Use of Cone-Beam Computed Tomography Angiography in Planning for Gamma Knife Radiosurgery for Arteriovenous Malformations

Abstract

The effectiveness of Gamma Knife radiosurgery (GKR) for cerebral arteriovenous malformations (AVMs) is predicated on inclusion of the entire nidus while excluding normal tissue. As such, GKR may be limited by the resolution and accuracy of the imaging modality used in targeting. We present the first case series to demonstrate the feasibility of using ultrahigh-resolution C-arm cone-beam computed tomography angiography (CBCT-A) in AVM targeting. From June 2009 to June 2013, CBCT-A was used for targeting of all patients with AVMs treated with GKR at our institution. Patients underwent Leksell stereotactic head frame placement followed by catheter-based biplane 2-dimensional digital subtraction angiography, 3-dimensional rotational angiography, as well as CBCT-A. The CBCT-A dataset was used for stereotactic planning for GKR. Patients were followed at 1, 3, 6, and 12 months and then annually thereafter. CBCT-A-based targeting was used in 22 consecutive patients. CBCT-A provided detailed spatial resolution and sensitivity of nidal angioarchitecture enabling treatment. The average radiation dose to the margin of the AVM nidus corresponding to the 50% isodose line was 15.6 Gy. No patient had treatment-associated hemorrhage. At early follow-up (mean, 16 months), 84% of patients had a decreasing or obliterated AVM nidus. CBCT-A-guided radiosurgery is feasible and useful because it provides sufficient detailed resolution and sensitivity for imaging brain AVMs.