颅内静脉和静脉窦血栓形成的磁共振影像诊断

MR Imaging of Cerebral Vein and Venous Sinus Thrombosis

研究脑脉窦闭塞的ＭＲ表现及其病理生理学基础，区分静脉闭塞与脑动脉闭塞ＭＲ表现的不同 点。介绍脑静脉窦闭塞的病因、发病机制及ＭＲ影像表现，并详细分析脑静脉窦闭塞后的病理生理学变化。脑 静脉闭塞与动脉闭塞有着显著不同的病理生理改变，脑动脉闭塞病理生理改变在于其闭塞供血区域缺血，造 成血脑屏障破坏，ＭＲ表现为脑肿胀，血管源性水肿和异常动脉系统及脑实质增强。相比，脑静脉闭塞后，静脉 系统内血容量聚积，脑脊液回流受阻，导致脑内总容量增加，引起颅内压升高产生脑水肿，最终血脑屏障破坏， 脑血肿形成。由此可见，脑静脉窦闭塞发病机理的影响因素较脑动脉性闭塞发病机理多而复杂，其中心环节与 颅内压动态平衡的维持有密切关系。脑静脉闭塞ＭＲ表现不同于动脉性闭塞，包括没有异常动脉和脑实质强 化。脑静脉窦闭塞通常表现为持续性脑肿胀，其Ｔ１加权像占位效应较Ｔ２加权像信号异常明显，通常无血脑屏 障破坏表现。因此与常规所认识的 ＭＲ Ｔ２加权像易于发现早期病变相反，仔细观察 ＭＲ Ｔ１加权像对脑静脉窦 闭塞早期诊断具有重要意义。

To study the MH finding of cerebral venous sinus occlusive diseases. The aim was to analyze its pathophysiological changes and mechanism of development and differentiation of venous sinus occlusive diseases from arterial ischemic diseases. The etiology, mechanism, pathophysiological changes and MR imaging features of cerebral occlusive diseases were introduced. Venous and sinus thrombosis is common in association with inflammatory processes; it may occur as an isolated condition secondary to blood diseases, or secondary to invasion of the sinuses by neoplasms. Sinus-vein thrombosis is a multistep process that probably begin when thrombus incompletely occluded a dural sinus, usually the superior sagittal sinus. The thrombus progresses, obstructing first the stuus then extending to involve bridgeing veins abterior to the obstruction. Once the tributary cortical vein are oecluded, petechial perivascular hemorrhages and cortical venous infarctions occur. imaging findings included cerebral swollen, abnormal signal, cerebral ventricle enlargement, hemorrhage, brain edema and abnomal venous enhancement. MR findings of venous sinus ccclusive disease have manifestations distinctively different from those arterial occlusiove diseases. It has its own pathophysiologic characters. Intensively of,serving TI. images of venous occlusive disease has its significance