Harada K, Fujita N, Sakurai K, Akai Y, Fujii K, Kozuka T
Department of Radiology, Osaka University Medical School, Japan.
AJNR Am J Neuroradiol. 1991 Nov-Dec;12(6):1143-8.
We developed a new pulse sequence and investigated whether the anisotropic diffusion in the human brain can be detailed with a standard whole-body MR imager. Apparent diffusion coefficient maps were produced by the proposed sequence using a 1.5-T MR unit. The sequence employed simultaneous application of three orthogonal gradients to achieve an optimal signal attenuation for imaging the brain without any increase in echo time. The orientation of the effective diffusion-encoding gradient was off-axis. On the in vivo apparent diffusion coefficient maps of four healthy volunteers, white matter tracts (the internal capsule and the corpus callosum) and the cortical and deep white matter showed anisotropic diffusion. In the gray matter, such as basal ganglia and thalami, anisotropic diffusion was not observed. A typical whole-body imager can provide in vivo human brain diffusion images of clinical quality. This technique has promising implications for the evaluation of brain development and the diagnosis of degenerative diseases.
我们开发了一种新的脉冲序列，并研究了使用标准全身磁共振成像仪能否详细观察人类大脑中的各向异性扩散。使用1.5-T磁共振单元，通过所提出的序列生成表观扩散系数图。该序列同时应用三个正交梯度，以在不增加回波时间的情况下实现对大脑成像的最佳信号衰减。有效扩散编码梯度的方向是离轴的。在四名健康志愿者的活体表观扩散系数图上，白质束（内囊和胼胝体）以及皮质和深部白质显示出各向异性扩散。在灰质中，如基底神经节和丘脑，未观察到各向异性扩散。典型的全身成像仪可以提供具有临床质量的活体人类大脑扩散图像。这项技术对大脑发育评估和退行性疾病诊断具有潜在的重要意义。
