Which finding suggests collateral circulation in a patient with ICA occlusion?

The presence of increased flow through the anterior communicating artery is indicative of collateral circulation in a patient with internal carotid artery (ICA) occlusion. In cases where there is an occlusion in the ICA, the body often finds alternative pathways for blood to reach the affected regions of the brain. The anterior communicating artery, which connects the two anterior cerebral arteries, can serve as a critical bypass route in such situations. When there is significant collateral flow, it often reflects the body's adaptation to reduced blood supply through the primary route, which is the occluded ICA.

This increased flow through the anterior communicating artery signifies that the collateral circulation is functioning effectively, redirecting blood to maintain cerebral perfusion and mitigating the potential ischemic effects of the ICA occlusion. In vascular assessment, this finding can be pivotal in diagnosing and understanding the extent and effects of chronic vascular occlusion.

Other options do not provide the same clear indication of collateral circulation; an increase in the ICA lumen diameter usually suggests a healthy artery rather than collateral flow, retrograde flow in the common carotid artery may indicate a severe compromise but doesn’t necessarily confirm the establishment of collateral flow, and high resistance in the external carotid artery (ECA) can be a sign of various flow dynamics but does