1、图解脑疝北京天坛医院神经内科杜万良（reflexhammer）脑疝n是指在颅内压增高的情况下，脑组织通过某些脑池向压力相对较低的部位移位的结果，即脑组织由其原来正常的位置而进入了一个异常的位置。脑疝的类型：na.大脑镰疝：一侧大脑半球占位病变可使同侧扣带回经大脑镰下缘疝入对侧，胼胝体受压下移。n小脑幕切迹疝 b.前疝：也称颞叶沟回疝，是颞叶沟回疝于脚间池及环池的前部；后疝：颞叶内侧部疝于四叠体池及环池的后部；f.小脑幕切迹上疝：后颅凹占位病变时，小脑上蚓部可向上疝入小脑幕切迹的四叠体池。nc.中心疝：幕上压力增高，致使大脑深部结构及脑干纵轴牵张移位。nd.颅外疝：脑组织通过颅外缺损疝出。ne.
2、枕骨大孔疝：后颅凹占位病变时，可致小脑扁桃体疝入枕骨大孔。ng.蝶骨嵴疝：颅前凹和颅中凹的占位病变，由于病变部压力相对高一些，则额眶回可越过蝶骨嵴进入颅中凹，可颞叶前部挤向颅前凹。示意图na)subfalcial(cingulate)herniation;镰下疝nb)uncal herniation;钩疝nc)downward(central,transtentorial)herniation;下行性小脑幕疝nd)external herniation;颅外疝ne)tonsillar herniation.扁桃体疝nf)ascending transtentorial herniation(r
3、eversed tentorial)上行性小脑幕疝ng)sphenoid herniation蝶骨嵴疝类型脑疝部位命名别名疝入脑组织命名1大脑镰下疝扣带回疝2小脑天幕疝 前疝 后疝小脑幕切迹疝、小脑幕下降疝脚间池疝环池疝，四叠体疝颞叶钩回疝海马回疝3小脑幕孔中心疝间脑 4小脑幕孔上疝小脑幕上疝 小脑蚓部疝 5枕骨大孔疝小脑扁桃体疝 示意图解剖关系解剖关系FQcMb3vTOSyCClvFPOSpCClvss解剖关系FTCesPd4th VFTMbCesThe suprasellar cistern&the quadrigeminal cisternnThe left and center ima
4、ges show the suprasellar cistern.Its anterior borders are formed by the frontal lobes(F).Its lateral borders are formed by the uncus(U)of the temporal lobes.The left image shows the 5-pointed star appearance of the suprasellar cistern where the posterior border is formed by the pons(Po).The black ar
5、row points to the fourth ventricle.The center image shows a higher cut where the suprasellar cistern has a 6-pointed star appearance since the posterior border is formed by the cerebral peduncles(P)which have a central cleft.nThe right image shows the quadrigeminal cistern(black arrow).Note the baby
6、s bottom appearance of its anterior border.When ICP is increased,the quadrigeminal cistern space is compressed or obliterated.The suprasellar cistern&the quadrigeminal cistern.nThe midline sagittal MRI scan shows the levels of the axial diagrams.The quadrigeminal cistern is located above(anterior to
7、)the Q in the highest cut shown(number 9).The anterior border of the quadrigeminal cistern is formed by the superior colliculi(c).Image 8(lower cut)also shows the quadrigeminal cistern.In this case,its anterior border is formed by the inferior colliculi(c).This gives the anterior border of the quadr
8、igeminal cistern the appearance of a babys bottom.The quadrigeminal plate is comprised of the superior and inferior colliculi.The quadrigeminal cistern is posterior to this quadrigeminal plate,thus its anterior border may be formed by the inferior or superior colliculi.镰下疝临床表现影像所见并发症头痛对侧下肢无力同侧额角截断大脑
9、镰前份不对称同侧侧脑室腔消失透明隔移位因大脑前动脉卡压到大脑镰上引起同侧ACA供血区梗塞伴有其他疝Subfalcine herniation(cingulate herniation)Transtentorial herniation nThe suprasellar cistern(left image)is obliterated.The quadrigeminal cistern is very compressed and pushed posteriorly(center image).nA subdural hematoma with a midline shift is note
10、d.There is central transtentorial and subfalcine herniation.ACA供血区梗塞Uncal herniation临床表现影像所见并发症同侧瞳孔散大、眼动受限（动眼神经受压）对侧偏瘫（同侧大脑脚受压）有时颞叶疝压迹会导致同侧偏瘫（对侧大脑脚受压。假定位体征）对侧颞角增宽同侧环池增宽同侧桥前池增宽钩回进入鞍上池大脑后动脉受压导致枕叶梗塞鞍上池缺角冠状位CT与MRI海马旁回褶皱对侧颞角增宽同侧桥前池增宽同侧环池增宽Uncal herniationUncal herniationnobliteration of the suprasellar c
11、istern(red arrow)and the quadrigeminal cistern(green arrow)Uncal herniationnThe ipsilateral ventricle,sulci,fissures are compressed and obliterated,isappeared.nobliteration of the suprasellar cistern(s)and quadrigeminal cistern(q)Uncal herniationnAcute infarctionn1st daynAcute infarction n4th daysqU
12、ncal herniationnBefore surgery,a big GBM in the left temporal lobe with uncal herniation.nAfter surgery,the GBM was removed,the suprasellar cistern and quadrigeminal cisterns are normal.Uncal herniationnAcute infarction of right posterior artery(PCA),this is a complication of uncal/transtentorial he
13、rniation,because the PCA was compressed by brain herniation.双侧大脑后动脉梗塞双侧大脑后动脉梗塞Durette hemorrhage Durette hemorrhageKernohans notch颞叶疝压迹Uncal herniationnWhen mass effects within or adjacent to the temporal lobe occur,the medial portion of the temporal lobe(uncus)is forced medially and downward over t
14、he tentorium.There is ipsilateral pupillary dilation.The uncus is pushed medially into the suprasellar cistern.There is bilateral uncal herniation.The suprasellar cistern is obliterated.early uncal herniation nThe right uncus is pushing into the suprasellar cistern;early right uncal herniation.中心疝临床
15、表现影像所见并发症意识改变呼吸模式改变去皮层、去脑小瞳孔因脉络膜前动脉受压引起苍白球和视束梗塞中心疝Superior vermian herniation(ascending transtentorial herniation)n由于后颅凹的占位效应，小脑蚓和小脑半球通过小脑幕切迹向上移动临床表现影像所见并发症恶心呕吐意识障碍中脑外观呈陀螺状双侧环池变窄四叠体池充满因小脑上动脉受压引起梗塞Galen静脉移位脑积水意识障碍迅速出现，并可能死亡陀螺状外观双侧环池变窄四叠体池充满不露齿的微笑皱眉第一天的四叠体池和环池第二天，四叠体池和环池消失脑积水ascending transtentorial h
16、erniation枕大孔疝临床表现影像所见并发症双侧上肢感觉减退意识障碍轴位像见到小脑扁桃体位于齿状突水平矢状位见到小脑扁桃体低于枕大孔5mm（成人）或7mm（儿童）小脑扁桃体出血性坏死意识障碍和死亡枕大孔疝Tonsillar herniation nIn tonsillar herniation(rare),a mass effect in the posterior fossa causes the cerebellar tonsils to herniate inferiorly through the foramen magnum compressing the medulla and
17、 upper cervical spinal cord.Conscious patients complain of neck pain and vomiting.They may have nystagmus,pupillary dilatation,bradycardia,hypertension and respiratory depression.Early tonsillar herniation is difficult to recognize in an unconscious patient.It may not be evident on CT scan since axi
18、al views cannot see the pathology well.It is best seen on sagittal MRI.Clinically changes in vital signs may be the only clinical clue in an unconscious patient.Tonsillar herniationa male patient in his 30s who died of brain stem herniation after completing a marathon.nThe CT shows(A)loss of the ros
19、tral cerebral sulci suggesting increase in ICP,(B)and(C)a large hydrocephalus with widening of both temporal horns.The grey matter can still be differentiated from the white matter,but all sulci are lost.This suggests that the brain oedema is of relative recent onset and massive tissue ischaemia has
20、 not yet occurred.(D)Compression of the fourth ventricle with dilatation of the third ventricle and the caudal aspect of both temporal horns.This is observed with considerable brain oedema and obstructive hydrocephalus.(E)Herniation of the medulla and pons into the foramen magnum.(F)The tonsils are
21、located at the level of the dens which is a good indicator for foramen magnum herniation.n(A)The disc shows florid hemorrhages with relatively little swelling,indicating a rapid,dramatic increase in CSF pressure.Progressive changes of optic disc oedema are seen in a patient with an intracranial tumo
22、ur who declined treatment(B-D).(B)Early nerve fiber dilatation is seen particularly superiorly,inferiorly and nasally.(C)This increases and venous engorgement develops.(D)Temporal nerve fiber dilatation and swelling of the disc increases and hemorrhages appear.(E)In gross chronic disc oedema the nor
23、mal retinal vasculature is masked and dilated superficial capillaries are observed.(F)In atrophic optic disc oedema nerve fibers are eventually destroyed and the optic disc without viable nerve fibers does not swell.This patient had longstanding benign intracranial hypertension.Retinochoroidal venou
24、s collaterals are present(black arrowhead).颅外疝核磁选择n1.Subfalcine herniation.This is best seen on coronal MR images.n2.Descending transtentorial herniation(uncal herniation,hippocampal herniation).best seen on coronal images,but the compression of the brainstem is best observed on axial T2-WI.n3.Ascending transtentorial herniation.The sagittal imaging plane is preferred.n4.Cerebellar tonsillar herniation.Sagittal and coronal imaging planes are preferred.小结n占位效应引起的脑组织移位n影像上识别脑疝的关键是看脑池的变化
