System and method for localization of functional activity in the human brain
First Claim
1. A system for determining anatomical localization of functional activity of a human brain during a neurosurgical procedure comprising:
- a) illumination means for generating an illuminating light;
b) optical bandpass filter means disposed between the illumination means and the brain for enabling sequential illumination of an exposed surface of the brain with predetermined wavelengths of monochromatic light;
c) a video camera generating a video signal representing an image of the illuminated exposed surface of the brain;
d) video processing means coupled to the video camera for converting the generated video signal to a log signal which directly represents reflectance of said exposed brain surface;
e) image processing means coupled to said video processing means for digitizing and analyzing said log signal and for computing regional total hemoglobin concentration of said exposed brain surface;
f) display means coupled to said image processing means for displaying an image representing the computed regional total hemoglobin concentration of said exposed brain surface.
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Abstract
System and method for the localization of functional activity in the human brain during neurosurgery. The system includes an electronic flash illuminator for illuminating the surface of the exposed portion of the patient'"'"'s brain, optical bandpass filters for sequentially illuminating the exposed brain surface with monochromatic light of a number of predetermined wavelengths, a positioning mechanism for rapid positioning of the optical filters in the path of illumination, a video camera for acquiring an image of the exposed brain surface during illumination with each wavelength of monochromatic light, a circuit for converting the linear output signal of the video camera into a logarithmic signal in video format, a digitizer and frame storage memory for digitizing the logarithmic video signal to obtain multiple two-dimensional matrices. Each matrix represents the magnitude of light reflected at a particular wavelength from a regular grid of points over the exposed brain surface. The system also includes a video frame arithmetic circuit for computing two-dimensional matrices of regional total hemoglobin concentration utilizing the two-dimensional matrices of reflectance data and for transforming the computed matrices into gray-scale or color-scale maps representing total hemoglobin concentration at the grid of points on the exposed brain surface, and a circuit for displaying, on a high-resolution RGB color video monitor, gray-scale or color-scale maps representing either absolute total hemoglobin concentration over the exposed brain surface at a single point in time or the difference between total hemoglobin concentration on the exposed brain surface before and after functional activation of the brain. Functional activation of the brain is accomplished by applying a sensory stimulus to the patient or by having the patient perform a cognitive task in a neuropsychological paradigm appropriately modified for the neurosurgical setting.
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Citations
18 Claims
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1. A system for determining anatomical localization of functional activity of a human brain during a neurosurgical procedure comprising:
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a) illumination means for generating an illuminating light; b) optical bandpass filter means disposed between the illumination means and the brain for enabling sequential illumination of an exposed surface of the brain with predetermined wavelengths of monochromatic light; c) a video camera generating a video signal representing an image of the illuminated exposed surface of the brain; d) video processing means coupled to the video camera for converting the generated video signal to a log signal which directly represents reflectance of said exposed brain surface; e) image processing means coupled to said video processing means for digitizing and analyzing said log signal and for computing regional total hemoglobin concentration of said exposed brain surface; f) display means coupled to said image processing means for displaying an image representing the computed regional total hemoglobin concentration of said exposed brain surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for determining anatomical localization of functional activity of a human brain during a neurosurgical procedure comprising the steps of:
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a) sequentially illuminating an exposed surface of the brain with predetermined wavelengths of monochromatic light; c) generating a video signal representing an image of the illuminated exposed surface of the brain; d) converting the generated video signal to a log signal which directly represents reflectance of said exposed brain surface; e) selecting one of said log signal, said video signal after inverting and DC-restoring the video signal, and a reference voltage; f) computing regional total hemoglobin concentration of said exposed brain surface using said selected signal; and g) displaying an image representing the computed regional total hemoglobin concentration of said exposed brain surface. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification