Temporomandibular joint inflammation: comparison of MR fast scanning with T1- and T2-weighted imaging techniques

Temporomandibular joint MRI: a 2-D gradient-echo technique

Magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) has been most commonly performed using spin-echo sequences. Gradient-echo sequences have previously been investigated in the context of 3-D and 'dynamic' (pseudo-kinematic) imaging. We have used gradient-echo to improve image quality in static studies with rapid acquisition, high spatial resolution (512 x 512 matrix) and excellent contrast resolution. Using pragmatic methods and a non-randomized study group we have demonstrated a definite advantage to image quality, and thus diagnostic confidence, from the use of a gradient-echo high spatial resolution sequence incorporating split acquisition open mouth views.

The development of strains, forces and nociceptor activity in retrodiscal tissues of the temporomandibular joint of male and female goats

Chronic pain in the temporomandibular (TM) joint is predominantly manifested in women. We examined biomechanical and neural factors that could contribute to this differential representation. Relationships between jaw rotation, soft tissue strains and soft tissue forces were examined in the goat TM joint. Strains were minimal until the jaw was rotated beyond the normal range of motion (7.25 deg). There were no significant differences in rotation-strain patterns in males and females. Stress developed as strains were introduced by jaw rotation. Gender differences were observed. Males manifested higher failure loads (15.94 +/- 1.98 and 11.37 +/- 2.02 N, for males and females respectively) and higher elastic stiffness than females (5.62 +/- 1.19 N/mm and 1.64 +/- 0.31 N/mm, for males and females respectively). Recordings were made from cell bodies in the trigeminal ganglion whose distal processes innervated the retrodiscal tissue of the temporomandibular joint of the goat (n = 48). Nociceptor reactivity was characterized with respect to the capacity to transduce mandibular rotation (rotation-interval functions; n = 29). On the basis of established relationships between rotation, strain and tissue forces, rotation-interval functions were transformed into strain-interval and force-interval functions. Comparisons were made between nociceptor properties grouped by gender. No differences in properties were observed when nociceptors were characterized with respect to jaw rotation; however, gender differences were obtained when nociceptor reactivity was characterized with respect to retrodiscal strains or forces. Consistent with smaller failure loads, nociceptors of retrodiscal tissues of females manifested a smaller range (1.12 vs 4.33 N), force to average (1.51 vs 4.64 N), force to minimum (0.95 vs 2.48 N) and force to asymptotic discharge (2.07 vs 6.81 N). Consistent with lower elastic stiffness, nociceptors of female tissues manifested higher average strain (54.4% vs 41.9%) and peak strain (74.0% vs 58.1%) to asymptotic discharge relative to those sampled from male tissues. The implications of these findings for TM joint injury and chronic pain are considered.

The relationship between cervical whiplash and temporomandibular joint injuries: an MRI study

Temporomandibular joint (TMJ) symptoms are a common finding in motor vehicle accident (MVA) patients with hyperextension/hyperflexion injuries of the cervical spine (cervical whiplash). The relationship between cervical whiplash and TMJ injuries was documented with magnetic resonance imaging (MRI) in 87 consecutive MVA cervical whiplash patients who presented with TMJ symptoms and had sustained no direct trauma to the face, head or mandible and had no TMJ complaints prior to the MVA. One hundred sixty-four TMJ patients were evaluated for internal derangement, effusion and inflammation, utilizing T1 and T2 weighted images. A high percentage of the TMJ patients demonstrated abnormal findings: disk displacement with reduction (DDR), 118/164 (72%); disk displacement without reduction (DDNR), 25/164 (15%); effusion, 113/164 (69%); inflammation or edema, 84/164 (51%); total TMJ abnormalities, 156/164 (95%). The high percentage of TMJ abnormalities in this study significantly illustrates the proximate relationship between cervical whiplash and TMJ injuries.

Pseudodynamic imaging of the temporomandibular joint: SE versus GE sequences

Pseudodynamic MR imaging of the temporomandibular joints (TMJs) has been used for the evaluation of the functional aspects of the TMJs. To evaluate the value of T1-weighted spin-echo (SE) and gradient-echo (GE) techniques, both techniques were performed in 9 asymptomatic (mean 25.7 years, 22-23 years), and 25 symptomatic (mean 44.9 years, 20-71 years) subjects with signs and symptoms of internal derangement or osteoarthrosis of the TMJs. The imaging time for the SE (180 ms/15 ms/110 degrees; repetition time/echo time/flip angle) and GE (fast low angle shot; FLASH, 90 ms/12 ms/40 degrees) sequences was 27 and 28 s, respectively. In asymptomatic and symptomatic subjects, the confidence of the identification of the meniscal position was better on SE than GE images (3.6 +/- 0.6 vs. 2.9 +/- 0.9, p < 0.01, 3.2 +/- 0.8 vs. 2.8 +/- 0.8, p < 0.05), respectively and the sizes of the menisci were bigger on SE than GE images. The delineation of the condylar cortex was better on GE than SE images. For pseudodynamic imaging display of the TMJs, the SE images might be better than GE images to provide the stable recognition of the menisci.

Magnetic resonance imaging of the temporomandibular joint: value of pseudodynamic images

Magnetic resonance fast scanning technique (gradient recalled acquisition at steady state) has been reported to be useful when evaluating the dynamics of the temporomandibular joint and also to be accurate for determining the disk position. Yet in our clinical experience gradient recalled acquisition at steady state images have frequently been inferior to proton density images for diagnosis of temporomandibular joint internal derangement. The first aim of this study was to compare gradient recalled acquisition at steady state images with proton density images for diagnosis of disk position. The second aim was to identify what additional information could be gathered from gradient recalled acquisition at steady state images when compared with static proton density images. We obtained unilateral images from 20 patients with signs and symptoms of temporomandibular joint internal derangement and from 20 asymptomatic volunteers. Multiple gradient recalled acquisition at steady state images were obtained during mouth opening and closing and proton density images were obtained at the closed and open mouth positions. The results showed that the gradient recalled acquisition at steady state images were in accordance with the proton density images in 32 joints (80%) and were false negative in 8 joints (20%). Six of the joints with false-negative gradient recalled acquisition at steady state images showed sideways disk displacement, and two showed partial anterior disk displacement. Gradient recalled acquisition at steady state images, on the other hand, provided information about movement pattern and also demonstrated impingement of the joint structures on the muscles anterior to the joint at maximal mouth opening. It was concluded that gradient recalled acquisition at steady state images cannot replace proton density images for diagnosis of disk position but they can provide supplementary information for evaluation of joint function.

Radiographic diagnosis of temporomandibular disorders

Although many of the disorders involving the temporomandibular joint and associated structures can be diagnosed clinically on the basis of the history and physical findings, there are others that require the use of various imaging techniques to make an accurate diagnosis or to determine the extent of involvement. To take maximum advantage of the benefits of these procedures, however, it is not only important for the clinician to be able to select the correct methods, but also to understand their limitations as well as their capabilities. In this article the various techniques used for imaging the hard and soft tissues of the temporomandibular joint are reviewed and recommendations are made regarding their appropriate applications.

Imaging of the temporomandibular joint

Recent advances in imaging technology have greatly contributed to the understanding of diseases of the temporomandibular joint (TMJ). MRI is now the modality of choice in the evaluation of TMJ-related symptoms. This article describes normal anatomy and MRI characteristics of diseases affecting the TMJ including internal derangement, inflammation, and tumors.

The clinical diagnosis of temporomandibular disorders in the orthodontic patient

Because many of the diseases and disorders that affect the temporomandibular joint (TMJ) and associated masticatory muscles occur in the age group of patients generally seen by the orthodontist, their recognition is of great importance in planning and performing orthodontic therapy. This article discusses the diagnosis and clinical significance of the various conditions that may be encountered.

Correlation of magnetic resonance imaging and surgical findings in patients with temporomandibular joint disorders

PURPOSE

This study compared the magnetic resonance imaging (MRI) and surgical findings in patients with temporomandibular joint disorders.

MATERIALS AND METHODS

Forty-three patients and 30 asymptomatic volunteers underwent MRI using the three-dimensional (3D) FISP acquisition technique. The 43 patients (43 joints) then underwent discectomy, and the surgical and MRI findings were correlated.

RESULTS

In 28 joints (28 patients), splits surrounded by regions of high-signal intensity were seen in the discs and retrodiscal tissues on MRI. Surgically, a tear was confirmed in 26 (93%) of these joints. Histologically, these areas showed severe myxomatous degeneration. Disc deformity was visualized by MRI in all patients and increases in signal intensity were found in some discs. High-signal intensities also were observed in 30 joint spaces, in which serous joint effusion was confirmed surgically.

CONCLUSION

Pathologic intracapsular changes are accurately depicted by FISP-3D, and this method is particularly useful for diagnosing changes in the disc and retrodiscal tissues.

Computerized three-dimensional magnetic resonance imaging reconstructions of temporomandibular joints for both a model and patients with temporomandibular pain dysfunction

The aim of this study was to assess computerized three-dimensional reconstruction of magnetic resonance images generated of a temporomandibular joint model and the temporomandibular joints of five patients with varying degrees of temporomandibular joint pain and dysfunction. The three-dimensional image reconstruction of an artificial temporomandibular joint model, consisting of a human dried skull and synthetic disk, was used to test the accuracy and reproducibility of the three-dimensional technique. It was found that computerized three-dimensional reconstruction improved the display format of magnetic resonance imaging by enabling multiple two-dimensional images in shades of grey to be viewed as one three-dimensional image with anatomic structures colored as desired. Further, by rotating this image, the anatomic relationships of the temporomandibular joint could be seen from any viewpoint. Volume measurements showed accuracy and reproducibility by independent operators. Computerized three-dimensional reconstruction was applied to the magnetic resonance images obtained from patients. They were used to assess magnetic resonance imaging technique and its applications for interpreting the clinical findings. Disk position, as revealed by the three-dimensional images, was found to correspond with the clinical assessment, except in two instances when the original, right-sided, magnetic resonance imaging was unclear. Three-dimensional reconstruction was simple to apply, required no patient involvement, and made multiple magnetic resonance images easier to interpret.

Reliability and validity of imaging diagnosis of temporomandibular joint disorder

The purpose of this article is to review reliability and validity of imaging diagnosis of temporomandibular joint disorders. Plain-film and tomography are basic imaging techniques for assessment of the temporomandibular joint. These can be used for evaluation of osseous disease and as a baseline for follow-up. In patients with symptoms from the joint, plain-film and tomography are rarely definitive, and evaluation of the soft tissues is frequently necessary. Arthrography, computed tomography, and magnetic resonance imaging have all been used for evaluation of the soft-tissue components of the joints. Accuracy studies of these techniques have demonstrated the highest diagnostic accuracy for magnetic resonance imaging. Arthrography is relatively insensitive for detection of medial and lateral displacements. Magnetic resonance imaging accurately depicts both hard and soft tissues, and this technique is emerging as the prime diagnostic imaging technique in patients presenting with clinical signs and symptoms of a disorder of the temporomandibular joint. The most frequent findings when patients with clinical symptoms of temporomandibular joint disorders are "imaged" are different forms of disc displacement and degenerative joint disease. Studies have demonstrated a high prevalence of different forms of disc displacement in patients, although these abnormalities are also seen in some asymptomatic volunteers. Future research should further refine imaging techniques to come closer to an understanding of the association between morphologic alterations and patient symptoms.

Radiology of maxillofacial trauma

There has been a rising incidence of maxillofacial injuries during the past decade as a result of an increasing number of assaults and motor vehicle accidents. The maxillofacial region is one of the most complex areas of the human body, and the radiographic imaging of this region becomes even more difficult in traumatized patients because of their clinical condition and their inability to cooperate. Imaging modalities used in the evaluation of the traumatized maxillofacial region include conventional (plain) films, tomography, panoramic radiography, computed tomography, three-dimensional computed tomography, DentaScan, and magnetic resonance imaging. Each modality is discussed with regard to technique, advantages, and disadvantages. Plain films and computed tomography, the modalities that are used most in evaluating maxillofacial structures, are discussed in more detail. The normal anatomy and radiologic features are presented for both of these modalities. Radiographic evaluation of maxillofacial injury begins with a knowledge of the direct and indirect radiographic signs of injury seen on most imaging modalities. Computed tomography also has allowed a method of classifying facial fractures that is based on the involvement of the facial buttresses or struts. Three horizontal, two coronal, and five sagittal oriented struts are described. Limited fractures are differentiated from transfacial fractures by the lack of involvement of the pterygoid plates in the limited fractures. Limited fractures also can be subclassified as solitary (fracture of a single strut) or complex (fractures of multiple struts). A portion of the orbit is involved in almost every form of facial fracture; therefore, evaluation of facial injuries should always include the orbital structures. Although both can occur simultaneously, orbital injuries can be divided into soft tissue and bony vault injuries. Similar to midface fractures, orbital fractures also can be classified as solitary (fracture involves a single wall) or complex (fracture involves more than one wall or a part of a midface fracture). Computed tomography is of great value in evaluating both forms of injury. Magnetic resonance imaging is becoming increasingly important in the evaluation of orbital soft tissue injuries. Classification of midface injuries includes the solitary strut fractures and the complex strut fractures. Solitary strut fractures include fractures of the nasal arch, zygomatic arch, and isolated sinus wall fractures. Complex strut fractures include the nasal complex fractures, zygomatic (tripod) and zygomaticomaxillary fractures, transfacial fractures (LeFort fractures), and facial smash fractures. Each fracture type and its radiographic appearance are discussed.(ABSTRACT TRUNCATED AT 400 WORDS)

Pediatric internal derangements of the temporomandibular joint: effect on facial development

To evaluate the relationship between internal derangement(s) of the temporomandibular joint(s) (TMJ) and disturbed facial skeleton growth (dysmorphogenesis), 128 consecutive children (103 girls, 25 boys), who were 14 years of age or younger and had undergone combined radiographic and magnetic resonance (MR) imaging studies of both TMJs, were retrospectively analyzed. Imaging studies had been performed to investigate suspected TMJ derangement because of symptoms that included, either individually or in various combinations, pain, mechanical TMJ dysfunction, and facial skeleton abnormalities, such as mandibular deficiency (particularly retrognathia) and lower facial (mandibular) asymmetry, manifested by chin deviation from the midline. Of these patients, 112 were found to have at least one internally deranged TMJ on imaging studies; in 85 patients, both TMJs were abnormal. Of the 60 retrognathic patients 56 were found to have TMJ derangement, generally bilateral and often of advanced stage. In cases of lower facial asymmetry, the chin was uniformly deviated toward the smaller or more degenerated TMJ. Both TMJs were normal in 16 patients, most of whom had normal facial structure. We conclude that TMJ derangements are both common in children and may contribute to the development of retrognathia, with or without asymmetry, in many cases.

High resolution spin-echo imaging of the temporomandibular joint

High resolution thin section (1.5 mm thick) spin echo images (HRSE) with narrow bandwidth of TMJ were compared to the conventional (3 mm thick) spin echo images (CSE) in 20 symptomatic patients. Our results revealed that the disk delineation was superior with HRSE and the degree of confidence in making the diagnosis was significantly higher with HRSE than with CSE. Narrow bandwidth, high resolution spin echo technique offers better anatomic detail in the TMJ, resulting in improved degree of confidence, without penalty in additional imaging time.

Internal derangement of the temporomandibular joint: radiologic staging with clinical, surgical, and pathologic correlation

The radiologic findings from 60 patients with 86 internally deranged temporomandibular joints (TMJ) upon whom sequential imaging procedures had been performed over a period of two months to ten years were analyzed and correlated with clinical, surgical (72 joints), and pathological observations. Internal derangement of the TMJ disc (meniscus) and osseous structures was found to be an irreversible and progressive disorder with characteristic stages. Internal derangements of the TMJ were divided into early (stage one), intermediate (stages two and three) and late stage (stages four and five) categories based upon radiologic findings obtained with radiography, lateral TMJ tomography and either two compartment arthrography or high field, surface coil MR. After sequential imaging studies, each patient and 72 deranged joints underwent surgical joint exploration and meniscectomy because of progressive joint disease and clinical disability. Surgically removed tissues underwent routine histological evaluation. Surgical and pathologic observations included disc displacement, deformity, hyalination, myxomatous degeneration, perforation of the disc attachments, capsular adhesions, synovitis and mandibular condyle lesions including osteochondritis dissecans (OCD), avascular necrosis (AVN), osseous remodeling and degenerative arthritis. There was excellent correlation between imaging studies and surgical observations. Internal derangement of the TMJ is an irreversible, generally progressive disorder which may be staged and followed with radiography, tomography and either two-compartment arthrography or high field, surface coil MR.