Since the introduction of MRA much attention has been paid to the cervical and intracranial segments of the carotid and vertebral arteries, with significantly less attention to the region of the aortic arch. Fortunately, current time-of-flight (TOF) MRA methods are well suited to the evaluation of the aortic arch and proximal brachiocephahc arteries (Edelman et al. 1989; Lewin et al. 1991). Though a much less common cause of neurological symptoms than cervical carotid disease, disease of the aortic arch branches may arise from a variety of etiologies, including atherosclerosis, inflammatory arteritis, trauma, fibromuscular dysplasia, neoplasm, and radiation (Provan 1989). MRA can provide accurate noninvasive evaluation of stenosis and occlusion from these causes, and can allow for confirmation of vessel patency following surgical intervention. This chapter will discuss MRA methods applicable to evaluation of the aortic arch, with particular emphasis on 3D TOF techniques, followed by a discussion of pathological entities which may be encountered.