Figure 1.

Imaging for Case 1: A. Head CT shows SAH concentrated in the right carotid cistern. B. Head DSA shows a BBA in the right internal carotid artery supraclinoid segment. C. DSA shows that, after the right internal carotid artery was pressed, the blood flow in the right internal carotid artery was compensated by the blood flow from the anterior communicating artery. D, E. Surgical clipping of the BBA with blood clots observed around the BBA. F. Follow-up CTA after clipping shows no relapse of the aneurysm.