Diagnostic ultrasound assessment of temporomandibular joints: a systematic review and meta-analysis

Effectiveness of ultrasonography in the diagnosis of temporomandibular joint disorders: A systematic review and meta-analysis

BACKGROUND

Temporomandibular disorders (TMDs) pose diagnostic challenges, and selecting appropriate imaging modalities is crucial for accurate assessment. This study aimed to compare the diagnostic accuracy and efficacy of ultrasonography (US) and magnetic resonance imaging (MRI) in identifying TMDs.

METHODS

A comprehensive meta-analysis was conducted, including studies that compared US and MRI for TMJ disorder assessments. Fixed-effects models were utilized to calculate pooled odds ratios (ORs) and relative risks (RRs) with 95% confidence intervals (CIs). Heterogeneity was assessed using the chi-squared test and I2 statistic. Newcastle-Ottawa scale was used to assess the methodological quality of the studies included.

RESULTS

Six studies were included, involving a total of 281 participants. The meta-analysis demonstrated that MRI was statistically somewhat better than US in identifying TMJ disorders. The summary OR was 0.64 (95% CI: 0.46-0.90), and the summary RR was 0.80 (95% CI: 0.68-0.95). Heterogeneity among the studies was low (χ2 = 2.73, df = 5, p = .74; I2 = 0%). Demographic variables revealed variations in sample size, gender ratio and mean age across the studies.

CONCLUSION

This meta-analysis provides evidence that MRI may be more effective than US in diagnosing TMDs. However, the study is limited by the small number of included studies and variations in demographic variables and study designs. Future research with larger samples and standardised protocols is essential to confirm and strengthen these findings. Understanding the diagnostic accuracy of MRI and US for TMJ disorders will aid clinicians in making informed decisions for effective TMJ disorder assessments and patient management.

Ultrasonographic characteristics of myogenous temporomandibular disorders: A scoping review

OBJECTIVE

To identify the available evidence on the ultrasonographic characteristics of masticatory muscles in subjects with myogenous TMD, as well as the potential use of ultrasonography as a diagnostic and treatment assessment outcomes tool.

METHOD

An electronic search of the PubMed, Web of Science and Scopus databases was performed using the following terms: 'ultrasonography', 'ultrasound', 'masseter', 'temporal', 'masticatory muscles', 'temporomandibular disorders', 'temporomandibular joint disorders'. Full-text articles were obtained from the records after applying the inclusion/exclusion criteria.

RESULTS

Thirteen articles were included for analysis: one comparative cross-sectional study, five case-control studies, six clinical trials and one randomised clinical trial. Main ultrasonographic characteristic assessed were local cross-sectional dimension and intramuscular ultrasonographic appearance. Retrieved studies reported the use ultrasonography for diagnosis or treatment assessment purposes showing heterogeneous results. For diagnosis purposes, the results of local cross-sectional dimension are not consistent; therefore, its diagnostic value for myogenous TMD diagnosis is weak. However, more homogeneous results were observed for intramuscular ultrasonographic appearance showing a higher prevalence of type-II pattern in myogenous TMD subjects than non-TMD subjects. On the other hand, for treatment assessment purposes, muscles were observed thinner after treatment compared to pre-treatment. Also, results of intramuscular ultrasonographic appearance show disappearance or reduction of anechoic areas, higher prevalence of type-II pattern and significant distinction of echogenic bands were observed after treating TMD subjects.

CONCLUSION

Ultrasonography cannot be considered as a diagnostic instrument, but maybe as a complementary tool for treatment assessment of myogenous TMD subjects, even though future research is required to confirm its utility.

Relationship Between Temporomandibular Joint Effusion, Pain, and Jaw Function Limitation: A 2D and 3D Comparative Study

Purpose

This study aimed to investigate the relationship between temporomandibular joint (TMJ) effusion and TMJ pain, as well as jaw function limitation in patients via two-dimensional (2D) and three-dimensional (3D) magnetic resonance imaging (MRI) evaluation.

Patients and Methods

121 patients diagnosed with temporomandibular disorder (TMD) were included. TMJ effusion was assessed qualitatively using MRI and quantified with 3D Slicer software, then graded accordingly. In addition, a visual analogue scale (VAS) was employed for pain reporting and an 8-item Jaw Functional Limitations Scale (JFLS-8) was utilized to evaluate jaw function limitation. Statistical analyses were performed appropriately for group comparisons and association determination. A probability of p<0.05 was considered statistically significant.

Results

2D qualitative and 3D quantitative strategies were in high agreement for TMJ effusion grades (κ = 0.766). No significant associations were found between joint effusion and TMJ pain, nor with disc displacement and JLFS-8 scores. Moreover, the binary logistic regression analysis showed significant association between sex and the presence of TMJ effusion, exhibiting an Odds Ratio of 5.168 for females (p = 0.008).

Conclusion

2D qualitative evaluation was as effective as 3D quantitative assessment for TMJ effusion diagnosis. No significant associations were found between TMJ effusion and TMJ pain, disc displacement or jaw function limitation. However, it was suggested that female patients suffering from TMD may be at a risk for TMJ effusion. Further prospective research is needed for validation.

Associated risks with periodontal x-rays or CBCT scans: Are there any?

Periodontal and implant radiography, mainly including intra-oral peri-apical and cone beam computed tomography images, are crucial in the diagnosis and treatment planning process. However, radiation safety concerns have been a chronic concern over the years, leading to uncomfortable situations. It is therefore crucial to understand the actual radiation exposure to determine if the patients' fear of necessary diagnostic exams is justified. In this perspective article, we aimed to provide concise information on dental imaging exposure, risks, and benefits, comparing them to that of absorbed radiation from daily life activities; and secondarily, to help periodontists choose the best option for each case and become more confident in addressing patients' concerns and providing a summary of safety guidelines as a reference for them.

Ultrasound-guided injection and aspiration of small joints: techniques, pearls, and pitfalls

Ultrasound (US)-guided musculoskeletal intervention of small joints or joints other than the shoulder, elbow, hip, knee, and ankle can be technically challenging. Small joints produce a narrower landing zone for the needle and a smaller target that may be made even more inaccessible by bulky osteophytes. Sonographic (US) guidance offers important advantages including near-field visualization of the joint and soft tissues, ease of access, portability, ability to compare with the contralateral side, and lack of ionization radiation. This review article focuses on the performance of US-guided injections and aspirations involving small joints (joint capacity < 2 mL and/or typically evaluated or injected with a compact linear transducer). For each joint (temporomandibular, acromioclavicular, sternoclavicular, distal radioulnar, symphysis pubis, and joints of the digits of the hands and feet), a brief overview of the relevant anatomy, indications, procedural description, pearls and pitfalls will be highlighted. This article demonstrates the various approaches to diagnostic or therapeutic injection and aspiration of small joints with the aid of US images, cines and graphic illustrations, emphasizing joint positioning, anatomic landmarks, and needle trajectory for a safe and efficacious procedure. A brief review of available literature for each joint will also be provided.

Comparison of symptoms, signs and magnetic resonance imaging in children aged 5-18 years with temporomandibular joint disease

BACKGROUND

Temporomandibular joint diseases (TMD) are an important clinical condition in childhood as in adults. There is variation in the frequency and distribution of complaints in children about this disorder.

MATERIALS AND METHODS

This study was conducted on 407 children aged 5-18 years. Patients with dentofacial function problems, trauma, history of surgery, and malignancy were excluded from the study. Patients with temporomandibular magnetic resonance imaging in their records were classified as normal, reduction disc displacement and non-reduction disc displacement.

RESULTS

Patients symptoms were click (77.2%), pain (71.5%), headache (61.2%), bruxism (31.9%), locking (28%), difficulty in mouth opening (24.3%). The most common clinical findings are normal mouth opening (62.2%) and deviation (44.9%). When the MR results were examined, 55.1% of female and 66.6% of male were observed to be normal, and this statistically shows that males have more normal MR findings.

CONCLUSION

TMD are also observed in children. Clinical history and findings are helpful in diagnosis, but the contribution of imaging methods may be limited. If head and neck pain is detected in children, TMD should be kept in mind.

Comparison between ultrasound and magnetic resonance imaging of the temporomandibular joint in juvenile idiopathic arthritis: A systematic review

OBJECTIVES

The objectives of this systematic review were to evaluate the correlation between Ultrasound (US) and Magnetic Resonance Imaging (MRI) in patients with JIA and to investigate the association with Temporomandibular Disorders (TMD).

MATERIALS AND METHODS

The protocol was registered in PROSPERO (CRD42022312734). Databases Medline, Embase, Cochrane Central Register of Controlled Trials, Scopus, Web of Science, Latin American and Caribbean Health Sciences Literature were searched. Eligibility criteria were patients with JIA subjected to diagnostic evaluation using US and MRI. No language restrictions were applied. After duplicate study selection, data extraction and risk of bias assessment according to Cochrane were conducted. Data extraction of patients was conducted by two independent authors.

RESULTS

Five observational studies were included with 217 participants (153 females and 64 males; mean age 11.3 years). The quality of the studies was overall satisfactory. The correlation between US and MRI in children with JIA was 'moderate' in acute arthritis while the chronic arthritis correlated positively in two studies.

CONCLUSIONS

Even if MRI remains the more accurate imaging modality for the detection of TMJ of patients with JIA, US may be useful to early detect pathological conditions and to address the patient with JIA and putative TMJ involvement to a more accurate diagnosis with MRI and consequent appropriate treatment management.

CLINICAL RELEVANCE

MRI should be deemed necessary only secondary to less-invasive assessments with US just to confirm the diagnosis or to increase sensitivity, accuracy of positive predictive values detected.

Diagnostic efficacy of quantitative ultrasonography for anterior disc displacement of the temporomandibular joint

Background

Ultrasonography has been applied as an alternative method in the assessment of temporomandibular joint (TMJ) pathology including anterior disc displacement (ADD). However, a concrete screening or diagnostic method which is feasible in clinical practice has not yet been established. The study aimed to establish a quantitative ultrasonographic method and determine its diagnostic efficacy for ADD of the TMJ.

Methods

A total of 75 joints were allocated to either the normal disc position (NDP) group or the ADD group using magnetic resonance imaging (MRI) as the reference standard. Longitudinal scans of the lateral articular compartment were obtained by a 14-MHz L-shaped linear array transducer. The width of the lateral joint space (LJS), the upper lateral joint space (ULJS), and the lower lateral joint space (LLJS), as well as the position of the lateral articular disc edge (ADE), were investigated by stepwise logistic regression analysis to identify significant indicators of ADD and to build a diagnostic model. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were computed at the optimal cut-off value.

Results

MRI detected 25 joints in the NDP group and 50 joints in the ADD group. Correlation analysis indicated that all 4 variables were associated with ADD. With the best performance of the area under the receiver operating characteristic (ROC) curve (AUC) of 0.939, LJS and ULJS were identified as predictors of ADD and subsequently adopted to build a diagnostic model by stepwise logistic regression. The optimal cut-off value of the 2-variable regression model for diagnosing ADD was 0.800, with a sensitivity of 82%, specificity of 96%, PPV of 97.6%, NPV of 72.7%, and an accuracy of 86.7%.

Conclusions

The quantitative ultrasonographic diagnostic method showed promising diagnostic efficacy. It has the potential to be used for ADD screening in future clinical practice.

Do TMJ MRI diagnosis support clinical examination diagnosis following DC/TMD criteria?

PURPOSE

The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) has been validated as a clinical diagnostic guideline with high-sensitivity and -specificity in identifying TMDs. The purpose of this study was to evaluate the agreement between DC/TMD diagnoses and magnetic resonance imaging (MRI) diagnoses in patients with TMD.

METHODS

A prospective cohort study was conducted on patients with TMD. The predictor variable was the clinical diagnosis of TMD based on DC/TMD criteria. The outcome variable was the MRI diagnosis of TMD. The diagnoses used for both the predictor variable and the outcome variable were the same. They were normal, disc displacement with reduction (DDWR), DDWR with intermittent locking, disc displacement without reduction (DDWOR) with limited opening, DDWOR without limited opening, degenerative joint disease, and subluxation. Age and gender of the patients and number of joints evaluated were covariates. Each subject had clinical examination performed by two independent Oral and Maxillofacial Surgeons. All subjects had a bilateral temporomandibular joint (TMJ) MRI performed which was evaluated by a radiologist. The correlation between the clinical and MRI diagnoses was calculated using Cohen's kappa value with a P value of <.05 considered significant.

RESULTS

A total of fifty patients (100 TMJs) were enrolled with 38 females and 12 males. The mean ages were 31.92 and 31.75 years, respectively, with a total of 100 TMJs analyzed. Internal derangement was clinically identified in 76% of the joints and with MRI in 69% of joints. The Cohen's kappa value between DC/TMD and MRI diagnoses was found to be κ = 0.720 (P < .01). The respective sensitivity and specificity in determining disc position clinically for DDWR was 1 and 0.96; for DDWR with intermittent locking 0.78 and 0.91; for DDWOR with limited opening 0.9 and 0.98; for DDWOR without limited opening 1 and 0.9; for degenerative joint disease 0.63 and 0.97 and for subluxation 0.28 and 1.00.

CONCLUSION

The DC/TMD clinical examination performed well in all types of disc displacement but is less reliable in detecting the presence of degenerative disc diseases and subluxation.

Comparison of symptoms, signs, gender, and magnetic resonance images of temporomandibular joint disorder patients

OBJECTIVE

To compare patients' complaints, clinician's examination findings, and magnetic resonance imaging (MRI) findings by considering gender.

METHODS

Temporomandibular joint (TMJ) pain, difficulty in mouth opening, masseter tenderness, deviation, clicking sound, bruxism, restriction, normal occlusion and normal mouth opening symptoms, and findings of temporomandibular disorder (TMD) patients who came to the author's outpatient clinic were recorded. These recordings were compared with MRI.

RESULTS

In the study, symptoms, signs, and MRIs of 276 TMD patients were analyzed, including gender. No difference was observed in terms of symptoms, signs, or MRI results for either gender. MRI findings were correlated with restriction and normal mouth opening in both groups (p < 0.05). Normal MRI findings were observed in 52.5% of the MRI results.

CONCLUSION

Except for normal mouth opening and limitation, MRI findings did not provide a significant result. Therefore, careful detection of symptoms and signs rather than MRI helps in diagnosis.

The Role of Ultrasound in Temporomandibular Joint Disorders: An Update and Future Perspectives

Temporomandibular joint (TMJ) disorder is the second most common chronic pain condition affecting the general population after back pain. It encompasses a complex set of conditions, manifesting with jaw pain and limitation in mouth opening, influencing chewing, eating, speaking, and facial expression. TMJ dysfunction could be related to mechanical abnormalities or underlying inflammatory arthropathies, such as rheumatoid arthritis (RA) or juvenile idiopathic arthritis (JIA). TMJ exhibits a complex anatomy, and thus a thorough investigation is required to detect the TMJ abnormalities. Importantly, TMJ involvement can be completely asymptomatic during the early stages of the disease, showing no clinically detectable signs, exposing patients to delayed diagnosis, and progressive irreversible condylar damage. For the prevention of JIA complications, early diagnosis is therefore essential. Currently, magnetic resonance imaging (MRI) is described in the literature as the gold standard method to evaluate TMJ. However, it is a high-cost procedure, not available in all centers, and requires a long time for image acquisition, which could represent a problem notably in the pediatric population. It also suffers restricted usage in patients with claustrophobia. Ultrasonography (US) has emerged in recent years as an alternative diagnostic method, as it is less expensive, not invasive, and does not demand special facilities. In this narrative review, we will investigate the power of US in TMJ disorders based on the most relevant literature data, from an early screening of TMJ changes to differential diagnosis and monitoring. We then propose a potential algorithm to optimize the management of TMJ pathology, questioning what would be the role of ultrasonographic study.

Influence of Ultrasound Examination on Diagnosis and Treatment of Temporomandibular Disorders

Background: Disorders of the masticatory muscles and temporomandibular joints as well as the surrounding craniofacial structures are called temporomandibular disorders. These are dental diseases affecting an increasing number of people with a multifactorial etiology. Noninvasive ultrasonography imaging of temporomandibular joints was performed to obtain more detailed information on joint pathologies. Material and Methods: The aim of the study was to assess the influence of ultrasound examinations of the temporomandibular joints on the diagnosis and treatment planning in patients with temporomandibular disorders. The study included 110 patients examined with the use of the Research Diagnostic Criteria for Temporomandibular Disorders questionnaire, axis I and II, after which the initial treatment plan was created. All patients underwent an ultrasound examination of the temporomandibular joints. Results: The results reveal numerous morphological changes within the joint structures in all treatment groups. Comparative statistical analyses of symptoms were performed between study groups. Conclusions: The number of pathologies in the myofascial pain group was much higher than expected and required introduction of additional treatment procedures. Further studies confirming these results and the effectiveness of ultrasound diagnostic of temporomandibular disorders are recommended.

Evaluating the Effect of Conservative Therapy in Patients with Wilkes Stage III Temporomandibular Joint Derangement

The authors evaluated effects of physiotherapy in patients experiencing Wilkes III temporomandibular joint (TMJ) derangement with clinically limited joint mobility, but no pain. The group consisted of 31 patients with unilateral temporomandibular joint involvement, 3 men and 28 women (average age was 30.93, ranging from age 12 to 61). None of the patients in the group had experienced any previous TMJ therapy. The patients underwent conservative therapy in the form of home exercise (mobilisation and isometric exercises) as the first step in treatment. The authors evaluated the improvement in jaw movement (maximal interincisal opening - MIO) and the patients' subjective assessments of their condition. Disc position before and after two months of exercise was also evaluated using ultrasound examination. The average MIO value in patients before starting the exercises was 33.5 mm, and after two months of exercises, 42.4 mm. Subjective assessment by patients: 26 patients (83%) described their condition as completely satisfactory, not requiring further therapy. Of these patients, ultrasound examination showed 10 patients with complete disc reduction, 9 patients with a change in disc displacement with reduction, and 7 patients with a continuing (unchanged) state of disc displacement. Results of our study show the effect of conservative therapy in patients with painless TMJ due to disc displacement (WIII). Effect of home exercises which were easy to perform, simple and acceptable to the patient were demonstrated.

Hand-Carried Ultrasonography Instrumentation in the Diagnosis of Temporomandibular Joint Dysfunction

Internal derangement (ID) in the temporomandibular joint (TMJ) is defined as a mechanical problem of the joint that interferes with its function. It is attributed to an abnormal interaction among the articular disc, condyle, and joint eminence. The aim of this study is to evaluate diagnostic efficacy of non-invasive hand-carried ultrasonography instrumentation (US) to provide high-level images for a correct diagnosis of ID. Twenty-eight ID patients, 15 female and 13 males, were examined both clinically and by MRI images in order to achieve a diagnosis of ID (using Helkimo index). Then, they were submitted to US examination with a 12 MHz transducer by using hand-carried instrumentation by a clinician that was blind to their diagnosis and clinical data. TMJ US examination was performed with the mouth closed and mouth open, with proper technique. Each position was then evaluated with two different orientations of the transducer. US showed acceptable results in identifying bone structures. Lower values of diagnostic efficacy were obtained for disc position during joint movements with respect to MRI images. MRI still represents the gold standard for the identification of joint structures. If not corroborated by clinical and anamnestic data, the diagnostic efficacy of US in identifying the position of the disc during opening and closing jaw movements appears limited than compared to MRI.

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.

Role of thermography in the assessment of temporomandibular disorders and other musculoskeletal conditions: A systematic review

The aim of this review was to evaluate whether thermal imaging may constitute a reliable assessment method of musculoskeletal and temporomandibular disorders (TMD/MSD). A systematic review was conducted in the Pubmed, Scopus, Cochrane library, Web of Science, and Lilacs databases. The search terms were "musculoskeletal disorders,""temporomandibular disorders,""infrared thermography,""thermography," and "infrared imaging." The inclusion criteria were: studies published between January 1985 and January 2021, performed in humans, with sample size equal or greater than 20 patients, written in English, Portuguese, French and/or Spanish, and full text available. The exclusion criteria were: systematic reviews, case studies, and/or studies focused on pathologies beyond the review's domain. The risk of bias was evaluated using CASP 2018. A total of 2032 articles were retrieved. Of these, 25 studies met the inclusion criteria and were included to withdraw the following information: title, type of study, first author and year of publication, objective, number of participants, comparisons, and principal conclusions. No RCT were found. Despite some disparity, points of convergence among the majority of authors could be found. In general, healthy individuals show subtle thermal differences between contralateral homolog areas. Concerning orofacial structures, unilateral symptomatic individuals may show thermal differences equal or greater than 0.4°C. Infrared thermography accuracy in diagnosing TMD/MSD is still considered low to moderate. Despite some limitations, IRT might constitute a valuable supporting diagnostic tool in the medical field of TMD and MSD.

Ultrasound-guided vs conventional arthrocentesis for management of temporomandibular joint disorders: A systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to compare outcomes between ultrasound (US)-guided arthrocentesis and conventional arthrocentesis for the management of temporomandibular joint disorders (TMDs).

METHODS

PubMed, Embase, Scopus, BioMed Central, CENTRAL, and Google scholar databases were searched up to April 1 2020 for randomized control trials (RCTs) comparing US-guided and conventional arthrocentesis.

RESULTS

Four RCTs were included. Pooled analysis did not demonstrate any statistically significant difference in pain or maximal mouth opening (MMO) scores after 1 week and 1 month of follow-up between US-guided and conventional arthrocentesis. Studies also reported data on intra-operative needle relocations and operating time but with conflicting results.

CONCLUSION

This study indicates that the use of US during arthrocentesis may not improve postoperative pain and MMO in the short term. Data on intra-operative outcomes are scarce and conflicting for any definitive conclusions. Further high-quality adequately powered RCTs are required to strengthen current evidence.

Current advances and research in ultrasound imaging to the assessment and management of musculoskeletal disorders

Currently evidence-based practice has given scientific weight to the physical therapist profession; it is essential that all medical professional and physical therapists know the usefulness of new tools that optimize the effectiveness of their interventions and allow the growing of the scientific knowledge base. The use of ultrasound imaging (USI) by physiotherapists has evolved in recent years, consolidating as an increasingly standardized technique, low cost compared to other imaging techniques, quickly of execution, feasible and reliable tool. USI offers a wide range of opportunities in clinical practice as well as in different research areas. Therefore, ultrasound has been currently used as a diagnostic tool by physicians and in recent years there has been an expansion of the use of ultrasound equipment by non-physicians professionals such as physical therapist or physical trainers, who incorporates USI as a means of assessing musculoskeletal system architecture and composition, musculoskeletal changes in dysfunction, pain or injury conditions, as an interventional technique assisting echo-guided procedures or using the visual real-time information as a biofeedback in control motor approaches, as guiding tool in clinical decisions as well as to improve the understanding of tissue adaptations to exercise or movement. The purpose of this article is to review and provide an overview about the currently research of the USI applications and their benefits for the diagnosis and management in individuals with musculoskeletal conditions.

Imaging of the temporomandibular joint

Temporomandibular disorders are common, especially in young to middle-aged women, and most settle with supportive treatment. Imaging is indicated for the small percentage of cases that do not respond to conservative management and when the diagnosis is no doubt. The temporomandibular joint (TMJ) is a bilateral synovial articulation between the mandible and skull base. It has an intra-articular disc dividing the joint into superior and inferior compartments and the articular surfaces are lined with fibrocartilage. The normal imaging anatomy of the TMJ is described and illustrated. Different movements occur in each joint compartments: a hinge movement in the inferior joint space and translation or gliding in the superior joint space. Internal derangement is the commonest disorder affecting the TMJ and is most commonly due to disc displacement, followed by osteoarthritis and inflammatory arthritides. The imaging findings, primarily on magnetic resonance imaging (MRI) and computed tomography (CT), of internal derangement and less common disorders of the joint, are reviewed and illustrated. Optimal imaging protocols are discussed with detailed reporting guidelines.