Fig 5. High-resolution CT angiography (HCRTA) of a ruptured right posterior communicating artery (PcomA) aneurysm with Fisher IV SAH. This aneurysm is highly irregular with multiple blebs (A–C). Axial HRCTA images show unbalanced contact constraints with the mediotemporal lobe (A) and the free border of the tentorium cerebelli (B). Coronal plane reconstructions show the occulomotor nerve as a round nonenhancing structure and the free edge of the tentorium as an enhancing, linear, slitlike structure (D–L). The contours of the aneurysms are clearly deformed by the imprint of these 2 structures on its inferior surface. The PcomA is visualized medially to the aneurysm.

A and B, Axial HRCTA images. White arrow, PcomA aneurysm; asterisk, contact with the mesiotemporal lobe; arrowhead, contact with the free border of the tentorium cerebelli.

C, 3D reconstruction of HRCTA, posteroanterior view. Arrow, imprint from free border of tentorium cerebelli and right occulomotor nerve.

D–L, Coronal plane, sequential, back to front, thin section multiplanar reconstruction of the PcomA aneurysm. Double arrowhead, free border of the tentorium cerebelli; white arrowhead, PcomA; red arrow, right occulomotor nerve; white arrow, PcomA aneurysm; red arrowhead, cisternal internal carotid artery (ICA); blue arrow, ICA-PcomA aneurysm junction.