FIG 1. Representative cases showing severity of PPP.

A–C, Examples of mild (A), moderate (B), and severe (C) PPP on lateral views of the venous phase of cerebral angiogram. Mild PPP has small tortuous collateral veins (short wide arrows, A and B) with slight irregularity of the cortical veins (long thin arrows, A and B). These changes are more evident in moderate PPP and more dramatic in severe PPP.