头部扩散张量磁共振成像扫描方案的优选

目的 探索扩散张量磁共振成像应用于临床的合理扫描方案。方法 对20名成年健康志愿者行头部扩散张量成像，比较不同扫描参数(层厚／层间距、b值及扩散敏感梯度方向数)对图像质量的影响。结果 在三种不同的扫描参数中，以层厚／层间距对图像信噪比的影响最大，层厚／层间距越大，图像信噪比越高。高b值扫描虽然ADC图灰白质对比明显，但FA图噪声较大。方向数越多，图像信噪比越高，但扫描时间相应延长。结论 层厚／层间距3mm/1mm、b值=1000s／mm^2、扩散敏感梯度方向25个，此方案适用于研究脑白质的细微结构，是应用于临床的合理扫描方案。

Optimization of the Scanning Protocol for Diffusion Tensor Imaging of Head

Objective To search for the reasonable scanning protocol for diffusion tensor imaging in the clinical study of the head.Methods Diffusion tensor imaging of the head was performed in 20 healthy adult volunteers.Different parameters including slice thickness,b value and the number of the diffusion sensitive gradient direction were applied and their impaction on the quality of the images were compared.Results Slice thickness had the greatest impaction on the signal noise ratio of the images.Scans with higher b value revealed better contrast between gray matter and white matter in ADC map,but noise in FA map became greater.The more the number of the direction was,the greater the SNR was,but the longer the scanning time was.Conclusion Scanning with thickness of 3mm,b value 1000 s/mm 2 and 25 directions is the reasonable protocol in the clinical study of white matter.