Section Editor: Sandy Cheng-Yu Chen, M.D.
Taipei Medical University Hospital, Taipei, Taiwan
Craniocervical arterial dissection is considered to be either traumatic or spontaneous in origin. It occurs commonly just below the skull base where there is increased shear force and greater vascular mobility compared to the intracranial segments. Diagnostic angiography shows tapering of the right internal carotid artery (ICA) with distal widening and associated pseudoaneurysm. Volume-rendered CT angiograph (A) also shows tapered stenosis (arrow) with distal widening of the right ICA associated with pseudoaneurysm (arrowhead). Axial T1 MRI (B) obtained with fat saturation shows a narrowed eccentric flow void surrounded by a crescent-shaped circumferential subacute intramural hematoma (arrow) in the right ICA wall consistent with dissection.