Vasculitis of ascending aorta detected on FDG PET/CT in a patient with fever of unknown origin

The patient was found to have normal left ventricular size with borderline systolic function, left ventricular hypertrophy, right ventricle at the upper limit of normal size, mild systolic dysfunction and mild transvalvular aortic insufficiency on transthoracic echocardiography; while no vegetations were observed on transesophageal echocardiography. Subsequently, the patient underwent fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG-PET/CT) in search for the origin of the fever, which depicted increased radiopharmaceutical uptake in the aortic root with upward extension to the ascending aorta (figure 1), without any abnormal uptake of the prosthetic aortic valve in the non-attenuation corrected images. Coronal (A), sagittal (B) and axial (C) hybrid F-18 FDG PET/CT images together with coronal (D), sagittal (E) and axial (F) F-18 FDG PET views demonstrate increased metabolic activity in the aortic root with upward extension to the ascending aorta, which is mostly consistent with vasculitis.