Brain Aneurysm Biology: What Can We Learn From Imaging?

Aneurysmal subarachnoid hemorrhage portends a high risk of mortality and disability. The clinical and radiological assessment of the risk of a brain aneurysm rupture would aid clinicians in triaging patients for treatment versus observation. However, the specific mechanism underlying the formation, growth, and rupture of brain aneurysms is not known. The development of high-resolution magnetic resonance imaging and the refinement of postacquisition processing protocols have made it possible to analyze the aneurysm wall in detail. The 7T and 3T magnetic resonance imaging scanners provide high spatial resolution images with a high signal-to-noise ratio. The structure, morphology, location, and enhancement features of the aneurysm wall can be characterized with this level of detailed images. Abnormal wall characteristics can then be correlated with blood flow parameters, presence of inflammation, and pathological conditions of the wall. These imaging and analysis tools provide a unique opportunity to estimate the risk of aneurysm development and growth and to better identify novel markers of intracranial aneurysm instability. Morphological analysis of individual aneurysms combined with detailed characterization of the aneurysm wall, and clinical patient information could lead to an accurate and personalized risk prediction of aneurysm rupture.