Functional Magnetic Resonance Imaging and Optical Imaging for Dominant-hemisphere Perisylvian Arteriovenous Malformations

Department of Psychology, University of California, Los Angeles, Los Ángeles, California, United States
Neurosurgery (Impact Factor: 3.62). 11/2004; 55(4):804-12; discussion 812-4. DOI: 10.1227/01.NEU.0000137654.27826.71
Source: PubMed


In this study, we developed an a priori system to stratify surgical intervention of perisylvian arteriovenous malformations (AVMs) in 20 patients. We stratified the patients into three categories based on preoperative functional magnetic resonance imaging (fMRI) language activation pattern and relative location of the AVM.
In Group I (minimal risk), the AVM was at least one gyrus removed from language activation, and patients subsequently underwent asleep resection. In Group II (high risk), the AVM and language activation were intimately associated. Because the risk of postoperative language deficit was high, these patients were then referred to radiosurgery. In Group III (indeterminate risk), the AVM and language were adjacent to each other. The risk of language deficit could not be predicted on the basis of the fMRI alone. These patients underwent awake craniotomy with electrocortical stimulation mapping and optical imaging of intrinsic signals for language mapping.
All patients from Group I (minimal risk) underwent asleep resection without deficit. All Group II (high-risk) patients tolerated radiosurgery without complication. In Group III (indeterminate risk), three patients underwent successful resection, whereas two underwent aborted resection after intracranial mapping.
We advocate the use of fMRI to assist in the preoperative determination of operability by asleep versus awake craniotomy versus radiosurgery referral. In addition, we advocate the use of all three functional mapping (fMRI, electrocortical stimulation mapping, and optical imaging of intrinsic signals) techniques to clarify the eloquence score of the Spetzler-Martin system before definitive treatment (anesthetized resection versus radiosurgery versus intraoperative resection versus intraoperative closure and radiosurgery referral).

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Available from: Nader Pouratian
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    • "Signal artifacts, as well as physiologic alterations, may compromise fMRI, particularly in patients with high flow lesions (Lehericy et al 2002). Comparison of fMRI with ESM in patients with vascular lesions found 90–100% sensitivity but lower specificity for eloquent cortex (Pouratian et al 2002); effects may depend on lesion size and contiguity to language areas (Lee et al 2010, Cannestra et al 2004). Tumor infiltration, neovascularity, inflammation, or hemodynamic effects may suggest fMRI language dominance contralateral to ESM results, probably due to reduced left hemisphere BOLD signal, and apparent increased prominence of normal homologous right-sided activation in relation to diminished Left BOLD signal (Ulmer et al 2004). "
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    • "iOIS offers several potential advantages over preoperative fMRI language mapping. Spatial resolution for iOIS is one to two orders of magnitude superior to fMRI and hence the lesion and functional cortex may be easily distinguished by the surgeon on iOIS images (Cannestra et al., 2004). Intraoperative mapping is inherently more accurate as the lesion and functional maps may change after pre-operative images are obtained, either due to lesion evolution and cortical plasticity, or also due to tissue displacement due to operative procedures. "
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