METHOD AND SYSTEM FOR DETERMINING THE CONTRIBUTION OF HEMOGLOBIN AND MYOGLOBIN TO IN VIVO OPTICAL SPECTRA

• US 20080033263A1
• Filed: 08/03/2006
• Published: 02/07/2008
• Est. Priority Date: 08/03/2006
• Status: Active Grant

• Current Assignee: Washington University In St Louis
• Original Assignee: Washington University In St Louis
• Inventors: Conley, Kevin, Schenkman, Kenneth A., Marcinek, David J.
• Granted Patent: US 8,126,527 B2
• Time in Patent Office: Days
• US Class Current: 600/322
• 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 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/4519 Muscles A61B5/389, A61B5/224 take precedence
• CPC Class Codes: G01N 21/31 Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry G01N21/72 takes precedence

Abstract

This document discusses, among other things, quantification of hemoglobin content, and therefore blood volume, of muscle. An analysis of the optical spectra can determine the ratio of hemoglobin (Hb) to myoglobin (Mb) content in intact muscle. The peak position of the in vivo optical spectra from intact tissue is used to determine the ratio of Hb to Mb contributing to the optical signal. The wavelength of the peak is a linear function of the percent contribution of Hb to the optical spectra. Such analysis in combination with known Mb concentrations yields a non-invasive measure of the Hb content for in vivo muscle.

Claims

1. A method comprising:

receiving optical spectra from in vivo tissue;

receiving a calibration spectra;

determining a position between a spectral peak for hemoglobin and a spectral peak for myoglobin based on the optical spectra and the calibration spectra; and

calculating a ratio of Hb and Mb based on the position.

2. The method of claim 1 wherein the spectral peak for hemoglobin corresponds to peak deoxy-hemoglobin and the spectral peak for myoglobin corresponds to peak deoxy-myoglobin.

3. The method of claim 1 wherein the spectral peak for hemoglobin corresponds to peak oxy-hemoglobin and the spectral peak for myoglobin corresponds to peak oxy-myoglobin.

4. The method of claim 1 further including:

receiving a known concentration of myoglobin for the tissue; and

calculating a concentration of hemoglobin based on the known concentration of myoglobin and the ratio.

5. The method of claim 1 wherein receiving optical spectra includes receiving at least one of reflectance and transmission spectra.

6. The method of claim 1 further including calculating a second derivative of the optical spectra and wherein determining the position includes using the second derivative.

7. The method of claim 1 further including detecting a spectral shift.

8. The method of claim 1 wherein receiving the optical spectra includes receiving spectra in the near infrared or visible region.

9. A system comprising:

a data receiver configured to receive data corresponding to optical spectra of in vivo tissue;

a memory device configured to store the data and configured to store calibration spectra; and

a processor coupled to the memory device and configured to execute instructions to determine a peak position in the data and generate a ratio of hemoglobin and myoglobin based on the peak position.

10. The system of claim 9 wherein the peak position corresponds to at least one of deoxy-myoglobin, deoxy-hemoglobin, oxy-myoglobin, and oxy-hemoglobin.

11. The system of claim 9 further including an output device coupled to the processor and configured to render an output based on the ratio.

12. The system of claim 11 wherein the output device includes at least one of a printer, a display, and a transmitter.

13. The system of claim 9 further including a portable housing and wherein at least one of the data receiver, memory device and the processor are disposed therein.

14. The system of claim 9 wherein the processor is configured to execute instructions to generate a quantitative measure of hemoglobin based on the ratio.

15. The system of claim 9 wherein the processor is configured to generate a second derivative of the spectra.

16. The system of claim 9 further including a spectrograph coupled to the data receiver.

17. The system of claim 9 wherein the processor is configured to generate the ratio based on a position of a spectral shift of the spectra.

18. A method comprising:

receiving optical spectra from intact biological tissue;

detecting a spectral shift in a position of a peak in the optical spectra; and

determining a ratio of hemoglobin and myoglobin based on the position.

19. The method of claim 18 wherein receiving the optical spectra includes receiving optical spectra in a near infrared or visible region.

20. The method of claim 18 wherein detecting the spectral shift in the position of the peak in the optical spectra includes detecting a peak corresponding to at least one of deoxy-myoglobin, deoxy-hemoglobin, oxy-myoglobin, and oxy-hemoglobin.

21. The method of claim 18 wherein detecting the spectral shift in position of a peak in the optical spectra includes comparing a peak position to a peak position of a calibration set.

22. The method of claim 18 wherein detecting the spectral shift in position of a peak in the optical spectra includes comparing a peak position to a peak position of a calibration set.

23. The method of claim 18 wherein receiving optical spectra includes receiving at least one of reflectance spectra and transmission spectra.