Intra-operative optimal flow diverter selection for intracranial aneurysm treatment using angiographic parametric imaging: Feasibility study

During intracranial aneurysm (IA) treatment with flow diverters (FDs), the device/parent artery diameter ratio may influence the ability of the device to induce aneurysm occlusion. We propose to investigate a method for optimal FD selection using Angiographic Parametric Imaging (API) and data driven methods. We selected 379 pre-treatment angiographic sequences of IAs with known occluded/unoccluded status at six months follow-up. For each IA, we extracted six API imaging biomarkers, Time to Peak, Peak Height, Mean Transit Time, Area Under the Curve, Maximum Inflow Gradient, and the Cross Correlation between the time dilution input function and the aneurysm dome. Each IA biomarker was normalized to the inlet equivalent parameter and divided in four intervals using quartiles of the observed biomarker distribution. The ratio of the IA proximal artery to nominal device diameters was used as a parameter for device selection. Based on the nominal device/proximal artery diameter ratios(r), four FD situations were considered: significantly undersized (r ≤ 0.8), undersized (0.8 < r ≤ 1), oversized (1 < r ≤ 1.2), and significantly oversized (1.2 < r). For each parameter and device ratio combination, we recorded an estimated risk of treatment failure as a percent of unoccluded IAs to the total number of treated cases within determined subgroups. This retrospective analysis of the occlusion data demonstrated insightful trends between imaging biomarkers associated with increased IA inflow, selection of the device, and failure to achieve complete occlusion at six months, indicating excellent potential for this approach to be used for intraoperative device selection.