13 research outputs found
Patient respiratory-triggered quantitative T<sub>2</sub> mapping in the pancreas.
Long acquisition times and motion sensitivity limit T <sub>2</sub> mapping in the abdomen. Accelerated mapping at 3 T may allow for quantitative assessment of diffuse pancreatic disease in patients during free-breathing.
To test the feasibility of respiratory-triggered quantitative T <sub>2</sub> analysis in the pancreas and correlate T <sub>2</sub> -values with age, body mass index, pancreatic location, main pancreatic duct dilatation, and underlying pathology.
Retrospective single-center pilot study.
Eighty-eight adults.
Ten-fold accelerated multiecho-spin-echo 3 T MRI sequence to quantify T <sub>2</sub> at 3 T.
Two radiologists independently delineated three regions of interest inside the pancreatic head, body, and tail for each acquisition. Means and standard deviations for T <sub>2</sub> values in these regions were determined. T <sub>2</sub> -value variation with demographic data, intraparenchymal location, pancreatic duct dilation, and underlying pancreatic disease was assessed.
Interreader reliability was determined by calculating the interclass coefficient (ICCs). T <sub>2</sub> values were compared for different pancreatic locations by analysis of variance (ANOVA). Interpatient associations between T <sub>2</sub> values and demographical, clinical, and radiological data were calculated (ANOVA).
The accelerated T <sub>2</sub> mapping sequence was successfully performed in all participants (mean acquisition time, 2:48 ± 0:43 min). Low T <sub>2</sub> value variability was observed across all patients (intersubject) (head: 60.2 ± 8.3 msec, body: 63.9 ± 11.5 msec, tail: 66.8 ± 16.4 msec). Interreader agreement was good (ICC, 0.82, 95% confidence interval: 0.77-0.86). T <sub>2</sub> -values differed significantly depending on age (P < 0.001), location (P < 0.001), main pancreatic duct dilatation (P < 0.001), and diffuse pancreatic disease (P < 0.03).
The feasibility of accelerated T <sub>2</sub> mapping at 3 T in moving abdominal organs was demonstrated in the pancreas, since T <sub>2</sub> values were stable and reproducible. In the pancreatic parenchyma, T <sub>2</sub> -values were significantly dependent on demographic and clinical parameters.
4 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:410-416
The MEGAPIE-TEST Project
The goals of the MEGAPIE initiative are to design, build and operate a 1MW heavy liquid metal target. The first step towards the realization of the MEGAPIE target was the feasibility studies, which outlined the entire project. Contextually to the feasibility studies the conceptual design phase started with the establishment of R&D working groups assisting the design and validation of both the target and its ancillary systems. In this framework the EU project MEGAPIE-TEST has been structured in three work packages with tasks concerning the finalization of the engineering design, the components and subsystem testing, the integral test and the first irradiation period. The MEGAPIE-TEST consortium is composed by the 14 partners: FZK, PSI, CEA, ENEA, SCK-CEN, CNRS /IDFE, IN2P3, LMPGM, EMN, ISMRA, UNIV-NANTES, U-PSUDXI, USTL. Currently the engineering design of the target has been finalized, its manufacturing has been launched and the design activities on the ancillary systems were almost completed. R&D activities in the fields of materials, thermal – hydraulics, structural mechanics, neutronic and nuclear assessment and liquid metal technologies were performed in order to assist specific design issues. Some Subsystem and component tests were also performed and the preparation of the integral test is an ongoing activity
The combination of hepatobiliary phase with Gd-EOB-DTPA and DWI is highly accurate for the detection and characterization of liver metastases from neuroendocrine tumor.
To compare the diagnostic accuracy of dynamic contrast-enhanced phases, hepatobiliary phase (HBP), and diffusion-weighted imaging (DWI) for the detection of liver metastases from neuroendocrine tumor (NET).
Sixty-seven patients with suspected NET liver metastases underwent gadoxetic acid-enhanced MRI. Three radiologists read four imaging sets separately and independently: DWI, T2W+dynamic, T2WI+HBP, and DWI+HBP. Reference standard included all imaging, histological findings, and clinical data. Sensitivity and specificity were calculated and compared for each imaging set. Interreader agreement was evaluated by intraclass correlation coefficient (ICC). Univariate logistic regression was performed to evaluate lesion characteristics (size, ADC, and enhancing pattern) associated to false positive and negative lesions.
Six hundred twenty-five lesions (545 metastases, 80 benign lesions) were identified. Detection rate was significantly higher combining DWI+HBP than the other imaging sets (sensitivity 86% (95% confidence interval (CI) 0.845-0.878), specificity 94% (95% CI 0.901-0.961)). The sensitivity and specificity of the other sets were 82% and 65% for DWI, 88% and 69% for T2WI, and 90% and 82% for HBP+T2WI, respectively. The interreader agreement was statistically higher for both HBP sets (ICC = 0.96 (95% CI 0.94-0.97) for T2WI+HBP and ICC = 0.91 (95% CI 0.87-0.94) for DWI+HBP, respectively) compared with that for DWI (ICC = 0.76 (95% CI 0.66-0.83)) and T2+dynamic (ICC = 0.85 (95% CI 0.79-0.9)). High ADC values, large lesion size, and hypervascular pattern lowered the risk of false negative.
Given the high diagnostic accuracy of combining DWI+HBP, gadoxetic acid-enhanced MRI is to be considered in NET patients with suspected liver metastases. Fast MRI protocol using T2WI, DWI, and HBP is of interest in this population.
• The combined set of diffusion-weighted (DW) and hepatobiliary phase (HBP) images yields the highest sensitivity and specificity for neuroendocrine liver metastasis (NELM) detection. • Gadoxetic acid should be the contrast agent of choice for liver MRI in NET patients. • The combined set of HBP and DWI sequences could also be used as a tool of abbreviated MRI in follow-up or assessment of treatment such as somatostatin analogs
Dexamethasone-induced enhancement of resistance to ionizing radiation and chemotherapeutic agents in human tumor cells.
BACKGROUND: Dexamethasone-induced changes in radioresistance have previously been observed by several authors. Here, we examined effects of dexamethasone on resistance to ionizing radiation in 10 additional human cell lines and strains, and on resistance to carboplatin and paclitaxel in 13 fresh tumor samples.
MATERIAL AND METHODS: Eight human carcinoma cell lines, a glioblastoma cell line and a strain of normal human diploid fibroblasts were arbitrarily chosen for these in-vitro studies. Effects on radiosensitivity were assessed using a conventional colony formation assay. Effects on resistance to the drugs were investigated prospectively (ATP cell viability assay) using 13 fresh tumor samples from consecutive patients operated for ovarian cancer within the context of a Swiss nation-wide randomized prospective clinical trial (SAKK 45/94).
RESULTS: Dexamethasone promoted proliferation of 1 of the cell lines without affecting radiosensitivity, while it completely inhibited proliferation of another cell line (effects on radiosensitivity could thus not be examined). Furthermore, dexamethasone induced enhanced radioresistance in 1 of the 8 carcinoma cell lines examined. In the glioblastoma cell line, there was no effect on growth or radioresistance, nor in the fibroblasts. Treatment with dexamethasone enhanced resistance of the malignant cells to carboplatin in 4 of the 13 fresh tumor samples examined, while no enhancement in resistance to paclitaxel was observed.
CONCLUSIONS: In agreement with previous reports, we found that dexamethasone may induce radioresistance in human carcinoma cells. Including the published data from the literature, dexamethasone induced enhancement in radioresistance in 4 of 12 carcinoma cell lines (33%), but not in 3 glioblastoma cell lines, nor in 3 fibroblast strains. Dexamethasone also induced enhanced resistance to carboplatin with a similar probability in fresh samples of ovarian cancer evaluated prospectively (in 4 of 13 samples; 31%). We worry that induction of resistance by corticosteroids given to patients undergoing either radiotherapy or chemotherapy with agents causing DNA damage might be associated with a reduced clinical responsiveness in a significant fraction of patients with a carcinoma
Reduction of neointimal proliferation after implantation of a beta particle emitting gold Au 198 coated stent
Potential role of autoantibodies belonging to the immunoglobulin G-3 subclass in cardiac dysfunction among patients with dilated cardiomyopathy
Background- Immunoadsorption capable of removing circulating autoantibodies represents an additional therapeutic approach in dilated cardiomyopathy (DCM). The role played by autoantibodies belonging to the immunoglobulin (Ig) subclass G-3 in cardiac dysfunction remains to be elucidated. Methods and Results- Patients with DCM (left ventricular ejection fraction 80%). IgG-3 was effectively eliminated only by anti-IgG adsorption (eg, during the first immunoadsorption course; protein A, −37±4%; anti-IgG, −89±3%; P<0.001 versus protein A). The {beta}1-receptor autoantibody was effectively reduced only by anti-IgG (P<0.01 versus protein A). Hemodynamics did not change in the protein A group. In the anti-IgG group during the first immunoadsorption course, cardiac index increased from 2.3±0.1 to 3.0±0.1 L · min−1 · m−2 (P<0.01 versus protein A). After 3 months, before the last immunoadsorption course, cardiac index was 2.2±0.1 L · min−1 · m−2 in the protein A group and 3.0±0.2 L · min−1 · m−2 in the anti-IgG group (P<0.01 versus protein A). Left ventricular ejection fraction increased only in the anti-IgG group (P<0.05 versus protein A). Conclusions- Autoantibodies belonging to IgG-3 may play an important role in cardiac dysfunction of DCM. The removal of antibodies of the IgG-3 subclass may represent an essential mechanism of immunoadsorption in DCM
Low pt thin cathode layer catalyst layer by reactive spray deposition technology
National Research Council Canada's Institute for Fuel Cell Innovation, NRC-IFCI, has been developing the Reactive Spray Deposition Technology (RSDT) process to optimize composite electrode layer formation and develop novel electrocatalysts and catalyst layers. The RSDT process provides the means necessary to develop the next generation of thin, low platinum or alloy catalyst layers for PEM MEA's. In order to best manage water distribution, mass transport and conductivity, the structure should be a gradient with controlled porosity and controlled distribution of both platinum and ionomer across the catalyst layer. The RSDT process allows good control of the platinum particle size as they are created directly from metal vapors, which prevents agglomeration in the catalyst layer. Additionally, it has the flexibility to build a gradient layer structure across a very thin film catalyst layer (<1 um). In our design, a platinum sub-layer (100 nm) was deposited directly on a Nafion\uae 117 membrane as a columnar structure. After the sub-layer, the platinum loading was reduced in a co-deposited layer of Pt-Nafion (ionomer)-carbon with the lowest loading closest to the GDL. The combined loading of both layers was <0.05mg/cm2 Pt with this approach. The manufactured catalyst layer has a performance of 0.65V at 1 A/cm2 with 0.05mg/cm2 Pt loading using pure oxygen.Peer reviewed: YesNRC publication: Ye