脑静脉血栓形成影像学.pptx

Cerebral Venous ThrombosisBarbara Simons,Geert Lycklama a Nijeholt and Robin Smithuis Radiology department of the Medical Centre Haaglanden in the Hague and the Rijnland hospital in Leiderdorp,the Netherlands脑静脉性栓塞形成Introduction When to think of venous thrombosis Dense clot sign Empty delta sign Absence of normal flow void on MR Venous infarction Imaging in suspected thrombosis CT-venography MR-venography DSA Pitfalls in CT Arachnoid Granulations Mimick of dense clot sign Pseudo empty delta sign Wrong bolus timing Pitfalls in MRI Hypoplastic transverse sinus Low signal intensity in thrombus Flow void on contrast-enhanced MR Chronic dural sinus thrombosis and related syndromes DAVF Thrombosis and increased CSF pressure Venous territories Publicationdate October 21,2010 Cerebral venous thrombosis is an important cause of stroke especially in children and young adults.It is more common than previously thought and frequently missed on initial imaging.It is a difficult diagnosis because of its nonspecific clinical presentation and subtle imaging findings.In this article we will focus on:Findings on routine imaging that should make you think of unsuspected venous thrombosis.How to image patients in suspected venous thrombosis.Pitfalls.此时应想到静脉栓塞可能致密斑块征空三角征MR上正常流空征消失静脉性脑梗塞疑似此病的成像方法CT静脉成像MR静脉成像DSACT陷阱蛛网膜颗粒酷似致密凝块征假性空三角征错误的团注时间MRI陷阱横窦发育不良血栓内低信号强度MR对比增强时的流空硬膜窦栓塞临床与相关综合征DAWF（硬膜动静脉瘘）栓塞和脑脊液压力增高静脉分布图静脉性脑梗塞是中风的重要原因，尤其是在儿童或年轻人。它比以前更常见而且常常在最初的成像中漏诊由于临床上缺少特征而且影像所见微妙，因而诊断困难这里主要讨论的内容：*提示可疑静脉性脑梗塞的常规影像学表现*疑为静脉性脑梗塞如何进一步进行影像学检查*陷阱Cerebral venous thrombosis is located in descending order in the following venous structures:Major dural sinuses:Superior sagittal sinus,transverse,straight and sigmoid sinuses.Cortical veins:Vein of Labbe,which drains the temporal lobe.Vein of Trolard,which is the largest cortical vein that drains into the superior sagittal sinus.Deep veins:Internal cerebral and thalamostriate veins.Cavernous sinus.Clinically patients with cerebral venous thrombosis present with variable symptoms ranging from headache to seizure and coma in severe cases.In neonates shock and dehydration is a common cause of venous thrombosis.In older children it is often local infection,such as mastoiditis,or coagulopathy.In adults,coagulopathies is the cause in 70%and infection is the cause in 10%of cases.In women,oral contraceptive use and pregnancy are strong risk factors.重要的解剖与临床 脑静脉性栓塞多位于以下的静脉结构*主要静脉窦：上矢状窦、横窦、直窦和乙状窦。*皮质静脉：Labbe静脉，颞叶的引流静脉；Trolard 静脉，为最大的皮质静脉，汇入上矢状窦。*深静脉：大脑内静脉和丘脑纹状体静脉。*海绵窦。*临床上，脑静脉栓塞可有多种症状，严重病例如头痛 、癫痫、昏迷。*新生儿休克或脱水是脑静脉栓塞常见的原因。*在儿童，局灶性的感染如中耳炎或凝血障碍。*成人中，70%的病因为凝血障碍；10%源自感染 女性，口服避孕药与妊娠也是其危险因素。When to think of venous thrombosisOn a routine non-enhanced MR or CT you should think of the possibility of venous thrombosis when you see:Direct signs of a thrombusInfarction in a non-arterial location,especially if it is bilateral and hemorrhagicCortical or peripheral lobar hemorrhage Cortical edemaVenous thrombosis has a nonspecific presentation and therefore it is important to recognize subtle imaging findings and indirect signs that may indicate the presence of thrombosis.Although these findings are often present on initial scans,they are frequently detected only in retrospect.Clinically patients with venous thrombosis often present with seizures,which is not a symptom in patients with an arterial infarction.什么情况下考虑静脉窦栓塞呢？在常规的CT或MR平扫图像若有下面的表现应该想到静脉性脑栓塞可能：*静脉血栓的直接征象*脑梗塞非动脉性的常见部位，尤其是为双侧性、出血性*皮质或周围脑叶的出血*脑皮质水肿脑静脉血栓形成为非特异性的表现，因此，认识这些微妙的影像学的表现以及间接征象很重要，它可以指出血栓形成之存在。静脉血栓形成的病人在临床上常表现癫痫，但这不是动脉性脑梗塞病人出现的症状。尽管这些表现经常地出现在最初的扫描中，但却经常只是在回顾中发现这些异常。11、透明隔静脉12、丘脑纹状体静脉13、大脑内静脉14、大脑大静脉15、基底静脉24、直窦25、蝶顶窦26、海绵窦27、海绵间窦29、岩上窦30、岩下窦1、上矢状窦2、下矢状窦3、窦汇4、横窦5、乙状窦6、颈静脉球7、颈内静脉8、浅表皮层静脉9、静脉10、大脑中浅静脉Trolard静脉Labbe静脉Rosenthal基底静脉附加：正常解剖图与静脉栓塞的病理解剖示意图正常脑静脉窦示意图上矢状窦及脑静脉栓塞伴发的脑肿胀及损伤损伤的脑组织出血Dense clot sign（1）Direct visualization of a clot in the cerebral veins on a non enhanced CT scan is known as the dense clot sign.It is seen in only one third of cases.Normally veins are slightly denser than brain tissue and in some cases it is difficult to say whether the vein is normal or too dense(see pitfalls).In these cases a contrast enhanced scan is necessary to solve this problem.*致密凝块征（1）：CT平扫见到的脑静脉血栓的直接表 现，出现率为1/3.*正常的脑静脉表现为密度较脑组织轻度高，但有些 病例的正常与否判断确有困难（参见陷阱）。*CT增强扫描可准确地解决该问题。Dense clot sign(2)Visualization of a thrombosed cortical vein that is seen as a linear or cord-like density,is also known as the cord sign.Another term that is frequently used,is the dense vessel sign.Dense clot sign(3)On the left images of a patient with a hemorrhagic infarction in the temporal lobe(red arrow).Notice the dense transverse sinus due to thrombosis(blue arrows).*致密凝块征（2）：CT平扫见到的脑皮质静脉血栓的表 现，呈线样或绳索样高密度影，即所谓绳索征（上图 红箭）。也有称其为致密血管征。*致密凝块征（3）：CT平扫显示颞叶出血性梗 塞（红箭）。*注意因血栓导致的左侧横窦高密度（蓝箭）。Two cases of empty delta sign due to thrombosis of the superior sagittal sinus.Empty delta sign（1）The empty delta sign is a finding that is seen on a contrast enhanced CT(CECT)and was first described in thrombosis of the superior sagittal sinus.The sign consists of a triangular area of enhancement with a relatively low-attenuating center,which is the thrombosed sinus.The likely explanation is enhancement of the rich dural venous collateral circulation surrounding the thrombosed sinus,producing the central region of low attenuation.In early thrombosis the empty delta sign may be absent and you will have to rely on non-visualization of the thrombosed vein on the CECT.The sign may be absent after two months due to recanalization within the thrombus.空三角征（1）：*空三角征是增强CT检查的表现，用来描述上 矢状窦栓塞。*该征由强化的三角组成，其中心为相对低的 密度，窦内的血栓所致。*硬膜窦周边的对比强化是血栓周围的静脉血流。*静脉窦血栓早期，CT增强扫描上，该空三角 征可能缺乏，以至于出现增强CT为假阴性。*治疗再通后2个月左右，该征像消失。Empty delta sign(2)On the left a case of thrombosis of the right transverse sinus and the left transverse and sigmoid sinus(arrows).There is enhancement surrounding the thrombosed hypoattenuating veins.空三角征（2）：*左图一例右侧横窦、左侧横窦及乙 状窦栓塞的病例（箭）。*栓塞的静脉窦呈低密度并周围强化。Venous thrombosis with absence of normal flow void on T2-weighted image.Absence of normal flow void on MR（1）On spin-echo images patent cerebral veins usually will demonstrate low signal intensity due to flow void.Flow voids are best seen on T2-weighted and FLAIR images,but can sometimes also be seen on T1-weighted images.A thrombus will manifest as absence of flow void.Although this is not a completely reliable sign,it is often one of the first things,that make you think of the possibility of venous thrombosis.The next step has to be a contrast enhanced study.On the left a T2-weighted image with normal flow void in the right sigmoid sinus and jugular vein(blue arrow).On the left there is abnormal high signal as a result of thrombosis(red arrow).正常正常MRMR流空消失（流空消失（1 1）*自旋回拨成像，由于流空而使得静脉窦呈低信号。最宜显示“流空征”是T2WI或FLAIR，有时T1WI 也能看到。*当静脉窦血栓时，血“流空征”消失，尽管它 不是完全可靠的征象，也是首先值得注意的表现 ，由此应想到静脉窦血栓的可能。*接下来必须做MR增强扫描。*左图T2WI右侧乙状窦及颈静脉（蓝箭）表现正 常的血“流空征”，而左侧的乙状窦则由于静 脉窦栓塞而形成不正常的高信号。Absence of normal flow void on MR(2)The images on the left show abnormal high signal on the T1-weighted images due to thrombosis.The thrombosis extends from the deep cerebral veins and straight sinus to the transverse and sigmoid sinus on the right.Notice the normal flow void in the left transverse sinus on the right lower image.Absence of normal flow void on MR-images can be very helpful in detecting venous thrombosis,but there are some pitfalls as we will discuss later.Slow flow can occur in veins and cause T1 hyperintensity.Venous thrombosis with absence of normal flow void on T1-weighted image.正常正常MRMR流空消失（流空消失（2 2）*左图显示由于静脉栓塞而导致的T1WI异常 信号血栓由右侧乙状窦、横窦、直窦并延 伸至大脑的深静脉。*注意右下图上左侧横窦的正常“流空征”。*在搜寻静脉窦栓塞中，MR上正常流空征的 缺失，是非常有用的征象。但却有陷 阱（后续讨论）*当静脉内血流缓慢时，可引起T1WI高信号。Venous infarction(1)The other sign that can help you in making the diagnosis of unsuspected venous thrombosis is venous infarction.Venous thrombosis leads to a high venous pressure which first results in vasogenic edema in the white matter of the affected area.When the proces continues it may lead to infarction and development of cytotoxic edema next to the vasogenic edema.This is unlike in an arterial infarction in which there is only cytotoxic edema and no vasogenic edema.Due to the high venous pressure hemorrhage is seen more frequently in venous infarction compared to arterial infarction.Since we are not that familiar with venous infarctions,we often think of them as infarctions in an atypical location or in a non-arterial distribution.venous infarctions do have a typical distribution静脉性脑梗塞（静脉性脑梗塞（1 1）*另一个能帮你从容诊断脑静脉血栓形成的 可靠征象是静脉性脑梗塞。*脑静脉血栓形成导致脑静脉高压并致使受累 区的脑白质早期出现血管源性水肿。*在当病情继续进展，紧随着血管源性水肿 而导致脑梗塞和细胞毒性水肿之进展。*这与动脉性脑梗塞仅细胞毒性水肿而没有 血管源性水肿的病理变化截然不同。*与动脉性脑梗塞比较，由高静脉压而导致 的出血在静脉性脑梗塞中更多见。*正是因为不熟悉静脉性脑梗塞，因此，当 发现脑梗塞位于非动脉性梗塞的好发部位 或为非动脉分布区的梗塞时，应该想到本病。大脑内静脉血栓上矢状窦血栓Labbe静脉血栓静脉性脑梗塞有典型分布区Since many veins are midline structures,venous infarcts are often bilateral.This is seen in thrombosis of the superior sagittal sinus,straight sinus and the internal cerebral veins.Venous infarction(2)-Superior sagittal sinus thrombosisThe most frequently thrombosed venous structure is the superior sagittal sinus.Infarction is seen in 75%of cases.The abnormalities are parasagittal and frequently bilateral.Hemorrhage is seen in 60%of the cases.On the left bilateral parasagittal edema and subte hemorrhage in a patient with thrombosis of the superior sagittal sinus.Bilateral infarction in superior sagittal sinus thrombosisvenous infarcts are often bilateral in the midline and hemorrhagic静脉性脑梗塞常常在中线的双侧并伴有出血上矢状窦栓塞伴中线两侧静脉性脑梗塞由于许多静脉是中线结构，静脉性脑梗塞常是双侧。该特征见于上矢状窦、直窦以及大脑内静脉栓塞。静脉性脑梗塞（静脉性脑梗塞（2 2）-上矢状窦栓塞上矢状窦栓塞*上矢状窦是最频繁形成静脉栓塞的结构。*75%的病例出现静脉性脑梗塞。*伴随的异常表现出现在矢状窦旁，多是双 侧性。*这与动脉性脑梗塞仅细胞毒性水肿而没有 血管源性水肿的病理变化截然不同。*60%的病例伴出血。*左图即是上矢状窦血栓伴双侧矢旁水肿及少 许出血。On the left reconstructed sagittal CT-images in a patient with bilateral parasagittal hemorrhage due to thrombosis of the superior sagittal sinus.The red arrow on the contrast enhanced image indicates the filling defect caused by the thrombus.Venous infarcts(3)-vein of LabbeAnother typical venous infarction is due to thrombosis of the vein of Labbe.On the left images demonstrating hypodensity in the white matter and less pronounced in the gray matter of the left temporal lobe.There is a broad differential diagnosis including arterial infarction,infection,tumor etc.Notice that there is some linear density within the infarcted area.This is due to hemorrhage.In the differential diagnosis we also should include a venous infarct in the territory of the vein of Labbe.The subtle density in the area of the left transverse sinus(arrow)is the key to the diagnosis.This is a direct sign of thrombosis and the next step is a CECT,which confirmed the diagnosis(not shown打药的CT图未提供).Venous infarct in Labbe territoryLabbe静脉分布区静脉性脑梗塞左图矢状CT重组图显示：上矢状窦血栓形成而导致的双侧矢旁脑实质出血。增强扫描图中红箭显示的为由血栓造成的上矢状窦的充盈缺损。静脉性脑梗塞（3）-Labbe静脉另一例典型的静脉性脑梗塞：源自Labbe静脉栓塞。左图示左侧颞叶灰质及白质密度明显减低区，这里需要鉴别的疾病很多，包括动脉性脑梗塞，感染，肿瘤等。注意：在梗塞区有一些线样高密度，是出血所致。鉴别诊断中当然也包括Labbe静脉分布区的静脉性梗塞。在左侧横窦（箭）区域的少许高密度影则是诊断的关键。这是血栓形成的一个直接征象，接下来就是做增强CT证实（打药的CT未提供）On the left images of a patient with hemorrhage in the temporal lobe.When the hemorrhagic component of the infarction is large,it may look like any other intracerebral hematoma with surrounding vasogenic edema.The clue to the diagnosis in this case is seen on the contrast enhanced image,which nicely demonstrates the filling defect in the sigmoid sinus(blue arrow).Hemorrhagic venous infarct in Labbe territoryOn the left a similar case on MR.There is a combination of vasogenic edema(red arrow),cytotoxic edema and hemorrhage(blue arrow).These findings and the location in the temporal lobe,should make you think of venous infarction due to thrombosis of the vein of Labbe.The next examination should be a contrast enhanced MR or CT to prove the diagnosis.Hemorrhagic venous infarct in Labbe territoryLabbe静脉分布区出血性静脉性脑梗塞Labbe静脉分布区出血性静脉性脑梗塞左图：左侧颞叶出血左图：当梗塞区出血成分较大时，看似像其他的脑内出血并环绕血管源性水肿。该病例的诊断线索是增强CT的所见，即乙状窦内的充盈缺损（蓝箭，对侧比较），它是最好的证据。左图：另一个类似病例的MR*这例表现：血管源性水肿（红箭）与细胞毒性水 肿及出血（蓝箭）的综合影。*这些表现和颞叶的病变定位应使我们想到Labbe 静脉血栓形成导致的静脉性脑梗塞。*接下来的检查应该是MRI或CT的增强扫描，从而 证实该诊断。Venous infarction(4)-Deep cerebral veinsOn the far left a FLAIR image demonstrating high signal in the left thalamus.When you look closely and you may have to enlarge the image to appreciate this,there is also high signal in the basal ganglia on the right.These bilateral findings should raise the suspicion of deep cerebral venous thrombosis.A sagittal CT reconstruction demonstrates a filling defect in the straight sinus and the vein of Galen(arrows).On the left a young patient with bilateral abnormalities in the region of the basal ganglia.Based on the imaging findings there is a broad differential including small vessel disease,demyelinisation,intoxication and metabolic disorders.Continue with the T1-weighted images in this patient.接下来看T1WI图静脉性脑梗塞（4）-脑深静脉*左上FLAIR图证实左侧丘脑高信号。*当仔细观察发现右侧底节区也有高信号。*这种双侧性异常应高度怀疑脑深部静脉的血栓形成。*矢状CT重建图证实直窦、Galen静脉（箭）内的 充盈缺损。*左图一个年轻病人，双侧基底节区的异常。*基于这种影像的表现，需要鉴别的疾病包括：小 血管病、脱髓鞘、中毒、代谢病。*这种双侧性异常应高度怀疑脑深部静脉的血栓形成。*矢状CT重建图证实直窦、Galen静脉（箭）内的 充盈缺损。Notice the abnormal high signal in the internal cerebral veins and straight sinus on the T1-weighted images,where there should be a low signal due to flow void.This was unlike the low signal in other sinuses.The diagnosis is bilateral infarctions in the basal ganglia due to deep cerebral venous thrombosis.Bilateral infarctions in the basal ganglia due to deep cerebral venous thrombosisVenous infarction(5)-EdemaIn some cases of venous thrombosis the imaging findings can resolve completely.左下图 a patient with a subcortical area of high signal intensity.The first impression was that this could be a low grade glioma.On a follow up scan the abnormalities had resolved completely.In retrospect a dense vessel sign was seen in one of the cortical veins and the diagnosis of venous thrombosis was made.The high signal intensity can be attributed to vasogenic edema due to the high venous pressure that resulted from the thrombosis.由于脑深部静脉血栓形成而导致的双侧基底节区脑梗塞。静脉性脑梗塞（5）-水肿*在一些静脉性血栓形成的病人中，其异常的表现 能够完全消失。*左下图示一个病人的皮质下区高信号影，低级别 星形细胞瘤可能会是第一印象。但在随后的复查 发现该异常影完全消失。*回顾中发现，皮质静脉的一支血管表现为“致密 血管征”并作出静脉血栓形成的诊断。*高信号强度归于血管源性水肿，这是由于静脉内 血栓形成而导致的脑静脉高压。Imaging in suspected thrombosisCT-venographyCT-venography is a simple and straight forward technique to demonstrate venous thrombosis.In the early stage there is non-enhancement of the thrombosed vein and in a later stage there is non-enhancement of the thrombus with surrounding enhancement known as empty delta sign,as discussed before.Unlike MR,CT-venography virtually has no pitfalls.The only thing that you dont want to do,is to scan too early,i.e.before the veins enhance or too late,i.e.when the contrast is gone.Some advocate to do a scan like a CT-arteriography and just add 5-10 seconds delay.To be on the safe side we advocate 45-50 seconds delay after the start of contrast injection.We use at least 70 cc of contrast.On the left some images of a CT-venography demonstrating thrombosis in many sinuses.疑为静脉血栓形成病人的成像检查CT静脉成像CT静脉成像作为证实静脉血栓形成的简单而直接的技术。在注药早期阶