2D and 3D Morphologic Metrics Associated Intracranial Aneurysm Rupture

Intracranial aneurysms (IAs) rupture results in severe morbidity and mortality. Therefore indentifying IA rupture risk is highly critical. Although it has been recognized that IA rupture is the result of a complex vascular degeneration process involving multiple mechanobiological factors, such information for each patient is not readily available in clinical setting. Alternatively, morphology and hemodynamic metrics can be derived from routine patient-specific imaging. In previous studies, a number of morphological metrics derived from analysis of reconstructed vascular 3D geometry have shown significance in discriminating ruptured from unruptued IAs, including in particular aneurysm size ratio, defined as IA size divided by the parent vessel diameter. However, these measures rely on 3D image segmentation and measurement, which makes them less practical in current angiographic rooms often equipped with only biplane angiogram capability and even when 3D rotational angiography is available, on-site 3D image segmentation and analyses are still not practical. Our foregoing study examined three parameters measured on 2D angiographs: aneurysm Size Ratio (SR), Aspect Ratio (AR) and Size. We found that SR had the strongest correlation with IA rupture. The current study further evaluates these geometric metrics, measured both from 3D and 2D images, with a larger cohort of saccular intracranial aneurysms.