Method and System for Intra Luminal Thrombus Detection

• US 20080161698A1
• Filed: 01/03/2007
• Published: 07/03/2008
• Est. Priority Date: 01/03/2007
• Status: Active Grant

• Current Assignee: Infraredx Incorporated (Nipro Corporation)
• Original Assignee: Infraredx Incorporated (Nipro Corporation)
• Inventors: Sum, Stephen Thomas, Meese, Thomas M., Lisauskas, Jennifer Blanche
• Granted Patent: US 8,000,774 B2
• Time in Patent Office: Days
• US Class Current: 600/473
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/0086 using infrared radiation
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: G01J 3/42 Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry beam switching arrangements G01J3/08
• CPC Class Codes: G01N 21/359 using near infrared light

Abstract

A method for detecting a complete or partial obstruction in a vessel through an intervening fluid includes receiving spectroscopic responses at different locations of a vessel wall, e.g., a vein or artery, through an intervening fluid, preferably blood. Spectroscopic responses are generated by irradiating the vessel wall at different locations and detecting spectra at those locations. In preferred embodiments, the radiation used is in the near infrared (NIR) region of the electromagnetic spectrum. The thrombus is located by determining whether fluctuations, spatial and/or spectral, of the spectral responses are indicative of thrombus.

Claims

1. A method for locating a vascular obstruction, the method comprising:

determining spectroscopic responses of a wall of a vessel through an intervening fluid;

analyzing spatial fluctuations in the spectral responses; and

locating the vascular obstruction based on the spatial fluctuations in the spectral responses.

2. The method of claim 1, wherein the step of determining the spectroscopic responses comprises irradiating different regions with a near infrared source and detecting diffuse reflectance spectra within the different regions.

3. The method of claim 1, wherein the step of determining the spectroscopic responses comprises irradiating different regions with a near infrared source and detecting absorption spectra within the different regions.

4. The method of claim 1, wherein the step of determining the spectroscopic responses comprises inserting a catheter into the vessel, irradiating via a head of the catheter and detecting returning light while rotating the head within the vessels and drawing the head through the vessel to generate a helical raster scan, and defining regions relative to the rotation of the head and longitudinal position of the head in the vessel.

5. The method of claim 1, wherein the step of analyzing the fluctuations farther comprises determining pixels in which spectral fluctuations of the spectral response exceed a threshold.

6. The method of claim 1, wherein the step of analyzing the fluctuations further comprises determining regions in which spatial fluctuations of the spectral response exceed a threshold.

7. The method of claim 1, wherein the step of analyzing the fluctuations comprises analyzing spectral images for spatial fluctuations.

8. The method of claim 1, wherein the step of analyzing the fluctuations comprises analyzing spectral images for pixels exhibiting spectral fluctuations.

9. The method of claim 1, wherein the step of analyzing the fluctuations comprises analyzing spectral images covering a wavelength band in which lipids have a strong signal response.

10. The method of claim 1, wherein the step of analyzing the fluctuations comprises comparing the fluctuations to thresholds determined based on averages of the spectral response.

11. The method of claim 1, wherein the step of analyzing the fluctuations comprises determining a root mean square of spectral differences.

12. A device for locating vascular obstructions, the device comprising:

an optical catheter that is inserted into a blood vessel;

a spectrometer for generating light into and receiving light from the optical catheter to resolve spectral responses of walls of the blood vessel; and

an analyzer that receives the spectral responses and searches for regions exhibiting fluctuations in the spectral responses to locate vascular obstructions based on the fluctuations in the spectral responses.

13. The device of claim 12, wherein the spectrometer comprises a near infrared source and a detector system for detecting diffuse reflectance spectra within the different regions.

14. The device of claim 12, further comprising a pullback and rotation unit for rotating and moving a head of the catheter through the blood vessel to determine the spectroscopic responses of the walls in helical raster scans of the walls.

15. The device of claim 12, wherein the analyzer determines regions in which the spatial fluctuations of the spectral response exceed a threshold.

16. The device of claim 12, wherein the analyzer determines pixels in which the fluctuations of the spectral response exceed a threshold.

17. The device of claim 12, wherein the analyzer operates on spectral images covering a narrowed wavelength band.

18. The device of claim 12, wherein the analyzer operates spectral images covering a wavelength band in which lipids have a strong signal response.

19. The device of claim 12, wherein the analyzer compares the fluctuations to thresholds determined based on averages of the spectral response.

20. The device of claim 12, wherein the analyzer determines a root mean square of spectral differences.