Department of Radiology, Qi Lu Hospital of Shandong University, Jinan, China.
J Magn Reson Imaging. 2013 Sep;38(3):650-4. doi: 10.1002/jmri.24004. Epub 2013 May 6.
To use MR with diffusion tensor imaging (DTI) and conventional and high b value to assess diffusion changes in normal-appearing white matter (NAWM) in patients with unilateral, severe stenosis, or occlusion of the middle cerebral artery (MCA).
In total, 28 patients with NAWM and unilateral, severe stenosis, or occlusion of the MCA underwent DTI with b values 1000 and 2200 s/mm(2) at 3.0T MR. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), radial diffusivity (eigenvalues λ1 , λ2 ), and axial diffusivity (eigenvalue λ3 ) were measured for the ipsilateral and contralateral corona radiata.
Mean FA was significantly lower for the ipsilateral than contralateral corona radiata with high b value, 2200 s/mm(2) , and ipsilateral corona radiata with conventional low b value, 1000 s/mm(2) (all P < 0.01). Mean ADC, λ1 , λ2 , and λ3 were significantly higher for the ipsilateral than contralateral corona radiata with high b value (all P < 0.05) but not for ipsilateral than contralateral corona radiata with low b value (P > 0.05).
DTI with a high b value detects diffusion changes in NAWM in patients with unilateral, severe stenosis, or occlusion of the MCA not seen with conventional b value or conventional MRI contrasts.
使用磁共振扩散张量成像（DTI）和常规及高 b 值评估单侧大脑中动脉（MCA）严重狭窄或闭塞患者正常表现白质（NAWM）中的扩散变化。
共 28 例单侧 MCA 严重狭窄或闭塞患者行 3.0T MR 检查，采用 b 值为 1000 和 2200 s/mm² 的 DTI。测量对侧和同侧放射冠的各向异性分数（FA）、表观扩散系数（ADC）、径向扩散系数（本征值 λ1、λ2）和轴向扩散系数（本征值 λ3）。
高 b 值 2200 s/mm² 时，患侧放射冠的 FA 明显低于对侧，常规低 b 值 1000 s/mm² 时，患侧放射冠的 FA 也明显低于对侧（均 P < 0.01）。高 b 值时，患侧放射冠的 ADC、λ1、λ2 和 λ3 均明显高于对侧（均 P < 0.05），但低 b 值时无此差异（P > 0.05）。
高 b 值 DTI 可检测单侧 MCA 严重狭窄或闭塞患者 NAWM 的扩散变化，而常规 b 值或常规 MRI 对比无法检测到这些变化。
