Barkovich A J
Department of Radiology, University of California, San Francisco, 94143, USA.
AJNR Am J Neuroradiol. 1998 Sep;19(8):1397-403.
MR imaging is a powerful tool for studying the anatomy of and the developmental changes that occur in the brain. The purpose of this project was to determine which structures can be distinguished on standard spin-echo MR sequences of a normal neonatal brain and with what frequency they can be identified.
The T1- and T2-weighted spin-echo MR images of 12 term neonates, all of whom had normal neonatal courses and were neurologically and developmentally normal at age 12 months, were reviewed retrospectively. All structures that differed in signal intensity from unmyelinated gray matter and unmyelinated white matter were recorded.
In general, myelinated gray matter structures, such as cranial nerve nuclei and other nuclei of the brain stem and deep cerebrum, were the structures best seen on T2-weighted images. Most of these nuclei were seen in 75% to 100% of our subjects on T2-weighted images. They were seen less well on T1-weighted images. Myelinated white matter structures, particularly axonal tracts, were the structures best seen on T1-weighted images. The medial and lateral lemnisci, median longitudinal fasciculus, optic tracts, superior and inferior cerebellar peduncles, and the posterior limbs of the internal capsules were seen in 75% to 100% of our subjects on T1-weighted images. Except for the posterior limbs of the internal capsules, these structures were seen less well on T2-weighted images.
A large number of small structures, such as the nuclei of the brain stem and deep cerebral nuclei, can be routinely identified on standard spin-echo MR imaging sequences. A knowledge of these structures is essential to proper interpretation of imaging studies in neonates and infants.
磁共振成像（MR）是研究脑解剖结构及脑内发生的发育变化的有力工具。本项目的目的是确定在正常新生儿脑的标准自旋回波MR序列上哪些结构能够被区分，以及它们的识别频率。
回顾性分析12例足月儿的T1加权和T2加权自旋回波MR图像，所有患儿均有正常的新生儿期病程，且在12个月龄时神经及发育正常。记录所有与未髓鞘化灰质和未髓鞘化白质信号强度不同的结构。
一般来说，髓鞘化灰质结构，如脑神经核、脑干和大脑深部的其他核团，是在T2加权图像上显示最佳的结构。在我们的大多数研究对象（75%至100%）中，这些核团在T2加权图像上可见。它们在T1加权图像上显示欠佳。髓鞘化白质结构，特别是轴突束，是在T1加权图像上显示最佳的结构。内侧丘系、外侧丘系、内侧纵束、视束、小脑上脚和小脑下脚以及内囊后肢在我们75%至100%的研究对象的T1加权图像上可见。除内囊后肢外，这些结构在T2加权图像上显示欠佳。
大量小结构，如脑干核团和大脑深部核团，可在标准自旋回波MR成像序列上常规识别。了解这些结构对于正确解读新生儿和婴儿的影像学研究至关重要。
