Adoptive immunotherapy monitored by micro-MRI in experimental colorectal liver metastasis

In this study we used the colon carcinoma DHDK12 cell line and generated single metastasis after subcapsular injection in BDIX rats as an experimental tumor model. The aim of the work was to set up in vitro experimental conditions to prepare immune effector cells and in vivo conditions for monitoring the effects of such cells injected as adoptive immunotherapy. Dendritic cells can process tumor cell antigens, induce a T-cell response and be used ex vivo to prepare activated lymphocytes. Lymphocytes were harvested from mesenteric lymph nodes and cocultured with bone marrow-derived autologous dendritic cells previously loaded with irradiated tumor cells. In vitro, the coculture: 1) induced the proliferation of lymphocytes, 2) expanded a preferential subpopulation of T CD8 lymphocytes, and 3) was in favor of lymphocyte cytotoxic activity against the DHDK12 tumor cell line. Activated lymphocytes were injected in the tumor-bearing rat portal vein. Parameters could be set to monitor tumor volume by micro MRI. This monitoring before and after treatment and immunohistochemical examinations revealed that: 1) micro MRI is an appropriate tool to survey metastasis growth in rat, 2) injected lymphocytes increase lesional infiltration with T CD8 cells even 15 days after treatment, 3) a dose of 50 millions lymphocytes is not sufficient to act on the course of the tumor

Is magnetic resonance imaging texture analysis a useful tool for cell therapy in vivo monitoring?

Assessment of anti-tumor treatment efficiency is usually done by measuring tumor size. Treatment may however induce changes in the tumor other than tumor size. Magnetic Resonance Imaging Texture Analysis (MRI-TA) is presently used to follow activated lymphocyte cell therapy. We used a 7T microimager to acquire high-resolution MR images of an experimental liver metastasis from colon carcinoma in rats treated (n = 4) or not (n = 3) with a cell therapy product. MRI-TA was then performed with Linear Discriminant Analysis and showed: i) a significant variation of tumor texture with tumor growth and ii) a significant modification in the texture of tumors treated with activated lymphocytes compared with untreated tumors. T2-weighted images or volume calculation did not evidence any difference. MRI-TA appears as a promising method for early detection and follow-up of response to cell therapy

L'imagerie par résonance magnétique comme moyen de suivre la croissance corporelle et le développement de la gonade chez l'huitre Crassostrea gigas

International audienceTo make a preliminary exploration of the possibilities and limits of magnetic resonance imaging (MRI) for assessing body growth and gonad development of the Pacific oyster, Crassostrea gigas, individual monitoring was conducted on diploid and triploid oysters in their second year, maintained from February to October in a pond on the French Atlantic coast. Magnetic resonance imaging was done on each oyster on five dates during the study period. From these images, variations in the volumes of the flesh, digestive glandgonad and adductor muscle, and the surface of the gills were measured over time. Apart from the well known differences between diploids and triploids related to maturation of gametes, other original observations of assessing growth were made from these MRI measurements using a non-invasive technique. The standard error of mean dry flesh variation was lower than that found by other commonly used measurement methods. A negative correlation was established between the volume of the gametes spawned and the increase in dry flesh volume after spawning. Moreover, these variations were correlated with the chemical composition of the adductor muscle. All these observations and conclusions need to be confirmed by further observations on oysters of different sizes or grown in different environments.Pour explorer les possibilités et les limites de l'imagerie en résonance magnétique (IRM) sur la croissance corporelle et le développement des gonades de l'huître, Crassostrea gigas, des suivis individuels ont été effectués sur des huîtres diploïdes et triploïdes âgées de 2 ans, élevées en bassins de février à octobre sur les côtes Atlantiques françaises. L'IRM a été effectuée sur chaque huître, à cinq dates durant la période d'étude. Les variations de volume de la chair, de la glande digestive et du muscle adducteur, et de la surface des branchies ont ainsi été mesurées. A part les différences bien connues entre huîtres diploïdes et triploïdes liées à la maturation des gamètes, d'autres observations originales sur la croissance ont été effectuées à partir de ces mesures au moyen de l'IRM, technique non-invasive. L'erreur standard sur les variations de la chair sèche sont plus faibles que celles trouvées par les méthodes classiques. Une corrélation négative est observée entre le volume des gamètes émis et l'accroissement du volume de chair sèche après la ponte. De plus, ces variations sont corrélées avec la composition chimique du muscle adducteur. Ces observations et conclusions demandent à être confirmées par d'autres observations sur des huîtres de différentes tailles ou cultivées en conditions environnementales différentes

MRI texture analysis on texture test objects, normal brain and intracranial tumors.

International audienceTexture analysis was performed in three different MRI units on T1 and T2-weighted MR images from 10 healthy volunteers and 63 patients with histologically confirmed intracranial tumors. The goal of this study was a multicenter evaluation of the usefulness of this quantitative approach for the characterization of healthy and pathologic human brain tissues (white matter, gray matter, cerebrospinal fluid, tumors and edema). Each selected brain region of interest was characterized with both its mean gray level values and several texture parameters. Multivariate statistical analyses were then applied in order to discriminate each brain tissue type represented by its own set of texture parameters. Texture analysis was previously performed on test objects to evaluate the method dependence on acquisition parameters and consequently the interest of a multicenter evaluation. Even obtained on different sites with their own acquisition routine protocol, MR brain images contain textural features that can reveal discriminant factors for tissue classification and image segmentation. It can also offer additional information in case of undetermined diagnosis or to develop a more accurate tumor grading