This is a prospective, double-blinded, pilot study to evaluate the ability of PET/CT with FDG to detect synovitis of the temporomandibular joint. Patients presenting to the Department of Oral and Maxillofacial Surgery at the Hospital of the University of Pennsylvania with symptomatic internal derangement of the temporomandibular joint requiring arthroscopy will be compared to control subjects. Key inclusion criteria include any individual found to have a primary diagnosis of internal derangement of the temporomandibular joint requiring arthroscopy as determined by the treating physician. All patients will have failed a trial period of "conservative treatment therapy" including occlusal splint therapy, NSAIDs, or muscle relaxants for a period no less than eight weeks. Exclusion criteria will include patients not medically stable to undergo arthroscopy under general anesthesia, patients with overlying infection of the skin, patients with conditions other than internal derangement causing temporomandibular pain or dysfunction.

Once a patient has been identified as eligible for the study, the treating physician will contact a member of the study team. Each participating patient will undergo a standardized exam, the research diagnostic criteria for TMD (RDC/TMD). A member of the research team, from the department of oral medicine, will administer this exam. This standardized exam has been previously validated in the literature, and each member of the research team will undergo training and calibration prior to administering the RDC/TMD. This exam will be performed on the day of the arthroscopy. In addition, each patient will be given a Wilkes score, based on the Wilkes classification of internal derangement.36 The patient will then undergo arthroscopy of the temporomandibular joint as per the treating physician. TMJ arthroscopy includes: a small incision in front of the ear, introduction of an arthroscope and irrigation needle into the joint space, irrigation of fluid, and at the discretion of the treating physician may include the lysis of adhesion and the introduction of medication into the joint. At the time of the procedure, the synovitis score will be determined based on an eleven point synovitis scale as described by Murakami, with zero being absence of synovial inflammation. This scoring is bone by observation, and is typically include in the arthroscopy procedure for diagnosis. The patient will also be given a binomial score of presence or absence of synovitis. A representative photograph will be obtained of the patient's joint during arthroscopy, as is routinely done during this procedures.

Prior to the procedure, the patients will have undergone a PET/CT scan to evaluate the TMJ. This radiographic exam will be limited to the head and neck region in order to minimize radiation exposure. The radiologists reading the study will be blinded to the results of the clinical exam and condition. The results of the PET/CT study will be given as a binomial score of positive or negative and given a continuous score based on uptake relative to the unaffected joint.

Control subjects will undergo the RDC/TMD standardized exam prior to the radiographic study, and only have the PET/CT performed, with no subsequent intervention. These patients will be aged matched to the treatment subjects. This information will then be utilized to determine the utility of PET/CT in the detection of synovitis of the temporomandibular joint.