ABSTRACT
Vasculitides are a broad group of diseases that can involve any kind of vessel in any organ. These can be classified according to the size of the affected vessels. The most used classification categorizes them in small, medium, and large vessel vasculitis. Large vessel vasculitis can be further divided in Takayasu arteritis and giant cell arteritis which can sometimes be indistinguishable, even with biopsy. Radiology plays an important role identifying distribution patterns and disease extension18. Fluorine-Fluorodeoxyglucose (FDG) PET-CT shows increased vessel wall FDG uptake in patients with active large vessel vasculitis. Multiple studies show that FDG PET-CT helps to identify the anatomic structures with the disease, as well as evaluate its progression with a high sensibility and specificity in non-treated patients with large vessel vasculitis.