FIG 1. Digital subtraction angiogram, superselective study of the right internal carotid artery, arterial phase, lateral projection, displays the MCA bifurcation.

A, A small saccular aneurysm (arrow) is seen at the right anterior choroidal artery origin. Note also the minute aneurysm at the MCA bifurcation.

B, On late arterial phase image, a characteristic aneurysmal inflow-outflow pattern ("yin-yang") may be observed.