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Developmental venous anomalies (DVAs) are the most common vascular malformation detected on intracranial cross-sectional imaging. They are generally benign lesions thought to drain normal parenchyma. Spontaneous hemorrhages attributed to DVAs are rare and should be ascribed to associated cerebral cavernous malformations, flow-related shunts, or venous outflow obstruction. Contrast-enhanced MRI, susceptibility-weighted imaging, and high-field MRI are ideal tools for visualizing vessel connectivity and associated lesions. DVAs are not generally considered targets for treatment. Preservation of DVAs is an established practice in the microsurgical or radiosurgical treatment of associated lesions., Competing Interests: Disclosure This study did not receive any funding or financial support. Dr B.A. Gross is a consultant for Medtronic, Stryker, and MicroVention., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Surgical planning for treating brain arteriovenous malformations (bAVMs) is challenging because it entails visualizing 3-dimensional (3D) relationships between the nidus, its feeding and en passage arteries, and draining veins. Surgical experience in developing the capacity to mentally visualize pathological bAVM angioarchitecture could be complemented by this software, and thus potentially lower the steep learning curve for understanding complex bAVM angioarchitecture. We evaluated the clinical application of freely available online 3D reconstruction software in facilitating visualization of AVM angioarchitecture for presurgical planning., Methods: Preoperative Digital Imaging and Communications in Medicine magnetic resonance imaging/magnetic resonance angiography images of 56 superficial bAVMs from 2013 to 2018 were processed using open-source software Horos. 3D rendered images were compared with the surgical view to evaluate software accuracy and determine its value as a preoperative tool. 3D reconstructed images were compared with intraoperative recordings., Results: A useful image identifying both the main feeding artery and draining vein was achieved in 35 of 56 cases (62.5%). Reconstructions of small AVMs (nidus ≤2 cm) and those located within the temporal or cerebellar cortex were less useful due to soft tissue artifacts. Frontal and parietal lobe lesions had significantly higher rates of identifying feeding arteries and draining veins (P < 0.05)., Conclusion: Presurgical planning for resection of superficial bAVMs using Horos software allows for a comprehensive 3D analysis of the bAVM angioarchitecture. This technique is most useful for frontal and parietal lobe lesions, and aids the surgeon in formulating an optimal surgical strategy. The 3D reconstruction of the brain surface offers a surgical map not influenced by brain shift., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Patients with intracranial arteriovenous shunt(s) have a risk of intracerebral hemorrhage (ICH). We investigated the signal intensity of draining veins on susceptibility-weighted imaging (SWI) and the status of venous drainage shown by digital subtraction angiography (DSA). We then evaluated whether the signal intensity of draining veins on SWI is related to normal venous flow (NVF) and/or ICH. We analyzed SWI and DSA in 10 consecutive patients with intracranial arteriovenous shunt(s). Opacification of draining veins in the normal venous phase by DSA was judged as NVF. We evaluated the relationship between the intensity of draining veins on SWI and the presence of NVF before and after treatment. The relationship between the intensity of draining veins on SWI and the presence of ICH surrounding the draining veins was also evaluated. Of 10 patients with untreated arteriovenous shunt(s), two had arteriovenous malformation and eight had a dural arteriovenous fistula with cortical venous reflux. We analyzed 26 draining veins before treatment. In preoperative analysis, draining veins with hypointensity were significantly more likely to show NVF than were draining veins with isointensity or hyperintensity (45.5% vs. 0.0%, P = 0.007). While 69.2% of the areas surrounding draining veins with isointensity or hyperintensity showed ICH, no veins with hypointensity showed ICH (P = 0.011, odds ratio 0.036; 95% confidence interval 0.0017-0.80). In conclusion, draining veins with hypointensity on SWI may contain NVF, despite arteriovenous shunting. The areas surrounding these veins might have a lower risk of ICH because of less venous hypertension., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Embolization of arteriovenous malformations is characteristically used as part of a multimodal treatment approach, pre-operatively to facilitate microsurgical resection or as a preradiosurgical adjunct. The concept of AVM cure via embolization alone has gained popularity in recent years. Embolization of AVMs has been most commonly performed transarterially, with the transvenous route traditionally eschewed given concern over precipitating premature venous occlusion and consequent hemorrhage. However, the transvenous approach in treating AVMs offers several distinct advantages compared to the transarterial route and can be used in instances when the latter is not feasible, with several series having proven its efficacy and safety. Conceptually, AVM embolization performed via the transvenous route achieves complete obliteration by directly and facilely targeting the nidus. Nidal embolisate penetration is facilitated by control of arterial inflow via systemic or local hypotension. Innovation in endovascular strategies has led to significantly improved obliteration rates. The experience with transvenous AVM embolization is reviewed and discussed., (Copyright © 2018. Published by Elsevier B.V.)

Aim: Surgery for intracranial complex vascular malformations can be quite exigent and involves considerable preoperative planning. Here, we present the advantages of using three-dimensional (3D) printed models as a preoperative investigational modality., Material and Methods: 3D printed models were made from thin-slice computed tomography (CT) angiography scans of 6 patients with arteriovenous malformations over an18-month period from August 2015 to December 2016. The locations of the arteriovenous malformations were in the Sylvian fissure in 1 patient, posterior frontal region in 2 patients, subfrontal region in 1 patient, and parietal region in 2 patients. The CT angiography was performed on a 64-slice CT scanner. Thin-slice axial CT sections were acquired and a volume file was created of the arteriovenous malformation and the required skull bones. The file was then transferred to the 3D printer for creating the model., Results: The model depicted the precise nature of the compactness and location of the nidus in relationship to the skull. It was possible to clearly delineate the course, size, and number of feeding vessels and draining veins. The model made identification of the normal and abnormal vessels easier and assisted in the preparation and conduct of surgery. The model was made to scale and was placed beside the surgeon during the operation. The limitation of current technology was that the exact differentiation of arteries and veins by color coding was not possible., Conclusion: 3D printed models can be helpful in getting information regarding the architecture and character of the arteriovenous malformation. The models are cost-effective and easy to build.

Cranial dural arteriovenous fistulae have been classified into high- and low-risk lesions mainly based on the pattern of venous drainage. Those with leptomeningeal venous drainage carry a higher risk of an aggressive clinical presentation. Recently, it has been proposed that the clinical presentation should be considered as an additional independent factor determining the clinical course of these lesions. However, dural shunts with leptomeningeal venous drainage include a very wide spectrum of inhomogeneous lesions. In the current study, we correlated the clinical presentation of 107 consecutive patients harboring cranial dural arteriovenous shunts with leptomeningeal venous drainage, with their distinct anatomic and angiographic features categorized into eight groups based on the "DES" (Directness and Exclusivity of leptomeningeal venous drainage and features of venous Strain) concept. We found that among these groups, there are significant angioarchitectural differences, which are reflected by considerable differences in clinical presentation. Leptomeningeal venous drainage of dural sinus shunts that is neither direct nor exclusive and without venous strain manifested only benign symptoms (aggressive presentation 0%). On the other end of the spectrum, the bridging vein shunts with direct and exclusive leptomeningeal venous drainage and venous strain are expected to present aggressive symptoms almost always and most likely with bleeding (aggressive presentation 91.5%). Important aspects of the above correlations are discussed. Therefore, the consideration of leptomeningeal venous drainage alone, for prediction of the clinical presentation of these shunts appears insufficient. Angiographic analysis based on the above concept, offers the possibility to distinguish the higher- from the lower-risk types of leptomeningeal venous drainage. In this context, consideration of the clinical presentation as an additional independent factor for the prediction of their clinical course seems superfluous and possibly misleading. Topography is connected to the clinical presentation of the dural shunts inasmuch as the former determines the venous anatomy and the angioarchitectural features of the lesions.

Intracranial pial arteriovenous fistulas (AVFs) are rare cerebrovascular lesions. The authors report a rare case of pediatric pial AVF treated by direct disconnection with the aid of indocyanine green (ICG) videoangiography. A 3-year-old girl presented with developmental problems. Magnetic resonance imaging revealed brain atrophy and an anomalous left temporal vascular mass. Angiography showed a high-flow pial AVF in the early arterial phase fed by the M1 portion of the left middle cerebral artery and draining into the superficial sylvian vein and the vein of Trolard with a large varix. Given that her fistula was located in a superficial region that was easily accessible by craniotomy, the authors successfully disconnected her pial AVF by direct surgery aided by ICG videoangiography, which clearly confirmed the shunting point. In this report, the authors discuss the existing literature and compare the relative merits of endovascular versus surgical options for the treatment of pial AVF.

Object: Sylvian fissure arteriovenous malformations (AVMs) present substantial management challenges because of the critical adjacent blood vessels and functional brain. The authors investigated the outcomes, especially hemorrhage and seizure activity, after stereotactic radiosurgery (SRS) of AVMs within or adjacent to the sylvian fissure., Methods: This retrospective single-institution analysis examined the authors' experiences with Gamma Knife surgery for AVMs of the sylvian fissure in cases treated from 1987 through 2009. During this time, 87 patients underwent SRS for AVMs in the region of the sylvian fissure. Before undergoing SRS, 40 (46%) of these patients had experienced hemorrhage and 36 (41%) had had seizures. The median target volume of the AVM was 3.85 cm(3) (range 0.1-17.7 cm(3)), and the median marginal dose of radiation was 20 Gy (range 13-25 Gy)., Results: Over a median follow-up period of 64 months (range 3-275 months), AVM obliteration was confirmed by MRI or angiography for 43 patients. The actuarial rates of confirmation of total obliteration were 35% at 3 years, 60% at 4 and 5 years, and 76% at 10 years. Of the 36 patients who had experienced seizures before SRS, 19 (53%) achieved outcomes of Engel class I after treatment. The rate of seizure improvement was 29% at 3 years, 36% at 5 years, 50% at 10 years, and 60% at 15 years. No seizures developed after SRS in patients who had been seizure free before treatment. The actuarial rate of AVM hemorrhage after SRS was 5% at 1, 5, and 10 years. This rate equated to an annual hemorrhage rate during the latency interval of 1%; no hemorrhages occurred after confirmed obliteration. No permanent neurological deficits developed as an adverse effect of radiation; however, delayed cyst formation occurred in 3 patients., Conclusions: Stereotactic radiosurgery was an effective treatment for AVMs within the region of the sylvian fissure, particularly for smaller-volume AVMs. After SRS, a low rate of hemorrhage and improved seizure control were also evident.

A 25-year-old man presented with right hemiparesis and was admitted to the local hospital. CT scan revealed an intracerebral hematoma in the left motor cortex. He was treated conservatively, the hematoma passed without increase and his right hemiparesis improved gradually. The cause of hemorrhage was examined at the local hospital without resolution. He came to our hospital for further examination. Angiography revealed pial arteriovenous fistulas near the hematoma. The fistulas were fed by small branches of the left anterior cerebral artery and drained into an abnormal cortical vein. Left parietal craniotomy was performed. A red dilated cortical vein existed under the thickened, cloudy arachnoid membrane. Retrograde observation of the red vein showed some small branches connected directly to the red vein at the central sulcus. There was no nidus. The color of the red vein changed to blue after disconnection of the fistulas by electrocoagulation. The dilated cortical vein was resected. Postoperative angiography revealed the disappearance of the fistulas. He was discharged without any new neurological deficits. Intracranial pial arteriovenous fistulas are rare cerebrovascular lesions. As symptomatic patients managed conservatively have a poor prognosis, radical treatment should be undertaken as soon as possible.

Background and Importance: High-grade cavernous sinus (CS) dural arteriovenous fistulae with cortical venous drainage often have a malignant presentation requiring urgent treatment. In the absence of a venous access to the lesion, transarterial embolization can potentially cure these lesions; however, the high concentration of eloquent arterial territories adjacent to the fistula creates a precarious risk of arterial-arterial reflux. In such cases, a combined surgical and endovascular approach may provide the least invasive option., Clinical Presentation: We describe a patient presenting with a venous hemorrhagic infarct caused by a high-grade CS dural arteriovenous fistula (Barrow type D caroticocavernous fistula) with isolated drainage via the superficial middle cerebral vein into engorged perisylvian cortical veins. No transfemoral or ophthalmic strategy was angiographically apparent, and the posterior location of the involved CS compartment mitigated a direct puncture. The patient underwent direct puncture of the superficial middle cerebral vein via an orbitozygomatic craniotomy and the CS was catheterized under fluoroscopic guidance. The CS was coil-embolized back into the distal superficial middle cerebral vein with complete obliteration of the fistula. The patient did well with no new deficits and made an uneventful recovery., Conclusion: This novel combined open surgical and endovascular approach enables obliteration of a CS dural arteriovenous fistula with isolated cortical venous drainage and avoids the additional manipulation with direct dissection and puncture of the CS itself.

We present a case of a symptomatic venous aneurysm that developed in the drainage network of a deep-seated basal ganglia and thalamic arteriovenous malformation. The venous aneurysm was treated selectively with platinum coils using a venous approach., (Copyright © 2009 by the American Society of Neuroimaging.)

Pediatric vascular malformations of the central nervous system differ from those seen in adults. Their classification may be based on symptoms, pathomechanics, patient's age, morphologic features, or presumed etiology. This review describes the different classification schemes and the endovascular management options of these rare and challenging diseases. The proposed etiologic classification of pediatric vascular malformations may add to our understanding of these diseases in general because the phenotypic expression of a given vascular malformation can shed light on the nature and timing of the causative agent, thereby potentially opening up treatment modalities in the future that are directed against the triggering event rather than against the clinical manifestations or the morphologic appearance. With current endovascular methods, most vascular diseases can be approached safely and with good clinical results., (Copyright 2010 Elsevier Inc. All rights reserved.)

A 41-year-old woman presented with progressive hemianopsia caused by compression of the lateral geniculate body by the dilated basal vein draining a contralateral frontal arteriovenous malformation (AVM). Magnetic resonance (MR) imaging revealed left frontal AVM and right lateral geniculate body compression due to the dilated basal vein. Emergent presurgical transarterial embolization and surgical removal were performed. Left hemianopsia completely recovered 3 months after surgery and MR imaging indicated improvement of the compression of the lateral geniculate body. Direct mechanical compression of the enlarged drainage vein is one of the causes of homonymous hemianopsia. Early surgical treatment is recommended to obtain a rapid recovery.

Purpose: The highly eloquent surroundings of brainstem arteriovenous malformations (AVMs) present particular surgical challenges. In the present pilot study we tried to examine whether to occlude the draining vein after control of major feeding arteries and then to coagulate the nidus retrogradely might be a viable concept for brainstem AVMs instead of the traditional perinidal dissection., Methods: A total of five patients harbouring pontine or mesencephalic AVMs were treated at our institution between February 2007 and August 2008. Three of them presented after haemorrhage. In two instances, partial endovascular obliteration was performed prior to surgery. Following exposure and control of major feeders, the principal draining vein was clamped to test tolerance. In none of the cases was major stasis and bleeding from the nidus seen. The draining vein was subsequently coagulated and then stepwise shrinking by retrograde coagulation of the nidus was done. The coagulated nidus was left in place., Results: The procedure was technically successful in all cases and no major postoperative complication related to the procedure was seen. Control angiography confirmed complete occlusion in all cases., Conclusions: Due to the usually small size of brainstem AVMs, retrograde coagulation of the nidus without additional resection can be a feasible approach in order to avoid additional damage by circumferential dissection.

Objective: Arteriovenous malformations (AVMs) treated by radiosurgery with complete obliteration of the nidus but a persisting early draining vein on follow-up angiography can be termed subtotally obliterated. However, these are persistent circulating AVMs. The significance of these lesions, their hemorrhage rate, and their management are analyzed., Methods: In a series of 862 consecutive patients with AVMs treated by radiosurgery, 121 patients (14%) achieved subtotal obliteration (STO). The angiographic evolution and rate of obliteration were studied. The pretreatment angiographic features, dosimetric parameters, and postradiosurgery hemorrhage rate were compared with those in the rest of the treated population. Finally, the options for follow-up and treatment were analyzed., Results: Of 121 subtotally obliterated AVMs, the bleeding rate was 0%; 53% of patients achieved complete obliteration. This occurred in 71% of those who had STO at 1 year. In the cases in which STO was detected at 2, 3, and 4 years, total obliteration eventually occurred in 43%, 28.5%, and 0%, respectively. Comparative analysis with AVMs in which a part of the nidus persisted showed a significant difference in the bleeding rate. Except for volume, no significant statistical difference in angiographic and dosimetric parameters was found between the STO group and the rest of the studied population with residual nidus. Six cases received further treatment, resulting in 2 cures and 2 treatment-related complications., Conclusion: Subtotally obliterated AVMs are different from other partially obliterated AVMs, with a 0% bleeding rate. Their complete obliteration is a function of delay of appearance on follow-up angiography. Invasive follow-up and further treatment of these AVMs do not seem warranted.

Background: Use of virtual reality planning and rehearsal for planning and training of cerebral aneurysm clipping was recently reported. We aimed to illustrate its applications in preoperative planning and training for cerebral AVM excision., Case Description: We illustrated the application of preoperative rehearsal for excision of cerebral AVM for 2 patients in a stereoscopic virtual reality environment. One patient was a 44-year-old lady with a right posterior temporal AVM, and 1 patient was a 23-year-old lady with a left frontal AVM. Through Dextroscope, an anatomical understanding of arterial feeders, nidus, and draining veins in relationship to surrounding cerebral cortex was obtained. It allowed one to see the exposure with the different angles of visualization, similar to what happened under the operative microscope., Conclusion: Dextroscopic virtual reality stimulation provided an illustrated preoperative planning and training for excision of cerebral AVM.

Object: The authors reviewed the experience of a single surgeon in the surgical treatment of arteriovenous malformations (AVMs) in children, with specific attention to the angioarchitectural appearance of these lesions. Methods The authors performed a retrospective review of pediatric cases of AVM treated at a single institution over a 15-year period. Inclusion criteria consisted of pediatric age at time of treatment and resection of a pial AVM. The AVMs were considered linear-based if they had a single, centrally located, dominant vein with a linear configuration rather than the typical central nidus., Results: Sixty-seven patients, ranging in age from 6 months to 17 years, underwent surgical treatment of an AVM between January 1, 1990, and December 30, 2005. In these patients, 31 AVMs (46%) had a distinct linear configuration that was centered on a dominant draining vein ("vein-based"). These AVMs presented with hemorrhage (61%), incidental findings on imaging (16%), or seizures (13%). In 4 cases, AVM recurrence was noted on angiographic follow-up after postoperative angiography showed no residual lesion. Recurrence was seen at 1 year in 2 cases, and at 3 and 11 years in 1 case each., Conclusions: A linear vein-based morphological pattern is common in pediatric AVMs and may recapitulate the embryological origins of the cerebral circulation. Surgical treatment in these cases can also be vein-based, through a narrow surgical corridor, which leads to minimal cortical disruption.

Object: Surgical intervention may be required if endovascular embolization is insufficient to completely obliterate intracranial dural arteriovenous fistulas (DAVFs). The authors report their 14-year experience with 23 patients harboring diverse intracranial DAVFs that required surgical intervention., Methods: Between 1993 and 2007, 23 patients underwent surgery for intracranial DAVFs. The following types of DAVFs were treated: superior petrosal sinus (in 10 patients); parietooccipital (in 3); confluence of sinuses and ethmoidal (in 2 each); and tentorial, falcine, occipital, transverse-sigmoid, superior sagittal, and cavernous sinuses (in 1 patient each). In all cases, the authors' goal was to obliterate the DAVF venous outflow by direct surgical interruption of the leptomeningeal venous drainage. Transarterial embolization was used primarily as an adjunct to decrease flow to the DAVF prior to definitive treatment., Results: Complete angiographic obliteration of the DAVF was achieved in all cases. There were no complications of venous hypertension, venous infarction, or perioperative death. There were no recurrences and no further clinical events (new hemorrhages or focal neurological deficits) after a mean follow-up of 45 months., Conclusions: The authors' experience emphasizes the importance of occluding venous outflow to obliterate intracranial DAVFs. Those that drain purely through leptomeningeal veins can be safely obliterated by surgically clipping the arterialized draining vein as it exits the dura. Radical excision of the fistula is not necessary.

Introduction: The use of integrated pre- and intraoperative imaging may be useful when resecting brain lesions in close proximity to eloquent areas, such as the primary motor cortex and language cortices., Case Report: A 32-year-old woman with an arteriovenous malformation (AVM) located in the primary motor cortex underwent surgery using functional neuronavigation. Blood-oxygenation-level-dependent functional magnetic resonance imaging (BOLD fMRI) and diffusion tensor tractography (DTT) were used for preoperative mapping of primary motor areas and the corticospinal tracts, respectively. The BOLD fMRI activations and DTT tractograms were integrated into the neuronavigation system and visualized intraoperatively throughout the operation. Furthermore, stereoscopic visualizations of the angioarchitecture based on 3D MRI angiograms were used to rehearse the surgical approach to the feeder vessels. Finally, intraoperative ultrasound was used to locate and clip the feeding vessels., Conclusion: The AVM was carefully resected with the aid of the above-mentioned imaging techniques, and the intuitive usefulness of the techniques was further substantiated by the rewarding postoperative outcome.

Purpose: Our purpose was to present our experience regarding embolization of intracranial dural arteriovenous fistulas (DAVFs) with cortical venous reflux using Onyx, a non-adhesive liquid embolic agent., Materials and Methods: From January 2006 to December 2007, 16 patients (12 men and 4 women) with a mean age of 61 years (range 42 - 78) with an intracranial DAVF with cortical venous reflux underwent at least one transarterial embolization using Onyx. According to the Cognard classification, 2 lesions were grade V, 5 were grade IV, 6 were grade III, 2 were grade IIa+b, and 1 was grade IIb. The clinical presentation included 5 hemorrhagic deficits, 10 non-hemorrhagic manifestations, and 1 patient was asymptomatic., Results: Twenty-four embolization sessions were performed in 16 patients with an average of 3 arterial feeders (range 1 - 9) embolized per DAVF. Immediately after embolization, complete occlusion was achieved in 9/16 (56%) patients after the first session. Further postembolization surgical treatment was performed in 3 patients. Partial reperfusion occurred in 1 patient at the time of mean follow-up of 3.7 months (range 0 - 12). Treatment has been completed for 11/16 patients with angiographic cure in 10/11 (91%). An infratentorial bleeding complication related to embolization occurred in one patient with temporary worsening of the patient's gait disturbance. At the time of mean clinical follow-up of 4.5 months (range 0 - 12), no procedure-related permanent morbidity was added to our cohort., Conclusion: According to our experience, embolization of intracranial DAVFs with cortical venous drainage using Onyx is feasible with promising results, indicating stability at the time of mid-term follow-up. In very complex DAVFs additional embolization material might be necessary, and in some cases surgery is warranted.

Objective: To present the results of arteriovenous malformation (AVM) radiosurgery using the Modified Rankin Scale (MRS) as the primary outcome measure and to analyze whether previous AVM rupture or other factors have an effect on outcomes after AVM radiosurgery., Methods: We reviewed outcomes after AVM radiosurgery for 243 patients from 1990 and 2001. The mean follow-up after radiosurgery was 65 months., Results: Forty-one patients (17%) sustained a decline in MRS (median -2) after AVM radiosurgery. We noted a decline in MRS in 4% of patients 1 year after radiosurgery, 8% of patients at 3 years after radiosurgery, and 15% of patients at 7 years after radiosurgery. The radiosurgery-based AVM score correlated with a decline in MRS after AVM radiosurgery in multivariate testing (odds ratio 2.1; 95% CI 1.2 to 3.6; p < 0.01)., Conclusions: Previous AVM rupture did not influence neurologic deterioration after AVM radiosurgery. The radiosurgery-based AVM score predicted the chance of a worse MRS after radiosurgery.

Objective: Once thought to be rare entities, mixed cerebrovascular malformations with pathological features of more than one type of malformation within the same lesion are now being recognized with increasing frequency. Their identification generates several hypotheses about common pathogenesis or causation-evolution among different types of lesions and leads to controversial discussion on therapeutic strategies., Methods: Fifteen patients drawn from a consecutive series of 58 patients harboring cavernous malformations (25.9%) were found to have an associated venous malformation (VM). Three (33.3%) of the first 9 patients, in whom the large draining vein of the VM had been left untouched at previous interventions, developed recurrent and/or de novo lesions., Results: Histopathological analysis, interestingly, revealed that the new lesions were different in nature (three arteriovenous angiomas in two patients, a capillary telangiectasia in one patient). During extirpation of the new malformation, the draining vein of the VM in these three patients could be coagulated without any adverse events. Coagulation and dissection of the draining vein of the associated VM was performed in six more patients of our series, and this has prevented development of new lesions up to now., Conclusion: Our results are in favor of the hypothesis that the draining vein of a VM is the actual underlying abnormality of mixed vascular malformations. Causing flow disturbances and having the potential for hemorrhages, the VM seems to promote the development of new adjacent malformations. Thus, permanent cure of associated malformations might depend on the surgical treatment of the VM. We present a preliminary personal series and a thorough review of the literature.

Objective: In this study, we developed an a priori system to stratify surgical intervention of perisylvian arteriovenous malformations (AVMs) in 20 patients. We stratified the patients into three categories based on preoperative functional magnetic resonance imaging (fMRI) language activation pattern and relative location of the AVM., Methods: In Group I (minimal risk), the AVM was at least one gyrus removed from language activation, and patients subsequently underwent asleep resection. In Group II (high risk), the AVM and language activation were intimately associated. Because the risk of postoperative language deficit was high, these patients were then referred to radiosurgery. In Group III (indeterminate risk), the AVM and language were adjacent to each other. The risk of language deficit could not be predicted on the basis of the fMRI alone. These patients underwent awake craniotomy with electrocortical stimulation mapping and optical imaging of intrinsic signals for language mapping., Results: All patients from Group I (minimal risk) underwent asleep resection without deficit. All Group II (high-risk) patients tolerated radiosurgery without complication. In Group III (indeterminate risk), three patients underwent successful resection, whereas two underwent aborted resection after intracranial mapping., Conclusion: We advocate the use of fMRI to assist in the preoperative determination of operability by asleep versus awake craniotomy versus radiosurgery referral. In addition, we advocate the use of all three functional mapping (fMRI, electrocortical stimulation mapping, and optical imaging of intrinsic signals) techniques to clarify the eloquence score of the Spetzler-Martin system before definitive treatment (anesthetized resection versus radiosurgery versus intraoperative resection versus intraoperative closure and radiosurgery referral).

The strategy for treating arteriovenous malformations (AVMs) has undergone changes and long-term follow-up results remain unclear. To compare the outcomes of different treatment strategies, we divided 112 patients with 113 AVMs into groups with hemorrhagic (n = 71, 62.8%) and nonhemorrhagic (n = 42, 37.2%) AVMs and subdivided these according to the period in which they were treated (before/after 1990). In the more recent period, treatment more frequently involved the use of the gamma-knife and microembolization to the AVM as well as combination therapy. Long-term follow-up showed that the complication rate was lower and the Rankin scale better, in the more recently treated group. Based on our findings we suggest that AVMs should be treated aggressively using a multimodality strategy.

Background: The role of intraoperative angiography in the surgical treatment of cerebrovascular malformations remains controversial. The authors report on their experiences with intraoperative angiography in a series of 20 cases with cerebrovascular malformation to determine whether the use of intraoperative angiography has a favorable impact on the surgical treatment of cerebrovascular malformations., Methods: Intraoperative angiography was performed in the surgical resection of arteriovenous malformation in 18 patients and in the surgical obliteration of arteriovenous fistula in 2 patients. The incidence of unexpected findings, such as residual nidus, demonstrated by intraoperative angiography was determined., Findings: High-quality subtraction images were obtained by intraoperative angiography in every case and the findings prompted an additional procedure in 1 case that displayed an unexpected residual nidus (5.6%). There were no complications from the intraoperative angiography procedure., Interpretation: Intraoperative assessment of technical results prior to wound closure offers the neurosurgeon the opportunity to resect or obliterate a vascular malformation completely, obviating a second operation.

The purpose of this study was to evaluate the usefulness of a new ultrashort contrast-enhanced (CE) MR angiography (MRA) for the morphologic evaluation of cerebral arteriovenous malformations (AVMs). The method was compared with conventional X-ray digital subtraction angiography (DSA) and time-of-flight (TOF) MRA in 22 patients to assess the angioarchitecture of the malformations which is essential for treatment planning and follow-up. Two experienced MR readers independently evaluated both techniques with regard to the assessment of feeding arteries, AVM nidus, and venous drainage patterns. Contrast-enhanced MRA was able to detect all AVMs seen on DSA, whereas the TOF MRA failed in 1 patient with a very small AVM. In the assessment of the different vessel components of the AVM there was no difference for the detection and delineation of feeding arteries and the AVM. The venous drainage patterns could always be clearly delineated in the CE MRA, whereas TOF MRA could demonstrate the exact venous drainage in only 9 patients. Contrast-enhanced MRA was found to be superior to conventional TOF MRA in the assessment of the angioarchitecture of cerebral AVMs especially regarding the assessment of the venous drainage patterns. The superiority is supported by the improved vessel-to-background contrast and contrast-to-noise ratios. The major limitations of this new technique consist of a low spatial resolution at the used time resolution which can be improved by further sequence modifications. Contrast-enhanced MRA is thus an important additional imaging technique for treatment planning and follow-up of AVMs.

Objective and Importance: Vein of Galen aneurysm is a rare congenital anomaly of cerebral circulation and occurs mainly in newborns and children. The spontaneously thrombosed vein of Galen aneurysm is especially rare and an uncommonly reported event., Clinical Presentation: Two patients with a spontaneously thrombosed vein of Galen aneurysm were operated on at our institute. CT and MRI demonstrated space-occupying lesions of the pineal region and two other masses in the posterior fossa in the second case. The first described case should be referred to as the true type of aneurysm. The vascular malformation, revealed in the second case should be referred to as the false type. In this case the vein of Galen was enlarged to a gigantic size due to the blood drainage from the arteriovenous malformation supplying it from the inferior posterior cerebellar artery., Technique: Thrombosed aneurysmal sacs were resected totally by subtentorial supracerebellar and median suboccipital approaches., Conclusion: The authors report two cases of successful surgical resection of a thrombosed vein of Galen aneurysm in children. Diagnostic features are considered and the informative value of magnetic resonance imaging is stressed. The principles of choosing the right approach and dissection techniques of thrombosed aneurysms of the vein of Galen are described.

This study was carried out in order to derive the radiobiological parameters of the dose-response relation for the obliteration of arteriovenous malformation (AVM) following single fraction stereotactic radiotherapy. Furthermore, the accuracy by which the linear Poisson model predicts the probability of obliteration and how the haemorrhage history, location and volume of the AVM influence its radiosensitivity are investigated. The study patient material consists of 85 patients who received radiation for AVM therapy. Radiation-induced AVM obliterations were assessed on the basis of post-irradiation angiographies and other radiological findings. For each patient the dose delivered to the clinical target volume and the clinical treatment outcome were available. These data were used in a maximum likelihood analysis to calculate the best estimates of the parameters of the linear Poisson model. The uncertainties of these parameters were also calculated and their individual influence on the dose-response curve was studied. AVM radiosensitivity was assumed to be the same for all the patients. The radiobiological model used was proved suitable for predicting the treatment outcome pattern of the studied patient material. The radiobiological parameters of the model were calculated for different AVM locations, bleeding histories and AVM sizes. The range of parameter variability had considerable effect on the dose-response curve of AVM. The correlation between the dosimetric data and their corresponding clinical effect could be accurately modelled using the linear Poisson model. The derived response parameters can be introduced into the clinical routine with the calculated accuracy assuming the same methodology in target definition and delineation. The known volume dependence of AVM radiosensitivity was confirmed. Moreover, a trend relating AVM location with its radiosensitivity was observed.

Background and Purpose: Description and critical review of our procedure of definition of the target of irradiation of a cerebral arteriovenous malformations., Patients: and method. Fixation of the stereotactic frame, performing of stereotactic angiography and CT scanner were described, and the target including nidus and venous collectors of the a cerebral arteriovenous malformations defined., Conclusion: The use of several three-dimensional imaging techniques can improve and simplify the method of delineating target with a reduction of radio-induced complications.

A case of arteriovenous malformation associated with venous malformation is reported. A 35-year-old male patient suffered intracerebral hemorrhage in the left occipital with acute subdural hematoma. Angiography showed an arteriovenous malformation fed by the left middle cerebral artery. The hematoma and nidus was operatively removed. He also had a venous malformation in the left temporal lobe. This rare case is reported with some discussion.

Object: The goal of this study was to evaluate the results of gamma surgery in nine patients treated for vein of Galen malformations (VGMs)., Methods: A consecutive series of nine VGMs in eight children aged 4 to 14 years and in one adult were treated with gamma surgery. Six of the patients were male, including the adult, and three were female. Among these patients there were three Yasargil Type I, one Type II, two Type III, and three Type IV malformations. Previous embolization had failed in four cases. Three VGMs were treated with gamma surgery twice. An additional patient with a Type III VGM underwent stereotactic angiography in preparation for gamma surgery but was judged to be suitable for direct embolization. Follow-up angiograms were obtained in eight of the VGMs treated. Four no longer filled; one has probably been obliterated, but this cannot be confirmed because the patient refused to undergo final angiography; one patient has residual fistulas not included in the initial treatment field, which were retreated recently; and two other patients have marked reduction of flow through their VGMs., Conclusions: Gamma surgery is a viable option in the treatment of VGMs in clinically stable patients. Combined endovascular therapy and gamma surgery is of benefit in complex malformations.

Recently, there has been increasing interest in the study, characterization, and management of infantile spasms. With technological advances, it is now possible to determine a specific diagnosis on many patients with infantile spasms, thus broadening the spectrum of conditions associated with this electroclinical syndrome. We report a child with infantile spasms who also had a vascular malformation of the vein of Galen. Both clinical and electroencephalographic findings improved rapidly after endovascular treatment of the vascular anomaly, suggesting a possible association.

Background: Tentorial dural arteriovenous fistulas (AVFs) are uncommon lesions usually treated surgically using a subtemporal exposure with division of the tentorium. This exposure requires significant retraction of the temporal lobe and has the possibility of significant arterialized venous bleeding if a draining vein is accidentally cut during division of the tentorium. Skull base surgical techniques may provide alternate approaches for the surgical treatment of tentorial dural AVFs., Methods: A tentorial dural arteriovenous fistula supplied by the tentorial artery and drained by the petrosal vein was exposed and obliterated using the petrosal (subtemporal-presigmoid) approach., Results: The petrosal approach allowed the exposure and division of the superior petrosal sinus and tentorium with direct visualization of the supratentorial and the infratentorial compartments, avoiding accidental damage to the draining veins. The dural fistula was easily obliterated after its venous drainage was interrupted and the tentorial artery occluded., Conclusions: Tentorial dural AVFs can be safely treated with interruption of the venous drainage. The exposure can be enhanced with a petrosal approach, decreasing the possibility of uncontrolled bleeding during the procedure.

We studied three patients with aneurysmal malformations of the vein of Galen: all underwent embolisation followed by MRI and conventional angiography; two also underwent postembolisation magnetic resonance angiography (MRA). MRI was performed before treatment in two patients, MRA in only one, diagnosed prenatally. Two patients had normal appearances on follow-up MR studies and were completely cured by embolisation. However, the last patient, after two embolisations, despite the stabilisation of the clinical condition, underwent surgery and died. We think MRI is mandatory before endoarterial treatment, to assess the conditions of the brain. Angiography is mandatory only at the time of endovascular treatment, while MRA and MRI have a role in follow-up. Endoarterial embolisation remains the treatment of choice, and surgery is not advisable.

Purpose: We sought to determine the prevalence of coexistent occult vascular malformations (OVMs) and developmental venous anomalies (DVAs) and to investigate the relationship between them., Methods: One hundred two patients with OVMs were examined with precontrast and postcontrast T1-weighted MR imaging and with noncontrast T2-weighted MR imaging. Seventy-two patients had surgery, with subsequent pathologic confirmation of the final diagnosis., Results: Coexistent DVAs and OVMs were present in 23 (23%) of 102 patients. Seventy-nine patients had OVMs without DVAs, and in this population, multiple OVMs (from two to 10 or more) were seen in 13 patients (16%). In contrast, multiple OVMs were seen in 10 (43%) of 23 patients with coexisting OVMs and DVAs. Twenty-five (83%) of 30 OVMs coexisting with DVAs were infratentorial. In 72 patients with surgically resected OVMs, 49 (68%) had pathologically confirmed cavernous malformations. Among the patients with coexistent DVAs, seven (46%) had cavernous malformations, four (27%) had thrombosed arteriovenous malformations, and four (27%) had vascular malformations that were not classifiable., Conclusion: Our study revealed a high prevalence of OVMs with coexistent DVAs, and a high percentage of these were in the posterior fossa. Contrast-enhanced MR imaging may increase the probability of finding these lesions, and therefore should be considered part of the preoperative evaluation, since the finding of unexpected coexistent lesions may affect surgical management.

We report an 11-year-old boy with a sinus pericranii. Magnetic resonance images demonstrated a small hole in the cranium underneath the subcutaneous mass. Magnetic resonance angiography (MRA) with sequential two-dimensional time-of-flight (2D-TOF) method demonstrated that the venous flow via the sinus pericranii was directed from the intra- to the extracranial venous system (the drainer type). This was confirmed by a combination of conventional cerebral angiography and percutaneous sinography. We advocate that both the correct diagnosis and classification of sinus pericranii can be established with a combination of current noninvasive neuroradiologic studies, especially for the pediatric age group. MRA with the 2D-TOF method is useful in the assessment of this venous anomaly.

Objective: Radical resection of meningiomas and dural arteriovenous fistulas involving functional major dural sinuses entails the risk of intracranial hypertension and venous infarction. Surgical reconstruction of dural sinuses and bridging veins increases the spectrum of dural sinus conditions that can be treated by complete resection, but indications for venous reconstructions and associated risks are still not well defined. We report our experience with sinus reconstruction based on the intraoperative assessment of collateral venous flow., Methods: Radical resection of meningiomas (n = 5) or dural arteriovenous fistulas (n = 5) involving critical segments of dural sinuses was performed in 10 patients. All but two patients were suffering from recurrent disease after incomplete treatment. Tolerance of sinus occlusion was assessed intraoperatively by measuring stump pressure in the superior sagittal sinus during test clamping of the involved sinus segment., Results: In five patients, the results of pressure monitoring suggested that occlusion of the sinus might not be tolerated. In two other patients, major bridging veins entered the diseased segment. In these patients, the resected sinus segment was reconstructed and bridging veins were reinserted as far as possible. Postoperative graft occlusion occurred in two patients. One patient who was managed without reconstruction sustained a transient postoperative neurological deficit resulting from venous congestion in the vein of Labbé. Postoperative imaging confirmed total elimination of the pathological process in all 10 patients. There was no recurrence of disease during follow-up periods of up to 8 years., Conclusion: The monitoring of sinus pressure, together with the possible reconstruction of the diseased sinus, allows complete surgical treatment of dural sinus abnormalities and involves acceptable risk.

Objective and Importance: The development of a venous aneurysm associated with dural arteriovenous malformations rarely has been documented in the literature., Clinical Presentation: A 64-year-old man with known dural arteriovenous malformations developed a venous aneurysms, as shown on sequential angiograms obtained during 2 years., Intervention: The dural arteriovenous malformations were treated with neuroendovascular embolization and then surgical excision., Conclusion: The clinical presentation, diagnosis, and treatment of this unusual case are presented.

Background: Vein of Galen aneurysm is a relatively rare vascular malformation, often resulting in high morbidity or mortality. Outcome is particularly poor in the neonatal population., Methods: We report staged surgical treatment of a vein of Galen aneurysm in a neonate who presented in congestive heart failure., Results: Cerebral angiography 6 months following staged surgical treatment revealed complete obliteration of the aneurysm. The patient tolerated surgery well, and at 6 years of age is free of neurologic or cardiovascular impairment., Conclusions: While the endovascular approach is the procedure of first choice, aggressive medical management followed by staged surgical clipping of aneurysm feeders produced excellent results in this case of neonatal vein of Galen aneurysm. Staged surgical obliteration of arterial feeders should be considered as a therapy when endovascular methods are unsuccessful in safely curing these difficult vascular lesions.

A case of isolated parenchymal venous varix not seen on angiography is reported. CT demonstrated a well-defined cystic lesion with peripheral enhancement deep within the left temporal lobe. MR demonstrated a high-signal-intensity lesion with hemosiderin rim.

The authors present three cases of vein of Galen aneurysmal malformations (VGAMs) diagnosed in infancy and submitted by the referring teams for stereotactic radiosurgery as the initial therapy (therapeutic doses ranging between 20-25 Gy and 40-50 Gy to the peak dose). After the conventional follow-up of 18-24 months, no change could be detected in the angioarchitecture of the lesions. All three cases were then referred for endovascular treatment and underwent embolization by the transarterial route using liquid adhesives (N-butyl cyanoacrylate). This resulted in complete anatomical exclusion of the lesion. Regardless of the theoretical efficiency of radiosurgery in the management of brain arteriovenous malformations, the present authors believe that transarterial embolization remains the treatment of choice in VGAMs. It offers a high rate of morphological cure and the best chances for normal neurocognitive development. The time required by radiosurgery to achieve a significant result is too long for developing and maturing brain and may not prevent the negative effects of the lesion, mainly in regard to hemo- and hydrodynamic disorders (atrophy, subcortical calcifications, etc.) created by the VGAM, thus leading to irreversible mental retardation.

The case of a young girl with a pericallosal venous malformation associated with multiple cryptic vascular malformations (CVM's) is described. The presenting cryptic malformation, which hemorrhaged, was completely excised, but the venous malformation was not. Routine follow-up magnetic resonance images obtained over the past 9 years have documented the development of multiple new cryptic malformations along the radicles of the venous malformation. Magnetic resonance imaging and cerebral angiography revealed venous outflow obstruction at the junction of the venous malformation with the straight sinus. The association of CVM's with anomalous venous drainage patterns and the role of venous hypertension in the pathogenesis of cryptic malformations are discussed. This case suggests that CVM's associated with a venous malformation may recur and new ones may develop if the venous malformation is not excised, particularly if venous hypertension is also present. The likelihood of a surgical cure in these patients may depend on complete excision of both anomalies, which is rarely feasible because of the potentially devastating results of resecting a venous malformation. Alternative treatments for patients with both types of lesions are discussed.

A case of neonatal intracerebral hemorrhage (ICH) secondary to rupture of an arteriovenous malformation (AVM) is reported. The baby began to vomit frequently 9 h after birth. Computed tomographic scan revealed the presence of an ICH. Intravenous digital subtraction angiography (IVDSA) demonstrated an AVM, which was successfully excised on the 2nd day after birth. It is stressed that IVDSA is safe and noninvasive in comparison with conventional angiography and is useful for diagnosis of cerebral vascular disease in neonates.

We reported a case of cavernous malformation (CM) associated with medullary venous malformation in the same area. The CM was located in the trigone of the lateral ventricle in the dominant hemisphere and drained into the longitudinal caudate vein of Schlesinger via deep medullary veins. By a transsylvian transventricular approach, the CM was totally removed with successful preservation of the medullary venous malformation. This approach is available for trigonal lesions, especially in cases with enlarged inferior horn. We stress that CM removal can be conducted with preservation of the adjacent medullary venous malformation.

Dural arteriovenous fistula, (AVF), a rare entity, presents most commonly in adults. An 11-month-old boy presented with symptoms of congenital toxoplasmosis associated with an extensive dural AVF of the torcular Herophili and bilateral occlusion of the transverse and sigmoid sinuses. His intracranial venous drainage had become rerouted via the cavernous sinuses to the ophthalmic veins. The relationship of toxoplasmosis and sinus thrombosis to the pathogenesis of dural AVF and their clinical and radiological features are discussed.