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Diagnostic apparatus for measuring changes of arterial and venous blood volumes in brain with respiration signal modulation

  • US 5,253,646 A
  • Filed: 03/18/1992
  • Issued: 10/19/1993
  • Est. Priority Date: 12/30/1991
  • Status: Expired due to Term
First Claim
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1. An apparatus used for diagnosing a living subject, comprising:

  • light source means for emitting light of different wavelength;

    light introducing/receiving means for introducing said light into a brain of the living subject and receiving light transmitted through the brain;

    detecting means for detecting occurrences of respirations of the living subject and outputting a respiration signal indicative of said occurrences of said respirations;

    deriving means for deriving the transmitted light from said introducing/receiving means in synchronism with the respiration signal and outputting a modulated light transmission signal indicative of the transmitted light which is modulated by the respiration signal;

    analyzing means for analyzing the modulated light transmission signal and providing an operation result, the operation result indicating variations in concentration of oxygenated media Δ

    X02 and disoxygenated media Δ

    X contained in venous blood of the brain;

    operation means for performing an arithmetic operation of
    
    
    space="preserve" listing-type="equation">K.sub.1 ×

    Δ

    X.sub.02 /{Δ

    X+Δ

    X.sub.02 } where K1 is a first predetermined constant, a result of the arithmetic operation indicating an oxygen saturation in the venous blood of the brain; and

    displaying means for displaying the result of the arithmetic operation.

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