PET imaging of large-vessel vasculitis: advancements and future trends

Large vessel vasculitis (LVV), comprising giant cell arteritis (GCA) and Takayasu arteritis (TAK), presents diagnostic and monitoring challenges due to the limited specificity of clinical manifestations and laboratory markers, particularly for detecting disease relapse. 18F-fluoro-2 deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) has evolved from an emerging tool to a cornerstone modality in the evaluation of LVV. Concurrent technological advances in PET imaging, including the increasing availability of digital PET/CT, long axial field-of-view devices, quantitative approaches, and the development of novel radio pharmaceuticals, have substantially expanded the role of PET/CT in the evaluation of LVV with broader clinical acceptance. This review summarizes major recent advances in the field, includ ing the validation of cranial LVV (C-LVV) assessment using digital PET, the use of dynamic whole-body (D-WB) PET, the emergence of hybrid PET/MRI with novel scoring systems, as well as emerging radiotracers, such as fibroblast activation protein inhibitors (FAPI). These inno vations may potentially overcome limitations of 18F-FDG, particularly in distinguishing active vascular inflammation from inactive disease or vascular remodeling.