Unusual 18F FDG Avidity in multiple major arteries and pulmonary trunk: A case report of active large-vessel vasculitis

Abstract

Large-vessel vasculitis (LVV), including Takayasu arteritis and giant cell arteritis, is a rare inflammatory condition affecting the aorta and its major branches. This case report describes a 33-year-old male with fever of unknown origin (FUO), anemia, and elevated inflammatory markers. Initial imaging was inconclusive, but Fluorodeoxyglucose Positron Emission Tomography - Computed Tomography (18FFDG PET-CT) revealed diffuse uptake in major arteries (carotid, subclavian, brachiocephalic, aorta, and pulmonary trunk) with an SUVmax of 6.91, indicating active vasculitis. The absence of 18FFDG-avid lymphadenopathy ruled out malignancy or infection, while faint uptake in bilateral femoral arteries suggested systemic involvement. Physiological uptake in organs like the gastrointestinal tract and adrenal glands showed no malignancy, and axial skeleton activity was linked to anemia. This case highlights 18FFDG PET-CT's role in early LVV detection, stressing the need for timely diagnosis to prevent irreversible vascular damage and the importance of integrating imaging with clinical evaluation for effective management.