1、图解脑疝1 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。2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.枕骨大孔疝：后颅凹占位病变时，可致小脑扁桃体疝入
2、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。3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(reversed tentorial)上行性小脑
3、幕疝ng)sphenoid herniation蝶骨嵴疝4类型5示意图6解剖关系7解剖关系FQcMb3vTOSyCClvFPOSpCClvss8解剖关系FTCesPd4th VFTMbCes9The suprasellar cistern&the quadrigeminal cisternnThe left and center images show the suprasellar cistern.Its anterior borders are formed by the frontal lobes(F).Its lateral borders are formed by the uncu
4、s(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 arrow points to the fourth ventricle.The center image shows a higher cut where the suprasellar cistern has a 6-pointed star appearanc
5、e 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 babys bottom appearance of its anterior border.When ICP is increased,the quadrigeminal cistern space is compressed or obliterated.10The
6、 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)the Q in the highest cut shown(number 9).The anterior border of the quadrigeminal cistern is formed by the superior colliculi(c)
7、.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 quadrigeminal cistern the appearance of a babys bottom.The quadrigeminal plate is comprised of the superior and inferior colliculi.The
8、 quadrigeminal cistern is posterior to this quadrigeminal plate,thus its anterior border may be formed by the inferior or superior colliculi.11镰下疝12Subfalcine herniation(cingulate herniation)Transtentorial herniation nThe suprasellar cistern(left image)is obliterated.The quadrigeminal cistern is ver
9、y compressed and pushed posteriorly(center image).nA subdural hematoma with a midline shift is noted.There is central transtentorial and subfalcine herniation.13ACA供血区梗塞14Uncal herniation15鞍上池缺角16冠状位CT与MRI17海马旁回褶皱18对侧颞角增宽19同侧桥前池增宽20同侧环池增宽21Uncal herniation22Uncal herniationnobliteration of the supra
10、sellar cistern(red arrow)and the quadrigeminal cistern(green arrow)23Uncal herniationnThe ipsilateral ventricle,sulci,fissures are compressed and obliterated,isappeared.nobliteration of the suprasellar cistern(s)and quadrigeminal cistern(q)24Uncal herniationnAcute infarctionn1st daynAcute infarction
11、 n4th daysq25Uncal 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.26Uncal herniationnAcute infarction of right posterior artery(PCA),this is a complication of uncal/t
12、ranstentorial herniation,because the PCA was compressed by brain herniation.27双侧大脑后动脉梗塞28双侧大脑后动脉梗塞29Durette hemorrhage 30Durette hemorrhage31Kernohans notch颞叶疝压迹32Uncal herniationnWhen mass effects within or adjacent to the temporal lobe occur,the medial portion of the temporal lobe(uncus)is forced
13、medially and downward over the 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.33early uncal herniation nThe right uncus is pushing into the suprasellar cistern;earl
14、y right uncal herniation.34中心疝35中心疝36Superior 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37陀螺状外观38双侧环池变窄39四叠体池充满40不露齿的微笑41皱眉42第一天的四叠体池和环池43第二天，四叠体池和环池消失44脑积水45ascending transtentorial herniation46枕大孔疝47枕大孔疝48Tonsillar herniation nIn tonsillar herniation(rar
15、e),a mass effect in the posterior fossa causes the cerebellar tonsils to herniate inferiorly through the foramen magnum compressing the medulla and upper cervical spinal cord.Conscious patients complain of neck pain and vomiting.They may have nystagmus,pupillary dilatation,bradycardia,hypertension a
16、nd respiratory depression.Early tonsillar herniation is difficult to recognize in an unconscious patient.It may not be evident on CT scan since axial 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
17、patient.49Tonsillar herniation50a male patient in his 30s who died of brain stem herniation after completing a marathon.nThe CT shows(A)loss of the rostral cerebral sulci suggesting increase in ICP,(B)and(C)a large hydrocephalus with widening of both temporal horns.The grey matter can still be diffe
18、rentiated 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 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
19、observed with considerable brain oedema and obstructive hydrocephalus.(E)Herniation of the medulla and pons into the foramen magnum.(F)The tonsils are located at the level of the dens which is a good indicator for foramen magnum herniation.51n(A)The disc shows florid hemorrhages with relatively litt
20、le swelling,indicating a rapid,dramatic increase in CSF pressure.Progressive changes of optic disc oedema are seen in a patient with an intracranial tumour who declined treatment(B-D).(B)Early nerve fiber dilatation is seen particularly superiorly,inferiorly and nasally.(C)This increases and venous
21、engorgement develops.(D)Temporal nerve fiber dilatation and swelling of the disc increases and hemorrhages appear.(E)In gross chronic disc oedema the normal retinal vasculature is masked and dilated superficial capillaries are observed.(F)In atrophic optic disc oedema nerve fibers are eventually des
22、troyed and the optic disc without viable nerve fibers does not swell.This patient had longstanding benign intracranial hypertension.Retinochoroidal venous collaterals are present(black arrowhead).52颅外疝53核磁选择n1.Subfalcine herniation.This is best seen on coronal MR images.n2.Descending transtentorial
23、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.545556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57
