不同b值对脑扩散加权图像质量的影响  

Influence of Different b Value in Normal Human Brain Diffusion Weighted Imaging

作　　者：邓小霞[1] 司建荣[1] 

机构地区：[1]惠州市中心人民医院MRI室,广东516001

出　　处：《放射学实践》2006年第5期523-525,共3页Radiologic Practice

摘　　要：目的:分析不同b值对扩散加权成像(DWI)质量的影响。方法:15例健康志愿者,分别采用b值为500、1000、1500、2000、2500及3000 s/mm2,进行MR DWI检查,选取内囊后肢、大脑皮层、胼胝体膝部及背景等部位进行信号强度和表观扩散系数(ADC)值的测定,并进行统计学分析。同时对所有患者进行常规T1WI和T2WI检查。结果:不同b值条件下,内囊后肢、大脑皮层、胼胝体膝部的信号强度差异有显著性意义(P<0.05),背景噪声间差异无显著性意义(P>0.05);随着b值升高,组织的信号强度降低。不同b值条件下,内囊后肢、大脑皮层、胼胝体膝部的ADC值差异有显著性意义(P<0.05);随着b值升高,组织ADC值降低。结论:在1.5 T场强条件下,b值为1000和1500 s/mm2时扩散加权图像上组织对比较好,清晰度较高。Objective： To evaluate the quality of diffusion weighted imaging of normal human brain at different b values. Methods： Difusion weighted imaging were performed on 15 healthy adaults at b= 500,1000,1500,2000,2500,3000s/mm^2. The signal and the ADC with various b values from 3 regions of interest in human brain were measured,as well as the noise of the background. All subjects were scanned with T1WI and T2WI at the same time. Results： The mean of the signal and the ADC from the 3 regions were affected by the strength of b value （P〈0. 05） ,the noise of the background were not affected by the strength of b value （P〉0.05）. The signal of the tissue increases with the b value increasing and the ADC decreases with the b value increasing. Conclusions： Under 1.5T MRI imager, diffusion weighted imaging at b= 1000s/mm^2 or 1500s/mm^2 has good contrast image,also with good resolution.

关 键 词：磁共振成像 扩散加权成像 脑 

分 类 号：R445.2[医药卫生—影像医学与核医学] R816.1[医药卫生—诊断学]