Giant Cell Arteritis is the most common primary vasculitis in adult patients. GCA is difficult to diagnose, and no single test allows perfect classification of GCA. Imaging in GCA such as high resolution ultrasound is gaining populatity and allows identification of patients that would have been otherwise missed.~Recently, optic nerve sheath enhancement on MRI has been described and associated with the presence of GCA. Evaluation of the optic nerve and optic nerve sheath using ultrasound is easy to perform but has never been assessed in GCA.~Objectives:~To assess the ability of optic nerve (ON), optic nerve sheath diameter (ONSD) and optic nerve sheath thickness (ONST) measured by ultrasound to predict Giant Cell Arteritis.~To evaluate changes in ON, ONSD, ONST measurements in patients with confirmed GCA after three months of therapy~To assess dynamic changes in ON, ONSD, ONST measurements in patients with relapsing GCA
The objectives of this observational cohort study are :~To assess the ability of optic nerve (ON), optic nerve sheath diameter (ONSD) and optic nerve sheath thickness (ONST) measured by ultrasound to predict Giant Cell Arteritis.~To evaluate changes in ON, ONSD, ONST measurements in patients with confirmed GCA after three months of therapy~To assess dynamic changes in ON, ONSD, ONST measurements in patients with relapsing GCA