[The additional value of imaging (excluding Doppler) for the diagnosis and follow-up of giant cell arteritis].

Since 2000, imaging is frequently used for the diagnosis and follow-up of giant cell arteritis (GCA). At diagnosis, the demonstration on imaging of an involvement of the temporal arteries is useful to guide the temporal artery biopsy, or, sometimes, to replace it. Large-vessel imaging is nowadays currently performed as some studies indicate that 30 to 80% of patients might demonstrate involvement of the aorta and its branches, often silently. Aorta CT angiography, positron emission tomography or magnetic resonance angiography show a high sensibility to detect large-vessel inflammation, and have become in current practice and recent studies a supplementary criteria to classify or diagnose GCA. Many studies indicate a different prognosis in patients with large-vessel inflammation, highlighting the need to diagnose such involvement. Large-vessel imaging is important in the patients' follow-up to analyze how large-vessel inflammation evolves under treatment and to detect morphologic changes (dilations, dissections, or stenoses) that are more frequent in these patients. Recent European recommendations analyze the different imaging procedures available for diagnosis and follow-up of patients with GCA.