足月新生儿动脉缺血性脑梗死早期磁共振成像特点

目的：探讨足月新生儿动脉缺血性脑梗死（NAIS）的早期MRI特点及不同MRI序列在NAIS的诊断价值。方法：回顾性分析2008年8月-2012年8月本院新生儿科收治的15例行MRI检查确诊的足月NAIS患儿的临床及MRI资料。15例患儿于出生后2～7d进行了头部MRI扫描，包括常规MRI及DWI检查，7例患儿同时行TOF—MRA检查。结果：15例NAIS患儿常规MRI中，14例T1WI呈异常信号，4例表现为受累区域弥漫低信号，10例稍低信号；15例T2WI呈异常信号，11例受累区域弥漫高信号，4例稍高信号，且灰白质分界不清。15例患儿首次DWI检查中均出现异常高信号，病灶边缘的较常规MRI清晰，DWI还显示了常规MRI未显示的胼胝体膝部、压部、丘脑及内囊后肢大脑脚等部位受累。7例患儿MRA检查中，6例出现梗死区域大脑中动脉（MCA）皮质分支增多增粗现象。结论：常规MRI可协助了解NAIS病程，DWI检查可早期诊断NAIS，并能清楚显示大脑深部小病灶的受累情况，尤其是皮质脊髓束的受累。NAIS早期MRA大多显示病变区MCA分支增多，与成人脑梗死的血管狭窄或完全闭塞不同。

Early MRI features of neonatal arterial ischemic strok in full term newborns

Objective：To study the early features of conventional MRI,DWI and MRA of neonatal arterial ischemic stroke （NAIS） in full term newborns as well as their clinical significance. Methods：The clinical records and imaging studies of 15 patients with NAIS admitted to our ward between August 2008 and August 2012 were reviewed. All cases underwent MRI examination during 2 to 7 days after birth including conventional MRI and DWI examination; 7 patients underwent MRA examination to evaluate the cerebral vessels. Results： In the first series of conventional MRI images, there were hy-pointensity on T1 WI in the affected areas （4 cases） and slight hypointensity （10 cases） ;there were hyperintensity on T2 WI in the affected areas （11 cases）,slight hyperintensity （4 cases） and with poor differentiation of grey and white matter. First series of DWI images showed distinct hyperintensity in 15 cases in affected areas, the edge of the lesions were clearer than routine MRI. In addition,DWI found more lesions than routine MRI including the genu and splenium of corpus callosum, thalamus,posterior limb of internal capsule and cerebral peduncle. 7 patients had MRA examination at the same time. 6 pa- tients showed increasing and dilatation of cortical branches in the affected areas. Conclusion：Conventional MRI can help to e-valuate the course of the disease and DWI can diagnose NAIS early and find small lesions in the deep brain, especially the corticospinal tract. The early MRA mostly show the increasing of cortical branches in the affected areas, which is different from arteriostenosis or occlusion in adults.