Giant cell arteritis is characterized by diffuse arterial inflammation that selectively involves the superficial temporal arteries but can occur in larger arteries. Various vascular investigations can assist in diagnosing and evaluating the extent of giant cell arteritis. Imaging techniques, mainly Doppler ultrasonography of the superficial temporal arteries, seem less reliable for the diagnosis than temporal artery biopsy, which is safe and remains indispensable. Investigations of larger arteries can detect asymptomatic stenotic lesions, which are common, particularly in the axillary and subclavian arteries. Involvement of the aorta can cause life-threatening dissection or aneurysmal rupture. Imaging techniques useful for diagnosing aortic involvement include ultrasonography, computed tomography, magnetic resonance imaging, and aortography. Although there is no standardized strategy for aortic lesion detection, helical computed tomography may be valuable.