Pre-clinical evaluation of implicit deformable models for three-dimensional segmentation of brain aneurysms from CTA images

Abstract

Knowledge of brain aneurysm dimensions is essential during the planning stage of minimally invasive surgical interventions using Guglielmi Detachable Coils (GDC). These parameters are obtained in clinical routine using 2D Maximum Intensity Projection images from Computed Tomographic Angiography (CTA). Automated quantification of the three dimensional structure of aneurysms directly from the 3D data set may be used to provide accurate and objective measurements of the clinically relevant parameters. The properties of Implicit Deformable Models make them suitable to accurately extract the three dimensional structure of the aneurysm and its connected vessels. We have devised a two-stage segmentation algorithm for this purpose. In the first stage, a rough segmentation is obtained by means of the Fast Marching Method combining a speed function based on a vessel enhancement filtering and a freezing algorithm. In the second stage, this rough segmentation provides the initialization for Geodesic Active Contours driven by region-based information. The latter problem is solved using the Level Set algorithm. This work presents a comparative study between a clinical and a computerized protocol to derive three geometrical descriptors of aneurysm morphology that are standard in assessing the viability of surgical treatment with GDCs. The study was performed on a data base of 40 brain aneurysms. The manual measurements were made by two neuroradiologists in two independent sessions. Both inter-and intra-observer variability and comparison with the automated method are presented. According to these results, Implicit Deformable Models are a suitable technique for this application.

Efficient pipeline for image-based patient-specific analysis of cerebral aneurysm hemodynamics: technique and sensitivity

“…The final segmentation is the zero level set of the embedding function. The method has recently been introduced and extensively validated [8].…”

“…The existence of a yield stress implies that blood requires a finite stress before it begins to flow, a fact that has been observed experimentally. The apparent viscosity of the Casson model can be written as (7) Since this expression diverges as the strain-rate becomes zero, it is typically modified in the following way: (8) where the parameter controls the maximum viscosity obtained when tends to zero. Typical values used for blood are , , and .…”

Vessel segmentation and blood flow simulation using Level-Sets and Embedded Boundary methods

“…When coupled [3], these numerical techniques can achieve the highest level of accuracy in a very short time, compared to other segmentation techniques like classical active contours that fail to capture complex shapes. These algorithms have been validated in numerous cases [4], and can be specifically optimized to extract long and thin tubular objects [5].…”

Three-Dimensional Segmentation of Brain Aneurysms in CTA Using Non-parametric Region-Based Information and Implicit Deformable Models: Method and Evaluation

“…The Geodesic Active Regions model [11] (GAR) combines the classical Geodesic Active Contours model (GAC) with regional information. This method has been successfully used in the segmentation of brain aneurysms [4,7]. These authors model region-based information by Gaussian descriptors.…”