Artery, Internal Carotid

The internal carotid artery (ICA) is a branch of the common carotid artery, it terminates into middle cerebral artery and anterior cerebral artery.

Cases

1

This DSA presents an interesting anatomical variation of the right ICA (magenta arrow) terminus, which bifurcates into the inferior M1 (blue arrow) and superior M1 (green arrow). The right ACA (yellow arrow) originates from the superior M1. Alternatively, one may argue that the ICA terminates into an M1 (green arrow) and an A1 (yellow arrow), while there is another M1 originating from the ICA trunk (blue arrow).

Cyan arrow: Posterior communicating artery/posterior cerebral artery.
White arrow: Callosomarginal artery.
Brown arrow: Pericallosal artery.

P.S.: (B) and (C) originate from the same injection, whereas (A) features a slightly different angle.

2 Stenosis

In this case, we observe the impact of an ICA stenosis on intracranial flow dynamics.

(A) and (B): Pre-internventional PA and lateral views of the capillary/venous phase (noting the ECA territories) following left CCA injection depict a severe cervical ICA stenosis (red arrow) and markedly delayed flow in the ICA. There is absence of visualization of the left ACA, and contrast dilution in the left MCA, attributable to competitive flow from the right ICA through the ACOM artery.
(C): Pre-interventional PA view of the right CCA injection reveals cross-filling of the left ACA and MCA via the patent ACOM artery.
(D) and (E): Post-interventional PA and lateral views of the arterial phase of the left CCA injection demonstrate notable amelioration of the left ICA stenosis (green arrow), reinstatement of normal intracranial flow dynamics, and ante-grade flow in the left ACA and MCA.