Hypofractionated Conformal Stereotactic Radiotherapy for Arteriovenous Malformations

Neurosurgery ◽  
2003 ◽  
Vol 53 (5) ◽  
pp. 1036-1043 ◽  
Author(s):  
Peter Lindvall ◽  
Per Bergström ◽  
Per-Olov Löfroth ◽  
Marwan I. Hariz ◽  
Roger Henriksson ◽  
...  
Keyword(s):  
Stereotactic Radiotherapy ◽  
Arteriovenous Malformations ◽  
University Hospital ◽  
Vascular Lesions ◽  
High Morbidity ◽  
Single Fraction ◽  
Eloquent Areas ◽  
Complete Obliteration ◽  
Cerebral Avms

Abstract OBJECTIVE Arteriovenous malformations (AVMs) are congenital vascular lesions that are associated with high morbidity and mortality if left untreated. There are several options for treatment, including radiotherapy. Safe and effective single-fraction radiotherapy for patients with large AVMs has been considered difficult. METHODS Between December 1986 and June 2001, 36 patients with cerebral AVMs were treated with hypofractionated conformal stereotactic radiotherapy at Umeå University Hospital. Twenty-nine patients have been followed angiographically to date and are reported in this study. RESULTS Twenty-four (83%) of 29 patients (mean AVM volume, 11.5 cm3) underwent complete obliteration of their AVMs. The rates of angiographically verified total obliteration at 2 years after treatment were 56% for AVMs 4 to 10 cm3 and 50% for AVMs larger than 10 cm3. The obliteration rate increased considerably with extended follow-up. Five years after treatment, the obliteration rates were 81% for AVMs 4 to 10 cm3 and 70% for AVMs larger than 10 cm3. CONCLUSION Hypofractionated conformal stereotactic radiotherapy may be an important alternative to single-fraction radiotherapy in patients with large AVMs or AVMs located in eloquent areas, because it allows the administration of a higher radiation dose than is possible to deliver in single-fraction radiosurgery. With our technique of hypofractionated conformal stereotactic radiotherapy, the rate of obliterating AVMs was comparable to that of single-dose radiosurgery, although the volumes of the irradiated AVMs in our study were larger than those reported previously.

scholarly journals Curative Glubran 2 Embolization of Cerebral Arteriovenous Malformations Patient Selection and Initial Results

2014 ◽  
Vol 20 (6) ◽  
pp. 722-728 ◽  
Author(s):  
Jie Liu ◽  
Ming Lv ◽  
Xianli Lv ◽  
Hongwei He ◽  
Aihua Liu ◽  
...  
Keyword(s):  
Clinical Outcomes ◽  
Arteriovenous Malformations ◽  
Gamma Knife Radiosurgery ◽  
Clinical Results ◽  
Hemorrhagic Complication ◽  
Cerebral Arteriovenous Malformations ◽  
Complete Obliteration ◽  
Glubran 2 ◽  
Cerebral Avms

The liquid embolic agents currently used for embolization of cerebral arteriovenous malformations are Onyx and NBCA. Glubran 2, a cyanoacrylate-based synthetic glue, has recently been applied for embolization of cerebral arteriovenous malformations (AVMs). We report the clinical results of selected cerebral AVMs treated with Glubran 2 targeting for curative embolization. Between October 2011 and March 2013, 31 patients with cerebral AVMs were selected for curative embolization with Glubran 2. There were 19 men and 12 women with a mean age of 32 years (range 4–65 years). Initial clinical presentation included hemorrhage in 28 and seizures in three patients. AVM location was frontal in eight patients, parietal in four, occipital in eight temporal in six, cerebellar in two and cerebellar vermis in three patients. Follow-up was performed clinically and with angiography examination at three to six months. Clinical outcomes were evaluated based on the modified Rankin Scale (mRS). A mean of 2.5 (range, 1–12) feeding pedicles were embolized per patient. Complete angiographic obliteration of AVM was achieved in 27 patients. A hemorrhagic complication was observed in one patient, an ischemic complication in one patient and technical complications in four patients. There was no procedure-related disabling neurological deficit or death at discharge. Additional gamma knife radiosurgery was performed in five patients, including one patient with recurrent AVM. All of the patients had favorable clinical outcomes at three to six month follow-up (mRS≤2). The curative embolization technique with Glubran 2 for selected cerebral AVMs achieved a high initial complete obliteration rate with an acceptable complication frequency.

scholarly journals Curative and adjunctive AVM Onyx embolization of AVMs through the choroidal arteries

2017 ◽  
Vol 23 (4) ◽  
pp. 392-398 ◽  
Author(s):  
Xianli Lv ◽  
Xiulan Hu ◽  
Wei Li ◽  
Hongwei He ◽  
Chuhan Jiang ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Endovascular Embolization ◽  
Anterior Choroidal Artery ◽  
Complete Obliteration ◽  
Lateral Posterior ◽  
Cerebral Avms ◽  
Anterior Choroidal ◽  
Choroidal Artery ◽  
Deep Location

Objective The anterior or posterior choroidal artery is often recruited to supply deep location arteriovenous malformations (AVMs). This study is to report curative and adjunctive AVM Onyx embolization through these arteries. Methods This study retrospectively reviewed six patients with cerebral AVMs who underwent endovascular embolization through the choroidal arteries between October 2015 and October 2016. Embolization was performed as a curative procedure in five patients and adjunctive procedure in one patient. Results Four patients underwent embolization through the anterior choroidal artery (AchA), and two patients underwent embolization through the lateral posterior choroidal artery (LPchA). One of the four patients in whom embolization was from the AchA (distal to the plexal point) developed transient hemiparesis. Complete obliteration was confirmed by angiography at the last follow-up in five patients. Conclusions Onyx embolization of cerebral AVMs through the choroidal arteries is possible as a curative or adjunctive procedure.

scholarly journals Arteriovenous Malformations Treated With Frameless Robotic Radiosurgery Using Non-Invasive Angiography: Long-Term Outcomes of a Single Center Pilot Study

2020 ◽  
Vol 10 ◽  
Author(s):  
Ryan Kelly ◽  
Anthony Conte ◽  
M. Nathan Nair ◽  
Jean-Marc Voyadzis ◽  
Amjad Anaizi ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
University Hospital ◽  
Catheter Angiography ◽  
Ct Guided ◽  
Single Fraction ◽  
Non Invasive ◽  
Robotic Radiosurgery ◽  
Ct Angiogram ◽  
Complete Obliteration ◽  
Pre Treatment

ObjectiveCT-guided, frameless robotic radiosurgery is a novel radiotherapy technique for the treatment of intracranial arteriovenous malformations (AVMs) that serves as an alternative to traditional catheter-angiography targeted, frame-based methods.MethodsPatients diagnosed with AVMs who completed single fraction frameless robotic radiosurgery at Medstar Georgetown University Hospital between July 20, 2006 – March 11, 2013 were included in the present study. All patients received pre-treatment planning with CT angiogram (CTA) and MRI, and were treated using the CyberKnife radiosurgery platform. Patients were followed for at least four years or until radiographic obliteration of the AVM was observed.ResultsTwenty patients were included in the present study. The majority of patients were diagnosed with Spetzler Martin Grade II (35%) or III (35%) AVMs. The AVM median nidus diameter and nidal volume was 1.8 cm and 4.38 cc, respectively. Median stereotactic radiosurgery dose was 1,800 cGy. After a median follow-up of 42 months, the majority of patients (81.3%) had complete obliteration of their AVM. All patients who were treated to a total dose of 1800 cGy demonstrated complete obliteration. One patient treated at a dose of 2,200 cGy developed temporary treatment-related toxicity, and one patient developed post-treatment hemorrhage.ConclusionsFrameless robotic radiosurgery with non-invasive CTA and MRI radiography appears to be a safe and effective radiation modality and serves as a novel alternative to traditional invasive catheter-angiography, frame-based methods for the treatment of intracranial AVMs. Adequate obliteration can be achieved utilizing 1,800 cGy in a single fraction, and minimizes treatment-related side effects.

Gamma knife radiosurgery as a single treatment modality for large cerebral arteriovenous malformations

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 113-119 ◽  
Author(s):  
D. Hung-Chi Pan ◽  
Wan-Yuo Guo ◽  
Wen-Yuh Chung ◽  
Cheng-Ying Shiau ◽  
Yue-Cune Chang ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Radiation Treatment ◽  
Gamma Knife Radiosurgery ◽  
Consecutive Series ◽  
Content Type ◽  
Obliteration Rate ◽  
Complete Obliteration ◽  
Fine Print

Object. A consecutive series of 240 patients with arteriovenous malformations (AVMs) treated by gamma knife radiosurgery (GKS) between March 1993 and March 1999 was evaluated to assess the efficacy and safety of radiosurgery for cerebral AVMs larger than 10 cm3 in volume. Methods. Seventy-six patients (32%) had AVM nidus volumes of more than 10 cm3. During radiosurgery, targeting and delineation of AVM nidi were based on integrated stereotactic magnetic resonance (MR) imaging and x-ray angiography. The radiation treatment was performed using multiple small isocenters to improve conformity of the treatment volume. The mean dose inside the nidus was kept between 20 Gy and 24 Gy. The margin dose ranged between 15 to 18 Gy placed at the 55 to 60% isodose centers. Follow up ranged from 12 to 73 months. There was complete obliteration in 24 patients with an AVM volume of more than 10 cm3 and in 91 patients with an AVM volume of less than 10 cm3. The latency for complete obliteration in larger-volume AVMs was significantly longer. In Kaplan—Meier analysis, the complete obliteration rate in 40 months was 77% in AVMs with volumes between 10 to 15 cm3, as compared with 25% for AVMs with a volume of more than 15 cm3. In the latter, the obliteration rate had increased to 58% at 50 months. The follow-up MR images revealed that large-volume AVMs had higher incidences of postradiosurgical edema, petechiae, and hemorrhage. The bleeding rate before cure was 9.2% (seven of 76) for AVMs with a volume exceeding 10 cm3, and 1.8% (three of 164) for AVMs with a volume less than 10 cm3. Although focal edema was more frequently found in large AVMs, most of the cases were reversible. Permanent neurological complications were found in 3.9% (three of 76) of the patients with an AVM volume of more than 10 cm3, 3.8% (three of 80) of those with AVM volume of 3 to 10 cm3, and 2.4% (two of 84) of those with an AVM volume less than 3 cm3. These differences in complications rate were not significant. Conclusions. Recent improvement of radiosurgery in conjunction with stereotactic MR targeting and multiplanar dose planning has permitted the treatment of larger AVMs. It is suggested that gamma knife radiosurgery is effective for treating AVMs as large as 30 cm3 in volume with an acceptable risk.

Fractionated Stereotactic Radiotherapy For the Treatment of Large Arteriovenous Malformations with or without Previous Partial Embolization

Neurosurgery ◽  
2004 ◽  
Vol 55 (3) ◽  
pp. 519-531 ◽  
Author(s):  
Erol Veznedaroglu ◽  
David W. Andrews ◽  
Ronald P. Benitez ◽  
M. Beverly Downes ◽  
Maria Werner-Wasik ◽  
...  
Keyword(s):  
Stereotactic Radiosurgery ◽  
Stereotactic Radiotherapy ◽  
Arteriovenous Malformations ◽  
Three Dimensional ◽  
Late Complications ◽  
Fractionated Stereotactic Radiotherapy ◽  
Medical Systems ◽  
Significant Treatment ◽  
Lost To Follow Up

Abstract OBJECTIVE: Despite the success of stereotactic radiosurgery, large inoperable arteriovenous malformations (AVMs) of 14 cm3 or more have remained largely refractory to stereotactic radiosurgery, with much lower obliteration rates. We review treatment of large AVMs either previously untreated or partially obliterated by embolization with fractionated stereotactic radiotherapy (FSR) regimens using a dedicated linear accelerator (LINAC). METHODS: Before treatment, all patients were discussed at a multidisciplinary radiosurgery board and found to be suitable for FSR. All patients were evaluated for pre-embolization. Those who had feeding pedicles amenable to glue embolization were treated. LINAC technique involved acquisition of a stereotactic angiogram in a relocatable frame that was also used for head localization during treatment. The FSR technique involved the use of six 7-Gy fractions delivered on alternate days over a 2-week period, and this was subsequently dropped to 5-Gy fractions after late complications in one of seven patients treated with 7-Gy fractions. Treatments were based exclusively on digitized biplanar stereotactic angiographic data. We used a Varian 600SR LINAC (Varian Medical Systems, Inc., Palo Alto, CA) and XKnife treatment planning software (Radionics, Inc., Burlington, MA). In most cases, one isocenter was used, and conformality was established by non-coplanar arc beam shaping and differential beam weighting. RESULTS: Thirty patients with large AVMs were treated between January 1995 and August 1998. Seven patients were treated with 42-Gy/7-Gy fractions, with one patient lost to follow-up and the remaining six with previous partial embolization. Twenty-three patients were treated with 30-Gy/5-Gy fractions, with two patients lost to follow-up and three who died as a result of unrelated causes. Of 18 evaluable patients, 8 had previous partial embolization. Mean AVM volumes at FSR treatment were 23.8 and 14.5 cm3, respectively, for the 42-Gy/7-Gy fraction and 30-Gy/5-Gy fraction groups. After embolization, 18 patients still had AVM niduses of 14 cm3 or more: 6 in the 7-Gy cohort and 12 in the 5-Gy cohort. For patients with at least 5-year follow-up, angiographically documented AVM obliteration rates were 83% for the 42-Gy/7-Gy fraction group, with a mean latency of 108 weeks (5 of 6 evaluable patients), and 22% for the 30-Gy/5-Gy fraction group, with an average latency of 191 weeks (4 of 18 evaluable patients) (P = 0.018). For AVMs that remained at 14 cm3 or more after embolization (5 of 6 patients), the obliteration rate remained 80% (4 of 5 patients) for the 7-Gy cohort and dropped to 9% for the 5-Gy cohort. A cumulative hazard plot revealed a 7.2-fold greater likelihood of obliteration with the 42-Gy/7-Gy fraction protocol (P = 0.0001), which increased to a 17-fold greater likelihood for postembolization AVMs of 14 cm3 or more (P = 0.003). CONCLUSION: FSR achieves obliteration for AVMs at a threshold dose, including large residual niduses after embolization. With significant treatment-related morbidities, further investigation warrants a need for better three-dimensional target definition with higher dose conformality.

The safety profile and angioarchitectural changes after acute targeted embolization of ruptured arteriovenous malformations

2021 ◽  
pp. 1-10
Author(s):  
Ann Mansur ◽  
Alex Kostynskyy ◽  
Timo Krings ◽  
Ronit Agid ◽  
Ivan Radovanovic ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Demographic Variables ◽  
Delayed Treatment ◽  
Kaplan Meier ◽  
Complete Obliteration ◽  
Management Paradigms ◽  
Weak Points ◽  
Martin Grade ◽  
Logistical Regression Analysis

OBJECTIVE The aim of this study was to 1) compare the safety and efficacy of acute targeted embolization of angiographic weak points in ruptured brain arteriovenous malformations (bAVMs) versus delayed treatment, and 2) explore the angioarchitectural changes that follow this intervention. METHODS The authors conducted a retrospective analysis of a prospectively acquired database of ruptured bAVMs. Three hundred sixteen patients with ruptured bAVMs who presented to the hospital within 48 hours of ictus were included in the analysis. The first analysis compared clinical and functional outcomes of acutely embolized patients to those with delayed management paradigms. The second analysis compared these outcomes of patients with acute embolization to those with angiographic targets who did not undergo acute embolization. Finally, a subset of 20 patients with immediate postembolization angiograms and follow-up angiograms within 6 weeks of treatment were studied to determine the angioarchitectural changes after acute targeted embolization. Kaplan-Meier curves for survival between the groups were devised. Multivariate logistical regression analysis was conducted. RESULTS There were three deaths (0.9%) and an overall rerupture rate of 4.8% per year. There was no statistical difference in demographic variables, mortality, and rerupture rate between patients with acute embolization and those with delayed management. Patients with acute embolization were more likely to present functionally worse (46.9% vs 69.8%, modified Rankin Scale score 0–2, p = 0.018) and to require an adjuvant therapy (71.9% vs 26.4%, p < 0.001). When comparing acutely embolized patients to those nonacutely embolized angiographic targets, there was a significant protective effect of acute targeted therapy on rerupture rate (annual risk 1.2% vs 4.3%, p = 0.025) and no difference in treatment complications. Differences in the survival curves for rerupture were statistically significant. Multivariate analyses significantly predicted lower rerupture in acute targeted treatment and higher rerupture in those with associated aneurysms, deep venous anatomy, and higher Spetzler-Martin grade. All patients with acute embolization experienced complete obliteration of the angiographic weak point with various degrees of resolution of the nidus; however, some had spontaneous recurrence of their bAVM, while others had spontaneous resolution over time. No patients developed new angiographic weak points. CONCLUSIONS This study demonstrates that acute targeted embolization of angiographic weak points, particularly aneurysms, is technically safe and protective in the early phase of recovery from ruptured bAVMs. Serial follow-up imaging is necessary to monitor the evolution of the nidus after targeted and definitive treatments. Larger prospective studies are needed to validate these findings.

scholarly journals P03.08 Large cerebral arteriovenous malformations management with Volume-staged gamma knife radiosurgery

2019 ◽  
Vol 21 (Supplement_3) ◽  
pp. iii26-iii26
Author(s):  
R M Emad Eldin ◽  
W A Reda ◽  
A M El-Shehaby ◽  
K Abdel Karim ◽  
A Nabeel ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Gamma Knife Radiosurgery ◽  
Cerebral Arteriovenous Malformations ◽  
Factors Affecting ◽  
Prescription Dose ◽  
The Mean ◽  
Cerebral Avms ◽  
Grade 3

Abstract BACKGROUND Large cerebral arteriovenous malformations (AVM) pose a management dilemma because of the limited success of any single treatment modality by itself. Surgery alone is associated with significant morbidity and mortality. Similarly, embolization alone has limited efficacy. Volume-staged gamma knife radiosurgery (VSGR) has been developed for the treatment of large AVMs, to increase the efficacy and improve safety of treatment of these lesions. The aim of the study was to assess the efficacy and safety of VSGR technique for the treatment of large cerebral AVMs. METHODS The study included patients treated by VSGR between May 2009 and July 2015. All cases had large AVMs (>10 cc). These were 29 patients. RESULTS Twenty-four patients completed radiographic follow up with 15 obliteration cases (62.5%). There was a total of 56 sessions performed. The mean AVM volume was 16 cc (10.1–29.3 cc). The mean prescription dose was 18 Gy (14–22 Gy). The mean follow up duration was 43 months (21–73 months). One patient died during follow up from unrelated cause. Two cases suffered haemorrhage during follow up. Symptomatic edema developed in 5 (17%) patients. The factors affecting obliteration were smaller total volume, higher dose/stage, non-deep location, compact AVM, AVM score less than 3, >18 Gy dose and <15 cc total volume. The factors affecting symptomatic edema were smaller total volume and shorter time between first and last sessions (p 0.012). T2 image changes were affected by SM grade 3 or more (p 0.013) and AVM score 3 or more (p 0.014). CONCLUSION VSGR provides an effective and safe treatment option for large cerebral AVMs. Smaller AVM volume is associated with higher obliteration rate.

Surgery for Unruptured Spetzler-Martin Grade 3 Brain Arteriovenous Malformations

Neurosurgery ◽  
2015 ◽  
Vol 77 (3) ◽  
pp. 362-370 ◽  
Author(s):  
Michael Kerin Morgan ◽  
Nazih Assaad ◽  
Miikka Korja
Keyword(s):  
Neurological Deficit ◽  
Arteriovenous Malformations ◽  
Late Recurrence ◽  
Adverse Outcomes ◽  
Brain Arteriovenous Malformations ◽  
Complete Obliteration ◽  
Martin Grade ◽  
Grade 3 ◽  
Permanent Neurological Deficit

Abstract BACKGROUND: There is uncertainty regarding the management of unruptured Spetzler-Martin grade 3 brain arteriovenous malformations (SMG3 ubAVM). OBJECTIVE: To analyze our series of patients treated by surgery. METHODS: A single-surgeon database of consecutively enrolled bAVMs (between 1989 and 2014) was analyzed. Adverse outcomes due to surgery were assigned within the first 6 weeks following surgery and outcome was prospectively recorded and assigned at the last follow-up visit by using modified Rankin Scale (mRS) score. RESULTS: Of the 137 reviewed patients, 112 (82%) were treated by surgery, 15 (11%) were treated elsewhere or by radiosurgery, and 10 (7%) were recommended for conservative management. Surgery for SMG3 ubAVM was associated with adverse outcomes with a new permanent neurological deficit of mRS &gt;1 in 23 of 112 (21%) patients. Permanent neurological deficit leading to a mRS &gt;2 from surgery was 3.6% (95% confidence interval, 1.1%-9.1%). Late recurrence of a bAVM occurred in 3 of 103 (2.9%) patients who had complete obliteration of bAVM confirmed immediately after surgery and who were subsequently later followed with radiological studies during the mean follow-up period of 3.0 years (range, 6 days to 18.8 years). CONCLUSION: When discussing surgical options for SMG3 ubAVM, a thorough understanding of the significance and incidence of adverse events and outcomes is required to fully inform patients. For our series, the additional subclassification of SMG ubAVM (based on variables contributing to the SMG or age) would not have been of use.

scholarly journals Supratentorial Brain AVM Embolization with Onyx-18 and Post-Embolization Management

2009 ◽  
Vol 15 (3) ◽  
pp. 275-282 ◽  
Author(s):  
J. W. Pan ◽  
H.J. Zhou ◽  
R.Y. Zhan ◽  
S. Wan ◽  
M. Yan ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Subsequent Treatment ◽  
Additional Surgery ◽  
Brain Avm ◽  
Initial Symptoms ◽  
Complete Obliteration ◽  
Long Term Follow Up ◽  
Long Term Prognosis

Onyx is increasingly used in endovascular therapy of intracranial arteriovenous malformations (AVMs). However, the embolic effect and post-embolization management are still under discussion. We report our experience in the treatment of supratentorial brain arteriovenous malformations (SBAVMs) with Onyx and discuss post-embolic management. From June 2006 to July 2008, 20 patients with SBAVM were embolized with Onyx. There were 14 men and six women ranging from 14 to 64 years of age (mean 38.3 years). Initial symptoms included spontaneous hemorrhage (n=12), headaches (n=4), seizure (n=3) and incidentally disclosed after head trauma (n=1). After the endovascular procedure, all had subsequent treatment (follow-up angiogram, stereotactic radiosurgery or microsurgery) according to the obliteration degree. At angiography, seven patients (35%, 7/20) were completely obliterated (over 95% closure) after embolization while one suffered a small subarachnoid hemorrhage without permanent clinical sequelae. Four patients (20%, 4/20) were subtotally obliterated (over 80% closure), one patient who suffered severe cerebral edema after embolization underwent decompressive craniectomy, two patients had additional radiosurgery and one patient had follow-up angiogram. Nine patients (45%, 9/20) were partially obliterated (20–80% closure), five patients had additional surgery, two patients had additional radiosurgery and two patients had follow-up angiogram (one patient had intraventricular hemorrhage three months after embolization). Of all 20 AVMs, an average of 2.2 ml Onyx was used per patient and average volume reduction was 80% (range, 30%–99%). Onyx is suitable for embolization of SBAVMs because of its diffuse controllable properties. We suggest clinical follow-up after complete obliteration, additional radiosurgery or angiographic follow-up after subtotal obliteration and additional surgery after partially obliteration. More cases with long-term follow-up are needed to evaluate the long-term prognosis of our post-embolization management.

scholarly journals A quantitative analysis of adverse radiation effects following Gamma Knife radiosurgery for arteriovenous malformations

2015 ◽  
Vol 123 (4) ◽  
pp. 945-953 ◽  
Author(s):  
Or Cohen-Inbar ◽  
Cheng-Chia Lee ◽  
Zhiyuan Xu ◽  
David Schlesinger ◽  
Jason P. Sheehan
Keyword(s):  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Radiation Effects ◽  
Late Onset ◽  
Gamma Knife Radiosurgery ◽  
Volumetric Analysis ◽  
Institutional Review ◽  
Complete Obliteration ◽  
Quantitative Changes

OBJECT The authors review outcomes following Gamma Knife radiosurgery (GKRS) of cerebral arteriovenous malformations (AVMs) and their correlation to postradiosurgery adverse radiation effects (AREs). METHODS From a prospective institutional review board–approved database, the authors identified patients with a minimum of 2 years of follow-up and thin-slice T2-weighted MRI sequences for volumetric analysis. A total of 105 AVM patients were included. The authors analyzed the incidence and quantitative changes in AREs as a function of time after GKRS. Statistical analysis was performed to identify factors related to ARE development and changes in the ARE index. RESULTS The median clinical follow-up was 53.8 months (range 24–212.4 months), and the median MRI follow-up was 36.8 months (range 24–212.4 months). 47.6% of patients had an AVM with a Spetzler-Martin grade ≥ III. The median administered margin and maximum doses were 22 and 40 Gy, respectively. The overall obliteration rate was 70.5%. Of patients who showed complete obliteration, 74.4% developed AREs within 4–6 months after GKRS. Late-onset AREs (i.e., > 12 months) correlated to a failure to obliterate the nidus. 58.1% of patients who developed appreciable AREs (defined as ARE index > 8) proceeded to have a complete nidus obliteration. Appreciable AREs were found to be influenced by AVM nidus volume > 3 ml, lobar location, number of draining veins and feeding arteries, prior embolization, and higher margin dose. On the other hand, a minimum ARE index > 8 predicted obliteration (p = 0.043). CONCLUSIONS ARE development after radiosurgery follows a temporal pattern peaking at 7–12 months after stereotactic radiosurgery. The ARE index serves as an important adjunct tool in patient follow-up and outcome prediction.

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