The great cerebral vein is a vein structure located in the midline. It is formed by confluence of the great cerebral vein and Rosenthal basal vein and converges with the inferior sagittal sinus backward, forming a straight sinus that mainly drains the thalamus, the inner side of the temporal lobe, the occipital lobe and the superior vermis of the cerebellum.The large cerebral vein aneurysm is mainly the tumor like expansion of the large cerebral vein rather than the real aneurysm, so it is also called the aneurysmal vascular malformation of the large cerebral vein.This disease is a relatively rare cerebrovascular malformation. Litvak first gave an accurate anatomical definition of this arteriovenous malformation in 1960.Traditionally, it was considered that its diagnosis and treatment were difficult and its prognosis was poor.However, due to the recent development and progress of neuroimaging, microsurgery and intravascular intervention technology, the diagnosis and treatment have significantly improved, and the prognosis has also improved.However, the disability rate and mortality rate of this disease are still high, which is still a difficult problem for neurosurgery.
Foreign name
galenic venous aneurysm
alias
Aneurysmal vascular malformation of great cerebral vein、Galen's phleboma
Visiting department
Vascular surgery
common symptom
Enlarged head circumference, cerebral ischemia, epilepsy, hemorrhagic infarction, etc
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The certification expert of this term is
Shaojiang|doctor
Department of Vascular Surgery, Peking Union Medical College Hospitalto examine
Aneurysmal vascular malformation of great cerebral vein、Galen's phleboma
Visiting department
Vascular surgery
common symptom
Enlarged head circumference, cerebral ischemia, epilepsy, hemorrhagic infarction, etc
pathogeny
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The great cerebral vein originates from the venous return system that drains the middle structure of the choroid plexus. At first, this vein did not communicate with the deep internal cerebral vein. About 11 weeks after embryonic development, the back of the vein communicated with the internal cerebral vein, forming the great cerebral vein. The front of the vein degenerated and eventually disappeared.During the 6th to 11th week of embryonic development, if the abnormal embryonic development is caused for some reason, the anterior part of the cerebral vein can not be normally degenerated and occluded, an arteriovenous fistula can be formed.This embryological change can explain that the arteriovenous communication of the primary great cerebral vein directly opens at the wall of the vein sac, and most of them are located at the front and bottom of the sac wall.The supply arteries of venous aneurysms can come from the paramesencephalic choroid plexus vessels, posterior choroid plexus arteries, branches of middle cerebral artery, superior cerebellar artery and meningeal vessels;The perforating branch of thalamus can also participate in blood supply due to siphon effect.The two basic mechanisms of this disease are high pressure blood flow shock caused by arteriovenous short circuit and dural venous sinus occlusion.
clinical manifestation
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According to the age of onset, the clinical manifestations of cerebral large vein tumors can be divided into four age groups:
1. Newborn group
The typical manifestation is high output and preload heart failure shortly after birth, which almost occurs in all children.The degree of heart failure depends on the size of the fistula and the presence or absence of venous embolism.Continuous intracranial murmur can be heard by auscultation of skull.The blood oxygen saturation of jugular vein increased significantly.Aneurysm like lesions can be found on head CR and MRI, and many small supply arteries can be seen on the front and lower edges of the lesions on angiography. Most of them belong to Yasargil type I, II and III, with type III being the most common.Ultrasonic examination can also find continuous blood flow in the internal jugular vein, which is different from the normal fluctuating blood flow.No echo shadow can be detected at the focus, and the blood flow is also continuous.Surgical treatment of intracranial lesions can not improve intractable heart failure, and may induce myocardial infarction due to the decrease of blood pressure during operation.Most children died of heart failure.The autopsy found that there were paraventricular malacia, deep hemorrhage of cerebral parenchyma, cortical gliosis, infarction and calcification, subcortical vacuolization and other pathological changes in the brain, abnormal enlargement of cerebral great veins, and connected with many small arteries.The mechanism of brain injury is mainly arterial steal, cerebral ischemia secondary to heart failure, hemorrhagic infarction, lesion compression and surgical trauma.
2. Infant group
Clinically, they were divided into two groups according to the history of cardiac decompensation.
(1) Cardiac decompensation occurred in neonatal period, but it was relieved or self relieved after treatment.Later (1~12 months after birth), the head circumference increased and intracranial murmur appeared, which was obvious in the posterolateral auscultation of the head.
(2) No history of cardiac decompensation.The baby saw a doctor due to the increased head circumference and found hydrocephalus.Chest radiographs can reveal cardiac hypertrophy.
The ventricles of children's brain can be significantly enlarged, involving the lateral ventricle and the third ventricle.In the past, it was believed that the reason for ventricular enlargement was that the enlarged cerebral vein compressed the midbrain aqueduct, resulting in obstructive hydrocephalus.However, pathophysiological studies and imaging studies showed that the children's aqueducts were always kept unobstructed, and there was no clinical manifestation of hydrocephalus in the children.There was no periventricular edema on CT or MRI.It is generally believed that the increase of pressure in the sagittal sinus and venous system, which affects the absorption of cerebrospinal fluid, is the main reason for ventricular enlargement.Usually, cerebral angiography can show the filling cystic lesions, and can dynamically observe the contrast agent rushing into the capsule to form turbulence.Occasionally, thrombosis in the focus completely occludes the capsule cavity and cannot be visualized.If thrombus forms on the capsule wall and the capsule cavity exists, "target sign" can be displayed on CT.Generally, the middle fistula of this type is smaller than that of the newborn group, and most of them have only one fistula, which is equivalent to Yasargil I type.
Epilepsy is also the main clinical manifestation of this group of children.Long term blood theft in the brain can cause cerebral ischemia.Cerebral infarction and degeneration are the pathological basis of epilepsy.
3. Children group
Most children over 2 years old get sick with increased head circumference.Some children may have subarachnoid hemorrhage, and the heart may also have mild enlargement.Intracranial murmurs can be heard by auscultation of skull.However, it should be differentiated from intracranial physiological murmurs in children.Generally, in normal infants or children, murmurs can also be heard in the skull or near the eyeball, which is obvious in the eyeball or temporal side. The systolic murmur increases, and the carotid artery murmur can disappear after compression.However, the murmur of cerebral large vein tumor is obvious near the parietal tubercle and the posterior midline. The murmur is strong in neonates and infants, and can be heard in both systolic and diastolic periods, and can also be continuous.
4. Adult group
This includes older children, adolescents or young people.The clinical manifestations are various: subarachnoid hemorrhage, space occupying in the pineal region, high intracranial pressure, hydrocephalus, etc.Head CT or MRI can be used for differential diagnosis.In pathophysiology, the arteriovenous fistula of the patient is small, the flow rate is low, or it belongs to the secondary large cerebral vein tumor.
inspect
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1. X-ray plain film of skull
In the infant group, calcification of diseased vessels was occasionally seen. In addition to intracranial hypertension, calcified spots were common in the child group and adult group.It shows complete or incomplete ring calcification shadow with a diameter of more than 2.5 cm in the pineal region.
2. Cerebral angiography
It is the main means to diagnose the large cerebral vein tumor.At least 3 selective cerebral angiography should be performed, including bilateral internal carotid artery angiography and unilateral vertebral artery angiography;It is better to perform digital subtraction whole brain selective angiography to make the display of cerebral large vein tumor more clear, and the "steal" artery and return vein more clear.
3. CT scanning
An oval high density image with regular edges in the pineal region is often accompanied by symmetrical ventricular enlargement above the third ventricle;Secondary patients may have irregular high and low density shadows with uneven density in front of them.On enhanced scanning, the round high-density phase can be seen, and the enhanced shadow continues to the skull, indicating the expansion of the straight sinus.
4. MRI examination
The MRI of cerebral large vein tumor is very typical. It is a circular area without signal, which is caused by the blood flow void effect. Its boundary is clear, especially in the sagittal position. Not only the tumor sac, but also the drainage straight sinus, cerebral falx sinus, etc. can be seen.
5. Others
MR angiography and Doppler ultrasound are effective auxiliary means for the diagnosis of cerebral large vein tumors.Especially for children with patent fontanelle, Doppler ultrasound can judge the changes of intracranial hemodynamics and the blood flow patterns in the focus, providing a non-invasive means for screening the lesions.The accompanying systemic conditions such as cardiopulmonary function and brain function can be evaluated by arterial blood gas analysis, chest radiograph, electroencephalogram, electrocardiogram, renal function, blood electrolyte examination, etc.
diagnosis
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It mainly depends on the age of onset and clinical manifestations, but the diagnosis needs radiological examination.The newborn has intractable heart failure with intracranial vascular murmur;The possibility of hydrocephalus in infants should be considered. For those who can hear intracranial vascular murmurs or have subarachnoid hemorrhage, the diagnosis can be basically determined.Further diagnosis can be made by cerebral angiography, CT scan or MRI.
treatment
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According to the patient's age and clinical manifestations, choose the appropriate time and the best treatment plan.Newborns often suffer from cardiovascular symptoms and threaten their lives, so the first choice of treatment should be to stabilize the general condition and control cardiac dysfunction.If the symptomatic treatment is effective, regular follow-up can be carried out. Brain CT, MRI, intracranial ultrasound and head circumference measurement can provide changes in intracranial lesions, which can be used as follow-up judgment means.If the condition is stable, further primary treatment will be given after the child is 6 months old.For children over 6 months old, attention should be paid to avoid long-term damage caused by intracranial ischemia.The large cerebral vein tumor may cause high pressure in adjacent veins and impeded reflux.Chronic brain stem ischemia can cause irreversible calcification in the brain and cause mental retardation.
If there is no symptom, the pathological changes found at an older age can be carefully examined, with the exception of other diseases, and closely followed up in combination with imaging examination.Individual large cerebral vein tumors, especially low flow lesions, have the possibility of self closure and thrombosis.For those with corresponding clinical symptoms, in principle, the main purpose of treatment is to remove venous hypertension and cerebral ischemia.
