Toft P B, Leth H, Peitersen B, Lou H C, Thomsen C
Danish Research Center of Magnetic Resonance, Hvidovre University Hospital, Denmark.
J Comput Assist Tomogr. 1996 Nov-Dec;20(6):1006-11. doi: 10.1097/00004728-199611000-00029.
The purpose was to obtain normal values of the apparent diffusion coefficient (ADC) in the infant brain and to compare ADC maps with T1- and T2-weighted images.
Diffusion was measured in nine infants with an ECG-gated SE sequence compensated for first-order motion. One axial slice at the basal ganglia level was investigated with the diffusion-encoding gradients in the slice-selection direction.
On ADC maps, the corpus callosum and the optic radiations appeared dark before the onset of myelination, and the crus posterior of the internal capsule could be visualized before it appeared on T1- or T2-weighted images. In gray and white matter, the mean ADC ranged from 0.95 x 10(-9) to 1.76 x 10(-9) m2/s. In the frontal and occipital white matter, in the genu corporis callosi, and in the lentiform nucleus, the ADC decreased with increasing age. The cortex/white matter ratio of the ADC increased with age and approached 1 at the age of 30 weeks.
ADC maps add information to the T1 and T2 images about the size and course of unmyelinated as well as myelinated tracts in the immature brain.
获取婴儿脑内表观扩散系数（ADC）的正常值，并将ADC图与T1加权和T2加权图像进行比较。
采用心电图门控SE序列对9名婴儿进行扩散测量，该序列对一阶运动进行了补偿。在基底节水平的一个轴位切片上，沿层面选择方向施加扩散编码梯度进行研究。
在ADC图上，胼胝体和视辐射在髓鞘形成开始前呈暗色，内囊后肢在T1加权或T2加权图像上显示之前即可在ADC图上显示。在灰质和白质中，平均ADC范围为0.95×10⁻⁹至1.76×10⁻⁹m²/s。在额叶和枕叶白质、胼胝体膝部和豆状核中，ADC随年龄增长而降低。ADC的皮质/白质比值随年龄增长而增加，在30周龄时接近1。
ADC图为T1和T2图像增添了关于未成熟脑内无髓鞘和有髓鞘纤维束大小及走行的信息。
