Visualization of anterior disc displacement in temporomandibular disorders on contrast-enhanced magnetic resonance imaging: comparison with T2-weighted, proton density–weighted, and precontrast T1-weighted imaging

Automatic detection of anteriorly displaced temporomandibular joint discs on magnetic resonance images using a deep learning algorithm

OBJECTIVES

This study aimed to develop models that can automatically detect anterior disc displacement (ADD) of the temporomandibular joint (TMJ) on MRIs before orthodontic treatment to reduce the risk of developing serious complications after treatment.

METHODS

We used 9009 sagittal MRI of the TMJ as input and constructed three sets of deep learning models to detect ADD automatically. Deep learning models were developed using a convolutional neural network (CNN) based on the ResNet architecture and the "Imagenet" database. Five-fold cross-validation, oversampling, and data augmentation techniques were applied to reduce the risk of overfitting the model. The accuracy and area under the curve (AUC) of the three models were compared.

RESULTS

The performance of the maximum open mouth position model was excellent with accuracy and AUC of 0.970 (±0.007) and 0.990 (±0.005), respectively. For closed mouth position models, the accuracy and AUC of diagnostic Criteria 1 were 0.863 (±0.008) and 0.922 (±0.009), respectively significantly higher than that of diagnostic Criteria 2 with 0.839 (±0.013) (p = 0.009) and AUC of 0.885 (±0.018) (p = 0.003). The classification activation heat map also improved our understanding of the models and visually displayed the areas that play a key role in the model recognition process.

CONCLUSION

Our CNN model resulted in high accuracy and AUC in detecting ADD and can therefore potentially be used by clinicians to assess ADD before orthodontic treatment, and hence improve treatment outcomes.

MRI-based observation of the size and morphology of temporomandibular joint articular disc and condyle in young asymptomatic adults

OBJECTIVE

To investigate the size and morphology of the temporomandibular joint (TMJ) articular disc and condyle in young asymptomatic adults by using magnetic resonance imaging (MRI) and to provide a reference for clinical diagnosis and scientific study of temporomandibular disorders (TMD).

METHODS

Overall, 93 undergraduate volunteers without TMD were enrolled from the freshmen pool at the Qingdao University. All participants underwent MRI of the oblique sagittal and oblique coronal TMJ planes. The articular disc and condyle were subsequently measured, and their morphology was evaluated. The obtained data were then grouped and analyzed statistically. Finally, intragroup correlation coefficient (ICC) was used to evaluate the interobserver measurement reliability.

RESULTS

We totally received 186 TMJ imaging samples. Based on our analysis, disc's anterior band in young asymptomatic adult females were thicker than males of the same age (p = 0.024). Moreover, the media-lateral dimensions of the condylar head of adult females were shorter than males of equal age (P＜0.001). The bilateral articular disc morphology was the same in 72.4% of subjects while the condylar morphology was the same in 63.4% of participants. Finally, using measurement reliability assessment, we demonstrated that our conclusions are reliable (ICC ≥0.7).

CONCLUSION

The thickness of the anterior band of the disc and the media-lateral dimensions of the condylar head were gender-related. Additionally, the morphology of the bilateral articular disc and condyle was different among the subset of young asymptomatic adults.

Stability of the contralateral temporomandibular joint disk position after disk repositioning on one side

OBJECTIVE

To evaluate the stability of the contralateral temporomandibular joint disk position after disk repositioning on 1 side.

STUDY DESIGN

Patients with unilateral anterior disk displacement (ADD) treated by disk repositioning from 2015 to 2019 were included in the study. The contralateral disk status was classified as follows: normal, ADD with reduction (ADDwR), and medial/lateral displacement. At 1-year follow-up, changes in the contralateral disk position were evaluated by MRI.

RESULTS

Two hundred thirty-four patients were included in the study. There were 84 disks with normal position, 51 with ADDwR, and 99 with medial/lateral displacement (M/LD) in the contralateral joint. At 1-year follow-up, all the repositioned disks were stable without relapse. In the contralateral joints, 75% of the disks with normal position were unchanged compared with 43.1% of the ADDwR and 54.5% of the M/LD. ADDwR had the highest rate of changing to ADDwoR compared with the disks in normal position (4.8%) and M/LD (7.1%, χ² = 16.13, P < .001). There were 28.3% of M/LD disks and 3.9% of ADDwR that changed to normal position.

CONCLUSIONS

After unilateral disk repositioning, most of the contralateral disks with normal position were stable. M/LD disks tended to move to normal position, whereas ADDwR was largely changed to ADDwoR.

MRI of Temporomandibular Joint Disorders: Recent Advances and Future Directions

Temporomandibular joint disorders (TMDs) are a prevalent disease covering pain and dysfunction of temporomandibular joints and masticatory muscles, which can be detrimental to quality of life. Magnetic resonance imaging (MRI) is a powerful and noninvasive tool for the imaging and understanding of TMD. With the recent technical development of dynamic and quantitative MRI techniques, including diffusion-weighted imaging, T₂ mapping, and ultrashort/zero echo time, it is now feasible in TMD imaging and has been preliminarily investigated with promising results. In this review we will discuss the recent advances of MRI techniques in TMD and its future directions, and hope to highlight the scientific potential and clinical value of novel MRI techniques in diagnosing and treating TMD. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY STAGE: 3.

A magnetic resonance imaging study on the temporomandibular joint disc-condyle relationship in young asymptomatic adults

The aim of this study was to assess the temporomandibular joint (TMJ) disc-condyle relationship in asymptomatic young adults. Ninety-three volunteers aged 19-23 years without temporomandibular disorder (TMD) symptoms underwent TMJ magnetic resonance imaging (MRI). The condylar centre and apex methods were used to measure and analyse the position of the disc in the oblique sagittal plane, and the reliability of the two methods was compared by calculating the intra-class correlation coefficient (ICC). Furthermore, 18 of the volunteers were randomly selected for three-dimensional (3D) reconstruction of the TMJ structure and the disc-condyle relationship. The 3D TMJ structure was established by semi-automatic segmentation of the condyle and articular disc in ITK-SNAP software; the condylar apex method was then performed. It was found that only 33.3% of the posterior edge of the articular discs were located in the normal 12 o'clock position with respect to the condyle. Moreover, this study suggests that the condylar centre method lacks accuracy when compared to the condylar apex method in regard to the measurement of the TMJ disc-condyle relationship (0 < ICC_cen < ICC_apex < 1). The position of the articular disc (left and right) was more forward in young women when compared to young men. However, there was no significant difference in the TMJ disc-condyle position between the left and right sides in the same individual, although the two joint discs in the same individual were not completely symmetrical.

Application of fused image in detecting abnormalities of temporomandibular joint

OBJECTIVES:

To present a method for image fusion of cone beam CT (CBCT)/CT and MRI and to explore whether the image data sets fused in such a way could aid the detection of temporomandibular joint (TMJ) anatomical structures and lesions.

METHODS:

There were five cases included in this study. One case was space occupying lesion giant cell tumour of tendon sheaths, one case was chronic inflammation in the condyle, one case was articular disc calcification of the bilateral TMJs, and the other two cases were TMJ disorders (anterior disc displacement without reduction). The digital imaging and communications in medicine format data of CT/CBCT and MRI of the cases were collected, and then imported to the Amira visual software where the registration process was conducted. Based on the different scan model, the registration process could be separated into automatic registration of CT/CBCT with quadrature slice MR images and the semi-automatic registration of CT/CBCT with oblique slice MR images by altering the registration parameters. Rigid transform model and the similarity metric of normalization mutual information was used for registration in the present study.

RESULTS:

The relationship between the soft mass and hard tissue was shown clearly in the fused images when compared to sole observation of CBCT/CT or MR images. The fused images could define the tumour outline and the destructive bone clearly in the same image. The fused results helped the observers to ensure uncertain defects which could not be confirmed only by one image data set.

CONCLUSIONS:

The CT/CBCT and MR images could be fused to aid detection of TMJ anatomical structures and related lesions.

The Efficiency of Anterior Repositioning Splints in the Management of Pain Related to Temporomandibular Joint Disc Displacement with Reduction

Background and Objective

Intra-articular temporomandibular disorders are often related to pain in the area of the temporomandibular joint, ear, and temple. The aim of the study was to investigate the efficiency of anterior repositioning splints in decreasing pain related to temporomandibular joint disc displacement with reduction.

Methods

The research material consisted of 112 patients, aged 24 to 45 years, of both genders, who reported for treatment at the Consulting Room of Temporomandibular Joint Dysfunctions at the Jagiellonian University in Cracow between 2014 and 2016 due to pain in the area of the temporomandibular joint(s) and noise(s) of temporomandibular joint(s) present during jaw movements with comorbid contracture of masticatory muscles. Subjects were examined according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) protocol and, after diagnosis of painful disc displacement with reduction and masticatory muscle contracture, they were assigned randomly to either the study or control groups (56 patients in each). In the study group, we used an anterior repositioning splint on the full lower arch for about 20 hours usage over a 4-month period. In the control group, a noninvasive therapy was applied using a biostimulation laser over 12 sessions performed every second day on the area of both temporomandibular joints with mouth open and while performing muscle self-exercises with a dominant protrusive position of the mandible. Pain intensity was evaluated using the Verbal Numerical Rating Scale (VNRS) immediately before the treatment and then after 4 and 16 weeks. The obtained data were analyzed using the Mann–Whitney U test (p ≤ 0.005).

Results

The VNRS values reported during the final examination for the study group were significantly lower than for the control group (p=0.0004).

Conclusions

The anterior repositioning splint is an efficient tool in decreasing pain related to disc displacement with reduction. This trial is registered with Clinicaltrials.gov NCT03057262.

Changes in disc status in the reducing and nonreducing anterior disc displacement of temporomandibular joint: a longitudinal retrospective study

Treatment procedures for anterior disc displacement (ADD) of temporomandibular joint (TMJ) are far from reaching a consensus. The aim of the study was to evaluate disc status changes of anterior disc displacement with reduction (ADDWR) and without reduction (ADDWoR) comparatively, to get a better understanding of the disease progress without intervention. This longitudinal retrospective study included 217 joints in 165 patients, which were divided into ADDWR group and ADDWoR group based on magnetic resonance imaging (MRI) examination. The joints were assessed quantitatively for disc length and displacement distance at initial and follow-up visits. Disc morphology, which was classified in 5 types, was also evaluated. Paired t-test and Wilcoxon signed rank test were used to assess intra-group differences and independent t-test for inter-group differences. Moreover, analysis of covariance was applied to analyze influential factors for changes in disc length and displacement distance. According to our results, discs tended to become shorter, move further forward and distort more seriously in ADDWoR group than in ADDWR group after follow-up. Moreover, discs were prone to become shorter and more anteriorly displaced in teenagers, type I and III morphologies, advanced Wilkes stages, or those with joint effusion. Follow-up period seemed to be not critical.

Biometric parameters of the temporomandibular joint and association with disc displacement and pain: a magnetic resonance imaging study

The aim of this study was to evaluate the relationship between biometric parameters of the components of the temporomandibular joint (TMJ), articular disc displacement, and TMJ pain. Magnetic resonance imaging (MRI) examinations of 185 patients were assessed (39 males and 146 females (370 TMJs), mean age 41.3 years, range 18-79 years). The antero-posterior length of the condyle was measured in its medial and lateral regions, as well as the transverse length of the condyle. Possible associations between linear measurements of the condyle, presence of disc displacement, and joint pain were tested. Although pain was more commonly reported among patients with disc displacements, this association was not statistically significant. We found statistically significant associations showing that the antero-posterior length of the condyle at the lateral pole (D1L), the antero-posterior length of the condyle at the medial pole (D1M), and the transverse length of the condyle (D2) were higher among patients without disc displacements when compared to those with unilateral or bilateral displacements. This study showed that disc displacement was associated with smaller condyles in the antero-posterior and transverse dimensions when compared to condyles in subjects with normal disc position.

Condyle-disk-fossa position and relationship to clinical signs and symptoms of temporomandibular disorders in women

OBJECTIVE

The aim of the present study was to assess the disk-condyle-fossa relationship through magnetic resonance imaging and determine its association with clinical signs and symptoms of temporomandibular disorder in patients with myofascial pain and disk displacement (with and without reduction).

STUDY DESIGN

Sixty-two female patients with complaints of pain were clinically examined using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and divided into the following groups: Group I, myofascial pain (n = 19); Group IIa, disk displacement with reduction (n = 32); and Groups IIb and IIc, disk displacement without reduction (n = 11). Classification of disk position was based on the positioning on a clock face (> or < than 11 o'clock) and condylar excursion was determined as (1) the proximal side of the apex of the articular eminence; (2) at the level of the articular eminence; and (3) beyond the apex of the articular eminence. Condylar position was determined in the sagittal images based on Gelb's template (normal, posteriorly displaced). Pain was assessed using a visual analogue scale (VAS). The univariate logistic regression, Mann-Whitney, Kruskall-Wallis and Pearson's correlation tests were used in the statistical analysis (P < or = .05).

RESULTS

No significant association was found between the independent variables (condylar position, disk position, and condylar excursion) and the dependent variables (pain, maximal opening of the mouth, maximal lateral movement). However, there was a significant association between increased condyle excursion and pain (P = .035) and also maximum mouth opening movement was associated with lateral movement (P = .01; r = 0.31).

CONCLUSIONS

Increase in condyle excursion may significantly influence pain perception in TMD patients. The type of dysfunction and severity of alterations on the imaging exams were not related to the severity of pain or range of motion of the mandible.

Evaluation of disk position and prevalence of internal derangement, in a sample of the elderly, by gadolinium-enhanced magnetic resonance imaging

OBJECTIVES

To assess disk position and the prevalence of disk displacement (DD) in a sample of the elderly by use of contrast agent-enhanced magnetic resonance imaging (MRI).

STUDY DESIGN

Thirty subjects (73-75 years old) were drawn from a representative sample and examined clinically. The position and contours of the temporomandibular disk was assessed by using gadolinium-enhanced MR images which were evaluated by 2 independent raters. Statistical assessment was performed by using descriptive statistics and nonparametric tests.

RESULTS

Agreement between raters with respect to disk position was excellent. The MRI showed that 8 subjects (27%; 2 men, 6 women) had DD.

CONCLUSION

Gadolinum-enhanced MRI showed that DD is common in the elderly (27%) and that DD occurs more frequently in women than in men. In women without DD the disk is positioned more anteriorly than in men.