一、MRI弥散加权影像的原理所谓弥散加权影像 ,是将组织中的水分子弥散运动的速度以信号强度反映出的影像。在通常的自旋共鸣法的脉冲序列 ,如果将倾斜磁场脉冲两次叠加 ,信号强度 S1由于此间产生的水分子弥散 ,比叠加前的 S0 减弱 ,即成为 S1=S0 exp( -b D)。其中 b是由倾斜磁 First, the principle of MRI diffusion-weighted imaging The so-called diffusion-weighted imaging, is the organization of water molecules dispersed motion speed signal reflected by the image. In the pulse sequence of the conventional spin resonance method, when the gradient magnetic field pulse is superposed twice, the signal strength S1 is weakened by the water molecules generated thereupon, which becomes S1 = S0 exp (-b D). Where b is the gradient magnet