FIG 2. Images obtained in a 57-year-old man with a sudden onset of severe headache and neck stiffness. a, Conventional angiogram of the right VA in a lateral projection shows a dissection aneurysm at the V4 segment (arrow). b and c, MIP CT angiograms more clearly demonstrate the multiple faces of this dissection aneurysm (arrow). d and e, Axial source CT angiograms at the level of the aneurysm and its upper part show no evidence of intramural hematoma (arrow).