1、概述血管周围间隙，也称为Virchow-Robin Spaces（VRS）VRS将血管与周围的脑组织分离开来，是脑实质内间质液体等引流的通道，具有一定的生理和免疫功能VRS增多和扩大见于老年脑、高血压、糖尿病、痴呆、脑白质病变、脑积水、多发性硬化、中枢神经隐球菌感染、儿童脑发育性疾MRI能清楚VRS，同时易误诊为其它病变10/21/20221脑血管VR间隙的MRI诊疗和鉴别诊疗解剖大脑半球的VRS与蛛网膜下腔并不直接相通VRS与软脑膜下腔接续的,是软脑膜随着穿通动脉和流出静脉进出脑实质的延续外界是神经胶质界膜，内界是血管外层，最后，胶质界膜与血管外层融合成盲端在大脑半球，VRS是由单层软膜构成
2、，在纹状体动脉周围是由双层软膜构成VRS常常很小，直径约1-2mm10/21/20222脑血管VR间隙的MRI诊疗和鉴别诊疗10/21/20223脑血管VR间隙的MRI诊疗和鉴别诊疗生理生理VRS内充满组织间液,而不是脑脊液生理意义是作为脑组织间液排出的一个主要通路同时也提供了外来抗原进入脑、细胞间液和脑脊液的机会10/21/20224脑血管VR间隙的MRI诊疗和鉴别诊疗VRS扩大一般认为，2mm被认为是VRS扩大扩大的VRS的特征是边界光滑清楚，呈圆形或管状（由于部位和切面不同），与穿通动脉的行径相一致扩大的VRS与年龄、高血压、痴呆、伴随的白质病变等有关10/21/20225脑血管VR间隙
3、的MRI诊疗和鉴别诊疗VRS扩大的机制动脉壁通透性增高脑脊液引流障碍引起的液体积聚血管迂曲和脑萎缩导致的细胞外水分的积聚：老年脑（VRS与年龄明显相关）组织间液经脑实质内小孔从细胞外向微血管周围软脑膜下间隙逐渐渗漏VRS纤维化和闭塞以及由此引起的液体流动阻力增加10/21/20226脑血管VR间隙的MRI诊疗和鉴别诊疗VRS的MRI表现信号特点各序列上均与脑脊液信号一致增强扫描无强化小的VR间隙(25 mm)周围脑实质通常无异常信号改变形态特点圆形或椭圆形或者管状，无占位效应边界清楚、光滑，通常为双侧大小一般小于5mm10/21/20227脑血管VR间隙的MRI诊疗和鉴别诊疗u位置及分型I型（
4、基底节型）：沿着豆纹动脉分布于基底节区周围（壳核外下部和外囊下部，常位于通常位于基底节区的下1/3）II型（大脑半球型）：沿着髓质穿支动脉分布，分布于皮层下白质（半卵圆中心、胼胝体和侧脑室附近）III型（中脑型）：随着来自大脑后动脉的穿通动脉进入中脑，分布于中脑、桥脑中脑连接处10/21/20228脑血管VR间隙的MRI诊疗和鉴别诊疗Bilateral type I VR spaces in a 6-year-old boy10/21/20229脑血管VR间隙的MRI诊疗和鉴别诊疗Bilateral type I VR spaces in a 53-year-old woman.10/21/2
5、02210脑血管VR间隙的MRI诊疗和鉴别诊疗10/21/202211脑血管VR间隙的MRI诊疗和鉴别诊疗Type II VR spaces in a 73-year-old womanType II dilated VR spaces in a 6-year-old boy.10/21/202212脑血管VR间隙的MRI诊疗和鉴别诊疗Type III VR space in a 25-year-old man.10/21/202213脑血管VR间隙的MRI诊疗和鉴别诊疗Type III型10/21/202214脑血管VR间隙的MRI诊疗和鉴别诊疗不典型表现VRS偶可明显增大，表现出占位效应，
6、类似囊样占位，FLARI序列上周围脑实质内见高信号影巨大的VRS常见于中脑-丘脑区域，可以压迫第三脑室引起脑积水10/21/202215脑血管VR间隙的MRI诊疗和鉴别诊疗 Giant VR spaces in the mesencephalothalamic region in a 19-year-old man10/21/202216脑血管VR间隙的MRI诊疗和鉴别诊疗 large VR spaceFollow up in 3 years10/21/202217脑血管VR间隙的MRI诊疗和鉴别诊疗10/21/202218脑血管VR间隙的MRI诊疗和鉴别诊疗 Differential Dia
7、gnosis1.lacunar infarctions-腔隙性脑梗塞2.cystic periventricular leukomalacia-脑室周围白质软化3.multiple sclerosis-多发性硬化4.cryptococcosis-脑隐球菌病5.cystic neoplasms6.neurocysticercosis-脑囊虫病7.arachnoid cysts-蛛网膜囊肿8.neuroepithelial cysts-神经上皮囊肿10/21/202219脑血管VR间隙的MRI诊疗和鉴别诊疗1.腔隙性脑梗死急性期T1低信号，T2高信号，FLAIR高信号慢性期病灶FLAIR上表现为中
8、心低信号，周围高信号环绕，提示胶质增生可有强化（亚急性期）10/21/202220脑血管VR间隙的MRI诊疗和鉴别诊疗腔隙性脑梗死10/21/202221脑血管VR间隙的MRI诊疗和鉴别诊疗Acute and chronic lacunar infarctions in a 66-year-old man10/21/202222脑血管VR间隙的MRI诊疗和鉴别诊疗2.囊性脑室周围白质软化u常见于未发育成熟的婴幼儿，常有脑缺血史u双侧脑室三角区附近最常见，FLAIR上周围可见高信号改变u常对称分布u周围脑室可代偿性增宽u可伴有胼胝体发育不良10/21/202223脑血管VR间隙的MRI诊疗和鉴别
9、诊疗 Cystic periventricular leukomalacia in a 3-year-old boy with a history of perinatal asphyxia who had delayed motor and mental development and epilepsy.10/21/202224脑血管VR间隙的MRI诊疗和鉴别诊疗3.多发性硬化u与侧脑室呈垂直分布(Dawson Fingers)u信号特点T1WI 等或稍低 急性期 中央低信号，周围呈稍高信号环 慢性期T2WI and FLAIR高信号增强扫描可见强化10/21/202225脑血管VR间隙的M
10、RI诊疗和鉴别诊疗 Ovoid MS lesion of the centrum semiovale in a 49-year-old man10/21/202226脑血管VR间隙的MRI诊疗和鉴别诊疗4.脑隐球菌病u新型隐球菌引起的机会性感染，见于免疫功能缺陷或使用免疫抑制剂患者u好发于颅底，通常引起轻度的炎症反应，常伴有脑膜感染u影像学上常表现为脑膜炎，脑膜急性渗出和脑膜粘连引起的脑水肿u基底节区/丘脑和中脑的小斑点状高信号，FLAIR表现为高信号有助于鉴别u一般没有强化，DWI可以表现为高信号10/21/202227脑血管VR间隙的MRI诊疗和鉴别诊疗5.囊性肿瘤u常呈囊实性u常有瘤周水
11、肿u信号常与脑脊液不一致 u可见强化u典型的部位及信号特点肿瘤VR spacepilocytic astrocytomahemangioblastoma10/21/202228脑血管VR间隙的MRI诊疗和鉴别诊疗 pilocytic astrocytoma of the right thalamus,cerebral peduncle in a 15-year-old girl10/21/202229脑血管VR间隙的MRI诊疗和鉴别诊疗6.脑囊虫病u颅内最常见的寄生虫感染u典型者卵圆形含液囊肿内可见头节u常见于灰白致交界处10/21/202230脑血管VR间隙的MRI诊疗和鉴别诊疗MRI表现u
12、早期囊泡期囊性肿块，各序列上与脑脊液相似 中央可见偏心性头节(hyperintense to CSF)通常无强化u胶质囊泡期较脑脊液信号增高；可见瘤周水肿及强化u肉芽肿结节期 囊壁明显增厚；结节或环形强化 瘤周水肿减轻u结节钙化期病灶萎缩、较小，完全钙化 10/21/202231脑血管VR间隙的MRI诊疗和鉴别诊疗10/21/202232脑血管VR间隙的MRI诊疗和鉴别诊疗7.蛛网膜囊肿u 好发于中颅窝、鞍上池u较明显的占位效应u鉴别主要依据部位Arachnoid cyst in the perisellar cistern area in a 16-year-old girl10/21/20
13、2233脑血管VR间隙的MRI诊疗和鉴别诊疗8.神经上皮囊肿u可有占位效应u各序列上均与脑脊液相似，周围无胶质增生u无强化u鉴别通常较困难10/21/202234脑血管VR间隙的MRI诊疗和鉴别诊疗 Neuroepithelial cyst of the cerebral peduncle and pons in a 60-year-old woman with epilepsy.10/21/202235脑血管VR间隙的MRI诊疗和鉴别诊疗脉络膜裂囊肿常位于海马回与下丘脑之间，内侧通于环池，外侧为侧脑室下角，前面是海马沟及杏仁体，后部与海马沟交通与脑脊液信号相仿冠状位上多呈“双凸透镜”形，显示最好矢状位上，脉络膜裂与海马沟交通，类似斜卧的入”字，其长轴沿后上至前下斜行为特征性结构10/21/202236脑血管VR间隙的MRI诊疗和鉴别诊疗脉络膜裂囊肿10/21/202237脑血管VR间隙的MRI诊疗和鉴别诊疗小结uVRS可见于任何年龄组uVRS可异常扩大，容易误诊u了解VRS的典型信号特点及位置有助于与其它病变相鉴别10/21/202238脑血管VR间隙的MRI诊疗和鉴别诊疗 谢谢10/21/202239脑血管VR间隙的MRI诊疗和鉴别诊疗
