The Study Of Susceptibility Weighted Imaging For Brain Tumor And Associated Molecular Imaging

Objective:This study was aimed to assess the role of multi-echo susceptibility weighted imaging in evaluation of brain tumors at3.0T high field MRI.Methods and materials:31adults with brain tumors (including20glioma cases,6meningioma cases,3metastasis cases and2lymphoma cases) underwent conventional MRI and contrast enhanced T1WI, multi-echo SWI with/without contrast enhancement. The pathological results were confirmed by craniotomy surgery and histopathology. Magnitude maps and phase maps were acquired separately. Filtering of phase maps, reconstruction of SWI maps, calculation of T2*maps and minimum intensity projection (mIP) were accomplished in the software SPIN. The images with the longest echo were collected for reconstruction of SWI mIP and phase mIP maps. T2*maps were calculated using all the eleven echoes. The basic characteristics included edge, edema, necrosis, parenchyma, bleeding and angiogenesis. The visualization was graded by four degrees, which were scored from0to3. The grading was accomplished by two senior radiologists respectively. Statistical analysis was performed using SPSS18.0software. Kruskal-Wallis test, one-way ANOVA analysis, Thamhane test and Mann-Whitney test were used for the statistical analysis.Results:Multi-echo SWI had advantages in exhibiting the characteristics of bleeding and angiogenesis in brain tumors over conventional MRI. SWI mIP maps, phase mIP maps and T2*mIP maps had the equal value in exhibiting the characteristics of bleeding and angiogenesis in brain tumors. SWI with or without contrast enhancement had no differences in exhibiting the bleeding and angiogenesis characteristics of brain tumors. T2*mIP maps had advantages in exhibiting edge, edema, necrosis and parenchyma characteristics of brain tumors than SWI mIP maps and phase mIP maps.Conclusion:Multi-echo SWI had advantages over conventional MRI in exhibiting the bleeding and angiogenesis characteristics of brain tumors. T2*maps derived from multi-echo SWI exhibited other basic characteristics of edge, edema, necrosis and parenchyma in brain tumors. Multi-echo SWI could replace single echo SWI for imaging of brain tumors. Objective:Our study was to explore the value of contrast enhanced Susceptibility Weighted Imaging in3.0T for grading of gliomas.Methods and materials:16adults with gliomas (7for low-grade gliomas,9for high-grade gliomas) confirmed by craniotomy surgery and histopathology underwent conventional MRI, contrast enhanced T1WI and SWI. Magnitude maps and phase maps were acquired separately. Filtering of phase maps, reconstruction of SWI maps and minimum intensity projection were accomplished in the software SPIN. The maximum transverse sections images of the masses were collected as the standard images. Intratumoral Susceptibility Signal Intensity (ITSS) was graded by two senior radiologists respectively. All data were analyzed with SPSS18.0software. ANOVA test and Mann-Whitney U test were used to detect the significant differences.Results:The average ITSS score of high-grade gliomas was2.2778±0.75190. The average ITSS score of low-grade gliomas was1.2l43±1.12171. Mann-Whitney U test showed the significant difference of ITSS between high-grade and low-grade gliomas.Conclusion:ITSS between high-grade and low-grade gliomas had significant difference. Contrast enhanced SWI can be used to assist grading of gliomas. Objective:The study was aimed to evaluate the HIF-la inhibitor2-methoxyestradiol (2ME2) for suppression of HIF-1α and VEGF in gliomas xenograft model by MRI and pathology.Methods and materials:12male SD rats were implanted F98EGFRvⅢ glioma cell line in situ. MRI scanning was done14days later to make sure the success of the xenograft model. The experiment group were treated by intraperitoneal injection of HIF-1α inhibitor2ME2daily for one week (dose:15mg/kg), and the control group were treated by normal saline. The tumor sizes were measured in contrast enhanced T1WI images by MRI. Susceptibility was graded by ITSS criterion in SWI mIP maps. The brain coronal sections including the maximum cross-section of tumor were stained by Hematoxylin-Eosin staining, immunohistochemical staining of HIF-la and VEGF. Image-Pro Plus6.0were used to measure the level of HIF-la and VEGF. SPSS18.0was used to analyze the data of MRI and immunohistochemical staining.Results:The xenograft models were successful and similar with human glioblastoma in MRI and pathological staining. There were no differences in tumor sizes and susceptibility grading between experiment and control group by MRI. HIF-la and VEGF were inhibited partially in immunohistochemical staining by2ME2intraperitoneal injection.Conclusion:The glioblastoma xenograft models of SD rats by implanting F98RGFRvⅢ glioma cell line in situ had high similarity with human glioblastoma. HIF-la and VEGF were inhibited partially by2ME2intraperitoneal injection, but the changes in tumor sizes and susceptibility might be not prominent. Objective:The study was aimed to synthesize dual modality imaging probes used both in fluorescent and magnetic resonance imaging.Methods and materials:Fluorescent magnetic colloidal nanoparticles (FMCNs) were produced by two-step seed emulsifier-free emulsion polymerization. The superparamagnetic iron oxide nanoparticles were first synthesized as the seed and Eu(AA)3Phen was copolymerized with the remaining St and GMA to form the fluorescent polymer shell in the second step.Results:The uniform core-shell structured FMCNs had a mean diameter of120nm. It exhibited superparamagnetism with the saturation magnetization of1.92emu/g. Red luminescence from the FMCNs was confirmed by the salient fluorescence emission peaks of europium ions at594and619nm as well as2-photon confocal scanning laser microscopy (CLSM). Cytotoxicity test in vitro conducted by MTT assay showed good cytocompatibility and the T2relaxivity of the FMCNs was353.86mM-1S-1suggesting its potential in magnetic resonance imaging (MRI). In vivo MRI studies based on a rat model showed significantly enhanced T2-weighted images of the liver after administration and Prussian blue staining of the liver slices revealed accumulation of FMCNs in cells.Conclusion:The cytocompatibility, superparamagnetism, and excellent fluorescent properties of FMCNs make them suitable for biological imaging probes in MRI and optical imaging.