腦疝分類及影像學表現(xiàn)圖解

1、圖解腦疝 北京天壇醫(yī)院神經(jīng)內(nèi)科 杜萬良（reflexhammer） 腦疝 n是指在顱內(nèi)壓增高的情況下，腦組織通過某些 腦池向壓力相對較低的部位移位的結(jié)果，即腦 組織由其原來正常的位置而進入了一個異常的 位置。 腦疝的類型： na.大腦鐮疝 ： 一側(cè)大腦半球占位病變可使同側(cè)扣帶回經(jīng)大腦鐮下緣 疝入對側(cè)，胼胝體受壓下移。 n小腦幕切跡疝 b.前疝：也稱顳葉溝回疝，是顳葉溝回疝于腳間池及 環(huán)池的前部；后疝：顳葉內(nèi)側(cè)部疝于四疊體池及環(huán)池的后部；f.小 腦幕切跡上疝：后顱凹占位病變時，小腦上蚓部可向上疝入小腦幕切 跡的四疊體池。 nc.中心疝：幕上壓力增高，致使大腦深部結(jié)構及腦干縱軸牽張移位。 nd.顱

2、外疝： 腦組織通過顱外缺損疝出。 ne.枕骨大孔疝 ： 后顱凹占位病變時，可致小腦扁桃體疝入枕骨大孔。 ng.蝶骨嵴疝：顱前凹和顱中凹的占位病變，由于病變部壓力相對高一 些，則額眶回可越過蝶骨嵴進入顱中凹，可顳葉前部擠向顱前凹。 示意圖 na) subfalcial (cingulate) herniation ;鐮下疝 nb) uncal herniation ; 鉤疝 nc) downward (central, transtentorial) herniation ; 下行性小腦幕疝 nd) external herniation ; 顱外 疝 ne) tonsillar herniat

3、ion.扁桃體 疝 nf) ascending transtentorial herniation (reversed tentorial)上行性小腦幕疝 ng) sphenoid herniation蝶骨 嵴疝 類型 腦疝部位命名別名疝入腦組織命名 1大腦鐮下疝扣帶回疝 2小腦天幕疝 前疝 后疝 小腦幕切跡疝、小腦幕下降疝 腳間池疝 環(huán)池疝，四疊體疝 顳葉鉤回疝 海馬回疝 3小腦幕孔中心疝間腦 4小腦幕孔上疝小腦幕上疝 小腦蚓部疝 5枕骨大孔疝小腦扁桃體疝 示意圖 解剖關系 解剖關系 F Qc Mb 3vT O Sy CC lv F P O Sp CC lv s s 解剖關系 F T Ce

4、s P d 4th V F T Mb Ce s The suprasellar cistern early right uncal herniation. 中心疝 臨床表現(xiàn)影像所見并發(fā)癥 意識改變 呼吸模式改變 去皮層、去腦 小瞳孔 因脈絡膜前動脈 受壓引起蒼白球 和視束梗塞 中心疝 Superior vermian herniation ( ascending transtentorial herniation ) n由于后顱凹的占位效應，小腦蚓和小腦半球通過小腦幕切 跡向上移動 臨床表現(xiàn)影像所見并發(fā)癥 惡心 嘔吐 意識障礙 中腦外觀呈陀螺狀 雙側(cè)環(huán)池變窄 四疊體池充滿 因小腦上動脈受 壓引

5、起梗塞 Galen靜脈移位 腦積水 意識障礙迅速出 現(xiàn)，并可能死亡 陀螺狀外觀 雙側(cè)環(huán)池變窄 四疊體池充滿 不露齒的微笑 皺眉 第一天的四疊體池和環(huán)池 第二天，四疊體池和環(huán)池消失 腦積水 ascending transtentorial herniation 枕大孔疝 臨床表現(xiàn)影像所見并發(fā)癥 雙側(cè)上肢 感覺減退 意識障礙 軸位像見到小腦扁桃體位 于齒狀突水平 矢狀位見到小腦扁桃體低 于枕大孔5mm（成人）或 7mm（兒童） 小腦扁桃體出血 性壞死 意識障礙和死亡 枕大孔疝 Tonsillar herniation nIn tonsillar herniation (rare), a mass

6、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 and re

7、spiratory 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 p

8、atient. Tonsillar herniation a 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

9、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 not yet occurred. (D) Compression of the fourth ventricle with dilatation of the third ventricle and the caudal aspect of both temporal horns

10、. 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 located at the level of the dens which is a good indicator for foramen magnum herniation. n(A) The disc shows florid hemorrhages with r

11、elatively little 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) Thi

12、s 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 normal retinal vasculature is masked and dilated superficial capillaries are observed. (F) In atrophic optic disc oedema ne

13、rve fibers are eventually destroyed 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). 顱外疝 核磁選擇 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