MRI is the gold standard of imaging modalities for the diagnoses of internal derangement (ID) of the Temporomandibular Joint (TMJ). MRI scans are non-invasive, use non-ionizing radiation, and provide valuable information on the position and morphology of joints, tissues and bony structures. MRI has disadvantages and patients with severe TMJ pain may find it difficult to complete a full TMJ scan series. The heavy demand for MRI utilization and resulting wait times prolong the interval between initial consultation and diagnosis. MRI is also expensive, inconvenient, and contraindicated in patients with certain metallic implants (Orhan & Aksoy, 2019). For these reasons, the author believes that finding an alternative diagnostic device for ID that is convenient and reliable is of critical importance.
There is a limited body of encouraging evidence demonstrating that mobile ultrasound sonography (mUS), can act as a diagnostic adjunct to MRI for assessment of Temporomandibular Joint Disorders (TMD’s), including ID and Degenerative Joint Disease (DJD). The use of mUS has no known contraindications, is readily accessible, comparatively inexpensive, and requires no special preparation (Orhan & Aksoy, 2019). The purpose of this paper is to summarize the findings of original research into the Accuracy of handheld ultrasound sonography (HHU), in comparison to MRI, for the diagnoses of patients with TMD. The scans focussed on Anterior Disk Displacement (ADD) without reduction (ADDwoR), ADD with reduction (ADDwR) and arthritic changes (OA). Using a 95% CI and 5% p-value, when diagnosing ADDwoR, HHU was found to have a Sensitivity of 96.77%, Specificity of 100%, PPV of 100%, and NPV of 90%. When diagnosing ADDwR, Sensitivity was 76.50%, Specificity 100%, PPV 100%, and NPV 85.20%. The perfect Specificity means HHU is good at identifying patients that have a normal disc-condyle relationship and do not have ADD, while the perfect PPV means a high likelihood the tested patient has ADD. Results indicate that HHU is a highly Specific test, with no false negatives, and an acceptable Sensitive test, with few false positives. HHU, in conjunction with questionnaires and clinical examination, shows promise as a first line imaging modality and screen for MRI referral.