胼胝体磁共振弥散张量成像技术参数研究

目的：探讨胼胝体磁共振弥散张量成像（DTI）临床应用的扫描参数.方法：对30名健康成年人行头部矢状位DTI,比较不同b值、层厚/层间距、扩散敏感梯度方向3个扫描参数对各向异性分数（FA）图像质量的影响.结果：不同的扫描参数对FA图像质量的影响各不相同.中间位b值（b=1与000 s/mm2）时FA 图像质量最佳,高b值（b=1 500 s/mm2） FA图像噪声大,低b值（b=500 s/mm2）FA图像对比度差.层厚/层间距越大,FA图像信噪比越高,但会遗漏细微结构的显示.13个与25个扩散敏感梯度方向FA图像质量差异无统计学意义（P〉0.05）,6个扩散敏感梯度方向FA图像质量较差.结论：临床实际应用中,胼胝体矢状位DTI的适用扫描参数为b=1,000 s/mm2、5 mm/0 mm层厚/层间距、13个扩散敏感梯度方向.

The parameters of magnetic resonance diffusion tensor imaging in corpus callosum

Objective：To explore the technical parameters of magnetic resonance diffusion tensor imaging（DTI） in corpus callosum. Methods：The DTI of the sagittal plane were detected in 30 nomarl brains. The effects of b value, slice thickness/interlamellar spacing and diffusion sensitive gradient direction on fractional anisotropy（FA） image quality were compared. Results：Different parameters had different effects on FA image quality. The quality of FA image was best when b value was middle（ b = 1 000 s/mm2） ,FA image noise was large at the high b value（b = 1 500 s/mm^2 ） ,and the contrast of FA image was poor at the low b value（b =500 s/mm2 ）. The signal to noise ratio was high with slice thickness/interlamellar spacing increasing, the subtle structure was easy to miss. The differences of FA image qualities at 13 and 25 diffusion sensitive gradient directions statistical significance （ P 〉 0.05 ）. The FA image quality at 6 diffusion sensitive gradient direction was worse hadno. Conclusions：The 1 000 s/mm2 of b value,5 mm/0 mm of slice thickness and 15 diffusion sensitive gradient directions are suitable for DTI of corpus callosum in the sagittal head in clinic.