Kinematic MRI has been extremely valuable in the biomechanics of the temporomandibular joint. The meniscocondylar dysfunction of the TMJ can be evaluated, along with the internal derangement and displacement of the meniscus. Asymmetrical motion can also be evaluated. Kinematic MRI has been used extensively to evaluate the TMJ joint, therefore many imaging centers are equipped to perform this procedure.
Abnormalities of the patellofemoral joint are a major cause of knee pain and occur as frequently as meniscal lesions. Patellar malalignment and its associated sequelae is the primary pathologic entity that affects the patellofemoral joint. The diagnosis of patellofemoral incongruence by physical examination alone is extremely difficult, because the clinical signs may mimic other forms of internal derangements of the knee and there is a high incidence of combined abnormalities. In addition, patients whose symptoms persist after patellar realignment surgery may become a particularly difficult diagnostic challenge. A kinematic MR imaging technique has been developed to identify and characterize the abnormal functional aspects of the patellofemoral joint. Many abnormalities occur during the early degrees of flexion and kinematic MR imaging is an extremely sensitive and effective means of evaluating the patellar alignment and tracking during the initial increments of flexion of the knee.
Kinematic MR imaging has only recently been applied to the examination of the wrist; its full potential in this application has not yet been realized. Despite limited experience to date with this imaging technique, kinematic MR has been helpful in detecting subtle abnormalities of carpal motion, as well as other instability patterns that are not easily evaluated by routine static MR imaging.
Like kinematic MR imaging of the wrist, kinematic MR imaging of the ankle is a relatively new procedure, and its role in the diagnostic assessment of this joint is still being defined. Initial data suggest that kinematic MR imaging helps provide a more thorough examination of the ankle, particularly in cases of functional abnormalities associated with bony subluxations or soft-tissue impingement.
Kinematic MRI studies of the cervical spine are also a relatively new procedure and limited experience to date suggests that alignments of the joints and disc displacements may be more accurately evaluated as to the areas of impingement with kinematic studies.
In the future, the use of echo planar and ultrafast MR imaging techniques will provide several benefits for kinematic MR studies of t\joints. The time required to perform these examinations will be significantly reduced, producing sufficient temporal resolution to allow actual dynamic movement of the joints. Kinematic MR imaging of the joints implemented in this manner will permit a more physiologic and functional examination to be performed, allowing the examination of contracting muscles and related soft-tissue structures to be assessed. Stay tuned for more kinematic developments in MR.
Deborah Pate, DC, DACBR
San Diego, California
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