Beyond clinical criteria: emerging biomarkers and advanced imaging in the diagnosis, monitoring and treatment of vasculitides.

Vasculitides represent a heterogeneous group of immune-mediated diseases characterized by inflammation of blood vessel walls, leading to variable degrees of ischemic injury across multiple organ systems. Despite significant advances in classification-notably the 2022 ACR/EULAR criteria-the clinical management of vasculitis remains challenging, particularly with regard to accurate diagnosis, assessment of disease activity, prediction of relapse, and monitoring of treatment response. Traditional clinical and laboratory markers, including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), lack specificity and are often insufficient for guiding individualized therapeutic decisions. In recent years, a new generation of biomarkers has emerged, encompassing serological proteins, urinary markers, cytokines, endothelial activation molecules, and exploratory multi-omic signatures. In parallel, advanced imaging modalities-including 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT), high-resolution vessel wall magnetic resonance imaging (VW-MRI), vascular ultrasound, and magnetic resonance angiography (MRA)-have substantially expanded our ability to visualize vascular inflammation with unprecedented anatomical and functional detail. This narrative review synthesizes current evidence on the most relevant biomarkers and imaging techniques across the principal vasculitic syndromes, including anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV), giant cell arteritis (GCA), Takayasu arteritis (TAK), and other major forms. We discuss the diagnostic and prognostic value of each approach, explore the emerging concept of integrated biomarker-imaging strategies, and identify key unmet needs and future research directions in the field.