Summary： The purpose of this study was to quantitatively analyze the relationship between three di- mensional arterial spin labeling （3D-ASL） and dynamic susceptibility contrast-enhanced perfusion weighted imaging ...Summary： The purpose of this study was to quantitatively analyze the relationship between three di- mensional arterial spin labeling （3D-ASL） and dynamic susceptibility contrast-enhanced perfusion weighted imaging （DSC-PWI） in ischemic stroke patients. Thirty patients with ischemic stroke were in- cluded in this study. All subjects underwent routine magnetic resonance imaging scanning, diffusion weighted imaging （DWI）, magnetic resonance angiography （MRA）, 3D-ASL and DSC-PWI on a 3.0T MR scanner. Regions of interest （ROIs） were drawn on the cerebral blood flow （CBF） maps （derived from ASL） and multi-parametric DSC perfusion maps, and then, the absolute and relative values of ASL-CBF, DSC-derived CBF, and DSC-derived mean transit time （MTT） were calculated. The rela- tionships between ASL and DSC parameters were analyzed using Pearson＇s correlation analysis. Re- ceiver operative characteristic （ROC） curves were performed to define the thresholds of relative value of ASL-CBF （rASL） that could best predict DSC-CBF reduction and MTT prolongation. Relative ASL better correlated with CBF and MTT in the anterior circulation with the Pearson correlation coefficients （R） values being 0.611 （P〈0.001） and-0.610 （P〈0.001） respectively. ROC curves demonstrated that when rASL 〈0.585, the sensitivity, specificity and accuracy for predicting ROIs with rCBF〈0.9 were 92.3%, 63.6% and 76.6% respectively. When rASL 〈0.952, the sensitivity, specificity and accuracy for predicting ROIs rMTT〉I.0 were 75.7%, 89.2% and 87.8% respectively. ASL-CBF map has better linear correlations with DSC-derived parameters （DSC-CBF and MTT） in anterior circulation in ischemic stroke patients. Additionally, when rASL is lower than 0.585, it could predict DSC-CBF decrease with moderate accuracy. IfrASL values range from 0.585 to 0.952, we just speculate the prolonged MTT.展开更多
Genes can be transferred using viral or non-viral vectors.Non-viral methods that use plasmid DNA and short interference RNA(si RNA)have advantages,such as low immunogenicity and low likelihood of genomic integration i...Genes can be transferred using viral or non-viral vectors.Non-viral methods that use plasmid DNA and short interference RNA(si RNA)have advantages,such as low immunogenicity and low likelihood of genomic integration in the host,when compared to viral methods.Non-viral methods have potential merit,but their gene transfer efficiency is not satisfactory.Therefore,new methods should be developed.Low-frequency ultrasound irradiation causes mechanical perturbation of the cell membrane,allowing the uptake of large molecules in the vicinity of the cavitation bubbles.The collapse of these bubbles generates small transient holes in the cell membrane and induces transient membrane permeabi-lization.This formation of small pores in the cell membrane using ultrasound allows the transfer of DNA/RNA into the cell.This phenomenon is known as sonoporation and is a gene delivery method that shows great promise as a potential new approach in gene therapy.Microbubbles lower the threshold of cavity formation.Complexes of therapeutic genes and microbubbles improve the transfer efficiency of genes.Diagnostic ultrasound is potentially a suitable sonoporator because it allows the real-time monitoring of irradiated fields.展开更多
基金supported by grants from the 12th Five-year Science and Technology Support Program of China(No.2011BAI08B10)the National Natural Science Foundation of China(No.81171308,No.81570462)
文摘Summary： The purpose of this study was to quantitatively analyze the relationship between three di- mensional arterial spin labeling （3D-ASL） and dynamic susceptibility contrast-enhanced perfusion weighted imaging （DSC-PWI） in ischemic stroke patients. Thirty patients with ischemic stroke were in- cluded in this study. All subjects underwent routine magnetic resonance imaging scanning, diffusion weighted imaging （DWI）, magnetic resonance angiography （MRA）, 3D-ASL and DSC-PWI on a 3.0T MR scanner. Regions of interest （ROIs） were drawn on the cerebral blood flow （CBF） maps （derived from ASL） and multi-parametric DSC perfusion maps, and then, the absolute and relative values of ASL-CBF, DSC-derived CBF, and DSC-derived mean transit time （MTT） were calculated. The rela- tionships between ASL and DSC parameters were analyzed using Pearson＇s correlation analysis. Re- ceiver operative characteristic （ROC） curves were performed to define the thresholds of relative value of ASL-CBF （rASL） that could best predict DSC-CBF reduction and MTT prolongation. Relative ASL better correlated with CBF and MTT in the anterior circulation with the Pearson correlation coefficients （R） values being 0.611 （P〈0.001） and-0.610 （P〈0.001） respectively. ROC curves demonstrated that when rASL 〈0.585, the sensitivity, specificity and accuracy for predicting ROIs with rCBF〈0.9 were 92.3%, 63.6% and 76.6% respectively. When rASL 〈0.952, the sensitivity, specificity and accuracy for predicting ROIs rMTT〉I.0 were 75.7%, 89.2% and 87.8% respectively. ASL-CBF map has better linear correlations with DSC-derived parameters （DSC-CBF and MTT） in anterior circulation in ischemic stroke patients. Additionally, when rASL is lower than 0.585, it could predict DSC-CBF decrease with moderate accuracy. IfrASL values range from 0.585 to 0.952, we just speculate the prolonged MTT.
文摘Genes can be transferred using viral or non-viral vectors.Non-viral methods that use plasmid DNA and short interference RNA(si RNA)have advantages,such as low immunogenicity and low likelihood of genomic integration in the host,when compared to viral methods.Non-viral methods have potential merit,but their gene transfer efficiency is not satisfactory.Therefore,new methods should be developed.Low-frequency ultrasound irradiation causes mechanical perturbation of the cell membrane,allowing the uptake of large molecules in the vicinity of the cavitation bubbles.The collapse of these bubbles generates small transient holes in the cell membrane and induces transient membrane permeabi-lization.This formation of small pores in the cell membrane using ultrasound allows the transfer of DNA/RNA into the cell.This phenomenon is known as sonoporation and is a gene delivery method that shows great promise as a potential new approach in gene therapy.Microbubbles lower the threshold of cavity formation.Complexes of therapeutic genes and microbubbles improve the transfer efficiency of genes.Diagnostic ultrasound is potentially a suitable sonoporator because it allows the real-time monitoring of irradiated fields.
