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Papers by Michael Teng

Research paper thumbnail of Transvenous Embolization of Cavernous Sinus Dural Arteriovenous Fistula Using the Direct Superior Ophthalmic Vein Approach: A Case Report

Neurointervention, 2011

Dural Arteriovenous Fistula (DAVF) refers to the abnormal direct connection between veins and art... more Dural Arteriovenous Fistula (DAVF) refers to the abnormal direct connection between veins and arteries in the dura mater and accounts for 10-15% of all intracranial arteriovenous malformations [1]. Compared with the transverse-sigmoid sinus as the most frequent site of occurrence in western countries, the cavernous sinus is the most common location of DAVF in Asians [2]. Treatments of DAVF include manual compression of ipsilateral common carotid artery, radiation therapy, surgery, and endovascular embolization. Treatment methods of cavernous sinus DAVF (CSDAVF) may vary depending on the severity 100

Research paper thumbnail of In-Room Assessment of Cerebral Blood Volume for Guidance during Intra-Arterial Thrombolytic Therapy

Interventional Neuroradiology, 2012

In acute ischemic stroke, the ability to estimate the penumbra and infarction core ratio helps to... more In acute ischemic stroke, the ability to estimate the penumbra and infarction core ratio helps to triage those who will potentially benefit from thrombolytic therapies. Flat-panel post-contrast DynaCT imaging can provide both vasculature and parenchymal blood volume within the angio room to monitor hemodynamic changes during the endovascular procedures. We report on an 80-year-old woman who suffered from an acute occlusion of the right distal cervical internal carotid artery. She was transferred to the angio room where in-room post-contrast flat-panel DynaCT imaging (syngo Neuro PBV IR) was performed to access the ischemic tissue, followed by successful mechanical thrombolytic therapy.

Research paper thumbnail of Transorbital direct puncture of the posterior cavernous sinus through the internal carotid artery for embolization of isolated cavernous sinus dural arteriovenous fistula

Journal of neurointerventional surgery, 2013

Most cavernous sinus dural arteriovenous fistulas (CSDAVFs) present with benign ocular symptoms; ... more Most cavernous sinus dural arteriovenous fistulas (CSDAVFs) present with benign ocular symptoms; isolated CSDAVFs with aggressive behavior are extremely rare. The treatment goal is to occlude the fistula totally. However, transarterial or venous access may not be possible because of complex angioarchitecture. A woman in her late 70s presented with progressive respiratory failure and rapid deterioration of limb muscle power. Imaging studies showed an isolated CSDAVF with exclusive venous drainage to the deep venous system leading to venous hypertension as well as ischemic changes in the brain stem, left thalamus and basal ganglia. Transvascular access of the cavernous sinus (CS) failed. The fistula was eventually occluded by transorbital direct puncture of the posterior CS through the internal carotid artery (ICA) with coils delivered into the CS. The holes in the walls of the ICA created by the puncture needle were sealed by detachable coils and the patient was discharged with mild ...

Research paper thumbnail of Toward the Era of a One-Stop Imaging Service Using an Angiography Suite for Neurovascular Disorders

BioMed Research International, 2013

Transportation of patients requiring multiple diagnostic and imaging-guided therapeutic modalitie... more Transportation of patients requiring multiple diagnostic and imaging-guided therapeutic modalities is unavoidable in current radiological practice. This clinical scenario causes time delays and increased risk in the management of stroke and other neurovascular emergencies. Since the emergence of flat-detector technology in imaging practice in recent decades, studies have proven that flat-detector X-ray angiography in conjunction with contrast medium injection and specialized reconstruction algorithms can provide not only high-quality and high-resolution CT-like images but also functional information. This improvement in imaging technology allows quantitative assessment of intracranial hemodynamics and, subsequently in the same imaging session, provides treatment guidance for patients with neurovascular disorders by using only a flat-detector angiographic suite—a so-called one-stop quantitative imaging service (OSIS). In this paper, we review the recent developments in the field of f...

Research paper thumbnail of Endovascular management of the traumatic cerebral aneurysms associated with traumatic carotid cavernous fistulas

AJNR. American journal of neuroradiology, 2004

Simultaneous traumatic carotid-cavernous fistulas(TCCFs) and traumatic cerebral aneurysms (TCAs) ... more Simultaneous traumatic carotid-cavernous fistulas(TCCFs) and traumatic cerebral aneurysms (TCAs) of the internal carotid artery (ICA) are rare. We describe the pitfalls of detecting a TCA before TCCF occlusion and the endovascular management of the TCA and TCCF. Over 12 years, 156 patients with TCCFs were treated at our institute. In four men (mean age, 34 years), associated TCAs were detected before (n = 1) or after (n = 3) endovascular occlusion of the TCCFs. Causes for the missed detection of the TCA before TCCF occlusion were masking by a parent artery and fistula drains (n = 1), steal phenomenon (n = 1), and a latent period (n = 1). The TCAs were in the supraclinoid ICA (n = 3) or the paraophthalmic artery (n = 1). Three TCAs were treated with the endosaccular placement of electrodetachable coils. Two TCCFs and associated TCAs were successfully occluded with preservation of the ICA. The paraophthalmic TCA was treated with coil occlusion of the TCA and TCCF. Spontaneous fatal ru...

Research paper thumbnail of Contrast enhancement patterns of acute spinal epidural hematomas: a report of two cases

AJNR. American journal of neuroradiology, 2003

The MR finding of an acute spinal epidural hematoma (SEH) can mimic epidural neoplastic or inflam... more The MR finding of an acute spinal epidural hematoma (SEH) can mimic epidural neoplastic or inflammatory lesions, because acute SEH appears hypointense on T1-weighted images and hyperintense on T2-weighted images. We report on two cases of acute SEH with unusual contrast enhancement patterns on MR images. Contrast enhancement can be an MR finding of acute SEH, especially in bleeding diathesis, which indicates an active lesion that needs early diagnosis and management.

Research paper thumbnail of Double-balloon technique for embolization of carotid cavernous fistulas

AJNR. American journal of neuroradiology, 2000

Embolization of a carotid cavernous fistula (CCF) by means of a detachable balloon is an establis... more Embolization of a carotid cavernous fistula (CCF) by means of a detachable balloon is an established method for treating CCFs while preserving a patent parent internal carotid artery (ICA). However, failure to embolize the CCF may occur on a few occasions, such as when the balloon cannot pass through the fistula into the cavernous sinus by blood flow, or when the inflated balloon in the cavernous sinus retracts to the carotid artery. Under these circumstances, the ICA may have to be sacrificed in order to treat the CCF. Herein we describe a double-balloon technique for embolization of a CCF. By applying this technique, we successfully treated nine of 11 CCFs, without compromise of the parent ICA when the conventional one-balloon technique failed.

Research paper thumbnail of Complications of carotid blowout syndrome in patients with head and neck cancers treated by covered stents

Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences, Jan 11, 2008

The purpose of this study was to improve clinical assessment of carotid-blowout syndrome (CBS) in... more The purpose of this study was to improve clinical assessment of carotid-blowout syndrome (CBS) in patients with head-and-neck cancers and with covered stents by evaluating immediate and delayed complications of reconstructive management. Eleven such patients were treated with self-expandable covered stents. We evaluated immediate and delayed complications by assessing clinical and imaging findings. Technical success and immediate hemostasis were achieved in all patients. Immediate complications were noted in four patients (36.4%), including thromboembolism in three patients and, in one patient, dissection of the carotid artery and type III endoleak by the overlapped self-expandable stent causing rebleeding. Delayed complications were noted in eight patients (72.7%), including six episodes of rebleeding in five patients, distal marginal stenosis in five patients, and delayed carotid thrombosis in three patients (one with brain abscess formation). We suggest close follow-up of the pat...

Research paper thumbnail of Endovascular Management of Delayed Vascular Lesions in the Cavernous Sinus after Transarterial Embolization of Traumatic Carotid-Cavernous Fistulas

Research paper thumbnail of Radiation carotid blowout syndrome in nasopharyngeal carcinoma: Angiographic features and endovascular management

Otolaryngology–Head and Neck Surgery, 2008

Objective To report clinical manifestations, angiographic features, and outcomes of endovascular ... more Objective To report clinical manifestations, angiographic features, and outcomes of endovascular management in 14 patients with 15 radiation carotid blowout syndromes of nasopharyngeal carcinomas. Study Design and Subjects Retrospective chart review of 14 patients with nasopharyngeal carcinomas (mean age 49 years) with 15 radiation carotid blowout syndromes who had undergone endovascular embolization to manage oronasal bleeding in the past 10 years. Results Average radiation dose to affected carotid artery was 73 gray units (latent period: 33 months). Radiation carotid blowout syndrome was detected in internal (n = 10), external (n = 4), or common carotid artery (n = 1). Detachable balloons were used in 11 affecting arteries for vascular occlusion; 4 were treated by liquid adhesives or coil. Endovascular treatment was successful in all 15 radiation carotid blowout syndromes with cessation of hemorrhage. One patient had hemiparesis after embolization. Mean clinical follow-up was 21 m...

Research paper thumbnail of Patients with head and neck cancers and associated postirradiated carotid blowout syndrome: Endovascular therapeutic methods and outcomes

Journal of Vascular Surgery, 2008

This study retrospectively evaluated the technical and hemostatic outcomes of reconstructive and ... more This study retrospectively evaluated the technical and hemostatic outcomes of reconstructive and deconstructive endovascular management in patients with head and neck cancers associated with carotid blowout syndrome (CBS). Methods: Twenty-four patients with head and neck cancers with CBS involving the main trunk of carotid artery underwent endovascular therapy. This included reconstructive management with self-expandable stent grafts to preserve the diseased carotid artery in 11 patients and deconstructive management with balloons, coils, or acrylic adhesives to occlude the diseased carotid artery in 13 patients. Based on clinical severity and therapeutic priority, we classified CBS in our patients into two groups: acute or impending and threatened. The angiographic severity was graded from 0 to 3. Evaluation of technical outcome included technical success, initial and delayed complications, and patency of stent graft in the reconstructive group. The hemostatic outcome was evaluated by immediate hemostatic result, rebleeding, and duration of hemostasis. Sex, age, clinical and angiographic severities, local wound complications, and location of the pathologic lesion were examined as predictors of the technical and hemostatic outcomes of endovascular management by using Cox regression method. Results: Technical success and immediate hemostasis were achieved in all patients of both groups. Initial complications during the procedures were encountered in four patients (36.4%) who underwent reconstructive management and in one patient (7.7%) who underwent deconstructive management (P ‫؍‬ .142). Delayed complications during the follow-up were seen in one patient (9.1%) with reconstructive management and one patient (7.7%) with deconstructive management (P > .99). Rebleeding occurred in five patients (45.5%) in the reconstructive management group and in three patients (23.1%) in the deconstructive management group (P ‫؍‬ .659). The mean duration of hemostasis after initial reconstructive and deconstructive management was 4.0 ؎ 8.1 and 8.5 ؎ 10.1 months, respectively (P ‫؍‬ .249). Rebleeding was noted in 7 of 11 patients (63.6%) with acute CBS and in 1 of 13 patients (7.7%) with impending and threatened CBS (P ‫؍‬ .008). Conclusion: There is no significant difference in technical and hemostatic outcomes between the reconstructive and deconstructive endovascular management methods. Hemostatic results were influenced by clinical severity. The rebleeding rate is higher in patients with advanced and acute clinical severity.

Research paper thumbnail of Multiple Intracranial Carotid Injuries: Pitfalls in Diagnosis by Angiography and Principles of Endovascular Treatment

The Journal of Trauma: Injury, Infection, and Critical Care, 2009

Simultaneous multiple intracranial carotid injuries (ICIs) after head trauma are rarely referred ... more Simultaneous multiple intracranial carotid injuries (ICIs) after head trauma are rarely referred for treatment and are often times fatal. The purpose of this study was to describe the potential angiographic pitfalls in diagnosis of multiple ICIs and to report the principles of endovascular management in 15 patients with 34 ICIs. A 12-year study of the 15 patients (8 men and 7 women) with 34 ICIs was completed, and patients were managed by endovascular treatment. Of the 34 ICIs, there were 22 traumatic carotid-cavernous fistulas (TCCFs), 6 traumatic carotid aneurysms, 5 meningeal arteriovenous fistulas, and 1 traumatic occlusion of carotid artery. Transarterial endovascular embolization was performed in 32 ICIs. Four traumatic carotid aneurysms, four meningeal arteriovenous fistulas, and a second hole of the TCCF were missed in early detection by initial cerebral angiograms. The causes of missed early detection of ICIs in angiograms were attributed to occur with TCCFs in the ipsilateral internal carotid artery territory due to overlooking (n = 4), overlap with nearby carotid artery and/or fistula drains of TCCFs (n = 2), steal phenomenon (n = 2), and a latent period of ICI (n = 1). Successful occlusion of 32 ICIs was achieved. On the modified Rankin scale applied in follow-up, 14 patients were assessed as stable clinical status. Early initial detection of ICIs in cerebral angiograms may be difficult if ICIs occur in the same carotid artery, particularly when they coexist with TCCF. However, as soon as TCCFs are occluded, postembolization angiograms should be scrutinized to find the potential associating ICIs, and endovascular management should be performed promptly.

Research paper thumbnail of Stent-assisted coil embolization of intracranial aneurysms: A single center experience

Journal of the Chinese Medical Association, 2012

Background: Endovascular detachable coil embolization has become an important method in the manag... more Background: Endovascular detachable coil embolization has become an important method in the management of intracranial aneurysms. However, coil embolization alone may fail to treat some wide-neck aneurysms. Herein, we report our experience with and outcome of stentassisted coil embolization (SACE) of intracranial aneurysms. Methods: Over a 5-year period, a total of 59 patients diagnosed with 63 intracranial aneurysms underwent SACE. Of the total 63 aneurysms, 6 aneurysms were treated by SACE as a salvageable procedure because of coil instability after detachment. There were 17 men and 42 women enrolled in the study, with ages ranging from 24 to 86 years (mean: 60 years). We retrospectively assessed the clinical data, aneurysm characteristics, and angiographic and clinical outcomes of all patient cases. Results: The mean aneurysm size was 9.4 mm, and the mean neck size was 5.5 mm. Clinical and angiographic follow-up exceeding 6 months were available in 51 and 40 patients, respectively. The mean clinical follow-up time was 28 months (range: 6e49 months). Successful stent deployment was found in 60 aneurysms (95%). Midterm total or subtotal angiographic aneurismal occlusion was obtained in 56 aneurysms (89%), with further thrombosis of the aneurismal sac occurring in 4 (10%). Stable coiling aneurysm was found in 24 (78%), aneurysm recurrence was observed in 5 (13%), and permanent procedural morbidity was observed in two patients (3.4%). During the follow-up period, there were no hemorrhagic events and no stent displacement. Conclusion: Despite a modest procedural complication rate, and some evidence of aneurismal recurrence, SACE was proved to be both effective and safe in managing wide-neck intracranial aneurysms. Our results also demonstrated the midterm durability and stability of aneurysm treated by SACE. Furthermore, SACE can be a salvageable procedure in cases with coil instability after detachment.

Research paper thumbnail of Distal Marginal Stenosis: A Contributing Factor in Delayed Carotid Occlusion of a Patient With Carotid Blowout Syndrome Treated With Stent Grafts

Journal of the Chinese Medical Association, 2010

Distal marginal stenosis is rarely reported to be a factor associated with poor long-term patency... more Distal marginal stenosis is rarely reported to be a factor associated with poor long-term patency of patients of head and neck cancers with carotid blowout syndrome treated with stent grafts. We report a case of laryngeal cancer with rupture of the right common carotid artery. A self-expandable stent graft was deployed, but bleeding recurred. Another stent graft was deployed for the pseudoaneurysm located distal to the first stent graft. Rebleeding occurred because of pseudoaneurysm formation from reconstituted branches of the right superior thyroid artery. We performed direct percutaneous puncture of the proximal superior thyroid artery for successful embolization. Distal marginal stenosis and asymptomatic thrombosis of the carotid artery were noted at 3.5-and 5-month follow-ups, respectively. We suggest aggressive early follow-up and reintervention for distal marginal stenosis by combined antibiotic therapy and angioplasty and stenting to improve the long-term patency of stent-graft deployment for management of carotid blowout syndrome.

Research paper thumbnail of Spontaneous Thrombosis and Complete Disappearance of Traumatic Carotid-cavernous Fistulas After Angiography

Journal of the Chinese Medical Association, 2005

Traumatic carotid-cavernous fistula (TCCF) is a direct shunting fistula due to a tear in the cave... more Traumatic carotid-cavernous fistula (TCCF) is a direct shunting fistula due to a tear in the cavernous portion of the internal carotid artery (ICA). Spontaneous thrombosis of the high-flow shunts in TCCFs is extremely rare. Most cases are treated using endovascular embolization to relieve the clinical presentations. We report 2 unusual cases of TCCF with spontaneous closure of fistulas at intervals of 2 and 10 days, respectively, after diagnostic angiograms. The possible mechanisms of spontaneous healing of the fistulas in these patients with minor head injury and small fistulas were presumed to be a transient decrease in fistula blood flow because of irritation of and/or subtle injury to the ICA by contrast media and/or catheter during diagnostic angiogram, with thrombosis formation at the fistula.

Research paper thumbnail of Spinal Cord Hemangioblastoma with Extensive Syringomyelia

Journal of the Chinese Medical Association, 2005

We present the case of a 20-year-old male with intermittent right upper extremity numbness for 3 ... more We present the case of a 20-year-old male with intermittent right upper extremity numbness for 3 months. His pain perception and temperature sensation were severely disturbed. An incidental magnetic resonance imaging (MRI) finding of one small intramedullary enhancing nodule at spinal cord level T10-11 with long-segment syrinx formation suggested the diagnosis of spinal hemangioblastoma with syringomyelia. Surgical removal of the tumor and decompression of the spinal cord with opening of the syrinx were performed smoothly, and the pathology confirmed the diagnosis of spinal hemangioblastoma. Reviewing the literature, MRI is the examination of choice for spinal hemangioblastomas, and is helpful in preoperative planning and the differential diagnosis of spinal cord neoplasms and vascular lesions. [

Research paper thumbnail of Role of CT and Endovascular Embolization in Managing Pseudoaneurysms of the Internal Maxillary Artery

Journal of the Chinese Medical Association, 2006

Background: The purpose of this study was to evaluate the role of computed tomography (CT) and en... more Background: The purpose of this study was to evaluate the role of computed tomography (CT) and endovascular embolization in managing 10 patients with 11 internal maxillary arterial pseudoaneurysms (IMPAs) with acute oronasal hemorrhage. Methods: A series of 10 patients with 11 IMPAs presenting with profuse oronasal hemorrhage, all treated with endovascular embolization, were reviewed. There were 9 males and 1 female ranging in age from 10 to 56 years (mean, 38 years). The predisposing factors of IMPA were trauma (n = 6) or head and neck carcinomas (HNCs) after surgical treatment and/ or postradiation therapy (n = 5). Before embolization, all patients had CT of maxillofacial regions to evaluate the extension of trauma or to evaluate the treatment outcome for HNCs. Endovascular embolization was employed to occlude the IMPAs by delivering the embolic agents of liquid adhesives (n = 9) or microcoils (n = 2) to the IMPAs. Results: On the lesion side, CT revealed maxillofacial fractures in all 5 trauma patients and recurrent or residual tumors in 3 patients with HNCs. In the other 2 patients with HNCs, CT showed no significant finding and contributed little to the catheter angiography in detecting the IMPAs. Endovascular treatment was technically successful in all 11 IMPAs, ceasing hemorrhage immediately after embolization. No recurrence of bleeding was observed. No patient developed neurologic deficit, skin, or mucosal necrosis at the maxillofacial region. Clinical follow-up was 2-36 months (mean, 14 months). Two patients with advanced carcinoma died during follow-up because of disease progression. Conclusion: CT is a useful tool for guiding catheter angiography to localize the majority of IMPAs. Endovascular embolization can succeed in managing IMPAs, and should be performed as soon as the IMPA is depicted. [

Research paper thumbnail of Endovascular Treatment of Intracranial High-flow Arteriovenous Fistulas by Guglielmi Detachable Coils

Journal of the Chinese Medical Association, 2006

Background: This study reports our experience in performing transarterial Guglielmi detachable co... more Background: This study reports our experience in performing transarterial Guglielmi detachable coil (GDC) embolization for intracranial high-flow arteriovenous fistulas (AVFs) and evaluates its efficacy and safety. Methods: Over 3 years, 13 patients with 14 intracranial high-flow AVFs had been managed by transarterial GDC embolization in our institution. There were 6 men and 7 women, with a mean age of 27 years. Of these 14 AVFs, 8 were traumatic carotid-cavernous fistulas (TCCFs); 5 were AVFs at the frontal, temporal, parieto-occipital lobes, or associated with arteriovenous malformation (n = 3); 1 was a tentorium AVF. Results: All of these high-flow AVFs were successfully occluded by a single session of transarterial GDC embolization. In 8 patients with TCCFs, the nearby parent arteries were preserved. The average number of coils was 8 and the average length was 126 cm. All AVF-related symptoms resolved immediately or gradually on clinical follow-up. No significant procedure-related neurologic complication or recurrent AVF was seen. All 13 patients were followed up clinically for an average of 16 months (range, 6-25 months). Conclusion: Transarterial GDC embolization is a useful method in the treatment of intracranial high-flow AVFs. GDC affords more control in the placement of coils and proved both efficient and safe in the management of intracranial high-flow AVFs. [

Research paper thumbnail of Intraprocedure aneurysm rupture in embolization: Clinical outcome with imaging correlation

Journal of the Chinese Medical Association, 2012

Background: Intraprocedural aneurysm rupture (IPAR) is the most feared complication of embolizati... more Background: Intraprocedural aneurysm rupture (IPAR) is the most feared complication of embolization for intracranial aneurysms. Here we report the immediate and long-term imaging outcomes of IPAR during embolization and the correlation with clinical outcomes. Methods: Of the 376 consecutive patients harboring 412 intracranial aneurysms who had underwent endovascular coil embolizations in the past 9 years, 10 patients (2.7% per patient, 2.4% per aneurysm) had IPAR. There were two men and eight women, with an age range of 40e71 years (mean: 52 years). Imaging findings, including immediate cerebral angiography, brain computed tomography (CT), and follow-up CT, were analyzed. Final clinical patient outcome was evaluated by modified Rankin scale (mRS). Results: The causes of the IPARs were coil protrusion (n ¼ 7), microcatheter perforation (n ¼ 2), or they were spontaneous (n ¼ 1). Nine cases involved previously ruptured aneurysms, while one was unruptured; aneurysmal location of the IPARs was the anterior (n ¼ 5) or posterior (n ¼ 4) communicating artery or the anterior cerebral artery (n ¼ 1). Angiographic cerebral hemodynamic compromise was observed in four patients and associated with poor clinical outcomes. Immediate CT showed contrast media and/or intracranial hemorrhage expansion in all the patients. Cerebral tissue loss due to ischemia and/or hemorrhagic occurred in six patients with more than 3 months of follow-up. On more than a 3-month clinical outcome, six patients presented with good recoveries (mRS: 2). One patient exhibited a moderate disability (mRS: 4), and three patients died (mRS: 6). Conclusion: IPAR is an uncommon complication and usually occurs during the advancement of the coil into the aneurysm sac. Angiographic hemodynamics is an important indicator to determine the outcome of the IPAR. Brain CT demonstrates the progression of the IPAR and the cerebral tissue loss resulting from ischemic or hemorrhagic events.

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

Journal of the Chinese Medical Association, 2014

Background: Transarterial embolization of intracranial dural arteriovenous fistulas (DAVFs) is us... more Background: Transarterial 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. Methods: In 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 ¼ 62 years). We retrospectively analyzed the injection volume and time of Onyx embolization as well as outcomes in different types of DAVFs. Results: The locations of the DAVFs were sigmoid sinus (n ¼ 6), tentorium (n ¼ 3), sinus confluence (n ¼ 2), transverseesigmoid sinus (n ¼ 1), sigmoid sinusejugular bulb (n ¼ 1) and the superior petrous sinus (n ¼ 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. Conclusion: Transarterial 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.

Research paper thumbnail of Transvenous Embolization of Cavernous Sinus Dural Arteriovenous Fistula Using the Direct Superior Ophthalmic Vein Approach: A Case Report

Neurointervention, 2011

Dural Arteriovenous Fistula (DAVF) refers to the abnormal direct connection between veins and art... more Dural Arteriovenous Fistula (DAVF) refers to the abnormal direct connection between veins and arteries in the dura mater and accounts for 10-15% of all intracranial arteriovenous malformations [1]. Compared with the transverse-sigmoid sinus as the most frequent site of occurrence in western countries, the cavernous sinus is the most common location of DAVF in Asians [2]. Treatments of DAVF include manual compression of ipsilateral common carotid artery, radiation therapy, surgery, and endovascular embolization. Treatment methods of cavernous sinus DAVF (CSDAVF) may vary depending on the severity 100

Research paper thumbnail of In-Room Assessment of Cerebral Blood Volume for Guidance during Intra-Arterial Thrombolytic Therapy

Interventional Neuroradiology, 2012

In acute ischemic stroke, the ability to estimate the penumbra and infarction core ratio helps to... more In acute ischemic stroke, the ability to estimate the penumbra and infarction core ratio helps to triage those who will potentially benefit from thrombolytic therapies. Flat-panel post-contrast DynaCT imaging can provide both vasculature and parenchymal blood volume within the angio room to monitor hemodynamic changes during the endovascular procedures. We report on an 80-year-old woman who suffered from an acute occlusion of the right distal cervical internal carotid artery. She was transferred to the angio room where in-room post-contrast flat-panel DynaCT imaging (syngo Neuro PBV IR) was performed to access the ischemic tissue, followed by successful mechanical thrombolytic therapy.

Research paper thumbnail of Transorbital direct puncture of the posterior cavernous sinus through the internal carotid artery for embolization of isolated cavernous sinus dural arteriovenous fistula

Journal of neurointerventional surgery, 2013

Most cavernous sinus dural arteriovenous fistulas (CSDAVFs) present with benign ocular symptoms; ... more Most cavernous sinus dural arteriovenous fistulas (CSDAVFs) present with benign ocular symptoms; isolated CSDAVFs with aggressive behavior are extremely rare. The treatment goal is to occlude the fistula totally. However, transarterial or venous access may not be possible because of complex angioarchitecture. A woman in her late 70s presented with progressive respiratory failure and rapid deterioration of limb muscle power. Imaging studies showed an isolated CSDAVF with exclusive venous drainage to the deep venous system leading to venous hypertension as well as ischemic changes in the brain stem, left thalamus and basal ganglia. Transvascular access of the cavernous sinus (CS) failed. The fistula was eventually occluded by transorbital direct puncture of the posterior CS through the internal carotid artery (ICA) with coils delivered into the CS. The holes in the walls of the ICA created by the puncture needle were sealed by detachable coils and the patient was discharged with mild ...

Research paper thumbnail of Toward the Era of a One-Stop Imaging Service Using an Angiography Suite for Neurovascular Disorders

BioMed Research International, 2013

Transportation of patients requiring multiple diagnostic and imaging-guided therapeutic modalitie... more Transportation of patients requiring multiple diagnostic and imaging-guided therapeutic modalities is unavoidable in current radiological practice. This clinical scenario causes time delays and increased risk in the management of stroke and other neurovascular emergencies. Since the emergence of flat-detector technology in imaging practice in recent decades, studies have proven that flat-detector X-ray angiography in conjunction with contrast medium injection and specialized reconstruction algorithms can provide not only high-quality and high-resolution CT-like images but also functional information. This improvement in imaging technology allows quantitative assessment of intracranial hemodynamics and, subsequently in the same imaging session, provides treatment guidance for patients with neurovascular disorders by using only a flat-detector angiographic suite—a so-called one-stop quantitative imaging service (OSIS). In this paper, we review the recent developments in the field of f...

Research paper thumbnail of Endovascular management of the traumatic cerebral aneurysms associated with traumatic carotid cavernous fistulas

AJNR. American journal of neuroradiology, 2004

Simultaneous traumatic carotid-cavernous fistulas(TCCFs) and traumatic cerebral aneurysms (TCAs) ... more Simultaneous traumatic carotid-cavernous fistulas(TCCFs) and traumatic cerebral aneurysms (TCAs) of the internal carotid artery (ICA) are rare. We describe the pitfalls of detecting a TCA before TCCF occlusion and the endovascular management of the TCA and TCCF. Over 12 years, 156 patients with TCCFs were treated at our institute. In four men (mean age, 34 years), associated TCAs were detected before (n = 1) or after (n = 3) endovascular occlusion of the TCCFs. Causes for the missed detection of the TCA before TCCF occlusion were masking by a parent artery and fistula drains (n = 1), steal phenomenon (n = 1), and a latent period (n = 1). The TCAs were in the supraclinoid ICA (n = 3) or the paraophthalmic artery (n = 1). Three TCAs were treated with the endosaccular placement of electrodetachable coils. Two TCCFs and associated TCAs were successfully occluded with preservation of the ICA. The paraophthalmic TCA was treated with coil occlusion of the TCA and TCCF. Spontaneous fatal ru...

Research paper thumbnail of Contrast enhancement patterns of acute spinal epidural hematomas: a report of two cases

AJNR. American journal of neuroradiology, 2003

The MR finding of an acute spinal epidural hematoma (SEH) can mimic epidural neoplastic or inflam... more The MR finding of an acute spinal epidural hematoma (SEH) can mimic epidural neoplastic or inflammatory lesions, because acute SEH appears hypointense on T1-weighted images and hyperintense on T2-weighted images. We report on two cases of acute SEH with unusual contrast enhancement patterns on MR images. Contrast enhancement can be an MR finding of acute SEH, especially in bleeding diathesis, which indicates an active lesion that needs early diagnosis and management.

Research paper thumbnail of Double-balloon technique for embolization of carotid cavernous fistulas

AJNR. American journal of neuroradiology, 2000

Embolization of a carotid cavernous fistula (CCF) by means of a detachable balloon is an establis... more Embolization of a carotid cavernous fistula (CCF) by means of a detachable balloon is an established method for treating CCFs while preserving a patent parent internal carotid artery (ICA). However, failure to embolize the CCF may occur on a few occasions, such as when the balloon cannot pass through the fistula into the cavernous sinus by blood flow, or when the inflated balloon in the cavernous sinus retracts to the carotid artery. Under these circumstances, the ICA may have to be sacrificed in order to treat the CCF. Herein we describe a double-balloon technique for embolization of a CCF. By applying this technique, we successfully treated nine of 11 CCFs, without compromise of the parent ICA when the conventional one-balloon technique failed.

Research paper thumbnail of Complications of carotid blowout syndrome in patients with head and neck cancers treated by covered stents

Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences, Jan 11, 2008

The purpose of this study was to improve clinical assessment of carotid-blowout syndrome (CBS) in... more The purpose of this study was to improve clinical assessment of carotid-blowout syndrome (CBS) in patients with head-and-neck cancers and with covered stents by evaluating immediate and delayed complications of reconstructive management. Eleven such patients were treated with self-expandable covered stents. We evaluated immediate and delayed complications by assessing clinical and imaging findings. Technical success and immediate hemostasis were achieved in all patients. Immediate complications were noted in four patients (36.4%), including thromboembolism in three patients and, in one patient, dissection of the carotid artery and type III endoleak by the overlapped self-expandable stent causing rebleeding. Delayed complications were noted in eight patients (72.7%), including six episodes of rebleeding in five patients, distal marginal stenosis in five patients, and delayed carotid thrombosis in three patients (one with brain abscess formation). We suggest close follow-up of the pat...

Research paper thumbnail of Endovascular Management of Delayed Vascular Lesions in the Cavernous Sinus after Transarterial Embolization of Traumatic Carotid-Cavernous Fistulas

Research paper thumbnail of Radiation carotid blowout syndrome in nasopharyngeal carcinoma: Angiographic features and endovascular management

Otolaryngology–Head and Neck Surgery, 2008

Objective To report clinical manifestations, angiographic features, and outcomes of endovascular ... more Objective To report clinical manifestations, angiographic features, and outcomes of endovascular management in 14 patients with 15 radiation carotid blowout syndromes of nasopharyngeal carcinomas. Study Design and Subjects Retrospective chart review of 14 patients with nasopharyngeal carcinomas (mean age 49 years) with 15 radiation carotid blowout syndromes who had undergone endovascular embolization to manage oronasal bleeding in the past 10 years. Results Average radiation dose to affected carotid artery was 73 gray units (latent period: 33 months). Radiation carotid blowout syndrome was detected in internal (n = 10), external (n = 4), or common carotid artery (n = 1). Detachable balloons were used in 11 affecting arteries for vascular occlusion; 4 were treated by liquid adhesives or coil. Endovascular treatment was successful in all 15 radiation carotid blowout syndromes with cessation of hemorrhage. One patient had hemiparesis after embolization. Mean clinical follow-up was 21 m...

Research paper thumbnail of Patients with head and neck cancers and associated postirradiated carotid blowout syndrome: Endovascular therapeutic methods and outcomes

Journal of Vascular Surgery, 2008

This study retrospectively evaluated the technical and hemostatic outcomes of reconstructive and ... more This study retrospectively evaluated the technical and hemostatic outcomes of reconstructive and deconstructive endovascular management in patients with head and neck cancers associated with carotid blowout syndrome (CBS). Methods: Twenty-four patients with head and neck cancers with CBS involving the main trunk of carotid artery underwent endovascular therapy. This included reconstructive management with self-expandable stent grafts to preserve the diseased carotid artery in 11 patients and deconstructive management with balloons, coils, or acrylic adhesives to occlude the diseased carotid artery in 13 patients. Based on clinical severity and therapeutic priority, we classified CBS in our patients into two groups: acute or impending and threatened. The angiographic severity was graded from 0 to 3. Evaluation of technical outcome included technical success, initial and delayed complications, and patency of stent graft in the reconstructive group. The hemostatic outcome was evaluated by immediate hemostatic result, rebleeding, and duration of hemostasis. Sex, age, clinical and angiographic severities, local wound complications, and location of the pathologic lesion were examined as predictors of the technical and hemostatic outcomes of endovascular management by using Cox regression method. Results: Technical success and immediate hemostasis were achieved in all patients of both groups. Initial complications during the procedures were encountered in four patients (36.4%) who underwent reconstructive management and in one patient (7.7%) who underwent deconstructive management (P ‫؍‬ .142). Delayed complications during the follow-up were seen in one patient (9.1%) with reconstructive management and one patient (7.7%) with deconstructive management (P > .99). Rebleeding occurred in five patients (45.5%) in the reconstructive management group and in three patients (23.1%) in the deconstructive management group (P ‫؍‬ .659). The mean duration of hemostasis after initial reconstructive and deconstructive management was 4.0 ؎ 8.1 and 8.5 ؎ 10.1 months, respectively (P ‫؍‬ .249). Rebleeding was noted in 7 of 11 patients (63.6%) with acute CBS and in 1 of 13 patients (7.7%) with impending and threatened CBS (P ‫؍‬ .008). Conclusion: There is no significant difference in technical and hemostatic outcomes between the reconstructive and deconstructive endovascular management methods. Hemostatic results were influenced by clinical severity. The rebleeding rate is higher in patients with advanced and acute clinical severity.

Research paper thumbnail of Multiple Intracranial Carotid Injuries: Pitfalls in Diagnosis by Angiography and Principles of Endovascular Treatment

The Journal of Trauma: Injury, Infection, and Critical Care, 2009

Simultaneous multiple intracranial carotid injuries (ICIs) after head trauma are rarely referred ... more Simultaneous multiple intracranial carotid injuries (ICIs) after head trauma are rarely referred for treatment and are often times fatal. The purpose of this study was to describe the potential angiographic pitfalls in diagnosis of multiple ICIs and to report the principles of endovascular management in 15 patients with 34 ICIs. A 12-year study of the 15 patients (8 men and 7 women) with 34 ICIs was completed, and patients were managed by endovascular treatment. Of the 34 ICIs, there were 22 traumatic carotid-cavernous fistulas (TCCFs), 6 traumatic carotid aneurysms, 5 meningeal arteriovenous fistulas, and 1 traumatic occlusion of carotid artery. Transarterial endovascular embolization was performed in 32 ICIs. Four traumatic carotid aneurysms, four meningeal arteriovenous fistulas, and a second hole of the TCCF were missed in early detection by initial cerebral angiograms. The causes of missed early detection of ICIs in angiograms were attributed to occur with TCCFs in the ipsilateral internal carotid artery territory due to overlooking (n = 4), overlap with nearby carotid artery and/or fistula drains of TCCFs (n = 2), steal phenomenon (n = 2), and a latent period of ICI (n = 1). Successful occlusion of 32 ICIs was achieved. On the modified Rankin scale applied in follow-up, 14 patients were assessed as stable clinical status. Early initial detection of ICIs in cerebral angiograms may be difficult if ICIs occur in the same carotid artery, particularly when they coexist with TCCF. However, as soon as TCCFs are occluded, postembolization angiograms should be scrutinized to find the potential associating ICIs, and endovascular management should be performed promptly.

Research paper thumbnail of Stent-assisted coil embolization of intracranial aneurysms: A single center experience

Journal of the Chinese Medical Association, 2012

Background: Endovascular detachable coil embolization has become an important method in the manag... more Background: Endovascular detachable coil embolization has become an important method in the management of intracranial aneurysms. However, coil embolization alone may fail to treat some wide-neck aneurysms. Herein, we report our experience with and outcome of stentassisted coil embolization (SACE) of intracranial aneurysms. Methods: Over a 5-year period, a total of 59 patients diagnosed with 63 intracranial aneurysms underwent SACE. Of the total 63 aneurysms, 6 aneurysms were treated by SACE as a salvageable procedure because of coil instability after detachment. There were 17 men and 42 women enrolled in the study, with ages ranging from 24 to 86 years (mean: 60 years). We retrospectively assessed the clinical data, aneurysm characteristics, and angiographic and clinical outcomes of all patient cases. Results: The mean aneurysm size was 9.4 mm, and the mean neck size was 5.5 mm. Clinical and angiographic follow-up exceeding 6 months were available in 51 and 40 patients, respectively. The mean clinical follow-up time was 28 months (range: 6e49 months). Successful stent deployment was found in 60 aneurysms (95%). Midterm total or subtotal angiographic aneurismal occlusion was obtained in 56 aneurysms (89%), with further thrombosis of the aneurismal sac occurring in 4 (10%). Stable coiling aneurysm was found in 24 (78%), aneurysm recurrence was observed in 5 (13%), and permanent procedural morbidity was observed in two patients (3.4%). During the follow-up period, there were no hemorrhagic events and no stent displacement. Conclusion: Despite a modest procedural complication rate, and some evidence of aneurismal recurrence, SACE was proved to be both effective and safe in managing wide-neck intracranial aneurysms. Our results also demonstrated the midterm durability and stability of aneurysm treated by SACE. Furthermore, SACE can be a salvageable procedure in cases with coil instability after detachment.

Research paper thumbnail of Distal Marginal Stenosis: A Contributing Factor in Delayed Carotid Occlusion of a Patient With Carotid Blowout Syndrome Treated With Stent Grafts

Journal of the Chinese Medical Association, 2010

Distal marginal stenosis is rarely reported to be a factor associated with poor long-term patency... more Distal marginal stenosis is rarely reported to be a factor associated with poor long-term patency of patients of head and neck cancers with carotid blowout syndrome treated with stent grafts. We report a case of laryngeal cancer with rupture of the right common carotid artery. A self-expandable stent graft was deployed, but bleeding recurred. Another stent graft was deployed for the pseudoaneurysm located distal to the first stent graft. Rebleeding occurred because of pseudoaneurysm formation from reconstituted branches of the right superior thyroid artery. We performed direct percutaneous puncture of the proximal superior thyroid artery for successful embolization. Distal marginal stenosis and asymptomatic thrombosis of the carotid artery were noted at 3.5-and 5-month follow-ups, respectively. We suggest aggressive early follow-up and reintervention for distal marginal stenosis by combined antibiotic therapy and angioplasty and stenting to improve the long-term patency of stent-graft deployment for management of carotid blowout syndrome.

Research paper thumbnail of Spontaneous Thrombosis and Complete Disappearance of Traumatic Carotid-cavernous Fistulas After Angiography

Journal of the Chinese Medical Association, 2005

Traumatic carotid-cavernous fistula (TCCF) is a direct shunting fistula due to a tear in the cave... more Traumatic carotid-cavernous fistula (TCCF) is a direct shunting fistula due to a tear in the cavernous portion of the internal carotid artery (ICA). Spontaneous thrombosis of the high-flow shunts in TCCFs is extremely rare. Most cases are treated using endovascular embolization to relieve the clinical presentations. We report 2 unusual cases of TCCF with spontaneous closure of fistulas at intervals of 2 and 10 days, respectively, after diagnostic angiograms. The possible mechanisms of spontaneous healing of the fistulas in these patients with minor head injury and small fistulas were presumed to be a transient decrease in fistula blood flow because of irritation of and/or subtle injury to the ICA by contrast media and/or catheter during diagnostic angiogram, with thrombosis formation at the fistula.

Research paper thumbnail of Spinal Cord Hemangioblastoma with Extensive Syringomyelia

Journal of the Chinese Medical Association, 2005

We present the case of a 20-year-old male with intermittent right upper extremity numbness for 3 ... more We present the case of a 20-year-old male with intermittent right upper extremity numbness for 3 months. His pain perception and temperature sensation were severely disturbed. An incidental magnetic resonance imaging (MRI) finding of one small intramedullary enhancing nodule at spinal cord level T10-11 with long-segment syrinx formation suggested the diagnosis of spinal hemangioblastoma with syringomyelia. Surgical removal of the tumor and decompression of the spinal cord with opening of the syrinx were performed smoothly, and the pathology confirmed the diagnosis of spinal hemangioblastoma. Reviewing the literature, MRI is the examination of choice for spinal hemangioblastomas, and is helpful in preoperative planning and the differential diagnosis of spinal cord neoplasms and vascular lesions. [

Research paper thumbnail of Role of CT and Endovascular Embolization in Managing Pseudoaneurysms of the Internal Maxillary Artery

Journal of the Chinese Medical Association, 2006

Background: The purpose of this study was to evaluate the role of computed tomography (CT) and en... more Background: The purpose of this study was to evaluate the role of computed tomography (CT) and endovascular embolization in managing 10 patients with 11 internal maxillary arterial pseudoaneurysms (IMPAs) with acute oronasal hemorrhage. Methods: A series of 10 patients with 11 IMPAs presenting with profuse oronasal hemorrhage, all treated with endovascular embolization, were reviewed. There were 9 males and 1 female ranging in age from 10 to 56 years (mean, 38 years). The predisposing factors of IMPA were trauma (n = 6) or head and neck carcinomas (HNCs) after surgical treatment and/ or postradiation therapy (n = 5). Before embolization, all patients had CT of maxillofacial regions to evaluate the extension of trauma or to evaluate the treatment outcome for HNCs. Endovascular embolization was employed to occlude the IMPAs by delivering the embolic agents of liquid adhesives (n = 9) or microcoils (n = 2) to the IMPAs. Results: On the lesion side, CT revealed maxillofacial fractures in all 5 trauma patients and recurrent or residual tumors in 3 patients with HNCs. In the other 2 patients with HNCs, CT showed no significant finding and contributed little to the catheter angiography in detecting the IMPAs. Endovascular treatment was technically successful in all 11 IMPAs, ceasing hemorrhage immediately after embolization. No recurrence of bleeding was observed. No patient developed neurologic deficit, skin, or mucosal necrosis at the maxillofacial region. Clinical follow-up was 2-36 months (mean, 14 months). Two patients with advanced carcinoma died during follow-up because of disease progression. Conclusion: CT is a useful tool for guiding catheter angiography to localize the majority of IMPAs. Endovascular embolization can succeed in managing IMPAs, and should be performed as soon as the IMPA is depicted. [

Research paper thumbnail of Endovascular Treatment of Intracranial High-flow Arteriovenous Fistulas by Guglielmi Detachable Coils

Journal of the Chinese Medical Association, 2006

Background: This study reports our experience in performing transarterial Guglielmi detachable co... more Background: This study reports our experience in performing transarterial Guglielmi detachable coil (GDC) embolization for intracranial high-flow arteriovenous fistulas (AVFs) and evaluates its efficacy and safety. Methods: Over 3 years, 13 patients with 14 intracranial high-flow AVFs had been managed by transarterial GDC embolization in our institution. There were 6 men and 7 women, with a mean age of 27 years. Of these 14 AVFs, 8 were traumatic carotid-cavernous fistulas (TCCFs); 5 were AVFs at the frontal, temporal, parieto-occipital lobes, or associated with arteriovenous malformation (n = 3); 1 was a tentorium AVF. Results: All of these high-flow AVFs were successfully occluded by a single session of transarterial GDC embolization. In 8 patients with TCCFs, the nearby parent arteries were preserved. The average number of coils was 8 and the average length was 126 cm. All AVF-related symptoms resolved immediately or gradually on clinical follow-up. No significant procedure-related neurologic complication or recurrent AVF was seen. All 13 patients were followed up clinically for an average of 16 months (range, 6-25 months). Conclusion: Transarterial GDC embolization is a useful method in the treatment of intracranial high-flow AVFs. GDC affords more control in the placement of coils and proved both efficient and safe in the management of intracranial high-flow AVFs. [

Research paper thumbnail of Intraprocedure aneurysm rupture in embolization: Clinical outcome with imaging correlation

Journal of the Chinese Medical Association, 2012

Background: Intraprocedural aneurysm rupture (IPAR) is the most feared complication of embolizati... more Background: Intraprocedural aneurysm rupture (IPAR) is the most feared complication of embolization for intracranial aneurysms. Here we report the immediate and long-term imaging outcomes of IPAR during embolization and the correlation with clinical outcomes. Methods: Of the 376 consecutive patients harboring 412 intracranial aneurysms who had underwent endovascular coil embolizations in the past 9 years, 10 patients (2.7% per patient, 2.4% per aneurysm) had IPAR. There were two men and eight women, with an age range of 40e71 years (mean: 52 years). Imaging findings, including immediate cerebral angiography, brain computed tomography (CT), and follow-up CT, were analyzed. Final clinical patient outcome was evaluated by modified Rankin scale (mRS). Results: The causes of the IPARs were coil protrusion (n ¼ 7), microcatheter perforation (n ¼ 2), or they were spontaneous (n ¼ 1). Nine cases involved previously ruptured aneurysms, while one was unruptured; aneurysmal location of the IPARs was the anterior (n ¼ 5) or posterior (n ¼ 4) communicating artery or the anterior cerebral artery (n ¼ 1). Angiographic cerebral hemodynamic compromise was observed in four patients and associated with poor clinical outcomes. Immediate CT showed contrast media and/or intracranial hemorrhage expansion in all the patients. Cerebral tissue loss due to ischemia and/or hemorrhagic occurred in six patients with more than 3 months of follow-up. On more than a 3-month clinical outcome, six patients presented with good recoveries (mRS: 2). One patient exhibited a moderate disability (mRS: 4), and three patients died (mRS: 6). Conclusion: IPAR is an uncommon complication and usually occurs during the advancement of the coil into the aneurysm sac. Angiographic hemodynamics is an important indicator to determine the outcome of the IPAR. Brain CT demonstrates the progression of the IPAR and the cerebral tissue loss resulting from ischemic or hemorrhagic events.

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

Journal of the Chinese Medical Association, 2014

Background: Transarterial embolization of intracranial dural arteriovenous fistulas (DAVFs) is us... more Background: Transarterial 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. Methods: In 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 ¼ 62 years). We retrospectively analyzed the injection volume and time of Onyx embolization as well as outcomes in different types of DAVFs. Results: The locations of the DAVFs were sigmoid sinus (n ¼ 6), tentorium (n ¼ 3), sinus confluence (n ¼ 2), transverseesigmoid sinus (n ¼ 1), sigmoid sinusejugular bulb (n ¼ 1) and the superior petrous sinus (n ¼ 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. Conclusion: Transarterial 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.