Impact of the Spatial Resolution of Several Contrast-enhanced 3D T1-WI Sequences When Diagnosing Giant Cell Arteritis (GCA)

Inclusion Criteria: * Patient over 18 years of age * Referred for imaging for an injected MRI for suspected GCA * Suspicion of GCA based on the presence of three major criteria or two major and one minor criteria defined as follows: * Major criteria: Age \> 50 years; Headache of recent onset; Claudication of the jaw, tongue or swallowing disorders; Visual problems (blindness, diplopia, blurred vision - including visual accidents occurring during the first week of treatment); Sedimentation rate at 1st hour \> 50 and/or CRP \> 8mg/l * Minor criteria: Hypersensitivity or induration of the scalp or presence of nodules remote from the temporal artery; Temporal artery abnormalities on palpation; Facial pain or feeling of facial edema; General signs (fever \>38°C, weight loss \>10%, anorexia, malaise, asthenia). * Cconsent to participate in the study * Affiliated or beneficiary of a social security plan Exclusion Criteria: * Newly diagnosed malignant disease (diagnosed less than one year prior to inclusion) * Active infectious disease * Autoimmune disease (especially but not limited to: Wegener's disease, Takayasu vasculitis, ANCA vasculitis, rheumatoid arthritis, lupus erythematosus, periarteritis nodosa). * Systemic corticosteroid therapy for more than 10 days at high dose (\>0.5mg/kg/d of prednisone) * Contraindication to MRI * Patient benefiting from a legal protection measure * Pregnant or breastfeeding woman