The Role of Imaging in Monitoring Large Vessel Vasculitis: A Comprehensive Review.

Giant cell arteritis (GCA) and Takayasu arteritis (TAK) are forms of primary large vessel vasculitis (LVV) affecting the aorta and its major branches. Timely diagnosis and accurate monitoring are essential to prevent irreversible damage. Current assessment strategies rely heavily on symptoms, physical examination, and inflammatory markers, which lack sensitivity and specificity, particularly in patients treated with IL-6 inhibitors. This narrative review provides a comprehensive overview of the role of imaging in monitoring LVV. Ultrasound, magnetic resonance imaging, and positron emission tomography better reflect disease activity and treatment response compared to conventional clinical and laboratory measures. Notably, emerging imaging-based tools such as the OMERACT GCA Ultrasound Score, the Takayasu Ultrasound Index, and the TAK Integrated Disease Activity Index (TAIDAI) are promising treat-to-target instruments. While computed tomography is primarily used to assess structural damage, conventional angiography now plays a more limited role, mainly reserved for procedural planning and haemodynamic evaluation. A key challenge remains: interpreting persistent vascular abnormalities, which may indicate active disease, vascular remodelling, or irreversible damage. Standardisation of imaging protocols and interpretation is needed, alongside further research on the prognostic value of imaging for relapse risk. This review supports a multimodal, patient-tailored approach in which imaging is central to the long-term management of LVV.