Comparison of Imaging Modalities in the Quantification of Cerebral Aneurysm Geometry

Longitudinal studies of a large cohort of cerebral aneurysm patients are essential for assessing the ability of geometric and biomechanical indices in predicting their growth or rupture risk [1,2]. Patients with these lesions are routinely subjected to volumetric scans, but these can be one of four modalities — 3D rotational angiography (3DRA), Computed Tomography Angiography (CTA), Magnetic Resonance Angiography (MRA) and MR Time-of-flight (MR-TOF) — the choice of which is often dictated by clinical considerations. One of the challenges in geometric analysis of cerebral aneurysms is the consistency in the process of 3D reconstruction of aneurysm geometry when data from multiple imaging modalities are used. It is reasonable to wonder if the same aneurysm were imaged using different imaging modalities, whether the quantified measures of the aneurysm’s shape and size will be different. The objective of this study is to assess the sensitivity of geometric indices of cerebral aneurysms to the modality from which the image volume is obtained. A patient-specific silicone model of the head and neck vasculature with an aneurysm was imaged using all four modalities, geometric measures were estimated and compared.