Artikel
Optical imaging is a useful tool for intraoperative functional brain mapping
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Veröffentlicht: | 21. Mai 2013 |
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Gliederung
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Objective: Intraoperative optical imaging (IOI) is a new method (1) for a fast and contact free visualization of stimulated eloquent brain areas, (2) for the visualization of stimulation effects during brain mapping and (3) for the differentiation of functional and non-functional cortex using direct cortical stimulation.
Method: The intensity of the light reflected by the cortical tissue was measured in 72 patients during brain surgery 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 for the different applications was between 3 to 9 minutes. 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 as well as for non-eloquent functional cortex using direct cortical stimulation. 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 and 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. In addition, IOI seems to have great potential for general differentiation of functional and non-functional brain tissue.
(The study is funded by the Carl Zeiss Surgical GmbH and BMBF.)