FUNCTIONAL MAGNETIC-RESONANCE-IMAGING OF REGIONAL BRAIN ACTIVITY IN PATIENTS WITH INTRACEREBRAL ARTERIOVENOUS-MALFORMATIONS BEFORE SURGICALOR ENDOVASCULAR THERAPY

Functional magnetic resonance (MR) imaging was performed in six patien ts harboring proven intracerebral arteriovenous malformations (AVMs) u sing a noninvasive blood oxygen level-dependent technique based on the documented discrepancy between regional increases in blood flow and o xygen utilization in response to regional brain activation. Statistica l functional MR maps were generated and over:laid directly onto conven tional MR images obtained at the same session. In the six patients stu died. a total of 23 separate functional MR imaging activation studies were performed. Of these. two runs were discarded because of motion ar tifacts. All of the remaining 21 studies demonstrated activation in or near expected regions for the paradigm employed. Qualitatively reprod ucible regional localizations of functional activity in unexpected sit es were also seen. The authors' findings indicating aberrant mapping o f cortical function may be explained on the basis of the plasticity of brain function, in that the developing brain can take over function t hat would normally have been performed by regions of br ain encompasse d by the lesion. Preliminary results in this study's small number of c ases also indicate that activity demonstrated within the confines of t he apparent AVM nidus may help predict the development of a posttherap y deficit. The authors demonstrate that functional MR imaging can be s uccessfully and reproducibly performed in patients with intracerebral AVMs. Notwithstanding the paucity of normative data using functional M R imaging, the authors' findings support cortical reorganization assoc iated with these congenital lesions. Blood oxygen level-dependent MR i maging is a noninvasive method used to localize areas of eloquent cort ex in patients harboring AVMs; it may prove to be of value in treatmen t planning.