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Introduction
Additional affiliations
November 2008 - March 2015
Aquilab
Position
- Research Officer
Publications
Publications (87)
Caffeine consumption outcomes on Amyotrophic Lateral Sclerosis (ALS) including progression, survival and cognition remain poorly defined and may depend on its metabolization influenced by genetic variants. 378 ALS patients with a precise evaluation of their regular caffeine consumption were monitored as part of a prospective multicenter study. Demo...
Background:
Polycystic ovary syndrome (PCOS) is the most common reproductive-endocrine disorder affecting between 5 and 18% of women worldwide. An elevated frequency of pulsatile luteinizing hormone (LH) secretion and higher serum levels of anti-Müllerian hormone (AMH) are frequently observed in women with PCOS. The origin of these abnormalities i...
BACKGROUND Iron content is increased in the substantia nigra of persons with Parkinson's disease and may contribute to the pathophysiology of the disorder. Early research suggests that the iron chelator deferiprone can reduce nigrostriatal iron content in persons with Parkinson's disease, but its effects on disease progression are unclear. METHODS...
Background:
Iron content is increased in the substantia nigra of persons with Parkinson's disease and may contribute to the pathophysiology of the disorder. Early research suggests that the iron chelator deferiprone can reduce nigrostriatal iron content in persons with Parkinson's disease, but its effects on disease progression are unclear.
Metho...
Background
Dopamine responsiveness (dopa-sensitivity) is an important parameter in the management of patients with Parkinson’s disease (PD). For quantification of this parameter, patients undergo a challenge test with acute Levodopa administration after drug withdrawal, which may lead to patient discomfort and use of significant resources.
Objecti...
Background
Parkinson’s disease mild cognitive impairment (PD-MCI) is frequent and heterogenous. There is no consensus about its influence on subthalamic deep brain stimulation (STN-DBS) outcomes.
Objective
To determine the prevalence of PD-MCI and its subtypes in candidates to STN-DBS. Secondarily, we sought to identify MRI structural markers asso...
Background
The “dual syndrome hypothesis” distinguished two subtypes in mild cognitive impairment (MCI) in Parkinson's disease: frontostriatal, characterized by attentional and executive deficits; and posterior cortical, characterized by visuospatial, memory, and language deficits.
Objective
The aim was to identify resting‐state functional modific...
Background
The objective of breast reconstruction (BR) is to erase the after-effects of total mastectomy by allowing patients to restore their breast shape. The aim of our study was to investigate the body map integration of different types of BR using functional magnetic resonance (fMRI).Patients and Methods
We prospectively enrolled all women und...
Background
Cognitive impairment is frequent and disabling in multiple sclerosis (MS). The Brief International Cognitive Assessment in MS (BICAMS) is a recent short battery usable in clinical practice for cognitive evaluation of MS patients.
Objective
To find cortical areas or brain volumes on magnetic resonance imaging (MRI) structural sequences a...
Context : Cognitive impairments are common in patients with Parkinson’s disease (PD) and are heterogeneous in their presentation. The “dual syndrome hypothesis” suggests the existence of two distinct subtypes of mild cognitive impairment (MCI) in PD: a frontostriatal subtype with predominant attentional and/or executive deficits and a posterior cor...
There is a growing need for surrogate biomarkers for Parkinson’s disease (PD). Structural analysis using magnetic resonance imaging with T1-weighted sequences has the potential to quantify histopathological changes. Degeneration is typically measured by the volume and shape of morphological changes. However, these changes appear late in the disease...
Objective
To determine whether functional MRI connectivity can predict the long-term cognitive functions 36 months after minor stroke.
Methods
Seventy-two participants with first-ever stroke were included at baseline and followed up for 36 months. A ridge regression machine learning algorithm was developed and used to predict cognitive scores 36 m...
Background:
Anxiety is frequent in Parkinson's disease (PD) and has a negative impact on disease symptoms and quality of life. The underlying mechanisms remain largely unknown. The aim of this study was to identify anatomical and functional changes associated to PD-related anxiety by comparing the volume, shape and texture of the amygdala, the cor...
Introduction
Les troubles anxieux dans la maladie de Parkinson (MP) sont fréquents et ont un impact négatif sur la maladie. Néanmoins, il existe peu de données sur leur physiopathologie.
Objectifs
Déterminer les caractéristiques cliniques, anatomiques et fonctionnelles associées aux troubles anxieux liés à la MP.
Patients et méthodes
Des patients...
Introduction
Le tremblement est considéré comme invalidant réfractaire lorsque les traitements usuels sont insuffisants pour le contrôler. Il est alors possible d’avoir recours à une thalamotomie par Gamma-Knife (GKT).
Objectifs
Décrire les modifications fonctionnelles et anatomiques en imagerie induites par la GKT et identifier les facteurs assoc...
The optic radiations (OR) are white matter tracts forming the posterior part of the visual ways. As an important inter-individual variability exists, atlases may be inefficient to locate the OR in a given subject. We designed a fully automatic method to delimitate the OR on a magnetic resonance imaging using tractography. On 15 healthy subjects, we...
Although attentional impairments (particularly cognitive slowing) are frequent in Parkinson's disease (PD), the mechanisms underlying these phenomena have not been fully characterized. The MRI-compatible version of the Symbol Digit Modalities Test (SDMT) has been applied to healthy individuals but not previously to patients with PD. We sought to as...
The posterior parietal cortex (PPC) is a key structure for visual attention and upper limb function, two features that could be impaired after stroke, and could be implied in their recovery. If it is well established that stroke is responsible for intra- and interhemispheric connectivity troubles, little is known about those existing for the contra...
Objectives:
Early-onset Alzheimer's disease (EOAD) begins before the age of 65 and is characterized by a faster clinical course and the frequency of nonamnestic symptoms compared to late onset Alzheimer disease (LOAD). However, the pathophysiological process of EOAD remains unclear. We expected that ASL may show widespread cortical hypoperfusion i...
Résumé
Objectifs
L’objectif de cette étude était d’évaluer l’intérêt de la mesure de l’espace extra vasculaire extracellulaire (ve) par l’imagerie de perfusion T1 (DCE IRM) pour différencier une pseudo progression d’une progression des métastases cérébrales après traitement par radiochirurgie.
Matériels et méthodes
14 patients porteurs de 20 méta...
Introduction/Background
The posterior parietal cortex (PPC) is a key structure for visual attention and upper limb function, two features that could be impaired after stroke, and could be implied in their recovery. If it is well established that stroke is responsible for intra- and interhemispheric connectivity troubles, little is known about those...
Purpose:
Medial lobe temporal structures and more specifically the hippocampus play a decisive role in episodic memory. Most of the memory functional magnetic resonance imaging (fMRI) studies evaluate the encoding phase; the retrieval phase being performed outside the MRI. We aimed to determine the ability to reveal greater hippocampal fMRI activa...
Introduction
La maladie d’Alzheimer à début précoce (early-onset Alzheimer's disease ou EOAD), dont les symptômes apparaissent avant 65 ans, est caractérisée par une fréquence élevée de présentations cliniques atypiques non mnésiques associant une atteinte anatomopathologique plus sévère et une évolution clinique plus agressive que les présentation...
Objective
To assess the contralesional connectivity between the posterior parietal cortex (PPC) and the motor cortex (M1) in stroke patients, and to probe putative relationships with spatial neglect and motor impairment.
Material/patients and methods
In 12 right-side stroke patients and 12 age-matched healthy controls, we used paired-pulse transcr...
Objectives:
To assess the contralesional connectivity between the posterior parietal cortex (PPC) and the motor cortex (M1) in stroke patients, and to probe putative relationships with spatial neglect and motor impairment.
Methods:
In 12 right-side stroke patients and 12 age-matched healthy controls, we used paired-pulse transcranial magnetic st...
Background:
Postnatal adaptation requires liquid clearance and lung aeration. However, their relative contribution to the expansion of functional residual capacity (FRC) has not been fully investigated. We studied evolution of lung liquid removal and lung aeration after birth in preterm lambs.
Methods:
Lung liquid content and lung volume were as...
Stereotactic radiosurgery (SRS) is the accurate, conformal delivery of high-dose radiation to well-defined targets while minimizing normal structure doses via steep dose gradients. While inverse treatment planning (ITP) with computerized optimization algorithms are routine, many aspects of the planning process remain user-dependent. We performed an...
The purpose of this study was to demonstrate that Monte Carlo treatment planning systems require tissue characterization (density and composition) as a function of CT number. A discrete set of tissue classes with a specific composition is introduced. In the current work we demonstrate that, for megavoltage photon radiotherapy, only the hydrogen con...
Accurate delineation of organs at risks (OARs) is required for radiation treatment planning (RTP). However, it is a very time consuming and tedious task. The use in clinic of Image Guided Radiation Therapy (IGRT) becomes more and more popular, thus increasing the need of (semi-)automatic method for delineation of the OAR. In this work, an interacti...
Computer-aided segmentation of anatomical structures in medical images is a valuable tool for efficient Radiation Therapy Planning (RTP). As delineation errors highly affect the radiation oncology treatment, it is crucial to delineate geometric structures accurately. In this paper, a semi-automatic segmentation approach for computed tomography (CT)...
A dosimetric comparison was made of Helical Tomotherapy (HT) and Rapid'Arc® (RA) in 115 patients with head and neck carcinoma included in a prospective and multicentric study. HT and RA provided highly conformal plans that easily complied with dose volume constraints for organs at risk. HT reduced high doses to the planning target volumes (PTVs) co...
Calibration phantom and method for measuring and correcting geometric distortions in an image of a body part of a patient Calibration phantom (5) for a medical imaging system, comprising a plurality of separate detection elements (20) arranged in a determined pattern, each detection element (20) containing a product that is visible by the medical i...
Intensity Modulated Arc Therapy (IMAT) can be planned and delivered via several techniques. Advanced Radiotherapy (ARTORL) is a prospective study that aims to evaluate the treatment costs and clinical aspects of implementing these IMAT techniques for head and neck cancers. In this context, we evaluated the potential dosimetric gain of Helical Tomot...
To evaluate the benefits and limitations of helical tomotherapy (HT) for loco-regional irradiation of patients after a mastectomy and immediate implant-based reconstruction. Ten breast cancer patients with retropectoral implants were randomly selected for this comparative study. Planning target volumes (PTVs) 1 (the volume between the skin and the...
The recent concept of Dose Guided Radiotherapy (DGRT) consists in computing a cumulative dose distribution at each treatment fraction to decide if a treatment replanning is necessary. These cumulative dose distributions are obtained by mapping the daily dose distributions with the results of a non-rigid registration between the planning CT scan and...
Purpose: Regular measurement of the coincidence of CBCT image with the MV treatment beam isocentre is an important component of quality assurance for CBCT based IGRT. In this work the coincidence of the imaging isocentre (kV‐CBCT) with the treatment isocentre measured using the EPID (MV‐EPID) has been measured over an extended period using an algor...
Purpose: Rotational IMRT for HNC raises new challenges regarding the dose homogeneity within the PTV, and the dose delivered to the non‐tumour tissue (NTT). The purpose of this study is to: 1. develop a new parameter to assess PTV dose homogeneity. 2. evaluate the impact of the physicist's experience on the dose conformity to the PTV and conta...
The field of MR imaging has progressively grown from morphological imaging to physiological imaging and finally to interventional imaging. In fact, MRI is an imaging modality well adapted to the interventional practice, it is not only due to its high contrast to soft tissues and to the absence of ionizing radiations but also extensively benefited,...
Surgical and interventional procedures increasingly rely on spatial measurement systems. One of the most popular is NDI's Polaris Vicra. Unfortunately, this system cannot be used for magnetic resonance imaging (MRI) procedures because of the image artifacts that it produces.
Here, a simple method for hardware electrical shielding is presented which...
Purpose In this paper, we present a method to remove system induced geometric distortions in MR images.
Methods A large 3D phantom with spherical balls was used to characterize geometric distortion on an AIRIS Mate 0.2 T MR Scanner (Hitachi).
MR images of the phantom were acquired in axial, sagittal planes. Using 2D Fast Spin Echo (FSE) sequence,...
To study the lung liquid clearance in vivo at the time of birth, magnetic resonance experiments were conducted on newborn lambs immediately after uterine incision deliverance. Images obtained with a fast spin echo magnetic resonance imaging sequence enable to quantify lung liquid each 5 minutes for 30 minutes, then each 10 minutes for 1.5 hours. Af...
In medical imaging, many texture analysis methods were studied with different degrees of effectiveness. These last years, works showed the usefulness of the fractal geometry to characterize textures. The fractal dimension provides a global aspect of the texture, while the multifractal analysis provides a local and global aspect of the texture. In t...
Object
Developments in open magnetic resonance imaging (MRI) magnets have made possible the use of reproducible thermosensitive sequences to determine temperature distribution inside biological tissue. This study aimed to compare MR thermal mapping during laser-induced interstitial thermal therapy (LITT) with macroscopically observed thermal lesion...
Accurate localization and contouring of prostate are important issues in prostate cancer diagnosis and/or therapies. Although several semi-automatic and automatic segmentation methods have been proposed, manual expert correction remains necessary. Our paper introduces an original method for automatic 3D segmentation of the prostate gland from Magne...
In this paper, we present a method to characterize and correct geometric image distortion in 0.2 T MR images. A large 3D phantom with spherical balls was used to characterize geometric distortion on an AIRIS Mate 0.2 T MR Scanner (Hitachi). MR images of the phantom were acquired in axial, sagittal and coronal planes using 2D Fast Spin Echo (FSE) se...
One of the imaging modalities used for the diagnosis of epilepsy is SPECT (Single-Photon Emission Computed Tomography). Ictal and interictal images are registered to MR images (SISCOM (Substracted Ictal Spect COregistred to MR) to delineate the sources. However, in some cases and for many reasons, the used method does not lead to precise delimitati...
Due to its excellent soft tissue contrast and lack of ionizing radiation, MR imaging is well suited for interventional procedures. MRI is being increasingly used for guidance during percutaneous procedures or surgery. Technical advances in interventional MR imaging are reviewed in this paper. Ergonomical factors with improved access to patients as...
Due to its excellent soft tissue contrast and lack of ionizing radiation, MR imaging is well suited for interventional procedures. MRI is being increasingly used for guidance during percutaneous procedures or surgery. Technical advances in interventional MR imaging are reviewed in this paper. Ergonomical factors with improved access to patients as...
Fight against cancer witnessed the rise of new patient care enhancing technologies. Laser ablation is one of the most recent in situ destruction techniques for tumors. An optical fiber has therefore got to be introduced into the core of the tumor by inserting a sheath through skin. This laser diode sends photon so that the tumor can be burned local...
The purpose of our study is to propose a practical and easy to use method for the calibration of a freehand ultrasound machine. We introduce a new spatial calibration of the probe based on a simple phantom. The method includes automatic features extraction by the Hough transform algorithm and a robust parameters optimization. Experiments demonstrat...
This study presents a system designed to assist the surgeon during interventional procedures performed by Magnetic Resonance Imaging (MRI). In order to reach the target during guidance in a double obliquity trajectory, this system provides accurate information about both the entry point and the orientation of the needle.
To study the lung water clearance in vivo at the time of the birth, MR experiments were conducted on newborn lamb immediately after uterine incision deliverance. Images obtained with a fast spin echo sequence enable to quantify lung liquid each 5 minutes during 30 minutes then each 10 minutes for 1.5 hour. From the lung contours, pulmonary volume,...
ProCAD is a computer assisted diagnosis (CAD) software dedicated to prostate DCE-MRI analysis.
In addition to standard visualization features, 2D and multislice 2D contouring tools based on a seeded growing region algorithm were included in the software. Tumor volume assessment and semiquantitative analysis of suspicious lesions can be performed. A...
In this paper, we introduce an approach for selective segmentation of vascular structure which has been applied for intracranial vessels. Based on MIP and fuzzy set principles, this approach brings good results while segmentation is achieved rapidly. The added value of this approach is a minimal user interaction and the taking into account of the v...
This study aimed to compare MR thermal mapping during Laser-induced Interstitial Thermal Therapy (LITT) to thermal lesions observed macroscopically, in order to estimate the 3D size of the coagulative necrosis. Laser irradiation was performed ex-vivo with a 980 nm laser in pig liver in a open low-magnetic field (0.2T) scanner. The laser light was t...
The surgical treatments of genital prolapsus are still empirical and poorly valued. We plan to achieve a method for the objective assessment of the troubles of the pelvic statics and of the various surgical strategies. The methodology considers 3 axes: building a 3D mechanical model of the pelvic cavity, mechanical characterization of the concerned...
This article discusses a method for automatic prostate segmentation from abdominal ultrasound images. A statistical model of prostate is estimated from training set of manually delineated images. The segmentation starts by smoothing the image to enhance edges by applying a special filter designed for abdominal ultrasound images of prostate. It dete...
Background and Objectives: Liver metastasis is a major problem in public health. Laser-induced interstitial thermotherapy (LITT) is a recently developed, minimal invasive technique for local tumor destruction within solid organs. This technique consists in inserting a laser fiber inside the metastasis. The study aimed to determine laser parameters...
