• Imaging Science in Dentistry
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• v.33 no.1
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• pp.1-4
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• 2003

Purpose : The purpose of this study was to investigate the distribution and frequency of temporomandibular joint (TMJ) effusion in magnetic resonance (MR) images of patients with disc displacements. Materials and Methods: On T2 weighted MR images of 148 TMJs taken from 74 patients presenting with TMJ pain and dysfunction, we assessed the cases showing TMJ effusion, defined as an amount of fluid that exceeded the maximum amount seen in a control group of asymptomatic volunteers. The amount of TMJ fluid was graded as: I (none or minimal), II (moderate), III (marked), and IV (extensive), according to a standard set by a reference. Disc displacement categories were also recorded. Results: Of the 148 TMJs examined in this study, 52 joints (35.1%) presented with joint effusion, 24 (16.2%) showing bilateral joint effusion. 38 joints showed upper joint space effusion, 3 showed lower joint space effusion, and 11 showed both upper and lower joint space effusion. 96 joints (64.9%) had grade I joint fluid, 27 (18.2%) grade II, 15 (10.1 %) grade III, and 10 (6.8%) grade IV. 80.0% of the joints presenting with grade IV effusion showed disc displacement without reduction. Conclusion: Joint effusion was found not only in upper, but also in lower joint spaces. The higher the effusion grade, the greater the frequency of disc displacement without reduction.

• Imaging Science in Dentistry
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• v.31 no.2
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• pp.73-84
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• 2001

Purpose: The purpose of this study was to find the relationship among the joint status, pain and effusion in patients with temporomandibular joint disorders. Materials and Methods: Materials included 406 patients (812 joints) with clinical records and bilateral TMJ MRIs in TMJ clinic, Yongdong Severance Hospital. All joints were classified in 4 groups in MR images according to the disc status of joint; normal disc position, disc displacement with reduction (DDcR), early and late stage of disc displacement without reduction (DDsR), and also 2 groups according to the bony status of joint; normal bony structure and osteoarthrosis. MR evidence of joint effusion was categorized in 4 groups according to its amount. To determine the relationship between joint pain and joint effusion, 289 patients with unilateral TMJ symptoms were selected from total materials. Result: Joint effusion was found 8.0% in normal disc position, 32.6% in DDcR, and 59.2% in DDsR (83.1 % in early state and 23.1 % in late stage). Joint effusion was found 39.7% in osteoarthrosis and 35.0% in normal bony structure. Joint effusion was more found in the painful joints (49.8%) than in the painless joints (22.4% )(p<0.001). Joint effusion in the early stage of DDsR only was more found significantly in painful joints (91.9%) than in painless joints (62.1 %) (p<0.001). Conclusion : MR evidence of joint effusion might be related to disc displacement regardless of the presence of osteoarthrosis, and the early stage of DDsR was found more frequently combined with joint effusion and joint pain.

• Journal of Oral Medicine and Pain
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• v.25 no.1
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• pp.63-71
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• 2000

The authors assessed if there is a relationship between joint effusion and the presence of pain, and between joint effusion and disc displacement in 446 temporomandibular joints of 223 subjects who visited the Department of Oral Medicine, Kyungpook National University Hospital with the complaints of temporomandibular joint problem. The amount of joint effusion and the position of disc were determined from magnetic resonance images of the temporomandibular joints. The position of disc was classified into normal disc position, disc displacement with reduction (DDWR), and disc displacement without reduction (DDWOR). The amount of joint effusion was graded according to the extent of joint area of high signal intensity on T2-weighted MR images. These findings were correlated with one another and statistically analyzed. The results were as follows; 1. The incidence of temporomandibular joint pain Was higher in the joints with higher amount of joint effusion (P<0.001). 2. The proportion of temporomandibular joints with higher amount of effusion increased in the joints with more advanced articular disc displacement (P<0.001).

• Imaging Science in Dentistry
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• v.44 no.4
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• pp.293-299
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• 2014

Purpose: This study was performed to find the relationship between pain and joint effusion using magnetic resonance imaging (MRI) in temporomandibular disorder (TMD) patients. Materials and Methods: The study subjects included 232 TMD patients. The inclusion criteria in this study were the presence of spontaneous pain or provoked pain on one or both temporomandibular joints (TMJs). The provoked pain was divided into three groups: pain on palpation (G1), pain on mouth opening (G2), and pain on mastication (G3). MRI examinations were performed using a 1.5-T MRI scanner. T1- and T2-weighted images with para-sagittal and para-coronal images were obtained. According to the T2-weighted image findings, the cases of effusions were divided into four groups: normal, mild (E1), moderate (E2), and marked effusion (E3). A statistical analysis was carried out using the $X^2$ test with SPSS (version 12.0, SPSS Inc., Chicago, IL, USA). Results: Spontaneous pain, provoked pain, and both spontaneous and provoked pain were significantly related to joint effusion in TMD patients (p<0.05). However, among the various types of provoked pain, pain on palpation of the masticatory muscles and TMJ (G1) was not related to joint effusion in TMD patients (p>0.05). Conclusion: Spontaneous pain was related to the MRI findings of joint effusion; however, among the various types of provoked pain, pain on palpation of the masticatory muscles and TMJ was not related to the MRI findings of joint effusion. These results suggest that joint effusion has a significant influence on the prediction of TMJ pain.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.4
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• pp.373-382
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• 2000

Temporomandibular disorders arised from joint itself was caused by inflammation or mechanical irritation of the retrodiskal tissues. Histologic changes of the retrodiskal tissues of temporomandibular joint(TMJ) internal derangement, such as inflammatory cell infiltration, hyalinization, myxoid change, fatty change, arterial obliteration, and so on, were reported, but relationships between magnetic resonance imaging(MRI) findings and histologic findings of the retrodiskal tissue were few reported. The purpose of this study was to find histologic changes of the retrodiskal tissues for status of joint and joint effusion in MRI of the temporomandibular joint which had surgical treatment. Materials were surgically treated 52 temporomandibular joints with internal derangement or osteoarthritis in TMJ clinic, Yongdong Severance Hospital. All joints were confirmed by magnetic resonance T1- and T2-weighted imagings bofere surgery. Status of joint was categorized by normal position, disc displacement with reduction, disc displacement without reduction, disc displacement without reduction associated with osteoarthrosis using preoperative MR T1-weighted images. Magnetic resonance evidence of joint effusion was observed in T2-weighted images and classified by its amount; degree 0(not observed), degree 1(small amount), degree 2(moderate amount), degree 3(large amount). Histologic features were observed whether the retrodiskal tissue has inflammatory cell infiltration, myxoid change, hyalinization, chondroid metaplasia and arterial obliteration. The distribution of elastic fibers were also observed. The results were as follows; 1. Inflammatory cell infiltration was not observed in any retrodiskal tissues. 2. MRI findings such as status of joint and evidence of joint effusion did not have significant relationship with myxoid change, hyalinization, chondroid metaplasia, arterial obliteration of the retrodiskal tissues. 3. Hyalinization and chondroid metaplasia were found in 8 joints(15.4%) and 5 joints(9.6%). All of them were found in disc displacement without reduction and disc displacement without reduction associated with osteoarthrosis. 4. Arterial obliteration was observed more frequently in disc displacement without reduction(55.6%) than disc displacement without reduction associated with osteoarthrosis(28.6%). Further studies with proper controls and more materials will be necessary.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.4
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• pp.330-335
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• 2002

The study was performed to investigate the comparison of relative signal intensity of normal- and abnormal-side retrodiscal tissue, and relationship between clinical examination, joint effusion and relative signal intensity of retrodiscal tissue in patients with unilateral TMJ internal derangement. The study group comprised 19 females and 9 males, with a mean age of 29 years. After measurements of the signal intensity were made on the MR imager for the T2 weighted images on retrodiscal tissue and brain gray matter, we calculated relative value and tried to find relationship between clinical examination, joint effusion and relative signal intensity on normal- and abnormal-side. The results are as follows. 1. The gray matter is an appropriate reference point. 2. The relative signal intensity is high significantly in abnormal-side retrodiscal tissue compared with normal-side retrodiscal tissue. 3. The relative signal intensity is high significantly in painful joints compared with nonpainful joints and in joints with joint effusion compared with joints without joint effusion. 4. The relative signal intensity in normal joints, joints with reduction and joints without reduction is increased in order significantly.

• Imaging Science in Dentistry
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• v.43 no.4
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• pp.245-251
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• 2013

Purpose: This study was performed to evaluate the relationship between anterior disc displacement and effusion in temporomandibular disorder (TMD) patients using magnetic resonance imaging (MRI). Materials and Methods: The study subjects included 253 TMD patients. MRI examinations were performed using a 1.5 T MRI scanner. T1- and T2-weighted images with para-sagittal and para-coronal images were obtained. According to the MRI findings, temporomandibular joint (TMJ) disc positions were divided into 3 subgroups: normal, anterior disc displacement with reduction (DWR), and anterior disc displacement without reduction (DWOR). The cases of effusion were divided into 4 groups: normal, mild (E1), moderate (E2), and marked effusion (E3). Statistical analysis was made by the Fisher's exact test using SPSS (version 12.0, SPSS Inc., Chicago, IL, USA). Results: The subjects consisted of 62 males and 191 females with a mean age of 28.5 years. Of the 253 patients, T1- and T2-weighted images revealed 34 (13.4%) normal, DWR in 103 (40.7%), and DWOR in 116 (45.9%) on the right side and 37 (14.6%) normal, DWR in 94 (37.2%), and DWOR in 122 (48.2%) joints on the left side. Also, T2-images revealed 82 (32.4%) normal, 78 (30.8%) E1, 51 (20.2%) E2, and 42 (16.6%) E3 joints on the right side and 79 (31.2%) normal, 85 (33.6%) E1, 57 (22.5%) E2, and 32 (12.7%) E3 on the left side. There was no difference between the right and left side. Conclusion: Anterior disc displacement was not related to the MRI findings of effusion in TMD patients (P>0.05).

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.2
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• pp.136-142
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• 2006

Temporomandibular joint(TMJ) disorders have characteristic clinical findings such as pain, joint sound, and abnormal jaw function. With the rapid progress in TMJ imaging techniques, magnetic resonance imaging(MRI) especially provides the clinician and researcher with the ability to evaluate TMJ disorders(effusion, anterior disk displacement) and the hard and soft tissue of the TMJ. In order to manage the internal derangement of TMJ such as anterior disk displacement, the so-called appliance therapy is commonly used. This technique became the treatment of choice before surgical intervention by many practitioners. The purpose of the present study was to evaluate and determine the efficacy of anterior repositioning splint by means of the change of the position of the disk through pre- and post-treatment MRI. MRI and clinical symptom were carefully recorded in TMJ disorder patients. The relationship between TMJ symptoms such as pain, clicking sound, and disk displacement and effusion in MRI were analyzed. Then, splint therapy was applied for 3 months according to our protocol; at day 1, patients should wear 24 hours, in order to accomodate the splint and then, wearing time is reduced to 12 hours per day for one month. During next 2 months, it is tapered to 8 hours per day according to the evaluation of the clinical symptoms. Post-treatment MRI was obtained after 3 month protocol. This treatment strategy improved the clinical symptoms of TMJ disorder, and effusion and articular disk position showed a significant change. In conclusion, a treatment modality using an anterior repositioning splint therapy is an appropriate method for temporomandibular disorder patients.

• Imaging Science in Dentistry
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• v.31 no.2
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• pp.93-99
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• 2001

Purpose: To analyze the possible association between magnetic resonance imaging signal intensity of temporomandibular joint disk and posterior attachment, and the type and extent of disk displacement, disk configuration, effusion and clinical signs in patients with internal derangement. Materials and Methods: Magnetic resonance images of the 132 temporomandibular joints of 66 patients with temporomandibular joint displacement were analyzed. The clinical findings were obtained by retrospective review of the patients' records. The type and extent of disk displacement, disk configuration and effusion were evaluated on the proton density MR images. The signal intensity from the anterior band, posterior band and posterior attachment were measured on MR images. The associations between the type and extent of disk displacement, disk configuration, effusion and clinical signs and the MR signal intensity of disk and posterior attachment were statistically analyzed by student's t-test. Results: Of 132 joints, 87 (65.9%) showed anterior disk displacement with reduction (ADR) and 45 (34.1%) showed anterior disk displacement without reduction (ADnR). The signals from posterior attachments were lower in joints with ADnR than those of ADR (p<0.05). The results showed statistically significant (p<0.05) association between the type and extent of disk displacement and disk configuration, and decreased signal intensity of posterior attachment. There were no statistical associations between pain, noise and limited mouth opening, and signal intensity of disk and posterior attachment. Conclusions: The average signal from posterior attachment was lower in joints with ADnR than that of ADR. The type and extent of disk displacement and disk configuration appeared to be correlated with the signal intensity from posterior attachment.

• Imaging Science in Dentistry
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• v.52 no.4
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• pp.393-398
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• 2022

Purpose: This study proposed a generative adversarial network (GAN) model for T2-weighted image (WI) synthesis from proton density (PD)-WI in a temporomandibular joint(TMJ) magnetic resonance imaging (MRI) protocol. Materials and Methods: From January to November 2019, MRI scans for TMJ were reviewed and 308 imaging sets were collected. For training, 277 pairs of PD- and T2-WI sagittal TMJ images were used. Transfer learning of the pix2pix GAN model was utilized to generate T2-WI from PD-WI. Model performance was evaluated with the structural similarity index map (SSIM) and peak signal-to-noise ratio (PSNR) indices for 31 predicted T2-WI (pT2). The disc position was clinically diagnosed as anterior disc displacement with or without reduction, and joint effusion as present or absent. The true T2-WI-based diagnosis was regarded as the gold standard, to which pT2-based diagnoses were compared using Cohen's ĸ coefficient. Results: The mean SSIM and PSNR values were 0.4781(±0.0522) and 21.30(±1.51) dB, respectively. The pT2 protocol showed almost perfect agreement(ĸ=0.81) with the gold standard for disc position. The number of discordant cases was higher for normal disc position (17%) than for anterior displacement with reduction (2%) or without reduction (10%). The effusion diagnosis also showed almost perfect agreement(ĸ=0.88), with higher concordance for the presence (85%) than for the absence (77%) of effusion. Conclusion: The application of pT2 images for a TMJ MRI protocol useful for diagnosis, although the image quality of pT2 was not fully satisfactory. Further research is expected to enhance pT2 quality.