Intracranial Vessel Wall MRI to Evaluate the Effect of Aspirin in a Rabbit Elastase Aneurysm Model

Background: Intracranial aneurysms have a high mortality rate and can cause devastating neurological damage, despite modern therapies. At present, there are no known medications that can slow the progression of brain aneurysms and mitigate the potential for rupture. Because of the known role of inflammation in the remodeling of aneurysms and their progression to rupture, aspirin has been studied as a potential medical therapy. Furthermore, intracranial vessel wall MRI has emerged as a promising way of evaluating inflammatory changes in intracranial blood vessels. The purpose of this study was to use intracranial vessel wall MRI to evaluate the effect of aspirin on intracranial aneurysms in a rabbit elastase aneurysm model.

Methods: Aneurysms were induced in the right common carotid arteries of 24 adult New Zealand rabbits using reconstituted elastase and following an established rabbit aneurysm model. Aneurysm formation was assessed three weeks later via Time-of-Flight MRA and intracranial vessel wall MRI. Twelve rabbits were given daily oral aspirin for three weeks, before undergoing repeat MRI to assess for differences between treated and untreated groups. Aneurysm sections were then dissected and assessed histologically.

Results: In the group of rabbits that were treated with aspirin, intracranial vessel wall MRI demonstrated reduced vessel wall enhancement after treatment when compared with before treatment. Also, rabbits that underwent aspirin treatment showed reduced vessel wall enhancement when compared with rabbits that did not undergo treatment. There was no appreciable difference in aneurysm development or vessel wall enhancement between male and female rabbits undergoing treatment.

Conclusion: Rabbits treated with aspirin demonstrated reduced vessel wall enhancement, which corresponded to reduced inflammation on histological sections. This suggests that aspirin plays a measurable anti-inflammatory role in the pathophysiology of aneurysms and that intracranial vessel wall MRI may serve as an imaging biomarker in this disease. More studies are needed.

No conflict of interest has been declared by the author(s).