正常脑组织磁共振两b值及多b值扩散加权成像技术变异度对比分析

Variation analysis of diffusion weighted imaging in normal brain tissue between two b and multi-b value sequence

目的对比评估两b值及多b值扩散加权成像(diffusion weighted imaging,DWI)技术在正常脑组织中的变异度。材料与方法对29名正常脑组织行3.0 T GE磁共振两b值(0、1000 s/mm^2)及8b值(0、50 s/mm^2、100 s/mm^2、200 s/mm^2、400 s/mm^2、600 s/mm2、800 s/mm^2、1200 s/mm^2)DWI序列扫描,获取两b值参数表观扩散系数(apparent diffusion coefficient,ADC)值及多b值参数包括慢速ADC(D)、快速ADC(D*)、灌注相关体积分数ADC(f),应用变异系数评价脑组织各参数。结果脑组织的ADC值、D值、D*值、f值及其变异系数分别为:脑白质:(81.11±7.62)×10^(-5) mm/s,0.094;(78.47±6.72)×10^(-5) mm/s,0.086;(722.7±189.3)×10^(-5) mm/s,0.262;(8.97±3.63)%,0.404;脑皮质:(87.03±9.97)×10^(-5) mm/s,0.115;(81.83±7.51)×10^(-5) mm/s,0.092;(611.9±169.5)×10^(-5) mm/s,0.292;(9.55±3.41)%,0.357;基底节:(76.70±7.17)×10^(-5) mm/s,0.093;(73.72±6.40)×10^(-5) mm/s,0.087;(1221.9±743.4)×10^(-5) mm/s,0.608;(9.72±3.68)%,0.379。正常脑组织的ADC值及D值变异度接近且较低,而D*值及f值的变异度较高。结论多b值DWI技术获得的D值与两b值DWI技术获得的ADC值在正常脑组织具有同样低的变异度,而D*及f变异度较高,进行临床评价时结果需谨慎解读。

Objective:To observe the variation of two b and multi-b diffusionweighted imaging(DWI)in normal brain tissue.Materials and Methods:Applytwo b and multi-b DWI sequence to29normal appearance brain using GE3.0Tscanner.Two b and multi-b DWI related parameter including apparent diffusioncoefficient(ADC),true diffusion(D),perfusion related diffusion(D*),fractionof perfusion(f)was acquired using AW workstation.The coefficient of variation(CV)of these parameters was compared to evaluate the reliability.Results:The values of CV of ADC,D,D*and f of brain were(81.11士7.62)x10-5mm/s,0.094;(78.47士6.72)x10-5mm/s,0.086;(722.7士189.3)x10-5mm/s,0.262;(8.97士3.63)%,0.404in white matter;and(87.03士9.97)x10-5mm/s,0.115;(81.83士7.51)x10-5mm/s,0.092;(611.9士169.5)x10-5mm/s,0.292;(9.55士3.41)%,0.357in gray matter;and(76.70士7.17)x10"5mm/s,0.093;(73.72士6.40)x10"5mm/s,0.087;(1221.^743.4)x10-5mm/s,0.608;(9.72士3.68%),0.379in basal ganglia respectively.The CVs of ADC and Dwere similar and good and lower than others.Conclusion:D which derived fromMulti-b DWI has good reliability as ADC which derived from two b DWI in normalbrain.Otherwise,D*and f have higher variation in normal brains,and with which thecomparison between individual should be explained with caution.