Cerebral Vascular Malformations Research Articles

Cerebral vascular malformations adjacent to sensorimotor and visual cortex. Functional magnetic resonance imaging studies before and after therapeutic intervention.

It is not known how cerebral vascular malformations affect the function of the surrounding brain. Functional magnetic resonance imaging (fMRI) can provide information about normal functional neuroanatomy and its alteration by vascular lesions and therapeutic intervention. We performed fMRI studies in 24 patients harboring vascular malformations adjacent to primary somatosensory, motor, and visual cortex. The fMRI studies consisted of the acquisition of an image time series coupled with functional activation of motor, sensory, or visual cortex in both hemispheres. Activated voxels were identified using frequency domain analyses, and their number and anatomic location were compared between the affected and unaffected hemispheres. Every patient capable of performing the desired task showed functional activation. Eight patients without neurological deficits showed a symmetrical pattern of activation between the hemispheres. Each had a vascular malformation located one or more gyri from the functional region imaged. Three patients showed hemispheric symmetry in the location of activated cortex but with a marked asymmetry in the number of activated voxels. Each harbored vascular malformations located within one gyrus of the functional region and showed either subtle or no neurological deficit. Eleven patients showed hemispheric asymmetry in the location of activated cortex. In 6, the anatomic displacement appeared to be due to a mass effect of the lesion. In 5, the activation occurred at a different anatomic locale, and the patients exhibited gross neurological deficit in the respective function. Posttherapeutic changes in functional activation reflected elimination of the mass effect or recovery of clinical function. Systematic fMRI studies are possible in patients with vascular malformations in brain regions adjacent to primary somatosensory, motor, and visual cortex. Displacement of the activated region and hemispheric asymmetry in the number of activated voxels in the functional regions appear to reflect the anatomic and physiological impact of the vascular malformation. Changes in fMRI findings after intervention reflect the consequences of therapy and parallel clinical recovery.

Classification and natural history of cerebral vascular malformations: Arteriovenous, cavernous, and venous

Arteriovenous malformations (AVMs) represent the most commonly encountered symptomatic vascular malformations of the central nervous system (CNS) identified at either surgery or necropsy. AVMs are hamartomatous lesions of the brain characterized by elongated and enlarged feeding arteries that directly communicate with draining veins and are without intervening resistance vessels or capillary beds.

STEREOTACTIC RADIOSURGERY USING THE GAMMA KNIFE

BACKGROUNDWe discuss current indications and results after stereotactic radiosurgery for the management of cerebral vascular malformations, brain tumors, and functional disorders. The development of gamma knife and modified linear accelerator technology has been associated with a significant increas

Large diffuse arteriovenous malformation affecting the right cerebral and cerebellar hemispheres: Case report

A cerebral vascular malformation was triggered in a 24-year-old man by left hemiparesis resembling transient ischemic attack. Cerebral angiography revealed slight dilation of the right anterior cerebral artery, middle cerebral artery, superior cerebellar artery, and posterior inferior cerebellar artery, as well as marked capillary blush and dilation of medullary veins involving the right cerebral hemisphere, especially the frontal lobe and cerebellar hemispheres. This vascular malformation, a clinical rarity, seemed to be in the same family as diffuse arteriovenous malformation or “medullary venous malformation”. Single photon emission computed tomography showed a decline in cerebral blood flow in the right cerebral hemisphere, which was the probable cause of the left hemiparesis.

Embryological basis of some aspects of cerebral vascular fistulas and malformations

The literature on the formation of cerebral veins is reviewed to obtain a better understanding of some cerebrovascular anomalies. Clinical observations such as the entry of the superior ophthalmic vein into the cavernous sinus through the inferior rather than the superior orbital fissure, the relative infrequency of middle cerebral vein backflow in the presence of an extensive cavernous fistula, and the relative infrequency of hemorrhage in relation to the inferior petrosal fistula all relate to the persistence of an older venous pathway. The frequent occurrence of hemorrhage in association with the superior petrosal sinus fistula and the frequent failure of the superior petrosal sinus to connect to the cavernous sinus similarly have an embryological explanation. The frequent association of the vein of Galen aneurysm and an absent or deformed straight sinus probably relates to the time at which the paired internal cerebral veins fuse into one channel. It is speculated that the origins of cerebral venous malformations (CVMs) and arteriovenous malformations (AVMs) probably relate to sequential formation and absorption of surface veins, which occur in human embryonic development mainly in the 40- to 80-mm length interval, although persistent AVM growth is possible even after birth. The frequent absence or anomaly of the middle cerebral vein and its failure to communicate with the cavernous sinus in the presence of both CVMs and AVMs are linked to the late development of that vein and to its even later connection to the cavernous sinus.

Gamma knife radiosurgery

The concept of radiosurgery and its requirements are presented. Dedicated radiosurgical tools include the modified linear accelerators working with a single rotating beam and the Gamma Knife with multiple stationary radiation sources. The 201 gamma beams from the cobalt 60 sources of the Gamma Knife intersect within 0.3 mm and it is possible to align the selected target point with the focal point within a mechanical accuracy of 0.5 mm. The technical specifications of the Gamma Knife make it possible to safely produce sharply circumscribed lesions in a single session with superior accuracy and precision. Gamma Knife surgery is a four-step neurosurgical procedure including application of a stereotactic frame to the patient's head, stereotactic image acquisition, treatment planning, and the radiation. The system allows stereotactic acquisition of images from computed tomography, magnetic resonance tomography, cerebral angiography, and positron-emission tomography. Applications for Gamma Knife surgery include the treatment of cerebral vascular malformations, well-delineated benign and malignant tumors of the head, the treatment of certain pain conditions such as trigeminal neuralgia, as well as the treatment of some movement and psychiatric disorders. The results of treating arteriovenous malformations, acoustic neurinomas, and cerebral metastases are particularly outstanding.

Investigation of Late-Onset Migraine

Sixty-nine patients presenting with migraine, with or without aura, after age 40 were investigated with CT or MRI brain scanning, carotid ultrasound and serum antibody studies. A 2:1 female:male predominance was found, the mean age of presentation being 51.6 years. Migraine with aura was reported in 86% of patients. 46% of the females had active menopausal symptoms. No significant haematological or serological abnormalities were detected. CT or MRI brain imaging was normal in 93% of cases; 4 patients had evidence of cerebral infarction. No cerebral tumour or vascular malformation was found. Three patients had evidence of mild-moderate carotid atheroma on ultrasound scanning. Routine detailed investigation of late-onset migraine is unlikely to be of value unless the history is atypical or abnormalities are present on clinical examination.

Expression of basement membrane and endothelial cell adhesion molecules in vascular malformations of the brain: Preliminary observations and working hypothesis

Little is known about the pathogenesis and subsequent cellular biologic behaviour of human cerebral vascular malformations. Innovative therapeutic strategies will depend on more fundamental understanding of structural and functional lesion biology. We have freeze-processed four specimens of arteriovenous malformation (AVM), two cavernous malformations (CM), and resected cortex from one case of Sturge-Weber disease (SWD) for immunohistochemical studies. Probes of vascular maturity and cellular adhesion were examined, including Factor 8 related antigen (F8RAG), laminin, fibronectin, and adhesion molecules VCAM, ELAM and ICAM-1 (CD 54). Sections of the same lesions were permanently fixed and stained using Haematoxylin and Eosin, and MOVAT Pentachrome stain for identification of vascular wall structures. A double antibody staining battery was utilized with ultraviolet fluorescent microscopy, and was analysed by an observer blinded to the antibody and lesion type. All malformations showed strong expression on their luminal endothelial surface for F8RAG. There was no expression of ELAM in any lesion. Two AVMs expressed VCAM on the endothelial surface of some vessels. ICAM-1 was expressed faintly within two AVMs. The CMs expressed fibronectin within the endothelium and subendothelial matrix, and both lesions were devoid of laminin expression. The AVMs and the SWD vessels stained for laminin, while none of the AVMs expressed fibronectin. These preliminary observations are consistent with the hypothesis that AVMs and SWD represent more mature vessels, consistent with possible lesion genesis during early phases of embryonic vascular development (dysvasculogenesis). In contrast, CMs represent immature vessels devoid of laminin and other features of mature vessels, consistent with ongoing dysangiogenesis within a fibronectin rich matrix. Further studies should be aimed at better elucidation of these biologic probes, and correlation with specific lesion behaviour.

Vascular Malformations and Intractable Epilepsy: Outcome After Surgical Treatment

To review our recent experience with surgical treatment of patients with vascular malformations and intractable partial epilepsy. We retrospectively studied 20 consecutive Mayo patients who had undergone surgical treatment of medically refractory partial epilepsy and had cerebral vascular malformations. Seizures were the initial symptom in all 13 female and 7 male patients, none of whom had a history of a symptomatic intracerebral hemorrhage. Magnetic resonance imaging (MRI) or pathologic examination, or both, indicated the presence of remote hemorrhage associated with the vascular lesion in 18 patients. MRI disclosed 36 vascular malformations (32 cavernous and 4 arteriovenous malformations) in the 20 patients. MRI was more sensitive and specific than computed tomography for their detection and characterization. The operative strategy in all patients included complete resection of the vascular malformation. A modified Engel classification (based on four classes) was used to determine the outcome of seizures. Postoperatively, 15 patients were free of seizures, and 3 patients had at least a 90% decrease in number of seizures. Only two patients had an unfavorable outcome. Neither the age at onset of seizures nor the duration of seizures seemed to affect the outcome. The site of the vascular malformation was less important than precise correlation between the site of onset of seizure activity and the corresponding vascular malformation. The presence of coexistent ipsilateral atrophy of the hippocampal formation should be sought, and the operative strategy should be appropriately modified. In the absence of dual pathologic conditions, lesionectomy can yield a seizure-free outcome in patients with intractable partial epilepsy and cerebral vascular malformations.

Vascular Malformations and Intractable Epilepsy

A retrospective study of 20 consecutive patients with cerebral vascular malformations who were treated surgically for medically refractory partial epilepsy is reported from the Departments of Neurology and Neurologic Surgery, Mayo Clinic, Rochester, MN.

Vascular malformations of the brain in hereditary hemorrhagic telangiectasia (rendu-osler-weber disease)

Six patients with vascular malformation of the brain in hereditary hemorrhagic telangiectasia (HHT) were reviewed to determine clinical and radiographic characteristics of these lesions. There were two patients with arteriovenous fistula (AVF), three with arteriovenous malformation (AVM), and one with multiple AVMs associated with AVF. Seizures were the most common presenting symptom (seen in three patients), and two of them had intracerebral hematomas (ICH). In the remainder, the malformations were incidentally found in the course of evaluation of other diseases. Their locations were variable, but the majority was superficially confined to the cerebral cortex. Arterial supply was from mostly one feeding artery that was a cortical branch of either anterior, middle, or posterior cerebral artery. In six of nine malformations, the venous drainage was through a superficial cerebral vein into either the superior sagittal sinus or transverse sinus. Direct surgery was done on two patients with ICH, artificial embolization on one, and stereotactic radiosurgery on one. The cerebral vascular malformations in HHT are not infrequent, and in particular the importance of computed tomography and cerebral angiography should be recognized in patients with pulmonary AVF associated with HHT.

Angiographically Occult Vascular Malformations

WITH REFERENCE TO vascular malformations, the term cavernous has architectural as well as histologic connotations. It refers to a compact pattern of growth wherein no intervening brain parenchyma is evident, as well as to the histological nature of the vessels, which are hyaline and collagenous in appearance, lacking the microscopic features of arteries or veins. Historically, cavernous angioma has been defined as exhibiting both features. Twenty-five patients with neurological symptoms and neuroimaging abnormalities who underwent surgery for cerebral vascular malformations between 1987 and 1990 satisfied the following study criteria: their lesions were angiographically occult and both magnetic resonance imaging (MRI) and histological sections were available for review. The patients' ages ranged from 4 to 49 years (mean, 30 years), the male to female ratio being 1:2. Two thirds of the lesions were supratentorial in location and all were intraparenchymal. All patients had clinical improvement after resection. In 24 of the 25 lesions, the vascular channels were histologically cavernous in nature; one inadequate specimen precluded classification. Three demonstrated a purely compact or cavernous pattern, 20 a mixed cavernous and racemose pattern, and one a purely racemose pattern. The authors conclude that 1) histologically cavernous lesions are the commonest form of occult vascular malformation; 2) a purely compact or cavernous architectural pattern is uncommon, most lesions showing a partially racemose architecture; 3) some histologically cavernous malformations possess a capillary component; 4) clinical growth of cavernous malformations may have its basis in intraluminal thrombosis and subsequent recanalization; 5) the T2-weighted MRI pattern of cavernous malformations varies, the most common being a multifocal hyperintense center surrounded by a hypointense ring; 6) the MRI pattern reflects the histological appearance; 7) since no thrombosed arteriovenous malformations were encountered, such lesions must be rare; 8) in that the pathophysiological hallmark of a cavernous lesion is recurrent thrombosis and hemorrhage, a resolving hematoma cannot always be distinguished from a cavernous lesion; 9) MRI is the examination of choice in evaluating occult vascular malformations; and 10) microsurgical excision is a satisfactory method of treatment. Lastly, in that occult vascular malformations nearly always exhibit cavernous histology, we suggest the term cavernous angioma be based upon the histological appearance of the vessels and that the somewhat artificial requirement of architectural compactness be abandoned, at least as far as central nervous system lesions are concerned.

Angiographically Occult Vascular Malformations

With reference to vascular malformations, the term cavernous has architectural as well as histologic connotations. It refers to a compact pattern of growth wherein no intervening brain parenchyma is evident, as well as to the histological nature of the vessels, which are hyaline and collagenous in appearance, lacking the microscopic features of arteries or veins. Historically, cavernous angioma has been defined as exhibiting both features. Twenty-five patients with neurological symptoms and neuroimaging abnormalities who underwent surgery for cerebral vascular malformations between 1987 and 1990 satisfied the following study criteria: their lesions were angiographically occult and both magnetic resonance imaging (MRI) and histological sections were available for review. The patients' ages ranged from 4 to 49 years (mean, 30 years), the male to female ratio being 1:2. Two thirds of the lesions were supratentorial in location and all were intraparenchymal. All patients had clinical improvement after resection. In 24 of the 25 lesions, the vascular channels were histologically cavernous in nature; one inadequate specimen precluded classification. Three demonstrated a purely compact or cavernous pattern, 20 a mixed cavernous and racemose pattern, and one a purely racemose pattern. The authors conclude that 1) histologically cavernous lesions are the commonest form of occult vascular malformation; 2) a purely compact or cavernous architectural pattern is uncommon, most lesions showing a partially racemose architecture; 3) some histologically cavernous malformations possess a capillary component; 4) clinical growth of cavernous malformations may have its basis in intraluminal thrombosis and subsequent recanalization; 5) the T2-weighted MRI pattern of cavernous malformations varies, the most common being a multifocal hyperintense center surrounded by a hypointense ring; 6) the MRI pattern reflects the histological appearance; 7) since no thrombosed arteriovenous malformations were encountered, such lesions must be rare; 8) in that the pathophysiological hallmark of a cavernous lesion is recurrent thrombosis and hemorrhage, a resolving hematoma cannot always be distinguished from a cavernous lesion; 9) MRI is the examination of choice in evaluating occult vascular malformations; and 10) microsurgical excision is a satisfactory method of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Stereotactic microresection of small cerebral vascular malformations (SCVM).

Between 1988-1993 we performed CT-stereotactic guided microsurgical resection as a one-session-procedure in 46 patients bearing small (< 30 mm) cerebral vascular malformations (SCVM). The location of the SCVM was deep subcortical in 38 patients, temporal medio- basal in 3 and brainstem in 5. The surgical technique intended to minimise invasiveness by reducing the operative approach to a size less than the diameter of the lesion concerned. The mean diameter of our SCVM's was 20 mm ranging from 10 to 30 mm. Histologically we found 23 arteriovenous malformations, 22 cavernous malformations and 1 capillary telangiectasia (capillary malformation). Clinical symptomatology consisted mainly of seizures, (progressive) neurological deficit and (minute) acute intracerebral bleeding. The SCVMs could be demonstrated by contrast-enhanced CT as well as by MRI. 15 of the AVM's revealed as angiographically occult. Complete microsurgical resection of the SCVM was accomplished in all cases with a surgical morbidity of 6.5% and no operative mortality. In 14 patients, most of them with initial acute intracerebral haemorrhage, the pronounced focal neurological deficit improved. During the follow-up period (1/2-5 years) no rebleeding occurred. As far as epileptic seizures were concerned 13 patients became seizure-free without anticonvulsants and 11 patients seizure-free with anticonvulsant, in the remaining 4 patients seizures were reduced in frequency.

The pathology of arteriovenous malformations of the brain treated by embolotherapy. II. Results of embolization with multiple agents.

Light microscopic and immunohistochemical examination was undertaken of intracranial arteriovenous malformations (AVMs) surgically resected from 18 patients, each of whom had undergone preoperative angiographic embolization with multiple agents. Distinct patterns of tissue reaction to these agents were noted, even when more than one substance was present in a vascular lumen. Avitene produced the mildest tissue response but resulted in relatively early endothelialization and recanalization. Cyanoacrylates were longer-lasting but associated with more acute and chronic (including granulomatous) inflammation and vessel wall changes. Polyvinyl alcohol foam/ethanol mixture had intermediate properties. Endothelial proliferation over embolization material was confirmed using immunohistochemical application of an antibody to cell proliferation-specific proteins. The significance of these findings for combined endovascular and surgical treatment of cerebral vascular malformations is discussed.

First seizure in adults: a prospective study from the emergency department.

A prospective study of 98 consecutive adults with a first seizure to determine the most important etiological factors and the optimum diagnostics. 27 were thought to have cryptogenic seizures. Main causes of symptomatic seizures were: cerebral infarction, alcohol-withdrawal, CNS infections, tumors, vascular malformations, traumatism and miscellanea. Eight were infected by human immunodeficiency virus (HIV-1) representing 8.2% of all the patients with a first seizure and 20% of the 15-45-year age group. CT disclosed structural lesions in 33 cases. MRI in those with normal CT and no other explanation of seizure revealed additional lesions in 22.2%, but did not change management in any. We conclude that CT is essential in evaluation of adults with first seizure. MRI may be useful in selected cases. The HIV-infected now represent an important group with a first seizure.

Arteriovenous malformation of the vein of Galen: A rare cerebral arteriovenous malformation

A 32-year-old male presented to the emergency department for evaluation of a 12-day history of altered mental status. Workup revealed the presence of an arteriovenous malformation (AVM) of the great vein of Galen, an exceedingly rare and often fatal type of cerebral vascular malformation. Concurrent aneurysmic dilatation of the vein, a frequent finding associated with this type of AVM, resulted in compression of the aqueduct of Sylvius and acute hydrocephalus. A brief review of cerebral AVMs is presented, with specific attention to the pathophysiology, clinical presentation, and emergent treatment of those that involve the vein of Galen.

A comparative study of the cerebrovascular complications of cocaine

Cocaine, especially in its alkaloidal or "crack" form, has been increasingly associated with cerebrovascular disease. Before the crack epidemic, cocaine hydrochloride (HCl) was also implicated as a cause of stroke. However, less is known about the differences in stroke subtypes, age at stroke onset, or presence of underlying structural cerebrovascular disease with different forms of cocaine use. We compared 26 patients (previously reported) from our four institutions plus 16 cases reported in the literature of stroke associated with alkaloidal cocaine to 63 (57 reported in the literature and six not previously reported from our four institutions) cases of stroke associated with cocaine HCl. Ischemic and hemorrhagic strokes are equally likely after alkaloidal cocaine use, whereas cocaine HCl is more likely (approximately 80% of the time) to cause hemorrhagic stroke, with approximately half the intracranial hemorrhages occurring from ruptured cerebral saccular aneurysms or vascular malformations. The presence of an underlying cerebral aneurysm was more common among patients with cocaine HCl-associated strokes than alkaloidal cocaine-associated strokes. Cerebral infarction was significantly more common among the alkaloidal cocaine users than in all the cocaine HCl users, and this was also true when alkaloidal cocaine users were compared with parenteral cocaine HCl (intravenous and intramuscular) users. Only hemorrhagic stroke has been reported with intravenous cocaine HCl use. We conclude that the pathogenesis of cocaine-related stroke is heterogeneous, and depends, in part, on the form of cocaine used.

Vascular malformations and pregnancy

Between January 1975 and June 1989, 240 patients with cerebral vascular malformations were treated at Henry Ford Hospital. In 16 of the patients, the treatment was influenced by pregnancy. Eleven of the patients presented with hemorrhage, four with seizures, and one with hydrocephalus. There were no maternal or fetal deaths in the patients presenting with seizure or hydrocephalus. There were two maternal deaths and one fetal death among the cases presenting with hemorrhage. In the patients with seizure or hydrocephalus, the pregnancy was brought to term and obstetric indications used to determine the time and method of delivery. Hydrocephalus was treated by shunting, and seizures with medication. Antiepileptic drug levels fluctuate in pregnancy and hence were closely monitored to ensure therapeutic levels. Vascular malformations are the most common cause of subarachnoid hemorrhage in pregnancy. The risk of rebleed in the same pregnancy is about 27%. If an arteriovenous malformation ruptures during pregnancy and the patient's condition deteriorates, appropriate emergency surgery should be done. In stable patients, our policy has been to bring the pregnancy to term and then electively perform a craniotomy to excise the arteriovenous malformation.

血管撮影にて動静脈奇形の所見を呈し, 組織学的に静脈性血管腫と診断された脳血管奇形の2例

In the classification of cerebral vascular malformations, a mixed or transitional type of malformation has come to be recognized as distinct from the classical assortment, that is, AVM, capillary telangiectasia, cavernous angioma and venous angioma. We recently experienced two cases in which findings of cerebral angiography indicated arteriovenous malformation; however, histological examination of the lesion showed a typical venous angioma. We could not find a report of a similar case in the literature. We consider that these two cases belong to a transitional or mixed type of cerebral vascular malformation composed of arteriovenous malformation and venous angioma.