Severe portal and systemic acidosis during CO2-laparoscopy compared to helium or gasless laparoscopy and laparotomy in a rodent model: an experimental study

Background and aims: This experimental study assesses the influence of different gases and insufflation pressures on the portal, central-venous and peripheral-arterial pH during experimental laparoscopy. Methods: Firstly, 36 male WAG/Rij rats were randomized into six groups (n = 6) spontaneously breathing during anaesthesia: laparoscopy using carbon dioxide or helium at 6 and 12 mmHg, gasless laparoscopy and laparotomy. 45 and 90 min after setup, blood was sampled from the portal vein, vena cava and the common femoral artery with immediate blood gas analysis. Secondly, 12 animals were mechanically ventilated at physiological arterial pH during 90 min of laparotomy (n = 6) or carbon dioxide laparoscopy at 12 mmHg (n = 6) with respective blood gas analyses. Results: Over time, in spontaneously breathing rats, carbon dioxide laparoscopy caused significant insufflation pressure-dependent portal acidosis (pH at 6 mmHg, 6.99 [6.95-7.04] at 45 min and 6.95 [6.94-6.96] at 90 min, pH at 12 mmHg, 6.89 [6.82-6.90] at 45 min and 6.84 [6.81-6.87] at 90 min; p 0.05). Central-venous and peripheral-arterial acidosis was significant but less severely reduced during carbon dioxide laparoscopy. Laparotomy, helium laparoscopy and gasless laparoscopy showed no comparable acidosis in all vessels. Portal and central-venous acidosis during carbon dioxide laparoscopy at 12 mmHg was not reversible by mechanical hyperventilation maintaining a physiological arterial pH (pH portal 6.85 [6.84-6.90] (p = 0.004), central-venous 6.93 [6.90-6.99] (p = 0.004), peripheral-arterial 7.29 [7.29-7.31] (p = 0.220) at 90 min; Wilcoxon-Mann-Whitney test). Conclusion: Carbon dioxide laparoscopy led to insufflation pressure-dependent severe portal and less severe central-venous acidosis not reversible by mechanical hyperventilation. Keywords: Acidosis; Blood gases; Insufflation gas; Insufflation pressure; Laparoscop

Development and validation of a motorized focused ultrasound system for the controlled delivery of large molecules to the rodent brain under 7T MRI guidance

Congrès sous l’égide de la Société Française de Génie Biologique et Médical (SFGBM)National audienceThe use of focused ultrasound combined with microbubbles has shown the capability to increase the permeability of the Blood Brain Barrier (BBB) locally, transiently and non-invasively, allowing the delivery of large molecules to the brain. Magnetic Resonance Imaging is of great interest to precisely monitor the disruption. In this study, we have shown the possibility to use our motorized system to open the BBB along arbitrary trajectories under 7T MRI guidance and to test different acoustic conditions on a single animal

Prise en charge médicale des fibromes (mifépristone versus placebo)

POITIERS-BU Médecine pharmacie (861942103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

A Time-Dependent Joint Segmentation and Registration Model: Application to Longitudinal Registration of Hepatic DCE-MRI Sequences

International audienceWhile segmentation consists in partitioning a givenimage into meaningful constituents in order to identify relevantstructures such as homogeneous regions or edges, registration,given two images, aims at finding an optimal orientation-preserving one-to-one deformation aligning the structures visiblein an image into the corresponding ones in the other. Recently,intertwining both tasks into a single framework has proven toyield better results in terms of accuracy —in particular whenthe images exhibit weak boundary definition —and increase ofreliability of the encoded structure matching —since now, notonly based on intensity distribution comparison but also ongeometrical and topological features —. In line with this idea, wepropose going a step further by adding explicitly some dynamicsin the modelling,i.e., by making the minimization problemboth space and time-dependent so that the correlation betweenboth tasks is achieved through the process, connecting thus theproblem to an interpolation one. The shapes to be matched areviewed as Saint Venant-Kirchhoff materials, a special instanceof hyperelastic ones, and are implicitly modelled by level-setfunctions. These are evolved in order to minimize a functional in-cluding both a nonlinear-elasticity-based regularizer prescribingthe physical nature of the deformation and a term penalizingthe shape misalignment, thus promoting structure matchingrather than intensity pairing. Theoretical results emphasizingthe mathematical soundness of the model are provided, amongwhich the existence of minimizers and the existence of a weakviscosity solution to the related evolution problem. The model isthen applied to the longitudinal registration of hepatic dynamiccontrast-enhanced MRI sequences and shows good performance.This application has an important impact on the computer-aided follow-up of patients suffering from liver cancers

Saccharin induces resistance in wheat against Zymoseptoria tritici

International audienc

A new 3D Slicer plug-in for the interactive annotation and segmentation of liver anatomy

International audienc

The 3D Slicer RVXLiverSegmentation plug-in for interactive liver anatomy reconstruction from medical images

International audienceAnnotation plays a key role in the creation of reference datasets that are useful to evaluate medical image processing algorithms and to train machine learning based architectures. RVXLiverSegmentation is a 3D Slicer plug-in aiming at speeding-up the annotation of liver anatomy from medical images (CT -Computerized Tomography-scans or MRI -Magnetic Resonance Imaging- for instance). This organ has particular anatomy and physiology; within its parenchymal volume, the liver receives blood from the portal vein and hepatic artery (the former one being the most visible in medical images), and delivers filtered blood through the hepatic veins, toward inferior vena cava. The blood vessels subdivide into the liver as fine vascular tree structures, which make the segmentation difficult, mostly in MRI modality. To facilitate this task, our plug-in is decomposed into modules dedicated to the segmentation of the liver volume, inner vessels and possible tumors. RVXLiverSegmentation can be downloaded or installed from the 3D Slicer software as an official module

A new 3D Slicer plug-in for the interactive annotation and segmentation of liver anatomy

International audienc