Anastomosis, EC-IC

#DSA #anatomy

In this article, we gathered cases with interesting external carotid-internal carotid anastomoses.

Cases

1 MMA and Ophthalmic Artery

1.1

DSA - Right ICA Injection (PA [Top] and Lateral [Bottom])

The right middle meningeal artery (red arrows) is arising from the right ophthalmic artery (blue arrow), as observed during an injection into the right ICA. By the way, did you notice the aneurysm?

1.2

Right ICA Injection

This patient presented with stroke activation, and the right internal carotid artery run showed a right M 1 occlusion (yellow arrow). Interestingly, an anastomosis was also observed between the right ophthalmic artery (red arrow) and the right middle meningeal artery (green arrow). Subsequent mechanical thrombectomy achieved a TICI 2 C reperfusion (inset images).

(A): PA view.
(B): Lateral view.
Blue arrow: Anterior branch of the MMA.
Orange arrow: Posterior branch of the MMA.

1.3


This patient presented with chronic complete occlusion of the right cervical ICA. DSA showed an anastomosis between the right internal maxillary artery branches and the right ophthalmic artery (blue arrowhead). There is also cross-filling from the left ICA injection via the patent anterior communicating artery (orange arrow).

(A): Right CCA injection, PA view.
(B): Right CCA injection, lateral view.
(C): Left CCA injection, PA view.

Red arrow: Right occipital artery.
Magenta arrow: Right superficial temporal artery.
Brown arrow: Internal maxillary artery.
Cyan arrow: Middle meningeal artery.
White arrow: Choroidal blush.

1.4


On the right ICA run (top row), the right ophthalmic artery (red arrow) briefly opacified and disappeared with the retrograde flow. On the right ECA run (bottom row), an anastomosis (red circle) between the frontal branch (blue arrow) of the right MMA (yellow arrow) and right ophthalmic artery was observed with robust flow from the former to the latter. Note: The anastomosis point was right where the ophthalmic artery forward flow stopped on the ICA run.

Caution!

This type of anastomosis poses a potential risk of vision loss in the setting of MMA embolization.

Cyan arrow: Posterior branch of the MMA.
Magenta arrow: Superficial temporal artery.
Brown arrow: Internal maxillary artery.
Orange arrow: Internal carotid artery.
White arrow: Choroidal blush.

P.S. A similar case was described on Practical Neuroangiography page 135, Figure 10-6.

2 Occipital-Vertebral Anastomosis

2.1

DSA - Left ECA Injection (PA [Left] and Lateral [Right])

On this left ECA angiogram, an anastomosis (blue arrow) can be seen between the left occipital artery (red arrow) and the left VA (green arrow).

2.2

On this ECA angiogram, an anastomosis (blue arrow) can be seen between the occipital artery (red arrow) and the VA (green arrow).

3


This patient presented with a ruptured paraophthalmic aneurysm that necessitated urgent coiling. Subsequently, a flow diverter embolization was carried out in a delayed manner. Notably, there existed an ophthalmic artery origin stenosis (A, red arrow), showcasing normal flow (B). However, following the deployment of the flow diverter, a hindrance in the flow (C and D, yellow arrow) was observed. An external carotid artery injection (E) revealed a choroidal blush (F, green arrow), signifying an EC-ophthalmic artery anastomosis.