Arthro-CT in detecting sideways displacement of the temporomandibular joint disk.

One of the major disadvantages of sagittal arthrotomography of the temporomandibular joint is its limited capability to detect sideways (medial or lateral) disk displacement. Several arthrographic signs, suggesting sideways disk displacement have been described in recent reports. The most important one is the edge sign. In doubtful cases, arthro-CT can be used for depiction of medial or lateral disk displacement.     

Oblique head position in temporomandibular joint arthrography

Thirteen patients were prospectively studied with arthrography to determine whether oblique head positions were helpful in diagnosing internal derangement of the temporomandibular joint (TMJ). After injection of contrast material, inclined transcranial lateral spot films were obtained with the patient's head in upward oblique, downward oblique, and neutral positions. The spot films were analyzed for internal derangement by assessing the size of the mass effect on the arthrogram. Twelve of the 13 arthrograms showed evidence of internal derangement of the TMJ. However, the apparent size of the mass effect varied in different head positions. Each of the three views failed to demonstrate the mass effect in at least one instance (eight different patients). No head position was better than another in demonstrating the mass effect. Thus, oblique head positions are useful adjuncts for diagnosing internal derangement of the TMJ.     

Temporomandibular joint: relationship between MR evidence of effusion and the presence of pain and disk displacement.

OBJECTIVE. The purpose of this study was to correlate MR evidence of joint effusion in the temporomandibular joint with symptoms of joint pain and the presence of disk displacement and arthrosis. SUBJECTS AND METHODS. The temporomandibular joints of 379 patients with clinical symptoms of temporomandibular joint disorders and 11 asymptomatic volunteers were imaged bilaterally. Sagittal and coronal proton density-weighted and T2-weighted images were obtained. Imaging findings of joint effusion were correlated with the presence of disk displacement and arthrosis and the symptom of pain. RESULTS. MR showed effusion in 7% of the joints with normal superior disk position, 40% of the joints with disk displacement with reduction, 50% of the joints with disk displacement without reduction, and 27% of the joints with arthrosis. Two of the control subjects had disk displacement with reduction; MR did not show joint effusion in any of the control subjects. A strong association was seen between joint effusion and joint pain. Joint effusion was seen in 46% of the joints on the more painful side and in 13% of the joints on the less painful side. CONCLUSION. The results show that temporomandibular joint effusions primarily occur in joints with disk displacement and are strongly associated with joint pain.     

Disc displacement and changes in condylar position

Objectives:

To determine whether disc displacement (DD) can be a factor causing changes in condylar position in the glenoid fossa, using limited cone beam CT (LCBCT) images taken in the same time period as MRI that verified DD.

Methods:

The study included 60 joints in 57 male and female subjects aged 12–20 years (mean age 14.8 years). Subjects fulfilling the inclusion criteria were enrolled from a pool of post-orthodontic patients, and divided into four groups according to their disc status confirmed by MRI: partial DD (PDD), total DD with reduction (TDDWR), lateral DD (LDD) and medial DD (MDD). Changes in joint space from previously reported norms were measured on LCBCT images.

Results:

In PDD, the condyles were displaced posteriorly in the fossae with a mean anterior space of 2.7 ± 0.5 mm (normal 1.3 ± 0.2 mm) and a posterior space of 1.8 ± 0.4 mm (normal 2.1 ± 0.3 mm). In TDDWR, the condyles were displaced not only posteriorly as observed in PDD, but also vertically with a reduced superior space of 1.9 ± 0.4 mm (normal 2.5 ± 0.5 mm). In LDD, the lateral space was significantly increased to 2.5 ± 0.3 mm (normal 1.8 ± 0.4 mm), while central and medial spaces were significantly decreased to 2.2 ± 0.5 mm (normal 2.7 ± 0.5 mm) and 1.7 ± 0.4 mm (normal 2.4 ± 0.5 mm), respectively. In MDD, the medial space was increased and the lateral and central spaces were significantly decreased.

Conclusions:

These results indicate that DD in adolescents and young adults can cause the condyle to change its position in the fossa with alterations in joint space which depend on the direction and extent of DD.     

Correlation between temporomandibular joint morphology and disc displacement by MRI

Objectives:

The aim was to evaluate the morphology of the temporomandibular joint''s (TMJs) disc and condyle as well as its correlation with disc displacement, using MRI.

Methods:

190 TMJs were retrospectively analysed. The condyle morphology of each TMJ was evaluated by two observers using both axial and coronal views, as were their disc morphology and displacement, using sagittal view. Condyle morphology was classified as flat, convex, angled or rounded in the coronal sections and as anterior side flat/posterior side convex, biconvex, anterior side concave/posterior side convex, flat or biconcave in the axial view. Disc morphology was determined as biconcave, biplanar, biconvex, hemiconvex or folded. χ², Fisher exact and Bonferroni correction tests were used to evaluate the data. ANOVA followed by post hoc Tukey''s test was used to evaluate the interaction between age and disc displacement.

Results:

Anterior disc displacement with reduction; convex condyle morphology in the coronal view; anterior side concave/posterior side convex morphology in the axial view; and biconcave discs were found to be the most prevalent findings. An association was observed between disc morphology and disc displacement (p < 0.001). No correlation between condyle morphology and TMJ disc displacement was found (p = 0.291 for axial and p = 0.14 for coronal views).

Conclusions:

The results of this study suggest that TMJ disc morphology is associated with disc displacement.     

Synovial chondromatosis in the temporomandibular joint complicated by displacement and calcification of the articular disk: report of two cases.

Two cases of synovial chondromatosis of the temporomandibular joint (TMJ) are presented, including correlation of CT and MR imaging characteristics with surgical and pathologic findings. The usefulness of CT and MR imaging in the diagnosis of TMJ disorders is discussed.     

MRI analysis of the relationship between bone changes in the temporomandibular joint and articular disc position in symptomatic patients

Objectives

The aim of this study was to investigate bone changes in the condyle, articular eminence and glenoid fossa in relation to the position of the articular disc.

Methods

148 temporomandibular joints (TMJs) of 74 symptomatic patients who underwent MRI were evaluated. The position of the disc was classified as either normal (N), disc displacement with reduction (DDwR), disc displacement without reduction (DDwoR) and posterior displacement (PD). Bone changes were investigated in the condyle and temporal components of the TMJ and classified as osteophytosis, sclerosis or erosion.

Results

There were no bone changes in the glenoid fossa of the temporal bone. Of the total number of TMJs studied, 94 (63.5%) were N, 34 (23%) presented DDwoR, 19 (12.8%) presented DDwR and 1 (0.7%) presented PD. The bone changes in the condyle and posterior aspect of the articular eminence were associated with the position of the disc. The bone changes in the anterior aspect of the articular eminence were not associated with the position of the disc.

Conclusion

In cases of DDwoR, bone changes in the condyles were more common. The combination of erosion and osteophytosis in the condyle and the bone changes of the posterior aspect of the articular eminence were associated with disc position.     

Changes in condylar mobility and radiographic alterations after treatment in patients with non-reducing disc displacement of the temporomandibular joint

OBJECTIVES: The purpose of this study was to examine changes in condylar mobility and morphological changes in the affected condyles after treatment in patients with non-reducing disc displacement of the temporomandibular joint (TMJ). METHODS: Changes in condylar mobility and morphological changes of the condyle were examined radiographically in 55 patients who were diagnosed as having non-reducing disc displacement of the unilateral TMJ and had received pumping with injection of sodium hyaluronate. In all patients, standardized lateral oblique transcranial radiographs and panoramic jaw tomograms were taken both at initial visit and at 12 months or more follow-up (mean 28.1 months after treatment; range 12-104 months). 42 joints in 21 persons with no current or previous TMJ symptoms served as a control. RESULTS: Clinical signs and symptoms improved after treatment in the patients. Condylar mobility significantly increased after treatment in patients (P<0.001), although it did not reach levels of the control group. Frequency of radiographic changes of the condyle significantly increased after treatment (P<0.005). In most of the patients, no or only mild changes were observed. Frequency of changes of the condyle in patients at follow-up was significantly greater than that in controls (P<0.001). CONCLUSIONS: In the patients, condylar mobility increased in the subsequent course after treatment. However, bony changes of the condyle appeared more frequently. Long term-follow-up after treatment on bony changes of the condyle seems to be necessary in patients with non-reducing disc displacement of the TMJ.     

Optimizing MR signal contrast of the temporomandibular joint disk

Purpose:

To use a tissue specific algorithm to numerically optimize UTE sequence parameters to maximize contrast within temporomandibular joint (TMJ) donor tissue.

Materials and Methods:

A TMJ specimen tissue block was sectioned in a true sagittal plane and imaged at 3 Tesla (T) using UTE pulse sequences with dual echo subtraction. The MR tissue properties (PD, T₂, T₂*, and T₁) were measured and subsequently used to calculate the optimum sequences parameters (repetition time [TR], echo time [TE], and θ).

Results:

It was found that the main contrast available in the TMJ could be obtained from T₂ (or T₂*) contrast. With the first echo time fixed at 8 μs and using TR = 200 ms, the optimum parameters were found to be: θ ≈ 60°, and TE2 ≈ 15 ms, when the second echo is acquired using a gradient echo and θ ≈ 120°, and TE2 ≈ 15 ms, when the second echo is acquired using a spin echo.

Conclusion:

Our results show that MR signal contrast can be optimized between tissues in a systematic manner. The MR contrast within the TMJ was successfully optimized with facile delineation between disc and soft tissues. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.     

Visualization of the articular disk of the temporomandibular joint in near-real-time MRI: feasibility study

While static MRI of the TMJ is the method of choice to evaluate the articular disk (AD), dynamic MRI so far has failed to display the AD. The capability of a modified True-FISP sequence to visualize the AD in dynamic near-real-time imaging (NRTI) was evaluated. Twelve healthy subjects and 17 patients were investigated. Besides static routine imaging, sagittal NRTI of both TMJs was performed with a True-FISP sequence at 1.5 T with TE/TR=1.84/3.68 ms. Two temporal resolutions (250/500 ms) were tested. The quality of the visualization of the AD was rated on a four-point scale (1= very good to 4= poor visualization) by two observers in consensus. ADs of the volunteers were visualized with high quality in all stages of movement (score: 1.69). In patients with internal derangement, disk-motion was clearly depicted, including fast reposition movements. Due to degenerative changes of the AD, the quality of the depiction in patients was slightly lower (score: 2.4). According to the preliminary results of this feasibility study, the suggested NRTI True-FISP sequence is capable of visualizing the entire motion of the AD of the TMJ in normal and pathologic stages with high quality. Further studies are needed to prove the clinical usefulness of this new technique.Electronic Supplementary Material Supplementary material is available for this article at .     

Magnetic resonance images of patients with temporomandibular disorders: Prevalence and correlation between disk morphology and displacement

Using magnetic resonance imaging (MRI), this study aimed to evaluate the morphology of the articular disc of the temporomandibular joint (TMJ) in patients with temporomandibular disorder (TMD). There were 218 TMJ of 109 assessed patients; 88 were females and 21 males, and all were diagnosed as symptomatic for temporomandibular disorder. The articular disc positions were classified in the normal position and with anterior disc displacement with and without reduction. Regarding the morphology, the discs were classified as follows: biconcave (normal), biplanar, rounded, biconvex, folded, thickening in the posterior band, thickening in the anterior band and hemiconvex. The results indicated that females were the most affected by morphological changes of the articular disc (p = 0.008/Cramer's V = 0.295). There was no statistical significance when correlating the disc morphology with the sides (right and left). There was a significant correlation between the position and morphology of the articular disc (p < 0.001/Cramer's V = 0.609), and in the normal position of the discs presenting biplanar and biconcave morphologies. In TMJ with anterior displacement of the disc with reduction (ADDR), there was a greater correlation with rounded, hemiconvex and biconvex morphologies. Already in the TMJ with displacement without reduction (ADDWR), there was a higher prevalence of folded discs. It can be concluded that morphological changes in the disc are influenced by the type of displacement, and more serious deformations are associated with ADDWR cases.     

Frequency of bilateral temporomandibular joint disc displacement in patients with unilateral symptoms: a 5-year follow-up of the asymptomatic joint. A clinical and arthrotomographic study

Bilateral arthrotomography was performed in 50 consecutive patients with unilateral symptoms of disc displacement to evaluate the frequency of temporomandibular joint disc displacement in asymptomatic joints. Using well-defined clinical criteria, there were no false-positive findings of either reducing or non-reducing discs. On the other hand, a risk of false-negative diagnosis of non-reducing disc was apparent. Sixty per cent of the patients had a non-reducing displaced disc in the asymptomatic joint. Most of these patients could recall a previous spell of discomfort from this joint. Severe or moderate deformation had taken place in non-reducing discs, while reducing discs were normal in shape or had, at most, a thickening of the posterior band. The duration of symptoms was significantly correlated with the degree of deformation in the symptomatic joints (P less than 0.01). Perforation was statistically, significantly correlated with disc deformation and, in symptomatic joints, hard tissue changes. Fifty-seven per cent of the asymptomatic joints with displaced discs developed pain following the onset of symptoms from the contralateral side, most within 2 years. Less than half of them were free of pain at the end of the 5 year follow-up period. In view of this tendency for an asymptomatic joint with a displaced disc to subsequently develop pain refractory to treatment, such a joint must be considered a weakened link in the craniomandibular system, vulnerable to changes in mandibular function such as, for instance, displacement of the disc on the contralateral side.     

Disk displacement of the temporomandibular joint: sonography versus MR imaging

OBJECTIVE: The purpose of this study was to determine the value of dynamic sonography in the evaluation of internal derangements of a temporomandibular joint (TMJ) during maximal mandibular range of motion. SUBJECTS AND METHODS: Maximal mandibular range of motion was performed during high-resolution sonography of the TMJ in 64 consecutive patients (128 joints; nine males and 55 females; age range, 17-65 years; mean age, 35 years 6 months), all of whom subsequently underwent MR imaging. MR imaging confirmed disk displacement with reduction in 27 joints and disk displacement without reduction in 60 joints of the 128 examined. The high-resolution sonography and MR imaging findings for these 27 and 60 TMJs, respectively, were analyzed. RESULTS: Dynamic high-resolution sonography performed during the maximal range of motion helped to detect 81 instances (93%) of internal derangement, 22 instances (82%) of disk displacement with reduction, and 50 instances (83%) of disk displacement without reduction. There was one false-positive finding for internal derangement. The accuracy of prospective interpretation of high-resolution sonograms of internal derangement, disk displacement with reduction, and disk displacement without reduction was 95%, 92%, and 90%, respectively. CONCLUSION: When real-time images are interpreted by expert radiologists, dynamic sonography performed during maximal mandibular range of motion may provide valuable information about disk displacement of the TMJ.     

Diagnostic steps in disk dislocations and other frequent illnesses of the temporomandibular joint

Modern diagnosis of the temporomandibular joint (TMJ) consists of multiple steps, based on each other and amplifying one another. The first step is the clinical functional analysis, respecting general medical as well as specific dental aspects. If need arises electronic axiography, recording the movement of TMJ hingeaxis, is being added as well as occlusal analysis on mounted plaster casts. In case of open questions at this point of analysis, magnetresonance- and computer-tomographic imaging is brought in. The present paper is an overview describing the current step by step diagnosis of TMJ disorders, with special attention to luxation-reduction mechanism in the joints.     

Diagnostic imaging of pigmented villonodular synovitis of the temporomandibular joint associated with condylar expansion

Pigmented villonodular synovitis (PVNS) is a rare lesion of the temporomandibular joint. We report a case which was initially misdiagnosed as a parotid tumor. CT revealed a well-defined mass demonstrating higher attenuation than the adjacent soft tissue with marked expansion of the mandibular condyle. MRI clearly delineated the extent of the lesion which had very low signal intensity on both T1W and T2W sequences due to the effect of hemosiderin. The usefulness of these imaging procedures in diagnosis of PVNS is discussed.     

下颌髁突脱位骨折后颞下颌关节软组织改变的MRI表现

目的 分析下颌髁突脱位骨折后颞下颌关节(TMJ)软组织改变的MRI表现.方法 应用矢状面和冠状面质子密度加权成像(PDWI)和T2WI连续检查103侧(77例)患有下颌髁突脱位骨折的颞下颌关节(TMJ).结果 MRI上,103侧髁突脱位骨折后的TMJ异常表现有:(1)髁突骨折断片向前下(102侧,99.0%)和前(1侧,10%)脱位;(2)关节盘移位(100侧,97.1%),其中矢状面MRI显示关节盘随脱位的髁突向前下移位者99侧,向前移位者1侧;(3)关节腔积液(103侧,100%);(4)关节盘后区信号异常(91侧,88.3%);(5)关节盘下后附着异常(89侧,86.4%);(6)关节囊异常(89侧,86.4%);(7)关节盘上后附着异常(37侧,35.9%);(8)关节盘变形(8侧,7.8%);(9)关节盘撕裂(8侧,7.8%);(10)颞骨关节窝骨折(4侧,3.9%).结论矢状面MRI上,多数下颌髁突脱位骨折以TMJ关节盘随脱位的髁突向前下移位,并伴有关节腔积液为特点.     

组织工程重建兔颞下颌关节盘软骨

目的 应用组织工程学方法重建颞下颌关节盘软骨。方法 分离6只日本大耳白兔髁状突软骨细胞。进行细胞的微载体大规模扩增,将扩增后的软骨细胞接种于组织引导再生胶原膜,体外适当培养后植入4只同种成年兔皮下,植入后12周,对所获组织进行组织形态学观察。结果 髁状[突软骨细胞在胶原膜内生长良好,植入动物体内12周后可形成乳白色类软骨样组织,其表面光滑,有弹性。甲苯胺蓝染色,细胞周围基质呈异染性。结论 应用胶原膜结合软骨细胞共同培养,可形成软骨样组织,该方法将有可能成为软骨缺损及关节盘破损修复的有途径。