磁共振弥散加权及张量技术在新生儿缺血缺氧性脑病中的应用

缺血缺氧性脑病（HIE）是新生儿危害最大的常见病之一，其病理生理机制及损伤特点复杂。根据脑成熟度、损伤严重程度及持续时间不同，MRI的影像表现各异。本文总结了磁共振弥散加权成像（DWI）及弥散张量成像（DTI）的原理和检查优势。回顾性分析了新生儿HIE的DWI和DTI的各参数变化及其规律。提示DWI能早期检出脑组织缺血缺氧改变的范围，并能一定程度反映细胞分子水平的改变；DTI能连续性反映脑组织轴索、髓鞘细微结构的改变，显示解剖构造与脑功能区域的关联。上述MRI技术的临床应用将为新生儿缺血缺氧性脑病的早期诊断、预后评估、疗效评价提供新的有益支持和保证，具有明显的临床应用优势。

Neonatal hypoxic-ischemic encephalopathy: detection with diffusion-weighted and diffusion-tensor MR imaging

Hypoxic-ischemic encephalopathy （HIE） is the primary cause of neurological disorders during perinatal period. The pathophysiologic mechanism and patterns of injury in HIE are intricacy. There are different patterns in magnetic resonance imaging （MRI） as the results of the differences in brain maturity, severity and duration of insult. In this article, we review the principle of diffusion-weighted imaging （DWI） and diffusion-tensor imaging （DTI）, and their advantage for detection of HIE. The changes of DWI and DTI parameters in neonatal HIE were retrospectively analyzed and summarized according to the previous literatures. It indicates that DWI and DTI are earlier and more sensitive than the conventional MRI in detecting the lesion of neonatal HIE. Moreover, the DWI parameter is associated with the variation in cellular and molecular level. The injury in neural microstructures, such as the axon and myelin, can be illustrated by DTI fiber tracking and performed quantitative analysis by different DTI parameters. Therefore, it is no doubt that these new approaches in MRI techniques can help diagnosis, affect prognosis, and facilitate earlier treatment to the neonatal HIE in clinic.