MRI imaging of the temporo-mandibular joint (TMJ) with regard to degeneration and disk displacement.

MRI imaging of the temporo-mandibular joint (TMJ) with regard to degeneration and disk displacement. Poster No.: P-0023 Congress: ESSR 2015 Type: Educational Poster Authors: A. Hagenkord; Basel/CH Keywords: Anatomy, Musculoskeletal system, MR, Technical aspects, Education, Education and training, Pathology DOI: 10.1594/essr2015/P-0023 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.essr.org Page 1 of 23

Learning objectives The accurate diagnosis of diseases of the temporo-mandibular joint (TMJ) can be challenging. Also, many symptoms associated with the TMJ in the context of craniomandibular-dysfunction (CMD) can be misinterpreted and attributed to other potential causes. TMJ disease can cause severe pain or functional problems for the patient. MRI provides a non-invasive technique to evaluate the joint. Background Diseases of the TMJ are numerous, including degeneration, disc luxation and displacement, inflammatory as well as posttraumatic changes just to name some. This can be a substantial cause of pain to the patient as well as other functional problems, such as clicking, inhibited ability to open the mouth or to chew. A large amount of "idiopathic" headaches and muscular tenderness might actually be caused by TMJ-problems. Although MRI examination numbers of the TMJ seem to increase, it can still be considered one of the rarer examinations. Radiologists should be confident with regard to the scan protocol, anatomy and most common pathologies. Early and correct diagnosis can lead into the right treatment and can potentially slow down the progress of jointdestruction. Imaging findings OR Procedure Details This section begins with an overview of basic MRI sequences suitable for TMJ scanning, including optional sequences. After a short review of the anatomy, some imaging examples will be given, with a focus on degenerative changes and disc displacement. The cases have been selected from clinical routine. Page 2 of 23

Clinical aspects of cranio-mandibular-dysfunction (CMD) are addressed at the end of the section. Basic MRI sequences for TMJ evaluation - Suggestions Use of dual-surface coil in order to image both TMJ. Field strength: 3.0 T. Slice thickness 3 mm or less. Evaluation planes and sequences: Coronal: closed mouth, T1 or T2 Oblique sagittal (Fig. 1 on page 6): separate closed and open mouth acquisitions PD/ T2 with fat saturation Past studies have demonstrated that the fast spin-echo-wave sequence (oblique sagittal imaging plane) and PD imaging were the most suitable for the evaluation of the anatomic structures and disc or condylar position of TMJ [1]. PD-weighted images can provide higher contrast than T1-weighted images [2]. The fat saturation is helpful in identifying edema and effusion in the joint. In cases of suspected dislocation of the articular disc or clinically inhibited ability to open the mouth Sagittal (dynamic) sequence separately for each side (e.g. FIESTA, TrueFISP) Dynamic FIESTA MRI with a slow open and close movement (1-3 cycles) can be used to obtain additional dynamic TMJ images and might be helpful to evaluate the movement of the articular disc and condyle [3]. Page 3 of 23

An additional T1 fat saturated sequence with Gadolinium is suggested in cases of suspected synovitis. Anatomy The basic structure of the TMJ is formed by the mandibular fossa, the condylar head, the articular eminence and the articular disc (Fig. 2 on page 7). The meniscus, a biconcave fibrocartilaginous structure, divides the joint into a superior and inferior department. The disc prevents articular damage, as its intermediate zone is interposed between the temporal bone and the mandibular condyle, facilitating the opening of the mouth. The so called bilaminar zone is formed by the retrodiscal tissue. It can be subdivided into superior and inferior retrodiscal layers, which attach to the posterior band of the disc. Those structures are important for the stabilisation of the disc and also include neurovascular structures [4] (Fig. 3 on page 8). Stabilisation and attachment of the disc: anteriorly to the joint capsule and the lateral pterygoid muscle: superior belly of the lateral pterygoid muscle inserts onto the disc. inferior belly of the lateral pterygoid muscle usually inserts onto the mandibular condyle (Fig. 4 on page 9) posteriorly through bilaminar zone: Superior layer is attached to posterior mandibular fossa Inferior layer is attached to posterior margin of mandibular condyle The superior layer prevents slipping of the disc during wide jaw opening. The inferior layer prevents excessive rotation of the disc over the condyle [5]. In the closed-mouth position the posterior band or portion of the disc is usually at the 12 o'clock position (usually plus/minus 10 ) (Fig. 5 on page 10). Motions during jaw opening Page 4 of 23

Two different motions occur during jaw opening. The first motion is rotation around a horizontal axis through the condylar head. The second motion is anterior translation in which the condyle and disc move together anteriorly beneath the articular eminence and the central part of the disc is interposed between the condyle and the articular tubercle [4] (Fig. 6 on page 11, Fig. 7 on page 13, Fig. 8 on page 13). Degenerative changes and disc displacement Internal derangement is defined as an abnormal anatomic relationship of the disc to the mandibular condyle [4]. Disc displacement can be found in asymptomatic patients but is relatively more common in symptomatic patients. A displaced disc may be reduced in early stages of internal derangement, orrather recaptured with mouth opening when the condyle moves anteriorly (often causing a clicking noise). In a long standing disc displacement the disc may be nonreducible, resulting in limited motion (the absence of an audible click). Causes of disc displacement can be variable, including trauma, malocclusion, bruxism, stress, and primary osseous abnormalities. Most disc displacements occur anteriorly, some medially or laterally (30% of cases) [6]. Posterior disc displacement is rare. We can differentiate between: Disc displacement with reduction (usually anterior disc displacement in the closed-mouth position, normal position in open mouth position. Disc degeneration is frequent in this setting (loss of T1 and T2 signal) [6]. Disc displacement without reduction: increased laxity of retrodiscal soft tissues results in disc displacement without reduction presumably followed by adhesions [4] (Fig. 9 on page 14, Fig. 10 on page 15, Fig. 11 on page 16). Additional degenerative changes (osteoarthritis) include: cortical erosions (Fig. 12 on page 17) Page 5 of 23

limited anterior movement of condyle (Fig. 13 on page 18) condylar head flattening (Fig. 14 on page 19) osteophytes (Fig. 15 on page 20) subchondral marrow edema The internal derangement usually leads to a hyperactive and hypertrophic lateral pterygoid muscle which can be seen as a in a thickened attachment, a "double-disc sign" [7, 4] (Fig. 13 on page 18). Clinical issues Craniomandibular disorders (CMD) or temporomandibular disorders (TMD) can be used as umbrella terms, which mostly include the following [8]: disorders involving the temporomandibular joint (TMJ), disorders involving masticatory muscles, occlusion or mouth opening problems (such as pain, restricted movement), muscle tenderness, intermittent joint sounds. Pain in the TMJ seems to be relatively common, occurring in up to 10% of the population over age 18; it is primarily a condition of young and middle-aged adults [9]. Significant correlation was found between TMJ pain and the subtype of anterior disc displacement (ADD) without reduction, as compared to the ADD subtype with reduction [10]. CMD seems to have a high comorbidity with other typical chronic pain symptoms and orofacial pain is often accompanied by widespread pain [11]. Images for this section: Page 6 of 23

Fig. 1: Oblique sagittal plane Page 7 of 23

Fig. 2: Basic anatomy of the TMJ: 1 condyle; 2 temporal bone, mandibular fossa; 3 temporal bone, articular eminence; 4 disc; 5 bilaminar zone; 6 superior head of the lateral pterygoid muscle; 7 inferior head of the LPM Page 8 of 23

Fig. 3: 1 superior retrodiscal layer; 2 inferior retrodiscal layer; 3 capsular inferior attachment; 4 capsular superior attachment; a disc, anterior band; i disc, intermediate zone; p disc, posterior band; Sup: superior joint space; Inf: inferior joint space Page 9 of 23

Fig. 4: sup LPM: superior head of the lateral pterygoid muscle; inf LPM: inferior head of the LPM Page 10 of 23

Fig. 5: Normal position of disc usually at 12 o`clock position + or - 10 Page 11 of 23

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Fig. 6: Closed mouth position Fig. 7: Slight opening of the mouth. Rotation of condyle and beginning of anterior translation. Page 13 of 23

Fig. 8: Open mouth position with anterior translation. Page 14 of 23

Fig. 9: Anterior disc displacement. Closed mouth. Page 15 of 23

Fig. 10: Anterior disc displacement. Slight opening of the mouth. Page 16 of 23

Fig. 11: Anterior disc displacement without Reduction. Open mouth. Limited anterior movement of condyle. Page 17 of 23

Fig. 12: Anterior displacement of the disc (mouth closed and open) (grey arrow). Disc appears fragmented. Cystic, degenerative change in the condyle (yellow arrow). Page 18 of 23

Fig. 13: Same patient as in the previous figure. Limited anterior movement of condyle (open mouth position), disc remains anteriorly displaced. A "double disc sign" due to an overactive hyperactive lateral pterygoid muscle. Page 19 of 23

Fig. 14: Reduction in condylar size from superior surface ± thinning of cortex. Anterior displacement of the disc. Page 20 of 23

Fig. 15: Condylar osteophytes on the right side. Page 21 of 23

Conclusion TMJ alterations can seriously restrict a patient`s quality of life. In many cases, the diagnosis is not straight forward as associated symptoms, e.g. headaches and muscular tenderness, can have numerous causes. Therefore, it is of utmost importance to know and recognise the potential symptoms of TMJ disease and to be able to evaluate the joint properly. References 1. Yang ZJ1, Song DH, Dong LL, Li B, Tong DD, Li Q, Zhang FH: Magnetic resonance imaging of temporomandibular joint: morphometric study of asymptomatic volunteers. J Craniofac Surg 2015; 26(2):425-9. 2. Sano T, Widmalm SE, Yamamoto M, Sakuma K, Araki K, Matsuda Y, Okano T: Usefulness of proton density and T2-weighted vs. T1-weighted MRI in diagnoses of TMJ disc status. Cranio 2003; 21:253-258. 3. Sun Q, Dong MJ, Tao XF, Yu Q, Li KC, Yang C: Dynamic MR imaging of temporomandibular joint: an initial assessment with fast imaging employing steady-state acquisition sequence. Magn Reson Imaging 2015; 33(3):270-5. 4. Tomas X, Pomes J, Berenguer J, Quinto L, Nicolau C, Mercader JM, Castro V: MR imaging of temporomandibular joint dysfunction: a pictorial review. Radiographics 2006; 26(3):765-81. 5. Sommer OJ, Aigner F, Rudisch A, Gruber H, Fritsch H, Millesi W, Stiskal M: Cross-sectional and functional imaging of the temporomandibular joint: radiology, pathology, and basic biomechanics of the jaw. Radiographics 2003; 23(6):e14. 6. Helms CA, Kaban LB, McNeill C, Dodson T: Temporomandibular joint: morphology and signal intensity characteristics of the disc at MR imaging. Radiology 1989; 172:817-820. 7. Lafrenière CM, Lamontagne M, el-sawy R: The role of the lateral pterygoid muscles in TMJ disorders during static conditions. Cranio 1997; 15:38-52. 8. Dimitroulis G: Temporomandibular disorders: a clinical update. BMJ 1998; 317:190-4. 9. LeResche L: Epidemiology of temporomandibular disorders: implications for the investigation of etiologic factors. Crit Rev Oral Biol Med 1997; 8:291-305. 10. Lin WC, Lo CP, Chiang IC, Hsu CC, Hsu WL, Liu DW, Juan YH, Liu GC: The use of pseudo-dynamic magnetic resonance imaging for evaluating the relationship between temporomandibular joint anterior disc displacement and joint pain. Int J Oral Maxillofac Surg 2012; 41(12):1501-4. Page 22 of 23

11. Macfarlane TV, Gray RJM, Kincey J, Worthington HV: Factors associated with the temporomandibular disorder, pain dysfunction syndrome (PDS): Manchester case-control study. Oral Dis 2001; 7: 321-330. Personal Information Page 23 of 23