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 radiosurgery 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.