La Silla del Papa (Tarifa, Cádiz) : bilan de trois années de recherches

International audienceLes recherches engagées depuis 2007 sur le site de la Silla del Papa (Tarifa, province de Cadix, Espagne) ont mis au jour une importante agglomération perchée, probable berceau de la communauté d'origine bastulo-punique qui fonda, sous Auguste, la ville de Baelo. Ce site de hauteur, occupé du Xe au Ier siècle av. J.-C., a livré de nombreux vestiges d'un urbanisme singulier, conditionné en partie par des contraintes topographiques

Imagerie par resonance magnetique : Correction des non linearites des gradients de champ

Nous proposons une méthode de correction des distorsions géométriques induites en IRM par les non linéarités des gradients de champ. Nous présentons dans un premier temps l'effet des non linéarités sur les équations du signal de résonance magnétique, puis sur l'image reconstruite par transformation de Fourier. Nous proposons ensuite un modèle mathématique simple de ces non linéarités, basé sur la géométrie des bobines de gradient du système d'acquisition. L'estimation du modèle est effectuée par l'acquisition d'un fantôme cubique dont les fronts sont détectés puis recalés sur leurs positions théoriques, données par les dimensions du fantôme. Cette méthode, indépendante des paramètres d'acquisition, permet de réduire les erreurs de position initiales, de près de 4 mm, jusqu'en dessous de la résolution de l'image

Evaluation of Proton MR Spectroscopy for the Study of the Tongue Tissue in Healthy Subjects and Patients With Tongue Squamous Cell Carcinoma: Preliminary Findings

PurposeTo noninvasively assess spectroscopic and metabolic profiles of healthy tongue tissue and in an exploratory objective in nontreated and treated patients with tongue squamous cell carcinoma (SCC).MethodsFourteen healthy subjects (HSs), one patient with nontreated tongue SCC (NT-SCC), and two patients with treated tongue SCC (T-SCC) underwent MRI and single-voxel proton magnetic resonance spectroscopy (1H-MRS) evaluations (3 and 1.5T). Multi-echo-times 1H-MRS was performed at the medial superior part (MSP) and the anterior inferior part (AIP) of the tongue in HS, while 1H-MRS voxel was placed at the most aggressive part of the tumor for patients with tongue SCC. 1H-MRS data analysis yielded spectroscopic metabolite ratios quantified to total creatine.ResultsIn HS, compared to MSP and AIP, 1H-MRS spectra revealed higher levels of creatine, a more prominent and well-identified trimethylamine-choline (TMA-Cho) peak. However, larger prominent lipid peaks were better differentiated in the tongue MSP. Compared to HS, patients with NT-SCC exhibited very high levels of lipids and relatively higher values of TMA-Cho peak. Interestingly, patients with T-SCC showed almost nonproliferation activity. However, high lipids levels were measured, although they were relatively lower than lipids levels measured in patients with NT-SCC.ConclusionThe present study demonstrated the potential use of in-vivo1H-MRS to noninvasively assess spectroscopic and metabolic profiles of the healthy tongue tissue in a spatial location-dependent manner. Preliminary results revealed differences between HS and patients with tongue NT-SCC as well as tongue T-SCC, which should be confirmed with more patients. 1H-MRS could be included, in the future, in the arsenal of tools for treatment response evaluation and noninvasive monitoring of patients with tongue SCC

Autologous Hematopoietic Stem Cell Transplantation vs Intravenous Pulse Cyclophosphamide in Diffuse Cutaneous Systemic Sclerosis: A Randomized Clinical Trial

Importance: High-dose immunosuppressive therapy and autologous hematopoietic stem cell transplantation (HSCT) have shown efficacy in systemic sclerosis in phase 1 and small phase 2 trials. Objective: To compare efficacy and safety of HSCT vs 12 successive monthly intravenous pulses of cyclophosphamide. Design, Setting, and Participants: The Autologous Stem Cell Transplantation International Scleroderma (ASTIS) trial, a phase 3, multicenter, randomized (1:1), open-label, parallel-group, clinical trial conducted in 10 countries at 29 centers with access to a European Group for Blood and Marrow Transplantation–registered transplant facility. From March 2001 to October 2009, 156 patients with early diffuse cutaneous systemic sclerosis were recruited and followed up until October 31, 2013. Interventions: HSCT vs intravenous pulse cyclophosphamide. Main Outcomes and Measures: The primary end point was event-free survival, defined as time from randomization until the occurrence of death or persistent major organ failure. Results: A total of 156 patients were randomly assigned to receive HSCT (n = 79) or cyclophosphamide (n = 77). During a median follow-up of 5.8 years, 53 events occurred: 22 in the HSCT group (19 deaths and 3 irreversible organ failures) and 31 in the control group (23 deaths and 8 irreversible organ failures). During the first year, there were more events in the HSCT group (13 events [16.5%], including 8 treatment-related deaths) than in the control group (8 events [10.4%], with no treatment-related deaths). At 2 years, 14 events (17.7%) had occurred cumulatively in the HSCT group vs 14 events (18.2%) in the control group; at 4 years, 15 events (19%) had occurred cumulatively in the HSCT group vs 20 events (26%) in the control group. Time-varying hazard ratios (modeled with treatment × time interaction) for event-free survival were 0.35 (95% CI, 0.16-0.74) at 2 years and 0.34 (95% CI, 0.16-0.74) at 4 years. Conclusions and Relevance: Among patients with early diffuse cutaneous systemic sclerosis, HSCT was associated with increased treatment-related mortality in the first year after treatment. However, HCST conferred a significant long-term event-free survival benefit. Trial Registration: isrctn.org Identifier: ISRCTN5437125

Distinguer la radionécrose de la récidive de gliome cérébral traité (bases physiopathologiques et résultats de l'imagerie métabolique et par résonance magnétique)

CAEN-BU Médecine pharmacie (141182102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Relaxométrie dynamique appliquée à l'hépatocarcinogénèse (modélisation pharmacodynamique et essai préliminaire)

CAEN-BU Médecine pharmacie (141182102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Statistical shape model-based segmentation of brain MRI images

International audienceWe propose a segmentation method that automatically delineates structures contours from 3D brain MRI images using a statistical shape model. We automatically build this 3D Point Distribution Model (PDM) in applying a Minimum Description Length (MDL) annotation to a training set of shapes, obtained by registration of a 3D anatomical atlas over a set of patients brain MRIs. Delineation of any structure from a new MRI image is first initialized by such registration. Then, delineation is achieved in iterating two consecutive steps until the 3D contour reaches idempotence. The first step consists in applying an intensity model to the latest shape position so as to formulate a closer guess: our model requires far less priors than standard model in aiming at direct interpretation rather than compliance to learned contexts. The second step consists in enforcing shape constraints onto previous guess so as to remove all bias induced by artifacts or low contrast on current MRI. For this, we infer the closest shape instance from the PDM shape space using a new estimation method which accuracy is significantly improved by a huge increase in the model resolution and by a depth-search in the parameter space. The delineation results we obtained are very encouraging and show the interest of the proposed framework

Spectroscopie quantitative par résonance magnétique proton en conditions cliniques (étude de la variabilité d'un dispositif ERETIC et spectres de médicaments)

CAEN-BU Médecine pharmacie (141182102) / SudocSudocFranceF

L'IRM multiparamétrique et la TEP pour les gliomes (deux outils complémentaires pour la détermination du grade, l'évaluation de la survie et l'analyse spatiale)

L imagerie intervient à différentes étapes de la prise en charges des patients atteints de gliome avec notamment l IRM conventionnelle. Afin de mieux caractériser cette pathologie, d autres marqueurs physiologiques et/ou métaboliques plus spécifiques des cellules tumorales, de la vascularisation ou de l hypoxie sont notamment issus de l IRM multiparamétrique (IRMmp) comme la perfusion (CBV), la diffusion (ADC) et la spectroscopie par résonance magnétique (SRM) ou de la TEP avec les traceurs [18F]-FLT et [18F]-FMISO. Dans ce travail, hormis le FMISO, ces différents marqueurs d imagerie ont été étudiés pour la détermination du grade des gliomes, puis en lien avec la survie des patients atteints de glioblastome (GBM) pour évaluer leur valeur diagnostique et pronostique. Les modalités permettant une meilleure classification du grade de la tumeur sont l ADC et la captation de [18F]-FLT. De plus, une analyse multivariée fait aussi ressortir la TEP FLT et l ADC comme les meilleurs biomarqueurs d imagerie pour prédire la survie. L analyse des relations spatiales des différents biomarqueurs dans les GBM montre que des zones potentiellement agressives, de captation [18F]-FLT et d hypervascularisation, sont présentes à l extérieur des zones de prise de contraste habituellement traitées. Celles-ci pourraient être intégrées pour optimiser les traitements de chirurgie et de radiothérapie. Ces images multimodales permettent également d étudier des liens entre les différents phénomènes physiopathologiques tumoraux et de suggérer que la prolifération serait à l origine de l hypoxie et de la vascularisation et que ces deux phénomènes sont spatialement dissociés.Imaging is used at different stages of management of glioma patients including conventional MRI. To better characterize this disease, more specific physiological and / or metabolical markers of tumor cells, vascularization or hypoxia mesured from multiparametric MRI (IRMmp) as perfusion (CBV), diffusion (ADC) and magnetic resonance spectroscopy (MRS) or PET with tracer [18F]-FLT and [18F]-FMISO. In this work, except FMISO, these imaging markers have been studied to determine the grade of gliomas and in relationship with the survival of patients with glioblastoma (GBM) to evaluate their diagnostic and prognostic value. Modalities for a better classification of tumor grade are the ADC and uptake [18F]-FLT. In addition, multivariate analysis also highlights the FLT PET and ADC as the best imaging biomarkers to predict survival. The analysis of the spatial relationships of various biomarkers in GBM shows that potentially aggressive areas, uptake of [18F]-FLT and vascularity are present outside areas of contrast enhancement usually treated. These could be incorporated to optimize the treatment of surgery and radiotherapy. These multimodal images also allow us to study the links between the different pathophysiological mechanisms and suggest that tumor proliferation is the cause of hypoxia and vasculature and that these two phenomena are spatially dissociated.CAEN-BU Médecine pharmacie (141182102) / SudocSudocFranceF