快速STEAM序列脑扩散磁共振成像

Turbo STEAM Diffusion MR Imaging of the Human Brain in Vivo

目的:探讨快速STEAM 序列对脑扩散磁共振成像的可行性。材料和方法:分别用SE 序列和快速STEAM 序列对直径20cm 的圆球体水模进行扩散成像;同时对10 例正常自愿者应用快速STEAM 序列进行脑扩散磁共振成像。结果:对水模测定显示不同梯度指数b 值所测的数据完全拟合于扩散方程,相关系数r= 1 。SE 和快速STEAM 测得水的扩散系数分别为:2-00 ×10- 3cm2/s 和2-20 ×10 - 3cm2/s。对正常人脑测量显示各测量数据也有较好的直线拟合性,相关系数r> 0-9 。灰质和白质中水分子的扩散系数为(1-65 ±0-44) ×10 - 3 m m 2/s 和(1-10 ±0-34) ×- 3cm2/s,两者差异显著。结论:快速STEAM 法可以在不需特殊梯度埸强的设备下得到脑扩散图像,对水模测定显示该方法有较好的可行性,人脑测定显示灰白质间水的扩散系数差异显著。

Purpose:To investigate the clinical feasibility of Turbo STEAM diffusion MR imaging of the human brain in vivo.Materials and Methods:A water-content phantom was measured using both SE and turbo STEAM diffusion sequence for diffusion MR imaging.Meanwhile,10 normal volunteers were examined to get STEAM diffusion MR imaging of brain.Results:In phantom study,the measured data showed good fit to diffusion equation with correlation coefficient 1.The diffusion coefficient of free water was 2.00×10 -3 cm 2/s for SE and 2.20×10 -3 cm 2/s for turbo STEAM method.In human brain, the data were also good fit to diffusion equation with correlation coefficient large than 0.9. The apparent diffusion coefficient (ADC) of water molecule were (1.65±0.44)×10 -3 cm 2/s in gray matter and (1.1±0.34)×10 -3 mm 2/s in white matter,there was significant difference between gray and white matter.Conclusion:Turbo STEAM can be used to get diffusion MR imaging with short time and common gradient field.Phantom studies demonstrated the feasibility of quantitative determinations.Human studies showed the water molecule diffusion condition is difference between gray and white matter in human brain.