Revue des approches de segmentation des lésions de sclérose en plaques dans les séquences conventionnelles IRM

In frenchNational audienceDifferent sets of criteria are currently used for the diagnosis of multiple sclerosis (MS). Some are based on clinical features, while others are related to imaging findings. Among the image processing systems, specific criteria include spatial dissemination of lesions in one image or their temporal dissemination in images acquired at different time points. In addition, the evolution of the lesion load can be used to evaluate treatment efficiency in MS clinical research. Consequently, obtaining a precise segmentation of the MS lesion appears to be crucial. In the literature, a number of semi-automated or completely automated approaches have been proposed enabling a reduction of the inter- and intra-expert variability for manual delineations. A comprehensive state-of-the-art classification of the most representative systems is presented here

Early detection of cognitive impairment in relapsing-remitting multiple sclerosis: functional-anatomical correlations and longitudinal follow-up

[In French]Introduction. Cognitive impairment is frequent in relapsing remitting Multiple Sclerosis and is often diagnosed after disruption of occupational and social relations. METHODS: We studied at baseline a homogeneous population of 32 RRMS patients, diagnosed for less than 5 years, with spontaneous memory complaints, and 20 controls. Sixteen patients were followed for 2 years, combining physical examination, neuropsychological tests, and brain MRI. Neuropsychological tests used evaluated memory capacities, attentional capacities, executive functions, language, and visuo-constructive praxis. Lesion load on brain MRI was measured with semi-automatic segmentation procedures and manual control. RESULTS: Eighty percent of patients presented cognitive impairment, and this proportion was higher than that found in the literature. These disorders were more marked for verbal episodic memory, attention, and executive functions. Patients with brain MRI that initially fulfilled the Barkhof criteria and those with callous lesions had more memory disorders. No link between global T1 and T2 lesion loads and neuropsychological scores was found. A statistical link between posterior fossa lesions and attentional disorders was shown. In the longitudinal follow-up, patients had better performances in memory and attentional domains, and a lower number of cognitive domains with dysfunction for each patient. This improvement on neuropsychological tests, whereas EDSS levels were stable, underlined a possible test-retest effect. CONCLUSION: During the initial phase of the disease, most of the relapsing remitting patients present a mild cognitive impairment. Early detection, therapeutic propositions, and recognition of disorders are necessary

Traitement des images et radiothérapie

National audienceLa radiothérapie est un domaine privilégié d'application des techniques de traitement des images de par l'utilisation importante de données issues de l'imagerie. Celles-ci sont de plus en pleine expansion du fait de la progression des performances informatiques. Actuellement, les développements récents de la radiothérapie (radiothérapie de conformation, radiothérapie conformationnelle avec modulation d'intensité) procurent une place majeure à ces techniques. En effet, elles contribuent à répondre aux conditions de précision exigées par la radiothérapie moderne et permettent d'envisager d'améliorer les traitements. L'objectif de cet article est de présenter les différentes techniques du traitement d'image utilisées aujourd'hui en radiothérapie (segmentation et recalage en particulier) au travers de la littérature

Traitement des images et radiothérapie

National audienceLa radiothérapie est un domaine privilégié d'application des techniques de traitement des images de par l'utilisation importante de données issues de l'imagerie. Celles-ci sont de plus en pleine expansion du fait de la progression des performances informatiques. Actuellement, les développements récents de la radiothérapie (radiothérapie de conformation, radiothérapie conformationnelle avec modulation d'intensité) procurent une place majeure à ces techniques. En effet, elles contribuent à répondre aux conditions de précision exigées par la radiothérapie moderne et permettent d'envisager d'améliorer les traitements. L'objectif de cet article est de présenter les différentes techniques du traitement d'image utilisées aujourd'hui en radiothérapie (segmentation et recalage en particulier) au travers de la littérature

The contribution of automatic anatomical matching of sequential brain MRI scans in the monitoring of multiple sclerosis lesions

in FrenchInternational audienceINTRODUCTION: Magnetic resonance imaging (MRI) has transformed management of patients with multiple sclerosis. The exact contribution of brain MRI remains a subject of debate, but it is generally considered to provide a more specific and more sensitive outcome measure for monitoring purposes and for testing new therapies. The choice of MRI techniques, and measurement reproducibility for multiple sclerosis brain lesions are not defined with precision for routine practice. There are many sources of error when comparing successive images which can be overcome to some extent with repositioning and image processing techniques. METHODS: We evaluated the impact of image repositioning on treatment decision-making for twelve relapsing remitting patients. Brain MRIs were performed every three months for a one-year period. Two neurologists interpreted the non-repositioned and repositioned images giving their analysis of changes in the lesions visualized on the T2 sequences and their therapeutic decisions. RESULTS: For the first neurologist, analysis of the non-repositioned images yielded six patients whose lesions had worsened while for the repositioned images there were only three. For the second neurologist, four patients had more lesions with the non-repositioned images and only three with repositioning. The subjective interpretations were the same for the two neurologists when they used repositioned images. CONCLUSIONS: Comparison by two neurologists of non-repositioned and repositioned MRI, with no other image processing, affected the analysis and in certain cases propositions for treatment

Modèles Biomathématiques de Croissance Des Gliomes : Recherche en Informatique et Perspectives en Neuro-oncologie

no abstrac

Diffusion MRI-based Connectivity Enriched with Microstructure Information Predicts the Propagation of Cortico-Cortical Evoked Potentials

International audiencePropagation of Cortico-Cortical Evoked Potentials (CCEPs) varies depending on numerous structural features of brain tissue. In this work, we show that dMRI-based connectivity enriched with microstructure data has the potential to measure cortico-cortical communication as it predicts CCEP-based effective connectivity. Our multiple linear regression model incorporates q-space indices like Q-space Inverse Variance, Non-Gaussianity and Return to Plane Probability with minimum streamline lengths obtained from tractography to predict delays and amplitudes of the N1 peaks in CCEPs. In our experiment, we use presurgical dMRI and intrasurgical ECoG recordings of 9 patients operated on brain tumor in the awake condition

Towards Linking Diffusion MRI based Macro-and Microstructure Measures with Cortico-Cortical Transmission in Brain Tumor Patients

International audienceWe aimed to link macro-and microstructure measures of brain white matter obtained from diffusion MRI with effective connectivity measures based on a propagation of cortico-cortical evoked potentials induced with intrasurgical direct electrical stimulation. For this, we compared streamline lengths and log-transformed ratios of streamlines computed from presurgical diffusion-weighted images, and the delays and amplitudes of N1 peaks recorded intrasurgically with electrocorticography electrodes in a pilot study of 9 brain tumor patients. Our results showed positive correlation between these two modalities in the vicinity of the stimulation sites (Pearson coefficient 0.54±0.13 for N1 delays, and 0.47±0.23 for N1 amplitudes), which could correspond to the neural propagation via U-fibers. In addition, we reached high sensitivities (0.78±0.07) and very high specificities (0.93±0.03) in a binary variant of our comparison. Finally, we used the structural connectivity measures to predict the effective connectivity using a multiple linear regression model, and showed a significant role of brain microstructure-related indices in this relation

Hierarchical Segmentation of Multiple Sclerosis Lesions in Multi-Sequence MRI

International audienceno abstrac

Longitudinal MRI assessment of quality of life and disability in early treated relapsing remitting multiple sclerosis

American Academy of Neurology Annual Meetingno abstrac