Cognard Type Research Articles

Cognard Type V Intracranial Dural Arteriovenous Shunt

Prompt diagnosis of intracranial dural arteriovenous shunt (DAVS) with spinal venous drainage, classified as Cognard type V, is difficult. We investigated the angiographic and magnetic resonance imaging (MRI) characteristics of Cognard type V DAVS to determine the reason for the difficulty in early diagnosis. We systematically reviewed 54 published and 3 new cases of Cognard type V DAVS. The pattern of venous drainage was classified on the basis of relative dominance of the anterior and posterior spinal veins with the use of angiograms. T2-weighted sagittal MRIs were used to detect signal flow voids of enlarged spinal veins. Types of venous drainage were determined in 49 of the 57 cases. Twenty-eight and 8 cases showed a dominance of anterior and posterior spinal venous drainage, respectively. In 13 cases, venous drainage was equally distributed through the anterior and posterior spinal veins. Of 41 cases with an abnormally dilated anterior spinal vein, MRIs were available for 25 cases. Signal flow voids of enlarged anterior spinal veins were detected in 9 cases (36.0%), whereas dilatation of the posterior spinal veins was apparent in 9 of 16 cases (56.3%). Overall, MRI detected enlargement of either anterior or posterior spinal veins in 15 of 41 cases (36.6%). In Cognard type V DAVS, anterior venous drainage is dominant. Because the anterior spinal veins are located subpially, flow voids are less prominent on sagittal T2-weighted MRI. This may lead to difficulties in diagnosing. Evaluation with MR angiography may compensate for these limitations.

P-025 Qualitative Assessment of Intra-Arterial Cone Beam CT Angiography in Precise Anatomic Localisation and Treatment Planning of Intracranial and Spinal Arteriovenous Fistulas

Background and PurposeDigital subtraction angiography (DSA) is considered the standard for characterisation of intracranial/spinal arteriovenous fistulas (AVFs). Although DSA offers superior spatial and temporal resolution, it is limited by 2D...

P-026 Comparative 4D Flow MR Imaging in Quantification of Vascular Haemodynamics in Different Types of Intra-cranial Arteriovenous Malformations

Background and PurposeHaemodynamic characterisation of arteriovenous malformations (AVMs) may have implications for risk stratification. Gross visualisation and quantification of intracranial AVM flow dynamics have been investigated using various methods including...

Transarterial treatment with Onyx of Cognard type IV anterior cranial fossa dural arteriovenous fistulas

Background and purposeCognard type IV anterior cranial fossa dural arteriovenous fistulas (DAVFs) are rare lesions with a high risk of intracranial hemorrhage. We present our experience with the use of...

Role of Gamma Knife surgery in the treatment of intracranial dural arteriovenous fistulas

The goal of this study was to assess the efficacy of Gamma Knife surgery (GKS) in the management of dural arteriovenous fistulas (dAVFs). The authors performed a retrospective analysis of a group of 22 patients who underwent GKS for dAVFs at the University of Tokyo Hospital between 1991 and 2009. The patients underwent CT or MR imaging with contrast enhancement every 6 months after GKS; when obliteration of a dAVF was indicated by these images, patients also underwent angiography. Follow-up in these patients ranged from 12 months to 100 months (median 33 months) after GKS. Obliteration of the dAVF was confirmed by neuroimaging in 12 patients (55%). According to a Kaplan-Meier analysis, obliteration rates for the dAVFs were 51% at 3 years and 80% at 5 years. The obliteration rate for lesions without cortical venous drainage (CVD) was 86%, which was significantly higher than the rate for dAVFs with CVD (47%) (p = 0.007). Hemorrhage at presentation (p = 0.03), a target volume less than 1.5 cm(3) (p = 0.009), and Cognard Type III or IV dAVF (p = 0.005) were factors associated with a higher obliteration rate. Among 10 patients whose dAVFs were not obliterated by the initial GKS, 5 patients underwent additional treatment and complete obliteration was achieved in all. Relief of tinnitus was obtained in 5 (83%) of 6 patients with transverse-sigmoid sinus dAVFs, and ophthalmic symptoms improved in 2 (67%) of 3 patients with cavernous sinus dAVFs. No patient experienced interval hemorrhage or radiation-induced complications after treatment. Gamma Knife surgery is a safe and effective treatment for dAVF. It can be a first line of therapy in the multidisciplinary treatment strategy for dAVFs, especially when significant morbidity is anticipated with other therapeutic options. One should be very careful about recommending GKS for patients harboring dAVFs with CVD because of the expected natural history of such a lesion and the possibility of other therapeutic options.

The Natural History of Cranial Dural Arteriovenous Fistulae With Cortical Venous Reflux—The Significance of Venous Ectasia

The quoted risk of hemorrhage from dural arteriovenous fistulae with cortical venous reflux varies widely, and the influence of angiographic grade on clinical course has not previously been reported. To assess the risk of hemorrhage and the influence of angiographic grade on this risk, compared with known predictors of hemorrhage such as presentation. Seventy-five fistulae with cortical venous reflux identified in our arteriovenous malformations clinic between 1992 and 2007 were followed up clinically, and their angiograms were reviewed. There were 8 hemorrhages in 90 years of follow-up. The annual incidence of hemorrhage before any treatment was 13%, and 4.7% after partial treatment, giving an overall incidence of 8.9% before definitive treatment. Borden and Cognard grades were poor discriminators of risk for lesions with the exception of Cognard type IV lesions. These lesions, characterized by venous ectasia, had a 7-fold increase in the incidence of hemorrhage (3.5% no ectasia vs 27% with ectasia). Patients presenting with hemorrhage (20%) or nonhemorrhagic neurological deficit (22%) had a higher incidence of hemorrhage than those with a benign presentation (4.3%), but this may be directly linked to the presence of venous ectasia. In this series untreated dural arteriovenous fistulae with cortical venous reflux had a 13% annual incidence of hemorrhage after diagnosis. There was a significant difference between those with and without venous ectasia. This should be confirmed by further studies, but probably defines a high-risk subgroup of patients that requires rapid intervention.

O-014 Intra-arterial cone beam CT angiography for the precise anatomic localization of intracranial and spinal arteriovenous fistulas

PurposeCone beam CT angiography (CBCTA) provides enhanced vascular imaging for neurointerventional treatment planning, particularly of intravascular stents, thromboemboli, in-stent stenosis, and calcifications. In conjunction with traditional digital subtraction angiography (DSA)...

Cavernous region dural fistulas with venous drainage of laterocavernous sinus

We present our findings concerning the laterocavernous sinus (LCS) drainage of cavernous region dural fistulas, focusing our attention on the anatomy of LCS as it may have important implications in the treatment. Thirty-one consecutive patients with cavernous region dural fistulas treated endovascularly between 2005 and 2008 were reviewed. Five patients had angiographic features such as cavernous region dural fistulas draining with superficial middle cerebral vein (SMCV) via LCS. Clinical records of these 5 patients were focused upon to determine their presenting symptoms, angiographic features, endovascular treatments and clinical outcomes. Among 31 cases of cavernous dural arteriovenous fistula (DAVF), 5 (16%) cases with leptomeningeal veins [SMCV, petrosal vein] reflux via LCS were noted. The 5 cavernous region dural fistulas were defined as Cognard type III and Barrow type A (1/5), B (1/5), C (1/5) and D (2/5). All 5 patients underwent immediate obliteration of the cavernous region dural fistulas in 3 sessions of transarterial and 2 sessions of transvenous embolization. An angiographic obliteration and clinical cure was achieved in all patients. We encountered one minor complication of local hair loss induced by X-ray radiation. A complete resolution of the initial presenting symptoms was observed within a few days to weeks. Six-month follow-up angiogram in 5 patients showed obliteration and no recanalization of CCF. It is very important to diagnose the presence of laterocavernous sinus in dural arteriovenous fistulas during diagnostic angiography. It is believed that the knowledge of the existence of laterocavernous sinus might be relevant for the understanding and treatment of dural fistulas involving the cavernous sinus and its lateral wall.

Reversal of Diffusion Restriction After Embolization of Dural Arteriovenous Fistula: Case Report

We report a rare case of diffusion restriction caused by venous hypertension resulting from a dural arteriovenous fistula (DAVF) that completely reversed after successful embolization. A 54-year-old man presented with symptoms secondary to a DAVF. Magnetic resonance imaging (MRI) revealed left parieto-temporo-occipital diffusion restriction. The angiogram revealed a Cognard type III left lateral tentorial DAVF resulting in severe venous hypertension. Transarterial Onyx embolization was performed, resulting in angiographic cure of the fistula with normalization of the venous drainage in the left parieto-temporo-occipital region. A follow-up MRI examination performed 4 weeks after the embolization revealed resolution of the previously seen area of restricted diffusion. It is important to consider the possibility of diffusion restriction reversal, because misdiagnosis or the false assumption that irreversible cerebral infarction has occurred may inappropriately alter or delay the treatment of these aggressive lesions.

P-013 Vessel deconstruction of the ophthalmic artery: potential diagnostic utility of balloon test occlusion study with electroretinography

PurposeVessel deconstruction of the ophthalmic artery is occasionally required in the treatment of periophthalmic internal carotid artery (ICA) intracranial aneurysms or more rare lesions such as dural arteriovenous fistulas (AVF),...

Endovascular treatment of dural fistulas with the venous outflow of laterocavernous sinus

Objective To report our findings concerning the laterocavernous sinus (LCS) drainage of dural fistulas, focusing our attention on the important implications in treatment of the LCS, which is one of the principal drainage pathways of the superficial middle cerebral vein (SMCV). Methods Consecutive 32 patients with dural fistulas treated endovascularly between 2005 and 2008 were reviewed. Seven patients had angiographic features such as dural fistulas draining with SMCV via LCS. Clinical records for these 7 patients were focused to determine their presenting symptoms, angiographic features, endovascular treatments, and clinical outcomes. Results Over 3 years, 7 patients had 7 dural fistulas drained with SMCV via LCS were treated. Six-vessel angiography confirmed the presence of the dural fistulas. All fistulas were Cognard Type III featured by leptomeningeal veins drainage. One fistula involving the lesser sphenoid wing and 6 fistulas involving CS were supplied by external carotid artery branches with or without dural branches of the internal carotid artery. LCS was identified as a contiguous to SMCV drainage in these cases. One patient was treated with transvenous coil embolization alone, two with transvenous a combination of Onyx and coil embolization, and 4 with transarterial embolization. An angiographic obliteration and clinical cure was achieved in all patients. Complication was local hair loss due to X-ray radiation in one patient. Conclusion It is very important to diagnose the presence of LCS in dural fistulas during the diagnostic angiography. It is believed that the knowledge of LCS might be relevant for the understanding and treatment of dural fistulas involving the LCS.

Cranial dural arteriovenous fistulas: modification of angiographic classification scales based on new natural history data

This article presents a modification to the existing classification scales of intracranial dural arteriovenous fistulas based on newly published research regarding the relationship of clinical symptoms and outcome. The 2 commonly used scales, the Borden-Shucart and Cognard scales, rely entirely on angiographic features for categorization. The most critical anatomical feature is the identification of cortical venous drainage (CVD; Borden-Shucart Types II and III and Cognard Types IIb, IIa + b, III, IV, and V), as this feature identifies lesions at high risk for future hemorrhage or ischemic neurological injury. Yet recent data has emerged indicating that within these high-risk groups, most of the risk for future injury is in the subgroup presenting with intracerebral hemorrhage or nonhemorrhagic neurological deficits. The authors have defined this subgroup as symptomatic CVD. Patients who present incidentally or with symptoms of pulsatile tinnitus or ophthalmological phenomena have a less aggressive clinical course. The authors have defined this subgroup as asymptomatic CVD. Based on recent data the annual rate of intracerebral hemorrhage is 7.4-7.6% for patients with symptomatic CVD compared with 1.4-1.5% for those with asymptomatic CVD. The addition of asymptomatic CVD or symptomatic CVD as modifiers to the Borden-Shucart and Cognard systems improves their accuracy for risk stratification of patients with high-grade dural arteriovenous fistulas.

Angioplasty and stent deployment in acute sinus thrombosis following endovascular treatment of dural arteriovenous fistulae

We report on the successful treatment of acute sinus thrombosis associated with endovascular treatment of intracranial dural arteriovenous fistulae (DAVF) by sinus angioplasty with stent deployment. A 76-year-old man presented with intracerebral hemorrhage, Cognard type IIa+b DAVF of the left sigmoid sinus, and type IIa DAVF of the torcular herophili. During transvenous sinus embolization, acute thrombosis of the stenotic lesion in the left transverse sinus occurred. The thrombosis caused isolated sinus and cortical venous reflux (CVR). The patient was treated by stent-supported sinus angioplasty, which led to an immediate improvement of the sinus thrombosis and associated CVR.

Arterial Onyx Embolisation of Intracranial DAVFs with Cortical Venous Drainage

To present our experience with the endovascular management of intracranial dural arteriovenous fistulas with direct cortical venous drainage by trans-arterial embolisation using Onyx. Between January 2004 and April 2008, 12 consecutive high grade intracranial dural arteriovenous fistulas (Cognard type III (eight patients) or IV (three patients)) were treated by trans-arterial embolisation with Onyx. The majority of cases were treated by Onyx embolisation alone. One case had additional embolisation with n-butyl-2-cyanoacrylate at the same session. Imaging follow-up was obtained in all but one patient (mean 3.6 months). Nine patients had a technical success at the end of the embolisation procedure with complete angiographic exclusion of the fistula. Two patients had a small residual fistula at the end of embolisation, one of which had residual mild cortical venous drainage. Both were stable at follow-up angiography. One patient had a residual fistula supplied by the ophthalmic artery, which was thought to be unsafe to embolise and was sent for surgery, which was curative. In one patient the microcatheter ruptured, with a fragment of the distal microcatheter left in the occipital artery. No clinical complications were observed in this series at clinical follow-up (mean 3.3 months). Two patients were noted to have significant radiation dose. Endovascular management of intracranial dural arteriovenous fistulas with direct venous cortical drainage by trans-arterial Onyx embolisation is a safe and effective treatment according to our experience. Fluoroscopy times and radiation dose may be a concern.

A Thrombophilic Patient With a Dural Arteriovenous Fistula Presenting Sensory Aphasia and Complicated With an Acute Pulmonary Embolism

Neuropsychiatric symptoms as the initial presentation of dural arteriovenous fistula (DAVF) are unusual. Anticoagulation therapy may be warranted for prevention of further thromboembolism if an underlying thrombophilia condition is diagnosed. We present a 70-year-old woman with sensory aphasia, who was diagnosed with a DAVF, Cognard type II a + b, by cerebral angiography. Her stroke-like syndrome resolved after transarterial embolization of the left occipital and middle meningeal arteries. Meanwhile, hypercoagulability was found because of hyperhomocysteinemia and the presence of a lupus anticoagulant. One month later, she suffered an acute pulmonary embolism and was started on anticoagulation therapy before stereotactic radiosurgery. Sensory aphasia may be the initial manifestation of a transverse-sigmoid sinus DAVF even if there are no symptoms such as headache or tinnitus. We postulate that early anticoagulation therapy is indicated for preventing thromboembolism in DAVF patients with thrombophilia because the possibility of intracranial bleeding has been reduced by embolization.

Transarterial Embolization of Tentorial Dural Arteriovenous Fistulas with Onyx 18

Dural arteriovenous fistulas (DVAFs) have been reported to be treated transarterially with Onyx 18. We present a series of tentorial DAVFs treated by transarterial embolization with Onyx 18 over an 18-month period. Eight patients with tentorial DAVFs were treated between September 2005 and February 2007. All patients were treated transarterially with Onyx 18. The clinical presentation, treatment strategies and results were studied. Eight patients presented with intracranial hemorrhage or progressive neurological deficits. Retrograde leptomeningeal venous drainage was documented in every patient, classifying the lesions as Cognard Type IV. Post treatment angiography demonstrated complete obliteration in six cases. Clinical follow up ranged from six to 14 months. One patient experienced neurological decline after endovascular treatment and exhibited clinical improvement. There were no episodes of rehemorrhage or new neurological deficits. Outcomes were excellent in seven patients, fair in one case. Transarterial embolization of tentorial DAVF is feasible and may result in complete occlusion of the fistulous connection with liquid nonadhesives.

小脳静脈性うっ血にて発症したsingle cortical drainage 硬膜動静脈瘻の一例

●Abstract● A 56-year-old male presented with a floating sensation. Brain CT and MRI indicated a focal edematous lesion with mass effects on the left cerebellar hemisphere. Angiography showed a dural arteriovenous fistula (DAVF), classified as Djindjian Type Ⅲ and Cognard Type Ⅲ, that had developed on the left occipital artery and left posterior meningeal artery. Transarterial embolization was performed using N-butyl cyanoacrylate (NBCA). We discussed here a case of DAVF with single direct cerebellar cortical drainage and venous congestion. It drained into the left cerebellar cortical vein located in the mid-line, causing severe stagnation of venous drainage of the left cerebellar hemisphere.

Gamma Knife surgery for the management of intracranial dural arteriovenous fistulas

The purpose of this study was to assess the efficacy and safety of Gamma Knife surgery (GKS) for the treatment of cavernous sinus dural arteriovenous fistulas (CSDAVFs) and other intracranial dural arteriovenous fistulas (ODAVFs). Among the 238 GKS procedures performed for intracranial DAVFs in the authors' institute, 227 cases (146 CSDAVFs and 81 OIDAVFs) with clinical follow up formed the database from which the authors determined clinical outcome and the incidence of untoward events. One hundred ninety-five cases (118 CSDAVFs and 77 ODAVFs) with imaging follow up formed the database from which the authors determined the imaging results. Older age, female sex, higher incidence of diabetes, and shorter duration of symptoms were noted more in cases of CSDAVF than in ODAVFs. Most patients had symptomatic improvement after GKS. A symptomatic cure was observed in one patient with CSDAVFs as early as 6 weeks. The cumulative cure rate based on follow-up angiography of CSDAVFs approached 75% at 24 months, which was much better than that of ODAVFs (approximately 50% at 24 months). A neuroimaging-based cure lagged behind that of the clinical symptoms. Overall, there were only two nonfatal intracerebral hemorrhages during the follow-up period, both occurring less than 1 week after GKS and both being Cognard Type IIa+b with initial aggressive symptoms. Transient deterioration of neurological status without hemorrhage was noted in six patients with ODAVFs. Thrombosis of the superior ophthalmic vein occurred in 11 patients with CSDAVFs, in two of whom there were unilateral visual impairments. There were three cranial nerve neuropathies: transient in one CSDAVF and one ODAVF involving the jugular foramen, and another one was a CSDAVF previously treated by conventional radiotherapy. Gamma Knife surgery provides a safe and effective option for treatment of intracranial DAVFs with a low risk of complications. In cases of DAVFs with benign clinical presentation, GKS can serve as a primary treatment. In some cases of aggressive DAVFs in which there is extensive retrograde cortical vein drainage, combined treatment with embolization or surgery is suggested.

MR Findings of Dural Arteriovenous Fistula in Cavernous Sinus

Purpose : To evaluate the MR findings of dural arteriovenous fistula(DAVF) in the cavernous sinus and to de-termine the most useful imaging method for the diagnosis of DAVF. Materials and Methods : We evaluated the MR findings of 12 patients in whom DAVF was diagnosed in the cavernous sinus on the basis of angiographic findings. Axial T1- and T2-weighted, and axial and coronal Gd-enhanced T1-weighted images with 3-6mm slice thickness had been obtained, and the findings of DAVF on three pulse sequences were examined and compared. On the basis of the detection of DAVF on three pulse sequences, the MR findings were graded as excellent, fair or poor, and the location of DAVF in the cavernous sinus was analysed. We also classified DAVFs as group A or B on the basis of MR findings (group A: lesions in the cavernous sinus were as large as or larger than the cavernous internal carotid artery; group B: these were smaller than the cavernous internal carotid artery) and compared with cognard type on angiogram. Results : Multiple tortuous signal voids were found in all DAVFs. The signal voids were located mainly in the middle and posterior one third of the cavernous sinus, as seen on axial images, and the middle and inferior one third, as seen on coronal images. Axial and coronal enhanced T1-weighted images showed an excellent grade in 11 of 12 cases and a fair grade in 1 of 12. Axial T2-weighted images showed an excellent grade in 6 of 12 cases and a fair grade in 4 of 12. T1-weighted images showed an excellent grade in 4 of 12 cases and a fair grade in 6 of 12. Six cases were group A, and 5 of the 6 were Cognard type Ⅱa or Ⅱb; The other 6 cases were group B, 5 of the 6 were Cognard type I. Conclusion : MR findings of multiple tortuous signal voids in the cavernous sinus, especially in the posterior or inferior portion, suggest DAVF, and enhanced T1-weighted imaging could be the most useful sequence for its diagnosis.