A study of the relationship between the position of the condylar head and displacement of the temporomandibular joint disk.

OBJECTIVES: To examine the possible relationship between condylar position and disk displacement in the TMJ. METHODS: Forty-eight joints with no disk displacement (NDD), 84 joints with a reducible displaced disk (RDD) and 99 joints with a permanently displaced disk (PDD) were selected. The positions of the condyle and TMJ disk were calculated from lateral MR images. RESULTS: There were significant differences in condylar position between the joints with NDD and RDD, while there was no difference between those with NDD and PDD (Kruskal-Wallis and post-hoc test, P<0.05). There was also a significant correlation between the position of the condylar and the displaced disk (Spearman's rank correlation, P<0.05). The condyle was located more anteriorly with advancing disk displacement. CONCLUSIONS: We suggest that if the disk displacement is slight, the condyle is displaced posteriorly: as the disk displacement becomes more severe (i.e. more anteriorly displaced), the condyle returns to the concentric position.     

Decreased disk-eminence ratio is associated with advanced stages of temporomandibular joint internal derangement.

OBJECTIVE: To examine the possible correlation between the stage of internal derangement and the antero-posterior length of the disk in relation to the length of the articular eminence. STUDY DESIGN: Twenty asymptomatic volunteers with normal joints and 120 patients with TMJ dysfunction underwent MR imaging. The A-P length of the disk in relation to the length of the articular eminence (D/E ratio) was measured. RESULTS: The D/E ratio was 0.95 in the asymptomatic volunteers, 0.83 in patients with disk displacement with reduction, 0.74 in those with disk displacement without reduction and 0.57 in the patients with disk displacement and osteoarthritis. The relationship between the D/E ratio and the stage of internal derangement was statistically significant (P<0.01). CONCLUSION: The D/E ratio decreases with advancing internal derangement. We suggest that it is a reliable numerical method for staging the degree of the internal derangement.     

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.     

MR imaging of the juvenile temporomandibular joint: preliminary report.

Thirty-two children were evaluated by means of medical history and physical examination for signs and symptoms of internal derangement (ID) of the temporomandibular joint (TMJ) and mandibular dysfunction. These children also underwent magnetic resonance (MR) imaging of the TMJs. The study was double blind. At clinical examination, 19 patients (59%) had at least one positive finding of ID of the TMJ and/or mandibular dysfunction. MR images of the TMJ obtained in 60 of the 64 TMJs demonstrated 57 normal joints (95%) and three abnormal joints (5%). Two of these three joints had a mild anterior-lateral disk displacement, and one joint had an anterior dislocated disk. There were no false-positive MR examinations. MR imaging failed to depict abnormalities in 16 patients who had positive findings at history and/or physical examination. Although MR imaging may fail to depict ID of the TMJ in some patients, clinical techniques commonly used in population surveys probably overstate the prevalence of ID of the TMJ in children.     

Thickening of the glenoid fossa in osteoarthritis of the temporomandibular joint. An autopsy study

OBJECTIVE: To evaluate the thickness of the roof of the glenoid fossa of the temporomandibular joint (TMJ) in relationship to the stage of internal derangement from autopsy material. MATERIAL AND METHODS: The minimum thickness of the roof of the glenoid fossa was measured with a caliper in 61 TMJ autopsy specimens. Based on macroscopic examination the joints were categorized as normal (30 joints), disk displacement (eight joints), disk displacement with osteoarthritis (12 joints) and osteoarthritis with perforation of the disk or posterior attachment (11 joints). The relationship between thickness of roof of the glenoid fossa and status of the joint was analysed. RESULTS: The roof of the glenoid fossa was on the average 0.6 mm in normal joints, 1.1 mm in joints both with disk displacement and disk displacement with osteoarthritis and 2.6 mm in joints with osteoarthritis and perforation. The difference between the normal joints and those with perforation was significant (P<0.01). CONCLUSION: Progressive remodeling with thickening of the roof of the glenoid fossa seems to be associated with perforation of the disk or posterior attachment.     

The diagnosis of temporomandibular joint disease: two-compartment arthrography and MR

The reliability and accuracy of two-compartment temporomandibular joint (TMJ) arthrography was compared with MR imaging on the basis of an analysis of surgical findings obtained from joints that had been studied preoperatively with arthrography or MR or, in some cases, both procedures. Seven hundred forty-three consecutive TMJ arthrograms were successfully obtained in a total of 443 patients by using a single 27-gauge needle and a two-compartment technique in each joint. There was a 100% correlation with surgical findings in 218 radiologically abnormal joints operated on within 90 days of arthrography with respect to the presence or degree of meniscus displacement and normal or abnormal disk morphology and function. In 604 patients 1052 TMJs were studied with high-field-strength surface-coil MR. Surgical findings were available for correlation in 170 of the joints studied. Forty-three joints were studied with both two-compartment arthrography and MR. Eight operated joints had been imaged successfully with both two-compartment arthrography and MR. Both methods of evaluation provided highly reliable and accurate information regarding meniscus position and shape. Arthrography was superior to MR in detecting capsular adhesions and the presence or absence of perforation of the disk or meniscus attachments. Simple meniscectomy (with or without insertion of a temporary Silastic TMJ implant) was the most frequently performed surgical procedure in the series, followed by meniscus repositioning procedures. Joint effusions, failed TMJ implants, and avascular necrosis were demonstrated best with MR. Soft-tissue lesions, including intrinsic degeneration of the meniscus, anomalous muscle development, muscle atrophy, tendinitis, and injuries such as contusions and hematomas, were demonstrated only with MR. Partial-flip-angle GRASS (gradient-recalled acquisition in the steady state) techniques permit both fast scanning and study of functional joint dynamic. Joint fluid may appear as high signal intensity on GRASS images because of T2*-weighting. We recommend MR as the procedure of choice for diagnosis of uncomplicated internal derangements of the TMJ. Two-compartment arthrography with videofluoroscopy is an important ancillary procedure that should be performed whenever capsular adhesions or perforations are suspected and not demonstrated with MR and whenever MR is inconclusive.     

Temporomandibular joint: MR assessment of rotational and sideways disk displacements

The accuracy of coronal and sagittal magnetic resonance (MR) imaging was examined in the assessment of rotational and sideways displacements of the temporomandibular joint (TMJ) disk. Rotational disk displacement implies a combination of anterior and medial or lateral displacements, whereas sideways displacement implies pure medial or lateral displacement without an anterior component. Multiple 3-mm-thick coronal and sagittal MR images were obtained of 18 fresh TMJ autopsy specimens and compared with the observations in corresponding coronal cryosections. MR imaging correctly delineated the mediolateral position of the disk in 15 joints (83%) and incorrectly delineated it in three joints (17%). Osseous anatomy was correctly assessed in 17 joints (94%). On cryosections, six joints (33%) showed medial disk displacement and two joints (11%) showed lateral displacement. In five of these eight joints the medial or lateral displacement occurred in conjunction with an anterior displacement, that is, rotational displacement. Clinical MR imaging in 37 patients (61 joints with coronal images) showed medial or lateral disk displacement in 16 joints (26%). This study suggests that rotational and sideways displacements of the TMJ disk are an important aspect of internal derangement. The multiplanar capabilities of MR are suitable for an assessment of these abnormalities.     

Temporomandibular joint abnormalities associated with rheumatic disease: comparison between MR imaging and arthrotomography.

Nonenhanced magnetic resonance (MR) images and arthrotomograms of temporomandibular joints (TMJs) were compared in 18 patients with rheumatic disease. Of 22 symptomatic TMJs, arthrotomography was unsuccessful in three (14%). MR imaging showed extensive rheumatic abnormalities in two of these three joints and internal derangement in one. In another three joints (14%), both imaging modalities showed normal findings or internal derangement. In the remaining 16 joints (72%), arthrotomographic findings were interpreted as rheumatic, whereas MR findings were interpreted as rheumatic in 14 joints and as internal derangement in two. Surgical correlation in 11 joints indicated superiority of MR imaging for assessment of moderate and severe rheumatic TMJ involvement. MR imaging seemed to be of limited value in early diagnosis due to its inability to show synovial proliferation. Indirect signs of synovial proliferation could be shown with arthrotomography, which may be helpful in early diagnosis of rheumatic TMJ disease.     

Temporomandibular joint: MR imaging of internal derangements and postoperative changes

Nineteen abnormal temporomandibular joints (TMJs) imaged with high-field-strength surface-coil MR are presented to illustrate specific changes associated with disk derangement, trauma, and previous surgery. Cases were selected from a series of 248 TMJ MR studies in 144 patients (9-68 year old, 130 females and 14 males) performed during a 5-month period. Surgical findings were available for correlation in 44 of the 248 joints studied. Increased signal caused by myxoid degeneration within the degenerating meniscus was seen, as were pathologic changes including atrophy, fibrosis, and contracture of masticatory muscles occurring with internal derangements. Advantages and limitations of MR are discussed with reference to arthrography and videofluoroscopy. High-resolution and partial-flip-angle images of a normal joint are provided for comparison. In most clinical circumstances, MR is the procedure of choice when examining the TMJ, because it provides contrast resolution of soft-tissue structures superior to that of conventional imaging techniques.     

Rheumatic and nonrheumatic disease in the temporomandibular joint: gadolinium-enhanced MR imaging.

Magnetic resonance (MR) imaging of 36 temporomandibular joints (TMJs) in 27 patients and six healthy volunteers was performed before and after injection of gadopentetate dimeglumine. Twelve asymptomatic joints were used as controls, 12 TMJs had symptomatic internal derangement, and 12 TMJs had rheumatic inflammatory disease. A small or moderate joint effusion was seen in one asymptomatic joint, four joints with internal derangement, and one joint with rheumatic involvement; in all of these, contrast enhancement of the effusion was observed. A large effusion in one rheumatic joint was enhanced only after delayed imaging. In healthy controls and patients with internal derangement, no or only minimal enhancement of intraarticular tissues was seen. Eleven of the 12 rheumatic TMJs showed moderate or intense soft-tissue enhancement along the disk and articular surfaces (ie, in areas normally devoid of synovial membrane). The one rheumatic joint without enhancement had bony ankylosis and no remaining soft tissue within the joint space. Gadolinium-enhanced MR imaging of the TMJ may effectively depict the proliferating synovium of rheumatic inflammatory joint disease.     

Alteration of the horizontal mandibular condyle size associated with temporomandibular joint internal derangement in adult females

OBJECTIVES: The purpose of this retrospective study was to analyse the relationship between horizontal size of the mandibular condyle and internal derangement (ID) of the temporomandibular joint (TMJ). METHODS: One hundred and thirty-nine joints in 88 women aged over 18 years were included in this study. The horizontal condylar size was measured in the antero-posterior and medio-lateral (ML) dimensions using axial magnetic resonance (MR) images. Radiological findings of ID were also assessed from MR imaging. RESULTS: The condyles in the joints with permanent disk displacement were smaller than those in joints without displacement in both dimensions (Fisher's protected least significant difference, P<0.05). There were statistically significant correlations between horizontal condylar size in the ML dimension and both disk morphology and radiological stage of ID (Spearman's correlation coefficient by rank, P<0.05). CONCLUSIONS: The results of this study suggest a possible relationship between horizontal condylar size and disk displacement. It is also suggested that the condyle becomes smaller in the ML dimension with advancement of ID.     

Simultaneous pseudodynamic MR evaluation of bilateral temporomandibular joints]

Coordination of bilateral temporomandibular joints (TMJs) was evaluated using bilateral simultaneous pseudodynamic magnetic resonance (MR) imaging. Seven patients (6 patients with internal derangement and one with osteoarthritis) were examined by multiplanar gradient echo technique in closed-loop cine fashion on both sagittal and coronal planes. Incoordination of bilateral TMJ motion was observed in 2 of 7 patients. This technique might be suitable for evaluation of TMJ disorders.     

MRI and arthrography in the evaluation of TMJ disorders

Arthrosis of the temporomandibular joint (TMJ) is a noninfectious, noninflammatory condition characterized by joint pain, noise (clicking) and abnormal motion. It contains various disease processes, such as abnormalities in the menisci or masticating muscles, subluxation of the condyle and degenerative joint disease. Analysis of the morphology and dynamics of TMJ by means of imaging modalities has become highly advanced since the development of arthrography in the late 1970s. Magnetic resonance imaging (MRI) has become the modality of choice in the evaluation of TMJ owing to the development of surface coils. We retrospectively studied MRI and inferior joint compartment arthrography in the evaluation of TMJ disorders. Nineteen joints of 14 patients included 15 with internal derangement, two with osteoarthrosis and two normal joints. Sagittal MR images were routinely obtained in a resting position and in positions with the mouth half open, and also with the mouth fully open on balanced images. Although perforation of the menisci was difficult to evaluate, MRI and arthrography were equally useful in identifying the shape and position of the meniscus. However, MRI was more reliable in depicting TMJ abnormalities than arthrography. MR is considered to be the modality of choice in screening arthrosis of TMJ, making the definitive diagnosis of internal derangement and monitoring conservative therapy for arthrosis.     

MR tomographic diagnosis of internal derangement of the temporomandibular joint]

On the basis of MR imaging studies in 150 temporomandibular joints (TMJ) a classification system for internal derangement of the TMJ was defined. Clinically, internal derangement is characterized by disc displacement and disorders of the mandibular condyle. MR imaging enables a differentiation of early stages (I,II) with disc displacement, the intermediate stage (III), and the later stages (IV,V) with osseous destruction. Optimal diagnostic results (n = 140) allowed the use of proton-density sequences in both open and closed joint positions (TR/TE = 1000/28). Dynamic imaging of the TMJ was performed using fast-gradient echo sequences and a self-developed hydraulic opening device (n = 20). MR imaging has proved to be the method of choice for the pre- and post-therapeutic evaluation of internal derangement of the TMJ.     

The accuracy of dynamic Magnetic Resonance Imaging in evaluation of internal derangement of the temporomandibular joint; comparison with arthroscopic findings

Purpose

To determine the correlation between dynamic Magnetic Resonance Imaging (MRI) and arthroscopy findings in internal derangement of the temporo-mandibular joint (TMJ).

Material and methods

This study was conducted on 25 patients (of 28 TMJs), 18 females and 7 males their age ranging from 20 to 42 years (mean 31 years). All patients were submitted to MRI examination of the TMJ. All of these patients underwent arthroscopy for diagnosis and treatment and results were compared with dynamic MRI findings.

Results

Concerning disc position, MR examination revealed 24 TMJs out of 28 (85.7%) with anteriorly displaced discs, while 4 TMJs (15.3%) showed normal disc position. When type of displacement was considered, MRI revealed 8 TMJs (28.7%) with anterior disc displacement with reduction (ADDWR), while 16 TMJs (57.1%) with anterior disc displacement without reduction (ADDWOR). While arthroscopy revealed 6 TMJs out of 28 (21.4%) with ADDWR, 14 TMJs (50%) showed ADDWOR and 8 TMJs (28.6%) with normal disc position.MRI assessment of disc mobility revealed 12 out of 28 TMJs (42.8%) with limited asynchronous movements, while 3 TMJs (10.7%) with stuck disc, and 13 TMJs (46.4%) with normal mobility. While arthroscopy revealed 11 out of 28 TMJs (39.2%) with limited disc mobility, 1 TMJs (3.5%) with stuck disc, and 16 TMJs (57.1%) with normal mobility.The results of this study showed no significant statistical difference between arthroscopy and MRI in diagnosing disc position and disc mobility.

Conclusions

Both arthroscopy and dynamic MRI are statistically correlated with each other in detecting TMJ internal derangement. Nevertheless, reviewing the results highlighted the advantages of MRI augmented by dynamic protocol over arthroscopy in diagnosing disc position and mobility and hence, we recommend using MRI as a first line diagnostic modality when internal derangement is suspected.     

Dynamic MRI of temporomandibular joint: technique and application

Internal derangements or disk dysfunctions represent the most frequent pathology of the temporomandibular joint (TMJ). The radiological study of TMJ dysfunction was, for a long time, restricted to arthrography. More and more MR is used to study the TMJ, because MR, allows non-invasive visualisation of without the use of X-rays. Moreover a "dynamic" MR technique can be used to study disk movements during mouth opening. A lot of the internal derangement problems can be solved with this technique and arthrography can often be avoided. This dynamic MR technique is described and some cases are discussed.     

The accuracy of sonography for evaluation of internal derangement of the temporomandibular joint in asymptomatic elementary school children: comparison with MR and CT

BACKGROUND AND PURPOSE: In order to clarify the incidence and evolution of disk displacement in the temporomandibular joint (TMJ) in children, we performed a longitudinal analysis in 18 subjects. Some investigators have suggested that sonography can provide information about the articular disk position of the TMJ. The purpose of this study was to determine the diagnostic accuracy of sonography for revealing internal derangement of the TMJ in elementary school children compared with our standard of reference, MR imaging and helical CT. METHODS: Eighteen children were examined using both sonography and MR imaging or helical CT or both. The sonographically revealed distance between the articular capsule and the lateral surface of the mandibular condyle was measured and compared with that obtained by MR or helical CT scanning. RESULTS: Compared with our MR/CT standard of reference, sonography revealed a sensitivity of 83%, a specificity of 96%, and an accuracy of 92% for identifying disk displacement (defined as a distance of 4 mm or more between the articular capsule and the lateral surface of the mandibular condyle). CONCLUSION: Although sonography's sensitivity, specificity, and accuracy for the diagnosis of disk displacement were slightly inferior to those of MR or helical CT, we assert it is a useful imaging method for longitudinal investigations of a large group of elementary school children. Internal derangement of the TMJ should be suspected if sonography reveals a distance between the articular capsule and the lateral surface of the mandibular condyle of 4 mm or more.     

颞颌关节内错乱的直接矢状面CT检查

This paper reported the preliminary experience of direct sagittal CT of temporomandibular joint (TMJ) and its modalities of TMJ was made. By using a specially devised table, the bony structure and disc of TMJ can be well demonstrated. The major advantage of this technique is direct demonstration of the articular disc and a diagnosis of anteriorly displaced meniscus which is reducible or irreducible can thus be made. The application of CT in internal derangement of TMJ will open up new insight into the diagnosis and management of these patients.     

Temporomandibular joint disk displacement: comparison in asymptomatic volunteers and patients

PURPOSE: To compare the prevalence and type of temporomandibular joint (TMJ) disk displacement in asymptomatic volunteers with those in patients. MATERIALS AND METHODS: Bilateral oblique sagittal and oblique coronal intermediate-weighted magnetic resonance (MR) images of the TMJs in 58 patients with pain and dysfunction were analyzed and compared with corresponding MR images of 62 asymptomatic volunteers. RESULTS: Forty-five (78%) of 58 patients had disk displacement compared with 22 (35%) of 62 asymptomatic volunteers. Complete disk displacement was found in 46 (40%) of 115 joints in patients compared with three (2.4%) of 124 joints in asymptomatic volunteers, whereas partial disk displacement occurred in 26 (22.6%) and 27 (21.8%) joints, respectively. Two types of complete disk displacement, anterolateral and anterior, occurred frequently in patients, seldom in volunteers. Only minor differences were found between other types of disk displacement when prevalence in patients was compared with that of volunteers. The disk reduced to a normal position on open-mouth images in all joints in the volunteers compared with 76% of the joints in patients. CONCLUSION: TMJ disk displacement was less prevalent and was of a different type in asymptomatic volunteers compared with patients with pain and dysfunction.     

MR of osteochondritis dissecans and avascular necrosis of the mandibular condyle

We studied 40 patients exhibiting radiologic changes of either osteochondritis dissecans (OCD) or avascular necrosis (AVN) involving the mandibular condyle to evaluate the structural changes associated with these lesions when using high-field-strength MR imaging. Various clinical indications for imaging each patient with routine radiography, tomography, and surface-coil MR included headache, temporomandibular joint (TMJ) and/or ilsilateral facial pain, joint crepitus, clicking, locking, and either recently acquired or changing (unstable) occlusal disorder. Radiologic findings included alterations in condyle morphology and MR signal characteristics compatible with either OCD or AVN or, in some cases, both. Previous nonsurgical mandibular trauma was temporally related to the onset of symptoms in eight patients. Five patients exhibiting either unilateral or bilateral AVN involving the condyles and condylar necks had undergone previous orthognathic surgery, including sagittal split mandibular osteotomies followed by intermaxillary fixation. One patient exhibiting condylar AVN with articular surface collapse and osseous destruction had undergone previous TMJ meniscectomy followed by insertion of a permanent Proplast implant. Thirty-one of 34 patients with no prior surgery and MR changes of condylar OCD/AVN had associated internal derangement of the TMJ meniscus. There was surgical confirmation of findings in 10 joints. We assert that OCD and AVN are relatively common, clinically significant lesions of the mandibular condyle often associated with preexisting internal derangement of the temporomandibular joint.