Method and apparatus for cerebral oximetry

• US 8,433,384 B2
• Filed: 09/03/2010
• Issued: 04/30/2013
• Est. Priority Date: 05/03/2006
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Bechtel, Kate Leeann, Funk, Tobias, Wilfley, Brian Patrick, Heanue, Joseph Anthony
• Primary Examiner(s): Laballe, Clayton E
• Assistant Examiner(s): Smith, Linda B
• Application Number:
  US12/875,925
• Publication Number:
  US 20110066014A1
• Time in Patent Office: 970 Days
• Field of Search: 600/324
• US Class Current: 600/324
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0091 for mammography
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue
• CPC Class Codes: A61B 5/415 the glands, e.g. tonsils, adenoids or thymus
• CPC Class Codes: A61B 5/418 lymph vessels, ducts or nodes
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0205 Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/2823 Imaging spectrometer
• CPC Class Codes: G01J 3/4406 Fluorescence spectrometry
• CPC Class Codes: G01N 21/6408 with measurement of decay time, time resolved fluorescence
• CPC Class Codes: G01N 2201/0826 Fibre array at source, distributing
• CPC Class Codes: G01N 2201/0833 Fibre array at detector, resolving

Abstract

The present invention pertains to a method and apparatus for cerebral oximetry. A modulated optical signal based on a digital code sequence is transmitted to the human brain. A temporal transfer characteristic is derived from the modulated optical signal. Oxygen level in the brain is determined based on the temporal transfer characteristic.

Claims

1. A method for measuring oxygen level in a human brain comprising:

generating a digital modulation signal associated with a code sequence;

generating a modulated optical signal based on said digital modulation signal;

transmitting said modulated optical signal to said human brain;

receiving a modified version of said modulated optical signal after transmission through said human brain;

deriving a temporal transfer characteristic for said modified version of said modulated optical signal;

calculating said oxygen level based on said temporal transfer characteristic;

delaying said code sequence to generate a second code sequence;

generating a second digital modulation signal associated with said second code sequence;

generating a second modulated optical signal based on said second digital modulation signal;

transmitting said second modulated optical signal to said human brain;

receiving a second modified version of said second modulated optical signal after transmission through said human brain; and

deriving a second temporal transfer characteristic for said second modified version of said second modulated optical signal.

2. The method of claim 1 further comprising:

delaying said modulated optical signal to reduce noise effects.

3. The method of claim 1 further comprising:

determining an absorption coefficient of said human brain from said temporal transfer characteristic.

4. The method of claim 1 wherein said code sequence is circular.

5. The method of claim 1 wherein said code sequence is unipolar.

6. The method of claim 1 wherein said code sequence is orthogonal.

7. The method of claim 1 wherein said code sequence is a pseudorandom binary sequence.