the understanding of the complexity of TMJ movements.     

Diagnostic magnetic resonance imaging in synovial chondromatosis of the temporomandibular joint

The aim of this paper was to investigate the clinical and magnetic resonance imaging (MRI) features of synovial chondromatosis (SC) of the temporomandibular joint (TMJ). Fourteen patients with SC of the TMJ were included in the study. Clinical and MRI features were analysed and divided into three types based on MRI classification: type I with loose bodies, type II with homogeneous masses, and type III with a mixture of loose bodies and homogeneous masses. All SCs occurred in the superior compartment of the TMJ. There were two patients (14%) categorised as type I, five (36%) as type II and seven (50%) as type III. Four patients (29%) had disc perforation, and nine had bone erosion; among those nine, seven (78%) had type III and two (22%) type II. Histological examination showed inflammation and calcification in the synovial membrane and, and cartilage of the hyaline type in all cases. MRI has advantages in the diagnosis of SC.     

Dynamic magnetic resonance imaging of the temporomandibular joint using FLASH sequences

Magnetic resonance imaging (MRI) is a suitable modality for the visualization of the temporomandibular joint (TMJ) in both normal and pathologic conditions. Until recently, MRI had been unable to provide diagnostic dynamic images of the TMJ during opening. A series of 30 TMJ MRI examinations of 17 symptomatic patients and two normal volunteers (15 to 43 years old; 14 men and five women) was performed. Fast low angle shot (FLASH) sequences were used to provide a series of dynamic images of the TMJ in various phases of opening. In 30% of the joint examined, FLASH sequences contributed clinically significant information not available with standard T1-weighted sequences. These results suggest that FLASH images are particularly useful in distinguishing normal disc variants from pathologic conditions in which the disc is displaced anteriorly to a mild extent. The short imaging time of FLASH sequences decreases motion artifact in patients who have difficulty remaining still during the examination.     

Relationship between temporomandibular joint pain and magnetic resonance imaging findings in patients with temporomandibular joint disorders

The purpose of this study was to evaluate abnormal magnetic resonance imaging (MRI) findings related to temporomandibular joint (TMJ) pain. This study included 245 joints of 152 patients with temporomandibular disorders with anterior disc displacement; of these, 129 joints had joint pain whereas 116 joints had no joint pain. MRI was used to evaluate the reduction of anterior disc displacement, joint effusion, mandible condylar morphology, bone marrow oedema of the mandibular condyle, and signal intensity of the posterior disc attachment (PDA) on fat-suppressed T2-weighted images. The odds ratio (OR) for each MRI variable for the pain group versus the no pain group was computed using logistic regression analysis. Univariate logistic regression analysis showed significant correlations between TMJ pain and all MRI findings. Multivariate logistic regression analysis showed significant correlations with joint effusion (P = 0.03, OR 2.21), bone marrow oedema (P < 0.001, OR 11.75), and signal intensity of the PDA (P < 0.001, OR 6.21). These results suggest that bone marrow oedema, high signal intensity of the PDA on fat-suppressed T2-weighted images, and joint effusion, in descending order of influence, are factors related to TMJ pain.     

Three-dimensional reconstruction system for imaging of the temporomandibular joint using magnetic resonance imaging

This study was undertaken to develop a three-dimensional reconstruction system using magnetic resonance (MR) images in order to visualize three-dimensional images of the temporomandibular joint (TMJ) including the disk. The computerized reconstruction program (written using Visual Basic for Windows, Microsoft Corp.) could reliably generate three-dimensional images of the TMJ. Image processing techniques made the tracing of images unnecessary, reduced complex human manipulation and associated measurement errors. This system, capable of treating fifty thousand pixels or more, generates smooth three-dimensional images of the TMJ.     

Parameters for diffusion weighted magnetic resonance imaging for temporomandibular joint

The purpose of this study was to determine optimum diffusion parameters for diffusion weighted imaging (DWI) techniques, including echo planer imaging (EPI), single-shot fast spin echo (SSFSE), and steady-state free precession (SSFP) in Magnetic Resonance Imaging (MRI) of the Temporomandibular Joint (TMJ). A polyethylene tube with distilled water was individually positioned at the external acoustic meatus foramen in each of three volunteers with normal healthy TMJs. Images were obtained using three types of DWI at differing diffusion parameters, b-factors, and diffusion moment. Signal intensity and imaging ability for various anatomical structures, including the distilled water, were evaluated from each image. The details of the anatomical structures of the TMJ were unidentifiable in the images produced with EPI and SSFSE, but were identifiable on the SSFP images. A diffusion moment value from 100 mT/m(*)msec to 150 mT/m(*)msec for SSFP, in particular, restrained the signal intensity of the water, thereby protecting the comparably high image quality of the TMJ structure. In conclusion, only SSFP is capable of allowing interpretation of emerging pathologic conditions in the TMJ region, when used with a diffusion moment set at between from approximately 100 mT/m(*)msec to 150 mT/m(*)msec.     

颞下颌关节增强磁共振成像研究

目的：探讨磁共振对比增强剂Gd—DTPA对颞下额关节紊乱病的临床诊断意义。方法：对12名临床诊断为颞下颌关节紊乱病患进行磁共振增强前后扫描，观察影像增强效果。结果：Gd—DTPA对关节盘位置正常的关节闭口斜矢状位前伸部及张口位双板区具有显的增强效果；对可复性及不可复性关节盘前移位张闭口位前伸部及双板区均有明显的增强效果；对冠状位也有明显增强效果。结论：磁共振对比增强剂的增强效果明确，为提高临床诊断准确性及作为磁共振常规扫描的辅助手段提供理论依据。     

Magnetic resonance imaging of the temporomandibular joint

Correct diagnosis of internal derangements of the temporomandibular joint requires both a comprehensive clinical and radiographic evaluation. Plain film tomography, transcranial radiography, arthrography and computed tomography have all been used to assess the status of the joint structures. Magnetic resonance imaging is a relatively new modality used for imaging many different organ systems. Magnetic resonance imaging of the temporomandibular joint has certain distinct advantages over previously used techniques in evaluating patients for internal joint derangements. The applicability of magnetic resonance imaging in the diagnosis of internal derangements will be discussed.     

Orthodontic appliances and magnetic resonance imaging of the brain and temporomandibular joint

Experimental and clinical studies find that orthodontic appliances can produce artifacts in MRI, mostly in the facial region. Removal of removable components, especially archwires, with close checking of the security of banded and bonded attachments, should be sufficient in most cases requiring this diagnostic procedure.     

Improved magnetic resonance imaging of the temporomandibular joint by oblique scanning planes

This study was undertaken to investigate whether the quality of magnetic resonance images of the temporomandibular joint could be improved by scanning in oblique planes oriented according to the individual angle of the mandibular condyle (oblique images) instead of in the true anatomic sagittal and coronal planes (orthogonal images). Sagittal and coronal magnetic resonance images obtained by both methods in 21 patients were compared for image quality of the disk. In more than half the patients the oblique images demonstrated the anatomy of the disk better than the orthogonal images. Oblique images are therefore recommended.     

Cinematic study of temporomandibular joint motion using ultra-fast magnetic resonance imaging

Magnetic Resonance Images (MRI) of the temporomandibular joint (TMJ) are usually performed to study the opening/closing movements of the mandible and have up to now been pseudodynamic step-by-step images simulating condylar motion by post-processing reconstruction. The aim of this study was: 1. to optimize a TMJ cine-imaging method to give a better clinical result than the step-by-step methods; 2. to develop an ultra-fast MRI Gradient Echo (GE) sequence for this purpose; and 3. to analyze condylar movements in the sagittal, coronal and para-axial planes during border mandibular displacements and chewing. Both TM joints were studied in six asymptomatic volunteers. The method involved a compromise between in-plane resolution, slice thickness, signal-to-noise ratio and time resolution. Routine clinical use was found to be a GE pulse sequence providing three images per second with an isometric voxel resolution of approximately two millimeters in ridge. This did not allow visualization of the disk. Using this sequence enabled real and simultaneous condylar displacement observation in the three planes of space and therefore contributed to a better functional diagnosis of pathologic TMJ motions.     

颞下颌关节及下颌骨的磁共振三维重建

探讨对颞下颌关节进行ＭＲ影像三维重建的可行性,方法在对颞下颌关节颌骨进行磁共振扫描的基础上,运用计算机工作站的三维重建功能,对磁共振断层影像进行三维重建。结果重建后的髁突,关节盘、关节窝及下颌骨均具有较好的形态进行不同角度的旋转,可清楚地观察到关节窝、关节和髁突的位置关系。     

Long-term magnetic resonance imaging after temporomandibular joint discectomy without replacement.

PURPOSE: The intracapsular changes in patients who underwent discectomy without disc replacement were evaluated by magnetic resonance imaging (MRI) to determine the long-term outcome of this procedure. PATIENTS AND METHODS: Thirty-three patients observed for an average of 9 years 4 months (5 to 24 years) and 10 asymptomatic volunteers underwent MRI using T1- and T2-weighted images and 3-dimensional fast imaging with a steady precession sequence (FISP-3D) technique. The intracapsular changes, especially those in the joint space, were compared with the postoperative clinical findings. RESULTS: MRI examination of the temporomandibular joint in the 33 patients (35 joints) indicated the presence of tissue with an intermediate or high signal intensity in the joint space. This tissue covered the articular surface of the condyle and fossa. Thirty-two joints had no pain or only occasional, mild pain (3 joints). No patient had severe joint pain or a low signal intensity in the joint space on MRI examination. There was no correlation between joint noise and the presence of a tissue deformity in the joint space. MRI of 2 patients with limited mouth opening showed tissue with high signal intensity in the joint space as well as an exostosis on the eminence and hypertrophy of the condyle. CONCLUSION: Long-term success is possible with discectomy without replacement. This appears to be attributable to the formation of new tissue between the condyle and fossa that acts as a pseudodisc.