腦疝分類及影像學表現(xiàn)圖解

1、圖解腦疝,北京天壇醫(yī)院神經內科 杜萬良（reflexhammer,腦疝,是指在顱內壓增高的情況下，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,a.大腦鐮疝 ： 一側大腦半球占位病變可使同側扣帶回經大腦鐮下緣疝入對側，胼胝體受壓下移。 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：顳葉內側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。 c.中心疝：幕上壓力增高，致使大腦深部結構及腦干縱軸牽張移位。 d.顱外疝： 腦組織通過顱外缺損疝出

2、。 e.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。 g.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,a) subfalcial (cingulate) herniation ;鐮下疝 b) uncal herniation ; 鉤疝 c) downward (central, transtentorial) herniation ; 下行性小腦幕疝 d) external herniation ; 顱外疝 e) tonsillar herniation.扁桃體疝 f) ascending tra

3、nstentorial herniation (reversed tentorial)上行性小腦幕疝 g) sphenoid herniation蝶骨嵴疝,類型,示意圖,解剖關系,解剖關系,解剖關系,The suprasellar cistern early right uncal herniation,中心疝,中心疝,Superior vermian herniation ( ascending transtentorial herniation,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,陀螺狀外觀,雙側環(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,

4、第二天，四疊體池和環(huán)池消失,腦積水,ascending transtentorial herniation,枕大孔疝,枕大孔疝,Tonsillar herniation,In 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 upper cervical spinal cord. Conscious

5、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 axial views cannot see the patholog

6、y well. It is best seen on sagittal MRI. Clinically changes in vital signs may be the only clinical clue in an unconscious patient,Tonsillar herniation,a male patient in his 30s who died of brain stem herniation after completing a marathon,The CT shows (A) loss of the rostral cerebral sulci suggesti

7、ng 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 not yet occurred. (D

8、) 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 located at the

9、 level of the dens which is a good indicator for foramen magnum herniation,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 tumour who decli

10、ned 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 norma

11、l 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 ven

12、ous collaterals are present (black arrowhead,顱外疝,核磁選擇,1. Subfalcine herniation. This is best seen on coronal MR images. 2. 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. 3. Ascendi