Robust similarity metrics for the registration of 3D multimodal medical images

In this paper, we develop data driven registration algorithms, relying on pixel similarity metrics, that enable an accurate rigid registration of dissimilar single or multimodal 2D/3D medical images . Gross dissimilarities are handled by considering similarity measures related to robust M-estimators . Fast stochastic multigrid optimization algorithms are used to minimize these similarity metrics . The proposed robust similarity metrics are compared to the most popular standard similarity metrics on real MRI/MRI and MRI/SPECT image pairs showing gross dissimilarities . A blinded evaluation of the algorithm was performed, using as gold standard a prospective, marker-based registration method, by participating in a registration evaluation project (Vanderbilt University) . Our robust similarity measures compare favourably with all standard (non robust) techniques .Le recalage non supervisé d'images médicales volumiques reste un problème difficile en raison de l'importante variabilité et des grandes différences d'information pouvant apparaître dans des séquences d'images de même modalité ou dans des couples d'images multimodales. Nous présentons dans cet article des méthodes robustes de recalage rigide d'images 2D et 3D monomodales et multimodales, reposant sur la minimisation de mesures de similarité inter-images. Les méthodes proposées s'appuient sur la théorie de l'estimation robuste et mettent en oeuvre des M-estimateurs associés à des techniques d'optimisation stochastique multigrilles rapides. Ces estimateurs robustes sont évalués à travers le recalage d'images médicales volumiques monomodales (IRM/IRM) et multimodales (IRM/TEMP). Ils sont comparés aux autres fonctions de similarité classiques, proposées dans la littérature. Les méthodes de recalage robustes ont, en particulier, été validées dans le cadre d'un protocole comparatif mis en place par l'Université de Vanderbilt. Elles sont actuellement utilisées en routine clinique et conduisent, tant pour les images de même modalité que pour les images multimodales à une précision sous-voxel, comparable aux meilleures méthodes actuelles. Elles permettent de plus de recaler des couples d'images sur lesquels les méthodes classiques échouent

Metabolomic Characterization of Ovarian Epithelial Carcinomas by HRMAS-NMR Spectroscopy

Objectives. The objectives of the present study are to determine if a metabolomic study by HRMAS-NMR can (i) discriminate between different histological types of epithelial ovarian carcinomas and healthy ovarian tissue, (ii) generate statistical models capable of classifying borderline tumors and (iii) establish a potential relationship with patient's survival or response to chemotherapy. Methods. 36 human epithelial ovarian tumor biopsies and 3 healthy ovarian tissues were studied using 1H HRMAS NMR spectroscopy and multivariate statistical analysis. Results. The results presented in this study demonstrate that the three histological types of epithelial ovarian carcinomas present an effective metabolic pattern difference. Furthermore, a metabolic signature specific of serous (N-acetyl-aspartate) and mucinous (N-acetyl-lysine) carcinomas was found. The statistical models generated in this study are able to predict borderline tumors characterized by an intermediate metabolic pattern similar to the normal ovarian tissue. Finally and importantly, the statistical model of serous carcinomas provided good predictions of both patient's survival rates and the patient's response to chemotherapy. Conclusions. Despite the small number of samples used in this study, the results indicate that metabolomic analysis of intact tissues by HRMAS-NMR is a promising technique which might be applicable to the therapeutic management of patients

On the Assessment of Segmentation Methods for Images of Mosaics

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MHD in von Kármán swirling flows, development and first run of the sodium experiment

URL: http://www-spht.cea.fr/articles/s01/004 MHD dans les écoulements de von Kármán | Collaboration VKSNATO Science Series II 26, 35-50 (2001). NATO Advanced Research Workshop, Dynamo and Dynamics, A Mathematical ChallengeWe describe the motivations, development and first run of the Von Kármán Sodium (VKS) experiment built to study high Reynolds number magnetohydrodynamics and applications to the dynamo effect. The flow is optimized using water experiments at scale 1/2 and kinematic dynamo simulations. In VKS run1, induction measurements are made in the presence of an externally applied field. Results are reported concerning the geometry of the induced field and its fluctuations in time

Metabolomics approaches in pancreatic adenocarcinoma: Tumor metabolism profiling predicts clinical outcome of patients

Background: Pancreatic adenocarcinomas (PAs) have very poor prognoses even when surgery is possible. Currently, there are no tissular biomarkers to predict long-term survival in patients with PA. The aims of this study were to (1) describe the metabolome of pancreatic parenchyma (PP) and PA, (2) determine the impact of neoadjuvant chemotherapy on PP and PA, and (3) find tissue metabolic biomarkers associated with long-term survivors, using metabolomics analysis. Methods: 1H high-resolution magic angle spinning (HRMAS) nuclear magnetic resonance (NMR) spectroscopy using intact tissues was applied to analyze metabolites in PP tissue samples (n = 17) and intact tumor samples (n = 106), obtained from 106 patients undergoing surgical resection for PA. Results: An orthogonal partial least square-discriminant analysis (OPLS-DA) showed a clear distinction between PP and PA. Higher concentrations of myo-inositol and glycerol were shown in PP, whereas higher levels of glucose, ascorbate, ethanolamine, lactate, and taurine were revealed in PA. Among those metabolites, one of them was particularly obvious in the distinction between long-term and short-term survivors. A high ethanolamine level was associated with worse survival. The impact of neoadjuvant chemotherapy was higher on PA than on PP. Conclusions: This study shows that HRMAS NMR spectroscopy using intact tissue provides important and solid information in the characterization of PA. Metabolomics profiling can also predict long-term survival: the assessment of ethanolamine concentration can be clinically relevant as a single metabolic biomarker. This information can be obtained in 20 min, during surgery, to distinguish long-term from short-term survival. © 2017 The Author(s)

Application of an original RT-PCR–ELISA multiplex assay for MDR1 and MRP, along with p53 determination in node-positive breast cancer patients

The long-term prognostic value of tumoural MDR1 and MRP, along with p53 and other classical parameters, was analysed on 85 node-positive breast cancer patients receiving anthracycline-based adjuvant therapy. All patients underwent tumour resection plus irradiation and adjuvant chemotherapy (the majority receiving fluorouracil–epirubicin–cyclophosphamide). Median follow-up for the 54 alive patients was 7.8 years. Mean age was 53.7 years (range 28–79) and 54 patients were post-menopausal. MDR1 and MRP expression were quantified according to an original reverse transcription polymerase chain reaction multiplex assay with colourimetric enzyme-linked immunosorbent assay detection(β2-microglobulin as control). P53 protein was analysed using an immunoluminometric assay (Sangtec). MDR1 expression varied within an 11-fold range (mean 94, median 83), MRP within a 45-fold range (mean 315, median 242) and p53 protein from the limit of detection (0.002 ng mg−1) up to 35.71 ng mg−1(mean 1.18, median 0.13 ng mg−1). P53 protein was significantly higher in oestrogen receptor (ER)-negative than in ER-positive tumours (P = 0.039). The higher the p53, the lower the MDR1 expression (P = 0.015, r = –0.27). P53 was not linked to progesterone receptor (PR) status, S phase fraction, or MRP. Significantly greater MDR1 expression was observed in grade I tumours (P = 0.029). No relationship was observed between MDR1 and MRP. Neither MDR1 nor MRP was linked to ER or PR status. Unlike MDR1, MRP was correlated with the S phase: the greater the MRP, the lower the S phase (P = 0.006, r = –0.42). Univariate Cox analyses revealed that MDR1, MRP, p53 and S phase had no significant influence on progression-free or specific survival. A tendency suggested that the greater the p53, the shorter the progression-free survival (P = 0.076 as continuous and 0.069 as dichotomous). © 2000 Cancer Research Campaig

High-resolution magic angle spinning 1H nuclear magnetic resonance spectroscopy metabolomics of hyperfunctioning parathyroid glands

Background Primary hyperparathyroidism (PHPT) may be related to a single gland disease or multiglandular disease, which requires specific treatments. At present, an operation is the only curative treatment for PHPT. Currently, there are no biomarkers available to identify these 2 entities (single vs. multiple gland disease). The aims of the present study were to compare (1) the tissue metabolomics profiles between PHPT and renal hyperparathyroidism (secondary and tertiary) and (2) single gland disease with multiglandular disease in PHPT using metabolomics analysis. Methods The method used was 1H high-resolution magic angle spinning nuclear magnetic resonance spectroscopy. Forty-three samples from 32 patients suffering from hyperparathyroidism were included in this study. Results Significant differences in the metabolomics profile were assessed according to PHPT and renal hyperparathyroidism. A bicomponent orthogonal partial least square-discriminant analysis showed a clear distinction between PHPT and renal hyperparathyroidism (R2Y = 0.85, Q2 = 0.63). Interestingly, the model also distinguished single gland disease from multiglandular disease (R2Y = 0.96, Q2 = 0.55). A network analysis was also performed using the Algorithm to Determine Expected Metabolite Level Alterations Using Mutual Information (ADEMA). Single gland disease was accurately predicted by ADEMA and was associated with higher levels of phosphorylcholine, choline, glycerophosphocholine, fumarate, succinate, lactate, glucose, glutamine, and ascorbate compared with multiglandular disease. Conclusion This study shows for the first time that 1H high-resolution magic angle spinning nuclear magnetic resonance spectroscopy is a reliable and fast technique to distinguish single gland disease from multiglandular disease in patients with PHPT. The potential use of this method as an intraoperative tool requires specific further studies. © 2016 Elsevier Inc