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Retrospective Analysis of Imaging Techniques for Treatment Planning and Monitoring of Obliteration for Gamma Knife Treatment of Cerebral Arteriovenous Malformation

Amponsah, Kwame MD*; Ellis, Thomas L. MD*; Chan, Michael D. MD; Lovato, James F. MSc§; Bourland, J. Daniel PhD; deGuzman, Allan F. PhD; Ekstrand, Kenneth E. PhD; Munley, Michael T. PhD; McMullen, Kevin P. MD; Shaw, Edward G. MD, MA; Tatter, Stephen B. MD, PhD*

doi: 10.1227/NEU.0b013e3182672a83
Concepts, Innovations, and Techniques

BACKGROUND: It has been well established that Gamma Knife radiosurgery (GKS) is an effective treatment for brain arteriovenous malformations (AVMs).

OBJECTIVE: To evaluate complete obliteration rates for magnetic resonance imaging (MRI)–based GKS treatment planning performed with and without angiography and to conduct a preliminary assessment of the utility of using pulsed arterial spin labeling (PASL) magnetic resonance (MR) perfusion imaging to confirm complete obliteration.

METHODS: Forty-six patients were identified who had undergone GKS without embolization with a minimum follow-up of 2 years. One group was planned with integrated stereotactic angiography and MR (spoiled gradient recalled) images obtained on the day of GKS. A second technique avoided the risk of arteriography by using only axial MR images. Beginning in 2007, PASL MR perfusion imaging was routinely performed as a portion of the follow-up MRI to assess the restoration of normal blood flow of the nidus and surrounding area.

RESULTS: The overall obliteration rate for the angiography/MRI group was 88.0% (29 of 33). Patients in the MRI-only group had an obliteration rate of 61.5% (8 of 13), with P = .092 with the Fisher exact test, which is not statistically significant. A Kaplan-Meier analysis was also not statistically significant (log rank test, P = .474). Four of 9 patients with incomplete obliteration on angiography also had shown residual abnormal blood flow on PASL imaging.

CONCLUSION: This retrospective analysis shows that treatment planning technique used in GKS does not play a role in the eventual obliteration of treated AVMs. PASL may have potential in the evaluation of AVM obliteration.

ABBREVIATIONS: AVM, arteriovenous malformation

GKS, Gamma Knife radiosurgery

PASL, pulsed arterial spin labeling

Departments of *Neurosurgery and

Radiation Oncology

§Division of Public Health Sciences, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina

Correspondence: Kwame Amponsah, MD, Department of Neurosurgery, Wake Forest University Baptist Medical Center, Medical Center Boulevard, Winston Salem, NC 27157. E-mail:

Received December 17, 2011

Accepted June 20, 2012

Copyright © by the Congress of Neurological Surgeons