Chafiaa Hamitouche

• Professor
• Professor (Full) at IMT Atlantique

Plane wave imaging persists as a focal point of research due to its high frame rate and low complexity. However, in spite of these advantages, its performance can be compromised by several factors such as noise, speckle, and artifacts that affect the image quality and resolution. In this paper, we propose an attention-based complex convolutional re...

This paper presents a novel evaluation method for assessing the effectiveness of virtual reality serious games (In our work, we used virtual reality as a simulated 3D environment, not immersive headsets) in post-stroke rehabilitation. Stroke, which is a leading cause of long-term disability, requires effective rehabilitation approaches to facilitat...

The aim of this work is to present an adaptive serious game based on virtual reality (VR) for functional rehabilitation of the hand after stroke. The game focuses on simulating the palmar grasping exercise commonly used in clinical settings. The system’s design follows a user-centered approach, involving close collaboration with functional rehabili...

Background: This paper presents a novel evaluation method for assessing the effectiveness of virtual reality serious games in post-stroke rehabilitation. Stroke, which is a leading cause of long-term disability, requires effective rehabilitation approaches to facilitate motor recovery and enhance patients’ quality of life. The study aims to investi...

Purpose A new approach is proposed to localize surgical instruments for Computer Assisted Orthopaedic Surgery (CAOS) that aims at overpassing the limitations of conventional CAOS solutions. This approach relies on both a depth sensor and a 6D pose estimation algorithm. Methods The Point-Pair Features (PPF) algorithm was used to estimate the pose o...

A new algorithm, based on fully convolutional networks (FCN), is proposed for the automatic localization of the bone interface in ultrasound (US) images. The aim of this paper is to compare and validate this method with (1) a manual segmentation and (2) a state-of-the-art method called confidence in phase symmetry (CPS). The dataset used for this...

In CAOS, ultrasound imaging has been proposed as a solution for obtaining the specific bone morphology of the patient, avoiding limitations of existing technologies. However, this imaging modality presents different drawbacks that make difficult the automatic bone segmentation. A new algorithm, based on Fully Convolutional Networks (FCN), is propos...

In this study, we propose a virtual learning environment for ultrasonography gestures based on an ultrasound (US) learning database. The learning database is comprised of US probe position and orientation, US images and force applied on the skin for each image. The intermediate images were inferred using the set of two-dimensional (2D) US images ac...

In this study, the movement of climbing a step is decomposed in 4 EOS images. A patient-dependent 3D model of the knee is then created from MRI, and several numerical simulations are carried out according to the experimental boundary conditions (force and flexion angle), so as to ensure the global knee mechanical equilibrium. To validate this patie...

Aims: Restoring the pre-morbid anatomy of the proximal humerus is a goal of anatomical shoulder arthroplasty, but reliance is placed on the surgeon's experience and on anatomical estimations. The purpose of this study was to present a novel method, 'Statistical Shape Modelling', which accurately predicts the pre-morbid proximal humeral anatomy and...

Background: Embedding self-powered sensors into the knee implant for measuring in-vivo tibiofemoral force distribution can provide beneficial information to both clinicians and researchers. This information may help to reduce the risk of early failure after total knee arthroplasty. It can also be used to improve implant design, refine surgical tech...

In this paper, we present our results on the development of a new generation of instrumented knee implant. The proposed implant would allow for ligament imbalance monitoring and correction in addition to its use as a replacement of human knee joint. The custom-designed tibial component of this implant is equipped with an autonomous force distributi...

Objective With cartilage physiopathology, knee stability and therefore the subsequent loadings on ligaments have a strong impact in the development of knee osteoarthritis. To understand this phenomenon, authors are proposing different knee models. Most of them are without any flexion, some have been introduced by controlling actively muscular group...

Est-il possible de concevoir une nouvelle génération de prothèses du genou permettant au clinicien de suivre le patient en post-opératoire et de rétablir, grâce à des réglages fins, la fonctionnalité stabilisatrice, évitant ainsi une chirurgie de reprise ?

A self-powered device that can be embedded within the knee implant to measure tibiofemoral forces is presented. This device can be used intraoperatively during the knee surgery or postoperatively through the implant lifetime. The twofold use of piezoceramic elements simultaneously as force sensors and power harvesters makes the device small enough...

In Total Knee Arthroplasty (TKA), the collateral ligament tensioning stage cannot be standardised for all patients and relies heavily on the surgeon’s experience and perception. Intraoperative inaccuracies are practically unavoidable and may give rise to severe postoperative complications, leading to the need for revision surgery already a few year...

Our aim is to develop an accessible virtual learning environment for ultrasound exams. In this paper, we present an affordable way to localize the ultrasound probe using a Kinect sensor. The proposed localization procedure is coupled with an existing force acquisition schema to affordably associate each ultrasound image to its probe location and th...

The use of mobile and wireless communication technologies to facilitate and improve healthcare and medical services is bringing a shift to healthcare delivery. In this context, an important application scenario is represented by dentistry applications and more generally, intraoral sensors applications. An oral sensory system that allows real-time m...

Statistical Shape Models (SSMs) are efficient tools in several fields and especially medical applications. In order to be meaningful, SSM construction requires a dense correspondence matching between a significant number of objects, which remains a very challenging task. Nonrigid registration is an essential element in the SSM construction pipeline...

This study was designed to evaluate the reliability of a semi-automatic segmentation tool for dento-maxillary osteolytic image analysis compared with manually defined segmentation in CBCT scans. Five CBCT scans were selected from patients for which periapical radiolucency images were available. All images were obtained using Promax(®) 3D mid Planme...

Discrete curve evolution (DCE) algorithm is used to eliminate objects’ contour distortions while at the same time preserve the perceptual appearance at a level sufficient for object recognition. This method is widely used for shape similarity measure, skeleton pruning and salient point detection of binary objects on a regular 2D grid. Our paper aim...

The Minimally Invasive Procedures (MIP) in orthopedics have grown rapidly worldwide, as clinical results indicate that patients who undergo MIP typically experience minimized blood loss, smaller incision and shorter hospital stays. For most MIP, a preoperative 3D model of the patient anatomy is usually generated in order to plan the surgery. The ch...

Ligament tensioning is a key step in Total Knee Arthroplasty surgery. The surgeon has to manually set proper tension conditions for the two lateral ligaments of the knee. Inaccuracies may lead to severe postoperative complications and, in the worst-case scenario, to revision surgery. Unfortunately, suboptimal balance conditions are unavoidable and...

During Total Knee Arthroplasty surgery, the orthopaedic surgeon has to set up proper balance conditions for the two lateral ligaments of the knee. Such ligament tensioning procedure is performed manually and mainly depends on the surgeon's experience. Unfortunately, inaccuracies are unavoidable and may give rise to serious postoperative complicatio...

Our aim is to develop a frame work for virtually learning the ultrasound exams. In this paper we address the method used to build the image database required for this frame work. The used materiel and the proposed methodology are presented and explained. The realized prototype has been used to build the database of ultrasound images.

Our aim is to develop a frame work for virtually learning the ultrasound exams. In this paper we address the method used to build the image database required for this frame work. The used materiel and the proposed methodology are presented and explained. The realized prototype has been used to build the database of ultrasound images.

The Minimally Invasive Procedures (MIP) in orthopedics have grown rapidly worldwide, as clinical results indicate that patients who undergo MIP typically experience minimized blood loss, smaller incision and shorter hospital stays. For most MIP, a preoperative 3D model of the patient anatomy is usually generated in order to plan the surgery. The ch...

A system and method are provided for helping implant a hip prosthesis in an individual, which includes an acetabulum intended to be placed in the hip bone of the patient and a femoral part intended to be integrally connected to the femur of the individual. The method includes: obtaining, before the operation, images issued by a device that images a...

Ce papier a pour objet, l'analyse et la classification des descripteurs de texture pour la segmentation d'images IRM de tumeurs osseuses. La segmentation des images IRM préopératoires permet au chirurgien d'avoir le modèle tridimensionnel de ala tumeur. Aucune méthode de segmentation automatique des images IRM de tumeurs osseuses n'a été proposée a...

Over the last twenty years, image-guided interventions have been greatly expanded by the advances in medical imaging and computing power. A key step for any image-guided intervention is to find the image-to-patient transformation matrix, which is the transformation matrix between the preoperative 3D model of patient anatomy and the real position of...

Automated bone segmentation is one of the most challenging problems in medical imaging. The increasingly demanded MR imaging suffers from low contrast and signal-to-noise ratio when it comes to bones. To increase the segmentation robustness, a prior model of the structure could guide the segmentation when explicit information is missing or weakly p...

During TKA surgery, a correct tibiofemoral alignment of the installed prosthesis can be effectively achieved by means of Computer-Assisted techniques. Unfortunately, the achievement of perfect ligament balance conditions still remains as unsolved problem. Any inaccuracy during the operation may degenerate and lead to prosthesis failure. Our aim is...

The main purpose of this paper is to demonstrate the capability to optimize the design of a previously developed prototype of instrumented knee implant. The proposed implant may postoperatively provide the clinician with significant information about the coronal and sagittal instabilities during normal walking without the need to be powered from an...

This study concerns the general problem of the treatment of shoulder degenerative or traumatic lesions, based on total or partial joint replacement (shoulder arthroplasty). With baby boomers, increasingly complaining of shoulder pain, the number of shoulder arthroplasties increased by 15% each year. This surgical procedure is very difficult and lim...

In Total Knee Arthroplasty (TKA), accurate balancing of the medial and lateral collateral ligaments is considered by orthopedic surgeons as one of the most challenging and complicated tasks to achieve. Therefore, an efficient solution is needed to assist the surgeons in achieving this crucial task without resulting in tibiofemoral misalignment. The...

The goal of our paper is to quantify the electrical en- ergy that can be harvested within a new generation of instrumented knee implant during normal walking. This generation of knee im- plant is proposed to assess the in vivo anteroposterior and medi- olateral distributions of tibiofemoral force on the tibial baseplate without the need to be power...

For any image guided surgery, independently of the technique which is used (navigation, templates, robotics), it is necessary to get a 3D bone surface model from CT or MR images. Such model is used for planning, registration and visualization. We report that graphical representation of patient bony structure and the surgical tools, interconnectivel...

The goal of ligament balancing in total knee arthroplasty (TKA) is to distribute the tibiofemoral compressive forces symmetrically between the medial and lateral compartments of a well-aligned prosthetic knee, as well as to reestablish a rectangular and identical tibiofemoral gap in both flexion and extension. Nowadays, the proper alignment of knee...

Estimating in vivo the life span of a total knee replacement prosthesis is currently done by estimating the polyethylene (PE) wear rate from measurement of the femorotibial distance using X-ray photographies. This efficient method requires, however, waiting for few years to obtain a readout. This letter proposes using another metric that can be obt...

This paper describes an in-vivo polyethylene wear and knee prosthesis longevity estimation approach using an implantable ligament imbalance metric system. Four piezoelectric elements are used to measure the axial force components, on the tibial tray surface and their center of pressure is calculated. This can be used, along with a knee simulator, t...

In-vivo measurement of tibiofemoral forces transmitted through Total Knee Replacement (TKR) during normal walking allows the early detection of postoperative complications such as the tibiofemoral misalignment and soft-tissue imbalance. In addition, the in-vivo data can help to improve the design of TKR in order to reduce polyethylene wear and cons...

This paper describes two useful metrics to estimate the ligament imbalance for post Total Knee Arthroplasty (TKA) scenario: the center of pressure and the net moments (varus-valgus and anterior posterior). Both metrics have been evaluated using high level models and experimental measurement. Self-powered analog and digital architectures for the cen...

To obtain a long lifespan of knee joint implant, it is indispensable to balance the collateral ligaments of the knee and to restore a correct alignment of the mechanical axis of the lower limb during total knee replacement (TKR). Nowadays, a proper mechanical axis alignment of the lower limb is guaranteed by computer assisted orthopaedic surgery (C...

Three-dimensional freehand ultrasound has found several clinical applications, such as in Computer Assisted Orthopaedic Surgery CAOS. Since the last decade, the US applications in CAOS allow the surgeon to objectively plan out critical surgical variables, and would result in improved surgical outcomes. A key step of all the freehand ultrasound imag...

The risk of dislocation after THA reportedly is minimized if the acetabular implant is oriented at 45 degrees inclination and 15 degrees anteversion with respect to the anterior pelvic plane. This reference plane now is used in computer-assisted protocols. However, this static approach may lead to postoperative instability because the dynamic varia...

One of the main constraint in total hip arthroplasty (THA) is to optimize the position of the acetabular implant in order to avoid postoperative instability. The best orientation of the cup has been studied by several authors in order to avoid it, but for most of them, they don't take into account the dynamic behavior of the pelvis during daily act...

This paper evaluates various instrumented knee prostheses that have been used to measure in vivo forces and torques acting at human knee joint. Accurate measurement of implant forces and torques would be significant for both clinicians and implant designers. In the course of this work, we will compare different smart knee prostheses which have been...

1 LATIM (ISERM U650) / 2 ENST Bretagne / 3 CHU Brest Service d'Orthopedie-Traumatologie 4 LIME -Université Bretagne Occidentale F29200 Brest Tel: 1,3 02-98-01-81-13 manuel.gouriou@enst-bretagne.fr RESUME Cet article propose une synthèse des systèmes orthopédiques instrumentés afin de dégager les études qui pourraient conduire à une amélioration des...

This paper describes a fast procedure for the calibration of an ultrasound (US) probe using a 3D optical localizer. This calibration step allows us to obtain the 3D position of any point located on the 2D ultrasonic (US) image. To carry out correctly this procedure, a phantom of known geometric properties is probed and these geometries are found in...

In order to understand the relationship between the morphology and the functionality of articular surfaces, a unified representation has to be used. To this end the theory of ruled surfaces is considered. Both aspect of the problem are represented using such surfaces. Applied to a 3D navigation system it will allow surgeons to use new surgery proce...

A formal definition of a combinatorial topology is presented in this paper for the discrete N-dimensional space defined by the An* lattice. The use of this grid instead of the classical ℤn is based on two arguments: –It is the optimal sampling grid in the sense of Shannon’s sampling theorem in 2 and 3 dimensions,–It induces the simplest discrete to...

This paper deals with dual quaternion curve modeling. We propose a new method of interpolation between two dual quaternions based on the definition of two unit dual quaternions. These notions are thus used in order to define algorithms for Bezier curves and splines. Résumé - Le travail présenté dans cet article concerne le problème de modélisation...

The aim of this paper is to assess the accuracy of the localization of the knee center, computed intraoperatively during a surgery procedure, by a kinematic approach. We propose a method based on the estimation of the mean helical axis during flexion-extension motion using a 3D navigation approach. This validation study was successively performed o...

This study is concerned with a methodology for the acquisition, computation and modeling of joint anatomy and motion data in order to highlight the close relationship between the morphology of the joint and its functionality. The mathematical theory used for this modeling is detailed, steps in the computer elaboration are reported and first results...

Segmentation tools have to take into account the technical characteristics of the machine on which they are supported and, of course, the users needs. These tools have to be robust, ergonomic and also need to be fast enough. An ellipse fitting method in ultrasound images is presented in this paper. It makes use the Pascal's theorem and permits the...

This paper introduces the concept of structured deformable model and presents its application to 3D medical image analysis. A structured deformable model is composed of a group of basic shape elements. A generic model of a biological shape can be build following a growth process controlled by the morphogenesis. This model can be fitted to a specifi...

This paper presents an algorithm to trace discrete straight lines in regular grids of any dimension. Most known line tracing algorithms have been developed in Z ² and Z ³ orthogonal grids. The contribution of this paper is the definition of a method to trace lines in nonorthogonal grids in any dimension. This method is not res...

Presents a prototype of a virtual shared environment in which several users can interact inside a three dimensional scene. Actions of a user are visible to others thanks to a protocol of transmission parameters of the scene. The communications are managed under a protocol of distributed objects, the visualization as well as the user interface use m...

Introduces the concept of a structured deformable model and presents its application to 3D medical image segmentation. A structured deformable model is composed of a group of basic shape elements. The model can fit a biological shape by changing the characteristics of its elements. An application to bone joint modeling is presented and discussed

Poster

Ce travail s'inscrit dans le cadre d'un projet dont l'objectif est l'analyse des ressources halieutiques à l'aide de séquences d'images acquises par un sonar multi-faisceaux. Nous présentons quelques méthodes de segmentation, d'extraction, de visualisation et d'analyse 3D des bancs de poissons et du fond marin présents dans les séquences. Les carac...

Digital data from a high‐resolution multibeam sonar were processed to provide 3‐D fish school descriptors. The multibeam sonar operates at a carrier frequency of 455 kHz, with 60 beams of 1.5° each, allowing an observation angle of 90°. The envelope of the signal is sampled every 5 cm. The usual operating range is 100 m with a ping rate of 7 pings/...

The aim of this study is to provide 3D fish school descriptors. Digital data from a high resolution multibeam sonar are acquired in order to reconstruct the fish school volume and the bottom surface. This paper presents different steps required for data and image analysis. Data correction, objects extraction methods are focused in this paper

Presents a ray casting algorithm in the BCC grid. This grid is important in medical imaging applications due to its outstanding topological properties and its higher contents of symmetries. BCC grid is the optimal sampling grid in 3-D space, it is the best grid to apply mathematical morphology process and recently it has been used in tomographic im...

This paper describes a ray-tracing and an object description method for objects sampled not in the usual cubic grid, but in BCC (Body Centered Cubic) and FCC (Face Centered Cubic) grids, which are well known in crystallography. The use of this kind of grids is motivated by their interesting characteristics: they reduce the density of samples needed...

Riv. Ital. EPPOS (Numéro Spécial - 15èmes Journées Internationales sur les Huiles essentielles), 607-613 (1997).

This paper proposes 2D, 3D and 4D discrete sampling grids with optimal topological and spectral properties. It is shown here that those grids have advantages with respect to the classically used n grid. The proposed 3D grids are used to achieve surface extraction from volume data. Results are shown for a medical imaging application.

Proposes a moment-based operator using three edge profile models (step, linear and quadratic) to detect surfaces at sub-voxel precision in 3-D volume images. The segmentation is performed using two methods: (a) iso-density surfaces extraction, (b) physically significant surfaces extraction. Application is made to 3-D CT scan images. Results show th...