Objective:To evaluate the value of apparent diffusion coefficients(ADC)in Magnetic Resonance diffusion weighted imaging(MR DWI)with echo-planar technique in depicting the tumor cellularity and grading of astrocytomas....Objective:To evaluate the value of apparent diffusion coefficients(ADC)in Magnetic Resonance diffusion weighted imaging(MR DWI)with echo-planar technique in depicting the tumor cellularity and grading of astrocytomas.Methods:Thirty-four patients with astrocytomas(18 male,16 female,ages from 10-73 with average of 38.41)were examined by MRI and proved by surgery and pathology,and the number of gradeⅠ-Ⅱ(low-grade)and gradeⅢ-Ⅳ(high-grade)is 26 and 8 respectively.ADC values of astrocytomas were determined on MR DWI.Cellularity of astrocytomas was analyzed with Adobe Photoshop 7.0 software.Results:Mean ADC values of high-grade astrocytomas(7.34±2.95)×10^(-4)mm^(2)/s were significantly different from that of lowgrade astrocytomas(13.76±3.31)×10^(-4)mm^(2)/s(t=4.913,P<0.001).Cellularity of high-grade astrocytomas(19.81±9.73)%were significantly higher than that of low-grade astrocytomas(4.74±2.96)%(t=4.32,P=0.003).ADC values of astrocytomas significantly negatively correlated with their cellularities(r=-0.535,P=0.001).Conclusion:The cellularities of astrocytomas contribute very much to ADC values in MR DWI.MR DWI is very valuable in predicting and evaluating the cellularity of astrocytomas.MR DWI might have a potential in predicting the degree of astrocytomas.展开更多
Sensitivity analysis （SA） is a critical part of modeling any biological system due to the inherent uncertainty in model output, as introduced by parameter values that have not been experimentally determined. SA ther...Sensitivity analysis （SA） is a critical part of modeling any biological system due to the inherent uncertainty in model output, as introduced by parameter values that have not been experimentally determined. SA therefore provides deeper understanding of the system by painting a picture of the extent to which certain model outputs vary in rela- tionship to changes in model parameters. Here we explore two types of global SA for recently developed models of nascent focal adhesion formation, a key step in cellular movement. While many SA methods have been used for deterministic methods, we uti- lize methods for both stochastic and deterministic models, providing a more complete description of the parameters to which the focal adhesion model is most sensitive. Spe- cific recommendations for further experimentation in the process of cellular motility are proposed in response to the SA.展开更多
文摘Objective:To evaluate the value of apparent diffusion coefficients(ADC)in Magnetic Resonance diffusion weighted imaging(MR DWI)with echo-planar technique in depicting the tumor cellularity and grading of astrocytomas.Methods:Thirty-four patients with astrocytomas(18 male,16 female,ages from 10-73 with average of 38.41)were examined by MRI and proved by surgery and pathology,and the number of gradeⅠ-Ⅱ(low-grade)and gradeⅢ-Ⅳ(high-grade)is 26 and 8 respectively.ADC values of astrocytomas were determined on MR DWI.Cellularity of astrocytomas was analyzed with Adobe Photoshop 7.0 software.Results:Mean ADC values of high-grade astrocytomas(7.34±2.95)×10^(-4)mm^(2)/s were significantly different from that of lowgrade astrocytomas(13.76±3.31)×10^(-4)mm^(2)/s(t=4.913,P<0.001).Cellularity of high-grade astrocytomas(19.81±9.73)%were significantly higher than that of low-grade astrocytomas(4.74±2.96)%(t=4.32,P=0.003).ADC values of astrocytomas significantly negatively correlated with their cellularities(r=-0.535,P=0.001).Conclusion:The cellularities of astrocytomas contribute very much to ADC values in MR DWI.MR DWI is very valuable in predicting and evaluating the cellularity of astrocytomas.MR DWI might have a potential in predicting the degree of astrocytomas.
文摘Sensitivity analysis （SA） is a critical part of modeling any biological system due to the inherent uncertainty in model output, as introduced by parameter values that have not been experimentally determined. SA therefore provides deeper understanding of the system by painting a picture of the extent to which certain model outputs vary in rela- tionship to changes in model parameters. Here we explore two types of global SA for recently developed models of nascent focal adhesion formation, a key step in cellular movement. While many SA methods have been used for deterministic methods, we uti- lize methods for both stochastic and deterministic models, providing a more complete description of the parameters to which the focal adhesion model is most sensitive. Spe- cific recommendations for further experimentation in the process of cellular motility are proposed in response to the SA.
