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.
出处
《放射学实践》
2006年第5期523-525,共3页
Radiologic Practice
关键词
磁共振成像
扩散加权成像
脑
Magnetic resonance imaging
Diffusion weighted imaging
Brain