Fig. 3
From: Four collateral circulation pathways were observed after common carotid artery occlusion
DSA discovered another collateral circulation pathway that supplied ipsilateral ICA after CCAO. This was a left (ipsilateral) subclavian artery angiography (front position (a) and lateral position (b), arterial phase). Left CCA was occluded. The original part of left subclavian artery had moderate stenosis. The V1 segment of left vertebral artery had severe stenosis. The V4 segment of left vertebral artery became undeveloped after it gave out the posterior inferior cerebellar artery. The collateral circulation pathway was: ascending cervical artery from left thyrocervical trunk (arrow①) and deep cervical artery from left costocervical trunk (arrow②) – occipital artery (retrograde, arrow③) – ECA (retrograde, arrow④) – carotid bifurcation – ICA (arrow⑤)