Flourine-18 flourodeoxyglucose Positron Emission Tomography as a non-invasive test of disease activity in Takayasu's arteritis — A report of four cases

BackgroundTakayasu's arteritis (TA) is a rare disease affecting the large arteries, particularly the aorta. Standard test to demonstrate abnormal vascular anatomy is angiography. This invasive procedure is limited in differentiating inflammatory and fibrotic lesions. Acute phase reactants have shown to have poor sensitivity and specificity in confirming disease activity in TA patients. Fluorine-18 flourodeoxyglucose Positron Emission Tomography (FDG-PET) scan has been utilized to detect areas of active inflammation in neoplastic, infectious and recently, vasculitic conditions.ObjectiveTo describe the FDG-PET scan findings of patients with Takayasu's arteritis.MethodsThis is a case series of four patients fulfilling the American College of Rheumatology classification criteria for TA. They were evaluated with FDG-PET scan to establish disease activity in correlation with other clinical and laboratory features.ResultsThree out of four patients showed evidence of increased radiotracer uptake in the aorta. Of these three patients, one had increased radiotracer uptake in the lungs secondary to active pulmonary tuberculosis.ConclusionPET scan is a promising but non-specific tool that provides clinicians with a non-invasive measure of disease activity in TA patients. Further studies confirming its utility in monitoring disease activity and response to treatment is recommended.