扩散梯度方向数目对DTI参数SNR和FA的影响  

The Effect of the Number of Diffusion Gradient Directions on the DTI Parameters of SNR and FA

作　　者：付志辉[1] 贡志刚[2] 周建华[1] 朱建亚[1] 朱吉云 

机构地区：[1]江苏省苏州市中医医院放射科,215000 [2]江苏省苏州市中医医院神经外科,215000

出　　处：《临床放射学杂志》2014年第3期437-440,共4页Journal of Clinical Radiology

基　　金：苏州市科技发展计划项目(编号:SYSD2011154);江苏省中医药科技项目(编号:LB11022)

摘　　要：目的探索扩散张量成像(DTI)中扩散梯度方向数目对图像信噪比(SNR)和各向异性分数(FA)的影响。方法应用7种不同扩散梯度对17名志愿者进行了DTI扫描,计算多个感兴趣区(ROI)的SNR和FA值,分析这两个参数随扩散梯度不同的变化趋势。结果 17名志愿者皮质脊髓束均能清晰显示,且图像的视觉效果变化也很小。施加6、9、12、15、18、21、30不同数目的扩散梯度方向,图像SNR分别为60.45±1.01、60.08±0.91、62.60±1.22、62.96±0.97、62.82±1.21、63.84±1.09、63.33±0.98。各个ROI的FA值并不随扩散梯度的变化而发生明显改变,比较均无统计学意义(P>0.05)。结论在DTI的临床应用中,选择6个方向的扩散梯度也能达到目的。Objective To discuss the effect of diffusion gradient directions （DGD） on the DTI parameters SNR and FA. Methods 17 healthy volunteers underwent DTI with 7 DGD respectively, the SNR and FA values in ROIs were calculated and the relationship between SNR,FA and the variances of diffusion gradient directions were analyzed. Results The corticospinal tracts were well visualized by DT fiber tractography in 17 healthy volunteers and the visual performance was changed slight with different DGD. SNR for each DGD setting showed 60.45 ＋ 1.01 at 6 DGD, 60.08±0.91 at 9 DGD, 62.60±1.22 atl2 DGD, 62.96±0.97 at 15 DGD, 62.82±1.21 at 18 DGD, 63.84±1.09 at 21 DGD, and 63. 33±0.98 at 30 DGD. The FA values within all ROls did not change remarkably with DGD increasing, Statistically significant differences were not found within all ROIs （ P 〉 0.05 ）. Conclusion In clinical applications of DTI, 6 directional DGD is sufficient for clinic purpose.

关 键 词：扩散张量成像 图像信噪比 各向异性分数 扩散梯度 

分 类 号：R445.2[医药卫生—影像医学与核医学]