The research study is being conducted to determine the utility of magnetic resonance imaging (MRI) in identifying inflammation of arteries supplying blood to the head, brain, and eyes. The target population includes patient with suspected giant cell arteritis (GCA; temporal arteritis).

After signing the consent form, participants will complete an MRI scan within 2 weeks of enrollment and fill out questionnaires related to their disease. Follow up visits and MRI scans may occur at 6-months after the initial MRI scan or at the time of relapse.

Inclusion Criteria:

• Age 50 years or older
• First presentation of suspected GCA
• New or worsening cranial manifestations within 4 weeks of enrollment concerning for active GCA
• Elevated CRP greater than 1.0 mg/dl
• Plan to undergo temporal artery biopsy or ultrasound for diagnosis

Exclusion Criteria:

• Contra-indication to receiving MRI including:

Implanted medical devices, pacemaker, and metallic foreign fragments inside body/orbits Known gadolinium allergy Women who are pregnant or nursing

• Absence of cranial symptoms related to GCA (e.g., only large vessel GCA)

Participants will be recruited from the ambulatory clinic, emergency department, or inpatient settings.

This has not been approved by the ethics committee at some sites.