【作者】 何光武；

【导师】 沈天真；

【作者基本信息】 复旦大学 ， 影像医学与核医学， 2004， 博士

【摘要】 第一部分 大脑白质纤维磁共振弥散张量成像扫描参数研究目的:探讨不同的磁共振弥散张量成像扫描参数对大脑白质纤维弥散张量图像的影响,以期获得最佳的扫描参数。材料和方法:选取21名正常志愿者,随机分为3组:b值组、弥散敏感梯度方向组和层厚/层间距组。分别应用不同的扫描参数进行弥散张量磁共振扫描。将所成FA图像和DEC图分为三个不同的等级,进行综合评价。结果:不同的扫描参数所成大脑白质纤维弥散张量图像的质量是不相同的。在b值组,以低b值所成图像较佳,其中以b值=1000s/mm2为最佳,而高b值所成图像噪声较大。施加的弥散敏感梯度方向数并非越多越好,13个方向与21个方向所成图像没有明显差别,6个方向所成图像质量较差。层厚/层间距对图像的影响最大,层厚越厚,图像的信躁比越大。结论:在临床工作中,比较实用的大脑白质纤维大弥散张量成像扫描参数为:b值=1000s/mm2,弥散敏感梯度方向数为13,层厚/层间距为5mm/0mm。更多还原

【Abstract】 Part ⅠStudy of the scanning parameter for MR diffusion tensor of cerebral white matter fiberPurpose:To search for the best scanning parameter for MR diffusion tensor in the study of the cerebral white matter fiber.Material and methods:Diffusion tensor imaging of the cerebral white matter fiber was performed in 21 healthy adult volunteers,who are randomly divided into three groups.Different parameters including b value, the number of the diffusion sensitive gradient direction ,and slice thickness were applied and their impaction on the FA maps and DEC maps were evaluated.Results:Different parameters hnd different impaction on the quality of the FA and DEC map.The quality of the images was better when b value=1000 s/mm2 was used,and noise became greater b balue=3000 s/mm2 .The more the number of the direction ,the greater the signal noise ration was not.Slice thickness had the greatest impaction on the SNR of the images.Conclusion:Scanning with b value=1000 s/mm2 13 directions , and thickness of 5 mm is the practical protocol in the study of cerebral white matter fiber.更多还原