FIG 1. Case 1, a 75-year-old woman with an unruptured internal carotid-posterior communicating artery aneurysm.

A, Maximum intensity projection (MIP) image of the source CT angiography (CTA), superoinferior projection, shows aneurysmal complex and cranial base bone.

B, 3D CT angiogram (CTA), posteroanterior projection, shows the aneurysm (AN), posterior communicating artery (PCom), posterior clinoid process (PCP), dorsum sellae (DS), and petroclinoidal dural fold (PF). Arrowheads (1, 2) indicate the blebs.

C, Minimum intensity projection (MinIP) image of the MR cisternography (MRC), superoinferior projection, shows the aneurysm (AN) and perianeurysmal structures. A1 indicates the first segment of the anterior cerebral artery; M1, the first segment of the middle cerebral artery; C2, the second segment of the internal carotid artery; PCom, posterior communicating artery; PCP, posterior clinoid process; DS, dorsum sellae; PF, petroclinoidal dural fold; TL, temporal lobe.

D, 3D MRC, similar projection to 3D CTA in B, viewed from the basal cistern, shows the spatial expansion and contact of the aneurysm with the perianeurysmal structures. CN III indicates oculomotor nerve.

E, 3D MR angiogram (MRA), coordinated projection as to the 3D MRC in D, shows the aneurysm with 3 blebs (arrowheads 1–3).

F, Fusion image of the 3D MRC and MRA coordinated projection as to the 3D MRC in D shows the spatial relationship of the dome blebs to the adjacent structures.