Article
Stimulated functional brain areas can be visualized by optical imaging of intrinsic signals during brain surgery
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Published: | September 16, 2010 |
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Outline
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Objective: Optical imaging of intrinsic signals is a new method for a fast and contact free visualization of stimulated eloquent brain areas during neurosurgical interventions.
Methods: The intensity of the light reflected by the cortical tissue was measured in 28 patients with lesions around the somatosensory, visual or speech cortex using a high resolution camera mounted to an operating microscope. Using adequate stimulation methods the difference in the spectral absorption was used to differentiate between activated and non-activated brain areas. The data acquisition time was 9 minutes with alternating 30 seconds with and without stimulation. The difference between averaged frames was calculated and overlaid over an image of the operative site. Brain movements associated with heartbeat and respiration were compensated using a deformable registration algorithm.
Results: Localized activation of cortical tissue could be visualized for the somatosensory, visual and speech cortex. An excellent imaging quality could be achieved in most of the patients. The calculated location and the size of the activated region corresponded to anatomical landmarks, the results derived by electrophysiological examinations and confirmed the estimation of the neurosurgeon. The results were reproducible in independent examinations. In very few cases no activation of cortical tissue could be deciphered because of technical and biological artifacts.
Conclusions: Optical imaging of intrinsic signals provides an intraoperative high spatial resolution image of brain surface activation, allowing the localization of eloquent brain areas during surgery.
The study is funded by the Carl Zeiss Surgical GmbH.