Fluorescence Angiography for the Evaluation of Aneurysm Perfusion and Parent Artery Patency in a Rabbit Sidewall Aneurysm Model: Technical Note

Background: Brain aneurysm treatment focuses mainly on complete occlusion without any residual neck. Parent arterial flow should be patent. In neurosurgery, various techniques are used to control the blood flow. Techniques are Doppler ultrasonography, electrophysiological monitoring, and common cerebral angiography. Furthermore, other studies also mention fluorescein sodium and indocyanine green (ICG) as visualization methods. Only a few publications on fluorescein video angiography (FVA) are available. FVA was first introduced in neurosurgery in 1967 and was used to check the epicerebral blood circulation in therapeutic craniotomy.

The authors want to verify the real-time blood perfusion and occlusion of the aneurysm after inducing aneurysms in rabbits with FVA as an easy to use, reliable, and inexpensive method.

Methods: Twenty sidewall aneurysms were created in 10 rabbits by suturing an arterial vessel pouch on the carotid artery of a donor rabbit. One month after induction surgery, the aneurysms were controlled for patency. The artery was dissected and Fluoresceine Faure (10%, 1 mL) was injected intravenously via catherization of the ear vein. (The perfusion of the dye was recorded with a video camera.) Aneurysms were harvested and the patency was controlled macroscopically followed by histologically examination.

Results: All but one occlusions and patency diagnosed via fluorescein angiography could be confirmed macroscopically. FVA was feasible in 16/20 aneurysms and showed n = 12 cases with patent parent artery and n = 4 without flow at follow-up. The perfusion of the dye was recorded. No complications occurred. A catheter allows injection of more than one substance at the same time. Venous injections have less complications than arterial and the risk of contamination of the surgical field is lower in peripheral injections.

Conclusion: Fluorescein is cheap and easily applicable and no special equipment is needed. This is a safe and very effective method for evaluating in vivo perfusion status in an experimental setting with rabbits. Fluorescence videoangiography with fluorescein as contrast agent seems to be effective to control patency of aneurysms and underlying vessel or in bypass surgery. It gives a real-time picture of the patency and can be done without expensive equipment during surgery.