Confluence Of Sinuses Research Articles

Quantitative Evaluation of Noncontrast Computed Tomography of the Head for Assessment of Anemia.

Anemia is an underdiagnosed clinical entity with significant mortality and morbidity. We aimed to assess whether attenuation of dural venous sinuses correlates with hemoglobin/hematocrit and to determine if the degree of anemia can be predicted by quantitative analysis of unenhanced computed tomography (CT) of the head. This is an institutional review board-approved retrospective study including 500 patients who underwent emergency department investigation for potential central nervous system etiology of their symptoms with unenhanced CT head at a tertiary care center. Computed tomographic attenuation values were obtained by 2 independent readers, whereas 2 separate investigators collected clinical data. Regression analyses were performed to evaluate the strength of correlation and the predictability of anemia and its severity on unenhanced CT. Receiver operating characteristic curve analyses were performed to evaluate sensitivity, specificity, as well as positive and negative predictive values. A total of 243 met the inclusion criteria, and attenuation values for all the dural venous sinuses were averaged and categorized according to hemoglobin values of less than 8, 8 to 10, 10 to 14, and greater than 14. Mean CT attenuation values for both readers were 36.30, 42.35, 47.99, and 53.25 Hounsfield units. Regression analysis revealed the highest positive correlation of hemoglobin/hematocrit with attenuation at the confluence of sinuses with R value of 0.63 and 0.60. The sensitivity, specificity, and negative predictive value of detecting hemoglobin of less than 10 at confluence of sinuses were 91.2%, 88.5%, and 98.6%, respectively. Interobserver agreement was found to be good (0.64) using the κ statistic. Our study substantiates direct positive correlation between CT attenuation of dural venous sinuses and hemoglobin/hematocrit, with strongest correlation at the confluence of sinuses with good sensitivity, specificity, and negative predictive value.

上矢状静脈洞直接穿刺による静脈洞交会部硬膜動静脈瘻へのアプローチ

上矢状静脈洞直接穿刺による静脈洞交会部硬膜動静脈瘻へのアプローチ

Sickle Injury to Brain

We reported a case of a 12-year-old girl child with an uncommon intracranial metallic foreign body who was hit by her younger sister with sickle that got stuck to skull. Patient presented to us with stuck sickle in her head and was fully conscious with complaint of headache. She was very much afraid of her injury and was screaming with pain and fear. There was no neurological weakness. Computed tomography scan revealed that metallic foreign body was located adjacent to the confluence of major sinuses posteriorly on her skull. The location and position of foreign body suggested that it was of low velocity, and was hit from pointed end of sickle. It was taken out after doing craniectomy all around the sickle point and dural tear was repaired with pericranium. The postoperative course was uneventful.

Improved cerebral time-of-flight magnetic resonance angiography at 7 Tesla--feasibility study and preliminary results using optimized venous saturation pulses.

PurposeConventional saturation pulses cannot be used for 7 Tesla ultra-high-resolution time-of-flight magnetic resonance angiography (TOF MRA) due to specific absorption rate (SAR) limitations. We overcome these limitations by utilizing low flip angle, variable rate selective excitation (VERSE) algorithm saturation pulses.Material and MethodsTwenty-five neurosurgical patients (male n = 8, female n = 17; average age 49.64 years; range 26–70 years) with different intracranial vascular pathologies were enrolled in this trial. All patients were examined with a 7 Tesla (Magnetom 7 T, Siemens) whole body scanner system utilizing a dedicated 32-channel head coil. For venous saturation pulses a 35° flip angle was applied. Two neuroradiologists evaluated the delineation of arterial vessels in the Circle of Willis, delineation of vascular pathologies, presence of artifacts, vessel-tissue contrast and overall image quality of TOF MRA scans in consensus on a five-point scale. Normalized signal intensities in the confluence of venous sinuses, M1 segment of left middle cerebral artery and adjacent gray matter were measured and vessel-tissue contrasts were calculated.ResultsRatings for the majority of patients ranged between good and excellent for most of the evaluated features. Venous saturation was sufficient for all cases with minor artifacts in arteriovenous malformations and arteriovenous fistulas. Quantitative signal intensity measurements showed high vessel-tissue contrast for confluence of venous sinuses, M1 segment of left middle cerebral artery and adjacent gray matter.ConclusionThe use of novel low flip angle VERSE algorithm pulses for saturation of venous vessels can overcome SAR limitations in 7 Tesla ultra-high-resolution TOF MRA. Our protocol is suitable for clinical application with excellent image quality for delineation of various intracranial vascular pathologies.

Transarterial Onyx embolization of intracranial dural arteriovenous fistulas: A single center experience

BackgroundTransarterial embolization of intracranial dural arteriovenous fistulas (DAVFs) is usually associated with inadequate embolization. The purpose of this study was to report our experience of transarterial Onyx embolization of intracranial DAVFs with an emphasis on treatment outcome with this new embolic agent in different types of DAVFs. MethodsIn the past 3 years, a total of 14 intracranial DAVFs have been treated by transarterial Onyx embolization. Among these, there were nine males and five females, aged from 30 years to 82 years (mean = 62 years). We retrospectively analyzed the injection volume and time of Onyx embolization as well as outcomes in different types of DAVFs. ResultsThe locations of the DAVFs were sigmoid sinus (n = 6), tentorium (n = 3), sinus confluence (n = 2), transverse–sigmoid sinus (n = 1), sigmoid sinus–jugular bulb (n = 1) and the superior petrous sinus (n = 1). The mean volume and time of Onyx injection were 3.4 mL and 28 minutes, respectively (Cognard type I: 4.9 mL, 40 minutes; type II: 4.5 mL, 34 minutes; type III: 2.2 mL, 21 minutes; type IV: 2 mL, 22 minutes). Total fistula occlusion was achieved in six out of seven patients of type III and type IV DAVFs, and in four out of seven patients of type I and type II DAVFs. Nine patients had total resolution of their symptoms, whereas partial regression occurred in five patients. No significant periprocedural complication was found. Mean clinical follow-up period was 16 months. ConclusionTransarterial Onyx embolization of intracranial DAVFs is safe and effective. This technique is particularly useful in type III and type IV DAVFs with a high cure rate, and lower volume of Onyx as well as a short injection time.

Utility of the Analysis of Intracranial Venous Sinuses Using Preoperative Computed Tomography Venography for Safe Occipital Screw Insertion

Prospective descriptive study. To verify the feasibility and utility of evaluating venous sinuses (VSs) using computed tomography venography (CTV) concomitant with preoperative CT angiography (CTA) for safe occipital screw fixation. Preoperative evaluation of the vertebral artery by CTA is indispensable in occipitocervical spinal instrumentation surgery. Despite accumulating evidence showing the potential of CTV, no studies have reported the usefulness of concomitant use of CTV and CTA before placement of occipital plate-screw constructs. We analyzed 30 consecutive patients who underwent CTV simultaneously with CTA. First, we investigated VS anatomy in individual cases and classified the continuity patterns of relevant VSs. Subsequently, we evaluated the probable risk zones for VS injury, from the viewpoint of occipital screw insertion. VSs can be clearly visualized using CTV simultaneously with CTA examination without significant increase of radiation exposure or extra workload for radiographical technicians. VS continuity was classified into 4 categories: the confluence type (n = 9), bifurcation type (n = 8), transverse type (n = 11), and others (n = 2). The confluence of sinuses and their relevant VSs were greatly variable between individuals, and occasionally, some cases with high-risk morphology for VS injury in occipital screw placement were observed. Our findings indicate that there is no universal position for safe insertion of occipital screws that is applicable to all individuals. It is risky to determine optimal screw placement, only on the basis of traditional cadaveric information such as occipital bone thickness and several external bony landmarks. Spine surgeons must recognize that VS injury may occasionally lead to life-threatening complications. The detailed information on VSs obtained by preoperative CTV examination combined with CTA in individual cases can be useful in preoperative planning and can contribute greatly to the improvement of surgical safety. 2.

Studies on new MR venography in cerebral areas

Three-dimensional time of flight (3D TOF) venography images that had been used in magnetic resonance (MR) venography were compared with venography images in which the three-dimensional spoiled gradient-recalled (3D SPGR) sequence had been applied to evaluate the utility of the new MR venography images. From September 2010 to May 2011, venography images with 3D TOF venography or 3D SPGR sequence applied were obtained in 30 healthy individuals without a prior disease history and without brain diseases using 3·0 T MR imaging equipment. The acquired images were analysed qualitatively. On the sagittal images, the level of anatomical description of the internal cerebral vein (IVC), basal vein (BV), vein of Galen (VG), superior cerebral veins and sinus confluence (SC) was evaluated. On the coronal images, the level of anatomical description of the superior sagittal sinus (SSS), inferior sagittal sinus (ISS), sagittal sinus (SS) and transverse sinus (TS) was evaluated. The results show that the anatomical descriptions of the IVC, BV and SCV were comparable on the sagittal images, whereas the anatomical description of the VG was superior on the 3D SPGR venography images. On the coronal images, the anatomical descriptions of the SSS, ISS, SS and TS were comparable.

Angioarchitecture of Transverse-Sigmoid Sinus Dural Arteriovenous Fistulas: Evaluation of Shunted Pouches by Multiplanar Reformatted Images of Rotational Angiography

Recognition of shunted pouches dural arteriovenous fistula allows us to treat the disease effectively by selective embolization of the pouches at first. However, the shunted pouches in transverse-sigmoid sinus dural arteriovenous fistulas have not been well-documented. Our aim was to evaluate the angioarchitecture of transverse-sigmoid sinus dural arteriovenous fistulas, including the frequency and location of shunted pouches and their feeding arteries. MATERIALS AND METHODS Twenty-five consecutive cases of TSS-DAVFs that underwent rotational angiography and transvenous embolization between 2008 and 2011 were reviewed. Multiplanar reformatted images of rotational angiography and selective angiography were reviewed with a particular focus on the shunted pouches. All 25 cases showed SPs, with numbers ranging from 1 to 4 pouches (mean, 2.35). The SPs were located at the transverse-sigmoid junction in 16, close to the vein of Labbé in 9, at the dorsal-to-sigmoid sinus in 9, inferior to the sigmoid sinus in 6, at the sigmoid-jugular junction in 5, and inferior to the transverse sinus or the sinus confluence in 14. The SP at the sigmoid sinus was frequently fed by the jugular branch of the ascending pharyngeal artery and the stylomastoid artery. The SP at the transverse-sigmoid junction and the vein of Labbé was fed by the petrosal/petrosquamous and posterior branches of the middle meningeal artery and the transosseous branches of the occipital artery. The SP inferior to the transverse sinus and the sinus confluence was fed by the transosseous branches of the occipital artery and the posterior meningeal artery. All cases were successfully treated by transvenous embolization with sinus packing (n = 13) or selective embolization of the SP (n = 12). The presence of SP is a common angioarchitecture of TSS-DAVFs. Identification of the SPs would be useful for their treatment.

Occipital emissary foramina in South Indian modern human skulls.

An occipital emissary foramen has been traditionally described as a foramen present in the squamous part of the occipital bone at the occipital protuberance transmitting a vein that connects the confluence of sinuses with the occipital vein. The present study was done on 221 South Indian adult modern human skulls of unknown sex in the Department of Anatomy, St John's Medical College, Bangalore, India. The foramen was observed in 21/221 (9.50%) skulls, 6/21 (28.57%) to the right of, 10/21 (47.61%) to the left of, and 2/21 (9.52%) on the External Occipital Crest. It was seen more often near the posterior margin of foramen magnum rather than at the External Occipital Protuberance as has been traditionally described. A new finding is that bilateral foramina were observed in 3 skulls (14.28%). The incidence was higher than seen in other Indian population. Since it is present near the foramen magnum in most cases, knowledge of the number and position of the foramen is important for suboccipital craniotomies. The extensive connections of the veins with cranial venous sinuses may lead to intracranial infections and vice versa.

The influence of the blood pressure on the venous cerebral flow measured by magnetic susceptibility (SWI) technique

Susceptibility Weighted Image (SWI) is a Magnetic Resonance Imaging (MRI) technique that combines high spatial resolution and sensitivity to magnetic susceptibility differences between tissues, it is extremely sensitive to venous blood due to its iron content of deoxyhemoglobin. The aim of this study was to evaluate the differences in the cerebral venous vasculature produced by the value’s variation of blood pressure. 20 subjects (10 hypertensive and 10 normotensive patients) underwent a MRI system with field strength of 1.5 T using a synergy head coil (7 channels). The obtained sequences were T1w, T2w-FLAIR, T2* and SWI. The value of Contrast-to-Noise Ratio (CNR) was assessed in MinIP (Minimum Intensity Projection) and Magnitude images, through drawing free hand ROIs in venous structures: Superior Sagittal Sinus (SSS) Internal Cerebral Vein (ICV) and Sinus Confluence (SC). The obtained values were presented in descriptive statistics-quartiles and extremes diagrams. The results were compared between groups. CNR shown higher values for normotensive group in MinIP (108.89 ± 6.907) to ICV; (238.73 ± 18.556) to SC and (239.384 ± 52.303) to SSS. These values are bigger than images from Hypertensive group about 46 au in average. Comparing the results of Magnitude and MinIP images, there were obtained lower CNR values for the hypertensive group. There were differences in the CNR values between both groups, being these values more expressive in the large vessels-SSS and SC. The SWI is a potential technique to evaluate and characterize the blood pressure variation in the studied vessels adding a physiological perspective to MRI and giving a new approach to the radiological vascular studies.

A Unique Type of Dural Arteriovenous Fistula at Confluence of Sinuses Treated with Endovascular Embolization: A Case Report

Dural arteriovenous fistula (DAVF) is classically defined as abnormal arteriovenous connections located within the dural leaflets. Though the exact etiology is still not clear, they are generally accepted as acquired lesions. However, some DAVFs formed as the congenital disorders are called dural arteriovenous malformations and these lesions with a marked cortical venous reflux are considered to be aggressive and warrant an early intervention. The authors describe a case of 35-year-old man presented with unique type of DAVF. The fistula was located adjacent to the confluence of venous sinuses with multiple feeders. The feeders drained into a large venous pouch just anterior to the confluence which had a bilateral venous drainage. This was associated with multiple cerebellar venous ectasia along the draining cortical vein. It was managed by staged endovascular procedures and complete cure could be achieved. The pathogenesis and technique of embolization of this complex fistula/malformation are also discussed.

A Primo Vascular System Underneath the Superior Sagittal Sinus in the Brain of a Rabbit

The primo vascular systems (PVS) observed in the central nervous system have been limited to the ones floating in the cerebrospinal fluid. In those experiments, it was difficult to obtain the same results because the PVS was not fixed in a given anatomical position. In the current work, we report a finding of a PVS in a well-defined location, namely, underneath the superior sagittal sinus in the sagittal fissure, so that repetition of the experiments is possible. This provides a cornerstone for PVS research because the lack of reproducible sample-taking hindered a deeper study of the PVS, such as RNA sequencing or RNA microarray. This obstacle can be overcome through the discovery in the current work. This PVS showed characteristics of the PVS observed in other organs. It showed the bundle structure of subvessels, the parallel distributions of F-actins, and the rod-shaped nuclei. Furthermore, it had a primo node in front of the confluence of sinuses above the pineal body. It had branches shooting off from the main primo vessel in the subarachnoid space toward the cerebral hemispheres. The results indicate that this PVS underneath superior sagittal sinus has proper features to function as a flowing channel.

Resection of pineal region tumors in children through modified Poppen approach

Objective To evaluate the efficiency and safety of the surgical procedure to deal with the tumors in pineal region of children.Methods 9 children who suffered from the pineal region tumors received the modified Poppen approach in TianjinHuanhu hospital from January 2008 to October 2011.Three main techniques were included in the reformative Poppen approach:straight incision of scalp starting from the external occipital jut and then extending just between the lines of transversesinus and superiorsagittal sinus for 5 ～ 7 cm,a little rounded skull window with a diameter of 3.5 cm,and instead of along the straight sinus as the classical Poppen approach,the tentorial was incised just from the confluence of sinus and then agley go to the tentorial edge.The results were evaluated with indexes such as the rate of gross total resection (GTR) of tumors,the complication derived from the approach,the duration between cranial opening and closing.Results The GTR was 77.8％.The rate of bridging vein injury was 11.1％.The homonymous hemianopia rate was 22.2％.The duration between cranial opening and closing was ( 25.4 ± 4.4 ) mins.There was no death.Conclusions The modified Poppen approach could offer enough visual field and space to resect the pineal region tumorsof children drasticallyand safely. Key words: Children; Pineal region tumor; Poppen approach

The Assessment of Anemia From Attenuation Values of Cranial Venous Drainage on Unenhanced Computed Tomography of the Head

ObjectiveTo determine if prediction of anemia is possible from quantitative analyses of unenhanced cranial computed tomography (CT) images. MethodsA retrospective chart review revealed 101 patients who had hemoglobin and hematocrit levels obtained within 24 hours of an unenhanced cranial CT. Regions of interest were the place on the torcular Herophili (confluence of sinuses) and the left and right transverse sinuses. Attenuation values were correlated with hemoglobin and hematocrit to investigate any possible relationship. ResultsHemoglobin levels were correlated with torcular and transverse sinus attenuation levels. For every 10 Hounsfield unit (HU) increase in torcular attenuation, hemoglobin levels increased by 16.3 g/L (P < .001). When subgroup analysis was performed, by sex, for every 10 HU increase in torcular attenuation, hemoglobin levels increased by 22.6 g/L (P < .001) in men and 8.96 g/L (P < .05) in women. ConclusionThe attenuation values for venous drainage on unenhanced cranial CT constitute a practical adjunct in the assessment of anemia. Given the number of individuals undergoing CT without blood work, this rapid assessment technique for anemia is a convenient means for narrowing possible diagnoses.

The role of contrast- enhanced MRV in preoperative assessment of parasagittal meningiomas and sinusconfluence meningiomas

Objective The purpose of this study was to find whether contrast - enhanced magnetic resonance venography (CEMRV) is a good method for preoperative assessment of parasagittal meningiomas and sinus confluence meningiomas.Methods Thirty -five consecutive parasagittal meningiomas and sinus confluence meningiomas patients underwent surgery in eight months in our ward. All patients underwent CEMRV to define the degree of involvement of the sagittal sinus and depict collateral veins,and some patients also underwent TOFMRV or DSA.Results The CEMRV and DSA showed that sagittal sinus and sinus confluence were completely or partially patent in 25 patients and occluded in 10 patients,which were confirmed by the operations.The images of collateral venous and dural sinus were clearer in CEMRV and DSA than in TOF MRV. The numbers of collateral venous were more accurate in CEMRV than in TOFMRV.Conclusion CEMRV can well define the degree of involvement of the sagittal sinus and depict collateral veins,which make it a good choice for preoperative assessment of parasagittal meningiomas and sinus confluence meningiomas. Key words: Contrast- enhanced magnetic resonance venography; Sagittal sinus; Sinus confluence ; Meningioma ; Preoperative evaluation

Cerebral venous thrombosis presenting as multiple lower cranial nerve palsies

Cerebral venous thrombosis (CVT) is a well-recognized entity, but its clinical presentation is varied and often mimics many neurological disorders, making it a diagnostic challenge. Cerebral venous thrombosis has a wide spectrum of signs and symptoms, which may evolve suddenly or over weeks. It mimics many neurological conditions such as meningitis, encephalopathy, idiopathic intracranial hypertension, and stroke. Cerebral venous thrombosis presenting as multiple lower cranial nerve palsies, are rarely reported. We describe a pregnant lady who presented with sensorineural deafness of the right ear and paralysis of the 9th, 10th, and 12th cranial nerves on the right side. She was diagnosed to have thrombosis of the right transverse sinus and sigmoid sinus with extension to the jugular vein and confluence of sinuses. She improved with anticoagulant treatment.

Respiratory Arrest Due to Hematoma Caused by Thyreocervical Trunk Branch Laceration and Confluence of Sinuses Perforation

Central venous catheterization plays an important role in the treatment of emergency patients who require renal replacement therapy. Emergency patients with end-stage renal disease are at high risk for development of complications because of coagulation disorders, tissue, and organ changes due to uremia, anatomic variations, and obstruction of the large central veins. Complications associated with catheter placement can be mechanical, infectious, and thrombotic, and may occur during or following insertion of central venous catheterization which is a life-saving procedure for patients. We report a case of respiratory arrest in a 76-year-old woman suffering from end-stage renal disease for 14 years, because of large soft tissue subcutaneous hematoma in the right upper thoracic outlet. The rapid development of hematoma was a consequence of arterial bleeding from the branch of the thyreocervical trunk. Laceration of the thyreocervical trunk branch during central venous catheterization is a rare complication. Later diagnostic images revealed catheter perforation of confluence of sinuses which also complicated this case. We briefly discuss signs, symptoms, and management of the patient. Although arterial puncture of the carotid artery during the Seldinger technique is well-known life-threatening complication which can be recognized by light red pulsatile blood during aspiration, smaller arteries such as the thyreocervical trunk branch can be punctured during the procedure and lead to serious complications.

Microsurgical anatomy of the vein of Labbé

Venous drainage of the temporal lobe is of great importance in various neurosurgical and combined skull base approaches. The most significant draining vein of the temporal lobe is the inferior anastomotic vein (vein of Labbé). The purpose of this study was to examine the detailed anatomy and variations of the vein of Labbé (VL) from microsurgical perspective. Fourteen fixed human cadaver heads (28 sides) with perfused vessels were included to define microsurgical anatomy and variations of the VL. The main findings of the present study were as follows: (1) drainage pattern of the VL was found to be very variable in cadaveric dissections; (2) VL drained around the sinus confluence at the tentorium in one specimen (3.5%), into the large meningeal vein in the occipital dura mater in another specimen (3.5%). The VL rarely (7%) drains into the superior petrosal sinus (SPS) which may make combined skull base approaches very difficult or impossible. Results of this study suggest that careful and thorough evaluation of the VL is of great importance, especially in surgeries combining a subtemporal route with petrosal approaches by sectioning the SPS and the tentorium.

Dual-energy computed tomographic angiography of head and neck with dual-source computed tomography: image quality and radiation dose

To investigate the image quality and radiation dose of dual-energy (DE) computed tomographic angiography (CTA) of head and neck. We retrospectively analyzed two groups of patients (both n=30) undergoing 64-slice spiral CTA of cervical and cranial regions with different scan protocols. The DE group was obtained with 140/80 kVp, 64/272 mAs, 0.6 pitch, 80 ml of contrast medium, and caudal-cranial scan orientation. The single-energy (SE) group was obtained with 120 kVp, 220 mAs, 1.2 pitch, 60 ml of contrast medium and cranial-caudal scan orientation. The image quality and radiation dose were compared. The attenuation values and noises were measured on transverse images at 4 different vessels (the distal part of common carotid artery and adjacent vein in same axial image; the M1 segment of middle cerebral artery and sigmoid sinus or confluence of sinus in same image) and two muscles: erector spinae presenting average soft tissue enhancement and supraspinatus muscle presenting regions of great artifact. In cranial region the arterial enhancement and venous contamination were similar (P=0.1427,P=0.1116) . In cervical region the arterial enhancement was similar (P=0.9414) . DE group had significantly greater venous contamination (P<0.0001) , while the mean attenuation value of common carotid artery was still 127 Hu higher than that of jugular vein. No matter artifact of soft tissue was obvious or not, the noise of DE group was significantly less than that of SE group (both P<0.0001) , and the soft tissue enhancement was similar (P=0.0760,P=0.0793) . The radiation dose required for bone-subtraction angiography was significantly less in DE group than in SE group (P<0.0001) . DE group has comparable image quality to SE group and less scan dose for bone-subtraction. DE-CTA has great potential in clinical application. "

Dural arteriovenous fistula at the foramen magnum presenting with subarachnoid hemorrhage: case reports and literature review

Spinal dural arteriovenous fistulas (DAVFs) may arise at any level from the foramen magnum to the sacrum. Only a few case series of DAVFs at the foramen magnum have been reported, especially with patients presenting with subarachnoid hemorrhage (SAH). We performed a retrospective study of four such cases and summarize experiences in the diagnosis and surgical treatment of a DAVF at the foramen magnum. Four male patients, aged from 35 to 51 years, were admitted with severe headache. The cranial computerized tomography scans of all four patients showed SAH, with hemorrhage in the fourth ventricle with or without hemorrhage in the occipital horns of the lateral ventricles. Pre-operative digital subtraction cerebral angiography showed a DAVF at the foramen magnum draining to medullary veins and/or the straight sinus and the confluence of sinuses. Two DAVFs were fed by the vertebral artery, whilst the others were fed by dural branches of the occipital artery and/or the ascending pharyngeal artery. Three patients underwent direct microsurgical electrocoagulation and disconnection of the arteriovenous shunt via an enlargement of the foramen magnum and a hemilaminectomy at C1 by the far lateral suboccipital approach. Post-operative angiography confirmed complete obliteration of the fistula. Cerebral digital subtraction angiography is an effective and accurate method for examination of a DAVF at the foramen magnum. It can be treated effectively and with minimal surgical trauma by microsurgical electrocoagulation and disconnection of the shunt.