Geometric uncertainty in intracranial aneurysm rupture status discrimination: a two-site retrospective study

Abstract

ObjectivesAssessing the risk associated with unruptured intracranial aneurysms (IAs) is essential in clinical decision making. Several geometric risk parameters have been proposed for this purpose. However, performance of these parameters has been inconsistent. This study evaluates the performance and robustness of geometric risk parameters on two datasets and compare it to the uncertainty inherent in assessing these parameters and quantifies interparameter correlations.MethodsTwo datasets containing 244 ruptured and unruptured IA geometries from 178 patients were retrospectively analysed. IAs were stratified by anatomical region, based on the PHASES score locations. 37 geometric risk parameters representing four groups (size, neck, non-dimensional, and curvature parameters) were assessed. Analysis included standardised absolute group differences (SADs) between ruptured and unruptured IAs, ratios of SAD to median relative uncertainty (MRU) associated with the parameters, and interparameter correlation.ResultsThe ratio of SAD to MRU was lower for higher dimensional size parameters (ie, areas and volumes) than for one-dimensional size parameters. Non-dimensional size parameters performed comparatively well with regard to SAD and MRU. SAD was higher in the posterior anatomical region. Correlation of parameters was strongest within parameter (sub)groups and between size and curvature parameters, while anatomical region did not strongly affect correlation patterns.ConclusionNon-dimensional parameters and few parameters from other groups were comparatively robust, suggesting that they might generalise better to other datasets. The data on discriminative performance and interparameter correlations presented in this study may aid in developing and choosing robust geometric parameters for use in rupture risk models.

Inter‐model and inter‐modality analysis of left ventricular hemodynamics: Comparative study of two CFD approaches based on echocardiography and magnetic resonance imaging

“…For the shape comparison between TTE and MRI, focus was set on the LV. Besides the clinical measures as displayed in Table 1, the LV shape was compared in terms of the sphericity index (SI) [11], and several metrics from Dhar et al [10], which are commonly used to quantify the morphology of intracranial aneurysms [4,21]: non-sphericity index (NSI), undulation index (UI), and the ellipticity index (EI). The SI quantifies the deviation from a perfect sphere, the NSI the deviation from a perfect hemisphere, the UI the degree of surface concavity, and the EI the deviation of the LVs convex hull to a perfect hemisphere.…”