Stereotactic radiosurgery planning based on time-resolved CTA for arteriovenous malformation: a case report and review of the literature

Abstract

Stereotactic radiosurgery has long been recognized as the optimal form of management for high-grade arteriovenous malformations not amenable to surgical resection. Radiosurgical plans have generally relied upon the integration of stereotactic magnetic resonance angiography (MRA), standard contrast-enhanced magnetic resonance imaging (MRI), or computed tomography angiography (CTA) with biplane digital subtraction angiography (DSA). Current options are disadvantageous in that catheter-based biplane DSA is an invasive test associated with a small risk of complications and perhaps more importantly, the two-dimensional nature of DSA is an inherent limitation in creating radiosurgical contours. The necessity of multiple scans to create DSA contours for radiosurgical planning puts patients at increased risk. Furthermore, the inability to import two-dimensional plans into some radiosurgery programs, such as Cyberknife TPS, limits treatment options for patients. Defining the nidus itself is sometimes difficult in any of the traditional modalities as all draining veins and feeding arteries are included in the images. This sometimes necessitates targeting a larger volume, than strictly necessary, with stereotactic radiosurgery for treatment of the AVM. In this case report, we show the ability to use a less-invasive and three-dimensional form of angiography based on time-lapsed CTA (4D-CTA) rather than traditional DSA for radiosurgical planning. 4D-CTA may allow generation of a series of images, which can show the flow of contrast through the AVM. A review of these series may allow the surgeon to pick and use a volume set that best outlines the nidus with least interference from feeding arteries or draining veins. In addition, 4D-CTA scans can be uploaded into radio-surgery programs and allow three-dimensional targeting. This is the first reported case demonstrating the use of a 4D CTA and an MRI to delineate the AVM nidus for Gamma Knife radiosurgery, with complete obliteration of the nidus over time and subsequent management of associated radiation necrosis with bevacizumab.

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

“…developed permanent symptoms such as hemiparesis, reduced consciousness, visual, and ocular motor deficits. The median target volume in this study was larger than the aforementioned trials at 3.6 cm 3 (0.1-26.3 cm 3 ) with a median margin dose was 20 Gy (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27). The adverse event rates were found to be 3.2%, 5.8%, 6.7%, and 7.5% at 1, 2, 3, and 5 years, respectively.…”

“…Two separate studies by Willems et al and Essig et al have demonstrated that 4D-CTA can better delineate the AVM nidus when compared to traditional angiography (24,25). Additional studies have also demonstrated improved temporal resolution using 4D-CTA compared to angiography which can help distinguish the collateral and feeding vessels of the AVM (26)(27)(28). The benefits of the both these features in the radiosurgical planning is that it allows the physician to limit the treatment to the AVM nidus and spare the surrounding cerebral parenchyma decreasing the effects of radiation toxicity.…”

Resolution of Radiation-Induced Necrosis in Arteriovenous Malformation with Bevacizumab: A Case Report and Review of Current Literature

“…The results from Dashti et al [14] showed reduction or resolution of severe headaches and over a 70% reduction in T2 FLAIR in both the patients. Turner et al [2] reported full recovery from steroid-refractory RIN post-SRS for AVM, including complete resolution of severe headaches and hemiparesis with bevacizumab. Uysal et al [15] reported a patient with steroid-resistant RIN post-SRS for AVM who experienced improvement in headache, hemiparesis, and ambulation along with significant resolution of perilesional edema on computed tomography [15].…”

“…Stereotactic radiosurgery (SRS) is a proven treatment modality for inoperable high-risk arteriovenous malformations (AVM) [1]. However, SRS administration has been associated with late toxicities, such as radiation-induced necrosis (RIN), which can present symptomatically in 2–14% of patients and neuroradiologically in ≤46% [2]. Steroid therapy is the primary mean for managing RIN, while the efficacy of bevacizumab, an angiogenesis inhibitor, is currently under investigation.…”

Gamma Knife Radiosurgery for Arteriovenous Malformations Using a Four-Dimensional Dynamic Volume Computed Tomography Angiography Planning System as an Alternative to Traditional Catheter Angiogram

“…Here, we present the first series of AVM patients treated with GKRS using 4D dynamic volume CTA angiography for nidus localization and treatment targeting, either before or after the placement of the Leksell® Coordinate Frame G on the day of GKRS treatment. Previously, our institution has reported a single case in which the 4D-CTA was used as a DOS study for treatment planning, including the use of titanium frame pins, creating a significant image artifact [ 23 ]. This artifact has been well documented by other groups utilizing only CT-based treatment planning as an alternative to MRI [ 24 - 25 ].…”