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Créteil, France

Li F.,School of Engineering of Innovation, Energy and Advanced Technologies | Chenoune Y.,School of Engineering of Innovation, Energy and Advanced Technologies | Ouenniche M.,School of Engineering of Innovation, Energy and Advanced Technologies | Blanc R.,Rothschild | Petit E.,Laboratoire Images
2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2014 | Year: 2014

Diagnosis and computer-guided therapy of cerebral Arterio-Venous Malformations (AVM) require an accurate understanding of the cerebral vascular network both from structural and biomechanical point of view. We propose to obtain such information by analyzing three Dimensional Rotational Angiography (3DRA) images. In this paper, we describe a two-step process allowing 1) the 3D automatic segmentation of cerebral vessels from 3DRA images using a region-growing based algorithm and 2) the reconstruction of the segmented vessels using the 3D constrained Delaunay Triangulation method. The proposed algorithm was successfully applied to reconstruct cerebral blood vessels from ten datasets of 3DRA images. This software allows the neuroradiologist to separately analyze cerebral vessels for pre-operative interventions planning and therapeutic decision making. © 2014 IEEE.

Nakib A.,Laboratoire Images | Siarry P.,Laboratoire Images | Decq P.,French National Center for Scientific Research
Computerized Medical Imaging and Graphics | Year: 2012

In this paper, we propose a framework to automate the assessment of the movements of a third cerebral ventricle in a cine MR sequence. Indeed, the goal of this assessment is to build an atlas of the movements of the healthy ventricles in the context of the hydrocephalus pathology. This approach is composed of two phases: a contour extraction, using fractional integration and a registration method, based on dynamic evolutionary optimization. The first phase of the framework is based on the fractional integration thresholding, that allows delineating the contours of the area of interest. In order to track over time each point of the primitive and achieve the assessment of the deformation, a matching method, based on a new dynamic optimization algorithm, called Dynamic Covariance Matrix Adaptation Evolution Strategy (D-CMAES), is used. The obtained results for quantification have been clinically validated by an expert and compared to those presented in the literature. © 2011 Elsevier Ltd.

Li F.,School of Engineering of Innovation, Energy and Advanced Technologies | Li F.,Laboratoire Images | Tankyevych O.,Laboratoire Images | Chenoune Y.,School of Engineering of Innovation, Energy and Advanced Technologies | And 2 more authors.
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS | Year: 2015

Vascular imaging is crucial in the treatment of many diseases. In the case of cerebral ArterioVenous Malformation (AVM), where the vascular network can be deeply altered, an accurate knowledge of its topology is required. For this purpose, after a vessels segmentation and skeletization applied on 3D rotational angiographic images (3DRA), we build a symbolic tree representation of the vascular network thanks to topological descriptors, such as end points, junctions and branches. This leads to an efficient tool to assist the neuroradiologist to understand the feeding and the draining of the AVM and to apprehend its complex architecture in order to determine the best therapeutic strategy before and during embolization interventions. © 2015 IEEE.

Sassolas A.,Laboratoire Images | Catanante G.,Laboratoire Images | Fournier D.,IPBS | Marty J.L.,Laboratoire Images
Talanta | Year: 2011

A colorimetric protein phosphatase (PP) inhibition test for the detection of microcystin-LR (MC-LR) has been developed. Three PP2As, one recombinant and two natural versions, as well as one PP1 produced by molecular engineering, were tested. First, assays were performed using the enzymes in solution to compare their sensitivity to MC-LR. The PP2A purchased from ZEU Immunotec and PP1 appeared more sensitive to the toxin than the other enzymes. With PP2A from ZEU Immunotec, the colorimetric test showed a detection limit of 0.0039 μg L -1 and an IC 50 value of 0.21 μg L -1. With PP1, the assay gave a detection limit of 0.05 μg L -1 and an IC 50 value of 0.56 μg L -1. Therefore, this assay allowed the detection of lower microcystin-LR (MC-LR) concentrations than the maximum level (1 μg L -1) recommended by the World Health Organisation (WHO). The main drawback of this PP-based approach in solution is poor enzyme stabilisation. To overcome this problem, enzymes were entrapped within either a photopolymer or an agarose gel. PP2A from ZEU Immunotec and PP1 were immobilised at the bottom of microwells. The agarose-based tests performed better than the photopolymer-based assay for all of the enzymes. Therefore, the agarose gel is a good candidate to replace the photopolymer, which is generally used in PP-immobilising membranes. The assays based on enzyme-entrapping agarose gels showed detection limits equal to 0.17 μg L -1 and 0.29 μg L -1 with immobilised PP2A from ZEU and PP1, respectively. In view of these performances, these tests can potentially be used for monitoring water quality. © 2011 Elsevier B.V. All rights reserved.

Masson-Sibuta A.,Laboratoire Images | Masson-Sibuta A.,Aesculap AG | Nakib A.,Laboratoire Images | Petit E.,Laboratoire Images | Leitner F.,Aesculap AG
Progress in Biomedical Optics and Imaging - Proceedings of SPIE | Year: 2012

In Computer Assisted Orthopaedic Surgery (CAOS), surgeons have to acquire some anatomical landmarks as inputs to the system. To do so, they use manual pointers that are localized in the Operating Room (OR) space using an infrared camera. When the needed landmark is not reachable through an opening, it is palpated directly on skin and there is a loss of precision that can vary from several millimeters to centimeters depending on the thickness of soft tissues. In this paper, we propose a new framework based on three main steps to register the bone surface and extract automatically anatomical landmarks with an ultrasound probe. This framework is based on an oriented gradient calculation, a simulated-compound and a contour closure using a graph representation. The oriented gradient allows extracting a set of pixels that probably belong to the bone surface. The simulatedcompound step allows using ultrasound images properties to define a set of small segments which may belong to the bone surface, and the graph representation allows eliminating false positive detection among remaining segments. The proposed method has been validated on a database of 230 ultrasound images of anterior femoral condyles (on the knee). The average computation time is 0.11 sec per image, and average errors are: 0.54 mm for the bone surface extraction, 0.31 mm for the condylar line, and 1.4 mm for the trochlea middle. © 2012 SPIE.

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