Angiographic Obliteration Research Articles

Vein of Galen Malformations in Neonates

Untreated patients with symptomatic neonatal presentation of vein of Galen aneurismal malformations (VGAMs) carry almost 100% morbidity and mortality. Medical management and endovascular techniques for neonatal treatment have significantly evolved. To evaluate the clinical and angiographic outcomes of modern management of neonates with refractory heart failure from VGAMs. From 2005 to 2010, 16 neonatal patients with VGAM presented to our institution. Medical care from the prenatal to perinatal stages was undertaken according to specified institutional guidelines. Nine patients with refractory heart failure required neonatal endovascular intervention. All patients were treated by transarterial deposition of n-butyl cyanoacrylate into fistula sites. Short- and long-term angiographic studies and clinical outcomes were reviewed. Control of heart failure was achieved in 8 patients. One premature baby died shortly after treatment. Long-term angiographic follow-up shows total or near-total angiographic obliteration in all 8 patients. One patient has a mild hemiparesis from treatment. Another has a mild developmental delay. One patient developed a severe seizure disorder and developmental delay. Overall, 66.7% patients have normal neurological development with near-total or total obliteration of the malformation. Treatment of refractory heart failure in neonatal VGAM with modern prenatal, neurointensive, neuroanesthetic, and pediatric neuroendovascular care results in significantly improved outcomes with presumed cure and normal neurological development in most.

Stereotactic radiosurgery for arteriovenous malformations, Part 3: outcome predictors and risks after repeat radiosurgery

The object of this study was to evaluate the outcomes and risks of repeat stereotactic radiosurgery (SRS) for incompletely obliterated cerebral arteriovenous malformations (AVMs). Between 1987 and 2006, Gamma Knife surgery was performed in 996 patients with AVMs. During this period, repeat SRS was performed in 105 patients who had incompletely obliterated AVMs at a median of 40.9 months after initial SRS (range 27.5-139 months). The median AVM target volume was 6.4 cm(3) (range 0.2-26.3 cm(3)) at initial SRS but was reduced to 2.3 cm(3) (range 0.1-18.2 cm(3)) at the time of the second procedure. The median margin dose at both initial SRS and repeat SRS was 18 Gy. The actuarial rate of total obliteration by angiography or MR imaging after repeat SRS was 35%, 68%, 77%, and 80% at 3, 4, 5, and 10 years, respectively. The median time to complete angiographic or MR imaging obliteration after repeat SRS was 39 months. Factors associated with a higher rate of AVM obliteration were smaller residual AVM target volume (p = 0.038) and a volume reduction of 50% or more after the initial procedure (p = 0.014). Seven patients (7%) had a hemorrhage in the interval between initial SRS and repeat SRS. Seventeen patients (16%) had hemorrhage after repeat SRS and 6 patients died. The cumulative actuarial rates of new AVM hemorrhage after repeat SRS were 1.9%, 8.1%, 10.1%, 10.1%, and 22.4% at 1, 2, 3, 5, and 10 years, respectively, which translate to annual hemorrhage rates of 4.05% and 1.79% of patients developing new post-repeat-SRS hemorrhages per year for Years 0-2 and 2-10 following repeat SRS. Factors associated with a higher risk of hemorrhage after repeat SRS were a greater number of prior hemorrhages (p = 0.008), larger AVM target volume at initial SRS (p = 0.010), larger target volume at repeat SRS (p = 0.002), initial AVM volume reduction less than 50% (p = 0.019), and a higher Pollock-Flickinger score (p = 0.010). Symptomatic adverse radiation effects developed in 5 patients (4.8%) after initial SRS and in 10 patients (9.5%) after repeat SRS. Prior embolization (p = 0.022) and a higher Spetzler-Martin grade (p = 0.004) were significantly associated with higher rates of adverse radiation effects after repeat SRS. Delayed cyst formation occurred in 5 patients (4.8%) at a median of 108 months after repeat SRS (range 47-184 months). Repeat SRS for incompletely obliterated AVMs increases the eventual obliteration rate. Hemorrhage after obliteration did not occur in this series. The best results for patients with incompletely obliterated AVMs were seen in patients with a smaller residual nidus volume and no prior hemorrhages.

Microsurgical treatment of intracranial thrombotic giant aneurysms( report of 11 cases)

Objective To study the clinical features and surgical management of intracranial thrombotic giant aneurysms.Methods A retrospective study was performed for 11 patients with intracranial thrombotic giant aneurysms.The clinical presentation, clinical classification, surgical approaches and therapeutic efficacy were reviewed.Results The treatment included thrombectomy - aneurysm clip reconstruction in 9 cases, thrombectomy - aneurysm isolate in 1, and cervical internal carotid artery ligation in 1.The postoperative DSA or CTA showed that complete angiographic obliteration was achieved in 10 cases.Follow - up period was from 3 months to 6 months, the clinical outcomes of these patients were evaluated by Glasgow Outcome Scale grades.GOS of 8 cases were improved.There were minor deficit in 1 case, major deficit in 1 and one death.Conclusions The surgical treatment for intracranial thrombotic giant aneurysms is very difficult.It is a good method to occlude the parent artery temporally, eliminate intraaneurysmal thrombus and reconstruct parent artery.Intraoperative microvascular Doppler sonography (MVD) monitoring is helpful. Key words: Intracranial aneurysm; Thrombus; Microsurgical clipping; Thrombectomy

Endoscopically assisted intratumoral embolization of juvenile nasopharyngeal angiofibroma using Onyx

Juvenile nasopharyngeal angiofibromas are vascular tumors that may make resection difficult and potentially dangerous. Preoperative embolization is frequently used to decrease surgical morbidity and blood loss. Embolization has typically been performed via a transarterial route using a variety of embolic materials. The authors present a case in which endoscopic assistance was used for direct transnasal tumor puncture and intratumoral embolization using the liquid embolic agent Onyx. In this case there was excellent infiltration of the parenchymal vasculature with complete angiographic obliteration. There were no complications related to the embolization. The tumor was resected with minimal blood loss. To the authors' knowledge, there have been no previous reports of this novel direct intratumoral embolization technique using endoscopic guidance.

Predictors of Clinical and Angiographic Outcome After Surgical or Endovascular Therapy of Very Large and Giant Intracranial Aneurysms

Risk factors for poor outcome in the treatment of very large (≥20-24 mm) and giant (≥25 mm) intracranial aneurysms remain incompletely defined. To present an aggregate clinical series detailing a 24-year experience with very large and giant aneurysms to identify and assess the relative importance of various patient, aneurysm, and treatment-specific characteristics associated with clinical and angiographic outcomes. The authors retrospectively identified 184 aneurysms measuring 20 mm or larger (85 very large, 99 giant) treated at Stanford University Medical Center between 1984 and 2008. Clinical data including age, presentation, and modified Rankin Scale (mRS) score were recorded, along with aneurysm size, location, and morphology. Type of treatment was noted and clinical outcome measured using the mRS score at final follow-up. Angiographic outcomes were completely occluded, occluded with residual neck, partly obliterated, or patent with modified flow. After multivariate analysis, risk factors for poor clinical outcome included a baseline mRS score of 2 or higher (odds ratio [OR], 0.23; 95% confidence interval [CI]: 0.08-0.66; P = .01), aneurysm size of 25 mm or larger (OR, 3.32; 95% CI: 1.51-7.28; P < .01), and posterior circulation location (OR, 0.18; 95% CI: 0.07-0.43; P < .01). Risk factors for incomplete angiographic obliteration included fusiform morphology (OR, 0.25; 95% CI: 0.10-0.66; P < .01), posterior circulation location (OR, 0.33; 95% CI: 0.13-0.83; P = .02), and endovascular treatment (OR, 0.14; 95% CI: 0.06-0.32; P < .01). Patients with incompletely occluded aneurysms experienced higher rates of posttreatment subarachnoid hemorrhage and had increased mortality compared with those with completely obliterated aneurysms. Our results suggest that patients with poor baseline functional status, giant aneurysms, and aneurysms in the posterior circulation had a significantly higher proportion of poor outcomes at final follow-up. Fusiform morphology, posterior circulation location, and endovascular treatment were risk factors for incompletely obliterated aneurysms.

Endovascular treatment of traumatic direct carotid cavernous fistulas with n-Butyl-2-Cyanoacrylate

Objective To explore the method and safety of endovascular treatment of traumatic direct carotid cavernous fistulas with n - Butyl - 2 - Cyanoacrylate. Method A total of 11 patients with traumatic direct carotid cavernous fistulas treated by endovascular embolization with n - Butyl -2 - Cyanoacrylate( n - BCA ) were retrospectively analyzed, including the clinical presentations, methods of treatment and results of follow - up. Results In the 11 patients treated with n - BCA embolization, 3 with recurrent fistula because of premature balloon deflation or migration,4 with residual fistula after the balloons or microcoils detached, 3 unable to guide balloon into the small fistulous orifice and 1 repeated puncture of the detachable balloon by the bony fragment. The concentration of n - BCA ranged from 25% to 50%,protective balloon was used in 4 cases and there was no adhesion fo the n - BCA to the protective balloon or the microcatheter or n - BCA reflux into the parent arteries. Complete angiographic obliteration was documented in all patients right after the embolization. There was no permanent procedure - related morbidity. Clinical cure was achieved in all case and the clinical follow - up period ranged from 3 months to 5 years, all the patients restored to their normal life. Conclusions Endovascular embolization with n - BCA is a safe,efficient method for the treatment of traumatic direct carotid cavernous fistulas when angiographic cure and parent artery preservation are not achieved by detachable balloon embolization. Key words: Embolization; Carotid cavernous fistulas; Glue; Trauma

Endovascular Treatment of Middle Cerebral Artery Aneurysms: A Systematic Review and Single-Center Series

Middle cerebral artery (MCA) aneurysms are often considered unsuitable for endovascular coiling because of unfavorable morphological features. With improvements in endovascular techniques, several series have detailed the results and complications of endovascular treatment of MCA aneurysms. We performed a systematic review of published series on endovascular treatment of MCA aneurysms including our experience. We conducted a computerized MEDLINE search of the literature on endovascular treatment of MCA aneurysms. Only studies examining a consecutive case series of MCA aneurysms were included. We then extracted information regarding intraprocedural complications, procedural mortality and morbidity, immediate and long-term angiographic outcomes, and re-treatment rate. Analysis was done including 40 MCA aneurysms treated at our institution. Twelve studies including our institution's consecutive case series were included. Approximately 50% of the aneurysms presented as ruptured. Intraprocedural rupture rate in unruptured aneurysms was 1.7% (95% confidence interval [CI] = 0.7%-3.6%) compared with 4.8% (95% CI = 3.1%-7.4%) for ruptured aneurysms (P = .02). The risk of early postprocedural hemorrhage was 1.1% (95% CI = 0.5%-2.5%) for ruptured aneurysms. Overall procedure-related permanent morbidity and mortality were 5.1% and 6.0% for unruptured and ruptured aneurysms, respectively. The overall rate of complete or near-complete obliteration at angiographic follow-up was 82.4%. Endovascular treatment of MCA aneurysms is feasible and effective in selected cases. The combined periprocedural mortality and morbidity is not negligible (5.1%) and the overall rate of complete or near-complete angiographic obliteration at follow-up approaches 82%.

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.

Endovascular treatment of high-flow cervical direct vertebro-vertebral arteriovenous fistula with detachable coils and Onyx liquid embolic agent

We report the first experience in the treatment of high-flow cervical direct vertebro-vertebral arteriovenous fistula (VVAVF), which was successfully occluded with detachable coils and Onyx through transarterial approach. A 20-year-old female presented with 2-month history of paresis of bilateral extremities. Magnetic resonance imaging (MRI) showed that the dilated ventral epidural veins as well as the dilated left paraspinal veins compressed the spinal cord. Digital subtraction angiography demonstrated high-flow VVAVF between the left vertebral artery (VA) and the surrounding venous plexus at the C3 cervical level. The fistulas were also fed by backward flow from the right VA and left ascending cervical arteries. Transarterial endovascular treatment was performed by using detachable coils and Onyx; immediate angiographic obliteration was achieved. VVAVF-related symptoms resolved gradually, and there was complete neurologic recovery without clinical consequences on clinical follow-up. The fistulas remained closed, as ascertained by 2-month follow-up computed tomography angiography and MRI. No new neurological deficit related to the procedure was detected. The endovascular treatment of direct VVAVF with combination of detachable coils and Onyx is feasible, safe, and highly effective with low morbidity and mortality.

Gamma Knife surgery for arteriovenous malformations in children

The aim of this study was to evaluate the long-term imaging and clinical outcomes of intracranial arteriovenous malformations (AVMs) in children treated with Gamma Knife surgery (GKS). Between 1989 and 2007, 200 patients with AVMs who were 18 years of age or younger were treated at the University of Virginia Health System. Excluding 14 patients who had not reached 2-year follow-up, 186 patients comprised this study. Hemorrhage was the most common presenting symptom leading to the diagnosis of AVMs (71.5%). The mean nidus volume was 3.2 cm(3) at the time of GKS, and a mean prescription dose of 21.9 Gy was used. After initial GKS, 49.5% of patients achieved total angiographic obliteration. Forty-one patients whose AVM nidi remained patent underwent additional GKS. The obliteration rate increased to 58.6% after a second or multiple GKS. Subtotal obliteration was achieved in 9 patients (4.8%). Forty-nine patients (26.3%) still had a patent residual nidus. In 19 patients (10.2%), obliteration was confirmed on MR imaging only. Ten patients had 17 hemorrhages during the follow-up period. The hemorrhage rate was 5.4% within 2 years after GKS and 0.8% between 2 and 5 years. Six patients developed neurological deficits along with the radiation-induced changes. Two patients developed asymptomatic meningiomas 10 and 12 years after GKS. After a mean clinical follow-up of 98 months, less than 4% of patients had difficulty attending school or developing a career. Gamma Knife surgery offers a reasonable chance of obliteration of an AVM in pediatric patients. The incidence of symptomatic radiation-induced changes is relatively low; however, long-term clinical and imaging follow-up is required to identify delayed cyst formation and secondary tumors.

Transvenous injection of n-Butyl cyanoacrylate combined with placement of coils in cavernous sinus for treatment of cavernous dural arteriovenous fistulae

Objective To evaluate the technical aspects, efficacy and safety in the treatment of cavernous dural arteriovenous fistulae (DAVF) by transvenous liquid n-Butyl cyanoacrylate (NBCA) injection combined with coils placement in the cavernous sinus. Methods Eight patients with cavernous DAVF, treated by transvenous embolization with combination of detachable coils and glue between February 2006 and February 2009 in our hospital, were retrospectively analyzed, including the clinical presentations, patterns of angioarchitecture, methods of treatment and the results of follow-up. Results In all 8 patients, 9 transvenous and 1 transarterial interventions were carried out. A single endovascular procedure was performed in 6 patients and 2 patients had to be treated twice. Of the nine transvenous approaches, eight approaches were performed via inferior petrosal sinus (IPS) and 1 via the facial vein. Complete angiographic obliteration was achieved in all patients immediately after the embolization. There was no procedure-related morbidity except for mild headache for one to seven days after the embolization. Clinical cure was achieved in all cases during the clinical follow-up periods, ranging from 8 months to 3 years. The follow-up angiography periods averaged 6.6 months with a range of 5-9 months, in which no recurrence was observed. Conclusion In this small series, embolization with combination of glue and detachable coils by transvenous approaches was a safe, effective and economical method for the treatment of part of symptomatic patients presenting with complex cavernous DAVF.

Contrast-Enhanced Magnetic Resonance Characteristics of Arteriovenous Malformations After Gamma Knife Radiosurgery&lt;subtitle&gt;Predictors of Post-Angiographic Obliteration Hemorrhage&lt;/subtitle&gt;

The reported cumulative risk of post-angiographic obliteration (post-AO) hemorrhage from arteriovenous malformations (AVMs) following gamma knife radiosurgery (GKRS) over 10 years is 2.2%.To identify the warning signs of post-AO hemorrhage by analyzing the characteristics of enhancement on contrast-enhanced MRI magnetic resonance imaging (MRI) of AVMs with post-AO hemorrhage.We performed a retrospective analysis of 121 patients whose AVMs were angiographically obliterated within 5 years of GKRS without hemorrhage and who received at least 1 contrast-enhanced MRI after GKRS (group 1), and 7 patients who experienced post-AO hemorrhage (group 2). We analyzed the enhancement persistence ratio (the percentage of AVMs with persisting enhancement on contrast-enhanced T1-weighted image after obliteration) and the change in size of the enhanced region over time in each patient.The enhancement persistence ratio showed no significant difference between the 2 groups (89.4% vs 100% for groups 1 and 2, respectively; P=.401). While most cases in group 1 showed a tendency to decrease in size and gradually stabilize following GKRS, there were significantly more cases in group 2 with obvious increment of the enhanced regions within 1 year of angiographic obliteration compared with the previous measurement (4.96% vs 71.4% for groups 1 and 2, respectively; P<.0001).Our results suggest that AVMs that show an increase in the size of the enhanced region within 1 year of angiographic obliteration should be followed up with caution for post-AO hemorrhage. Persisting enhancement itself is not positively associated with subsequent hemorrhage.

Repeat Gamma Knife Surgery for Incompletely Obliterated Cerebral Arteriovenous Malformations

The causes of failure after an initial Gamma procedure were studied, along with imaging and clinical outcomes, in a series of 140 patients with cerebral arteriovenous malformations (AVMs) treated with repeat Gamma Knife surgery (GKS). Causes of initial treatment failure included inaccurate nidus definition in 14 patients, failure to fill part of the nidus as a result of hemodynamic factors in 16, recanalization of embolized AVM compartments in 6, and suboptimal dose (<20 Gy) in 23. Nineteen patients had repeat GKS for subtotal obliteration of AVMs. In 62 patients, the AVM failed to obliterate despite correct target definition and adequate dose. At the time of retreatment, the nidus volume ranged from 0.1 to 6.9 cm3 (mean, 1.4 cm3), and the mean prescription dose was 20.3 Gy. Repeat GKS yielded a total angiographic obliteration in 77 patients (55%) and subtotal obliteration in 9 (6.4%). In 38 patients (27.1%), the AVMs remained patent, and in 16 patients (11.4%), no flow voids were observed on magnetic resonance imaging. Clinically, 126 patients improved or remained stable, and 14 experienced deterioration (8 resulting from a rebleed, 2 caused by persistent arteriovenous shunting, and 4 related to radiation-induced changes). By using repeat GKS, we achieved a 55% angiographic cure rate. Although radiation-induced changes as visualized on magnetic resonance imaging occurred in 48 patients (39%), only 4 patients (3.6%) developed permanent neurological deficits. These findings may be useful in deciding the management of AVMs in whom total obliteration after initial GKS was not achieved.

Complete angiographic obliteration of intracranial AVMs with endovascular embolization: incomplete embolic nidal opacification is associated with AVM recurrence

BackgroundEmbolization of intracranial arteriovenous malformations (AVMs) is generally a preoperative adjunctive procedure in the USA. However, sometimes embolization can result in complete angiographic obliteration of the AVM. There is significant...

Spontaneous Angiographic Conversion of Intracranial Dural Arteriovenous Shunt

Dural arteriovenous shunt (DAVS) is a disease in which abnormal arteriovenous communications develop within the dura. Some case series have suggested DAVS may evolve over time, but the natural history is poorly understood. In this study, we aimed to define the incidence and clinical characteristics of patients with DAVS showing spontaneous angiographic pattern conversion. We assessed clinical and angiographic features of patients with angiographic conversion without any treatment from a single center database consisting of 335 DAVS cases. Spontaneous angiographic conversion was defined as complete occlusion of a pre-existing DAVS or conversion of a benign into an aggressive lesion on follow-up diagnostic subtraction angiography. One hundred twelve patients were followed without treatment after the initial diagnosis of DAVS. Overall, we saw pattern conversion on angiography in 18 of the 112 cases (16.1%). Fourteen patients showed spontaneous occlusion of the shunt (12.5%); the most common locations of spontaneous obliteration were the transverse and cavernous sinuses. Four patients showed conversion to an aggressive lesion from benign DAVS (4.0%); all of these cases were associated with occlusion of the ipsilateral draining vein. DAVS is a dynamic disorder, which will show chronological progression. Spontaneous angiographic obliteration or conversion into an aggressive type may occur on follow-up of untreated DAVSs.

Endovascular treatment of congenital brain arteriovenous fistulas with combination of detachable coils and onyx liquid embolic agent

Congenital brain arteriovenous fistulas (BAVFs) are rare vascular lesions, and conservative management was associated with a high mortality rate. We report our experience in the treatment of congenital BAVFs using detachable coils and Onyx liquid embolic agent. Over the past 5 years, 15 patients with congenital BAVFs were treated endovascularly at our hospital using detachable coils and Onyx-34. All patients were clinically followed-up for 12-48 months. We retrospectively reviewed the medical records, cerebral angiograms, and endovascular reports for each patient. There were 15 patients with a total of 16 BAVFs (six men and nine women, with a mean age of 29.4 years). The clinical presentations were intracranial hemorrhage in six patients, headaches in four patients, and seizure in three patients, with two patients diagnosed incidentally. In all of the cases, transarterial microcatheterization was performed, 13 patients were treated with a combination of detachable coils and Onyx-34, and two with balloon-assisted coils and Onyx-34 embolization. There was no significant morbidity or mortality. All BAVF-related symptoms resolved immediately or gradually on clinical follow-up. Immediate angiographic obliteration was achieved in all patients. The fistulas remained closed in all patients, as ascertained by follow-up angiograms. No new neurological deficits related to the procedure were detected. In our experience, the endovascular treatment of BAVFs with combination of detachable coils and Onyx is feasible, safe, and effective. This technique affords more control in the Onyx injection and minimizes the risk of distal embolization.

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.

Multimodality treatment of cerebral AVMs in children: a single-centre 20 years experience

The purpose of this study was to review our experience with a multimodality treatment approach in the management of cerebral arteriovenous malformation (AVM) in children. We retrospectively analysed a consecutive series of 56 children who harboured a cerebral AVM and were treated at our institution between 1988 and 2008. During the whole treatment period, a combined treatment strategy, including microsurgery, endovascular treatment and gamma knife radiosurgery, was used. Of the 56 patients (median age, 14.0; range, 3 months-18 years) reported, 36 (64.3%) were admitted after AVM rupture; of these, only one AVM (1.8%) was considered untreatable. In 30.9% (17/55) of the treated patients, a single treatment measure was sufficient to attain angiographic cure of the AVM. Among these, six patients (10.9%) had microsurgical AVM resection, four patients (7.3%) underwent endovascular treatment, and another seven patients (12.7%) underwent radiosurgical management of the AVM. The majority of the population (38/55; 69.1%) underwent combined treatment: 21 patients (38.2%) received embolisation followed by radiosurgery of the remnant nidus, ten patients (18.2%) underwent embolisation with subsequent surgical resection of the residual AVM, three patients (5.5%) had radiosurgery after incomplete surgical AVM nidus resection and another four patients (7.3%) required a combination of all three treatment modalities to achieve permanent angiographic cure of the AVM. We observed good clinical outcomes (Glasgow Outcome Scale 5 and 4) in 94.6% of the children. Complete angiographic obliteration was achieved in 93.3% of the patients treated. A multimodality treatment approach in children harbouring cerebral AVMs leads to excellent angiographic and clinical outcomes.

Early results of CyberKnife radiosurgery for arteriovenous malformations

The authors describe a method that utilizes an image-guided robotic radiosurgical apparatus (the CyberKnife) for treatment of cerebral arteriovenous malformations (AVMs). This procedure required the development of an original technique that allows a high degree of automation. Angiographic images were imported into the treatment planning software by coregistering CT and 3D rotational angiography. The nidus contour was delineated using the contouring tools of the treatment planning system. Functional MR imaging was employed for contouring critical cortical regions, such as the motor cortex and language areas. Once the radiation dose to be delivered to the target volume and dose constraints to critical structures were prescribed, the inverse treatment planning function determined the optimal treatment plan. A series of 279 patients with cerebral AVMs underwent CyberKnife radiosurgery. One transitory adverse effect of the radiation procedure was observed. Eight bleeding occurrences were noted before complete AVM obliteration. Of the 102 patients with follow-up > 36 months, 80 underwent angiographic evaluation. In this group, 65 patients (81.2%) showed complete angiographic obliteration of their AVM. In 8 more patients, complete angiographic obliteration was demonstrated by MR angiography only. This is the first report describing a technique developed for CyberKnife radiosurgery of cerebral AVMs. The use of different imaging modalities for automatic delineation of the target and critical structures combined with the employment of the inverse treatment planning capability is the crucial point of the procedure. The procedure proved to be safe and efficient.

84 FACTORS INFLUENCING PROPHYLACTIC CRANIAL IRRADIATION UTILIZATION IN LIMITED STAGE SMALL CELL LUNG CANCER

Purpose: To review the results of 75 patients with arteriovenous malformations (AVMs) treated with stereotactic radiosurgery (SRS). Materials and Methods: Thirty-five men and 40 women underwent linear accelerator-based single-fraction SRS from September 1997 to August 2005. The median age was 40 years. All lesions were deemed unsuitable for surgery and/or embolization due to large size or anatomic location, or had failed prior treatment. Twenty-one patients had prior surgery and/or embolization, five patients had prior radiosurgery, and 49 patients had no prior treatment. Median lesion volume was 2.56 cm3 (range, 0.11-13.9 cm). Median prescription dose was 20 Gy (range, 12-25 Gy) to the lesion periphery, resulting in a median “12 Gy volume” of 16.6 cm (range, 1.8-84.3 cm). Patients were followed using yearly magnetic resonance imaging (MRI), with digital subtraction angiography deferred until MRI evidence of complete obliteration or until three to four years post-treatment. Median follow up using MRI and angiography was 34.0 months. Results: The two, three, four and five-year angiographic obliteration rates using Kaplan-Meier analysis were 10.0%, 43.6%, 71.2%, and 77.6%. Eighteen patients developed radionecrosis (RN) on MRI, resulting in permanent neurologic changes in 15 patients. The one, two, three and four-year actuarial rates of RN were 6.8%, 19.8%, 21.4% and 32.8%. The median time till RN was 16 months (range, 9.8-38.9 months). Three patients had AVM haemorrhage in the latent period posttreatment. Conclusion: The obliteration rate in this cohort is comparable to most published series. However, the incidence of symptomatic RN is much higher than is previously reported. This could be due to our completeness of follow up or our case selection of lesions that were larger, located in eloquent regions, or had failed prior treatment. Hypofractionated stereotactic radiotherapy, as an alternative to single-fraction SRS, is being investigated as a method of reducing symptomatic complications for larger AVMs in eloquent areas of the brain.