BLOOD FLOW IMAGE DIAGNOSING DEVICE

• US 20110319775A1
• Filed: 04/20/2010
• Published: 12/29/2011
• Est. Priority Date: 05/13/2009
• Status: Active Grant

• Current Assignee: Kyushu Institute of Technology
• Original Assignee: Kyushu Institute of Technology
• Inventors: Fujii, Hitoshi, Okamoto, Kenji, Takahashi, Noriyoshi, Ishihara, Hiroyuki
• Granted Patent: US 9,028,421 B2
• Time in Patent Office: Days
• US Class Current: 600/504
• CPC Class Codes: A61B 3/1233 for measuring blood flow, e.g. at the retina
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/489 Blood vessels

Abstract

The present invention provides a blood flow image diagnosis device comprising: a laser beam irradiation system that irradiates an observation region of a body tissue with a laser beam; a light receiving system having a light receiver including a large number of pixels that detects reflected light from the observation region of the body tissue; an image capture section that continuously captures a plurality of images for a specified time that is one or more cardiac beats on the basis of a signal from the light receiver; an image storage section that stores the plurality of images; an arithmetic section that calculates a blood flow rate in the body tissue from the time variation of the output signal of each pixel corresponding to the plurality of the stored images; and a display section that displays the two-dimensional distribution of the calculation result as a blood flow map; wherein the blood flow image diagnosis device has a function for analyzing the blood flow map, the arithmetic section has a function that separates a blood flow of a blood vessel observed in a surface layer in the observation region of the body tissue from a peripheral background blood flow on the basis of a plurality of blood flow map data for a time that is one or more cardiac beats, and the display section has a function that distinguishably displays each blood flow on a blood flow map. The blood flow image diagnosis device has an additional function for diagnosing blood flow images as compared to a conventional device.

Claims

1. A blood flow image diagnosis device comprising:

a laser beam irradiation system that irradiates an observation region of a body tissue having a blood cell with a laser beam;

a light receiving system having a light receiver including a large number of pixels that detects reflected light from the observation region of the body tissue;

an image capture section that continuously captures a plurality of images for a specified time that is one or more cardiac beats on the basis of a signal from the light receiver;

an image storage section that stores the plurality of images;

an arithmetic section that calculates a blood flow rate within the body tissue from the time variation of the output signal of each pixel corresponding to the plurality of the stored images; and

a display section that displays the two-dimensional distribution of the calculation result as a blood flow map;

wherein

the blood flow image diagnosis device has a function for diagnosing the blood flow map,

the arithmetic section has a function that separates a blood flow of a blood vessel observed in a surface layer in the observation region of the body tissue (surface layer blood vessel) from a blood flow of a peripheral background region (background blood flow) on the basis of the plurality of blood flow map data covering the time that is one or more cardiac beats,

the display section has a function that distinguishably displays each blood flow map of both portions,

the arithmetic section has a function that calculates and compares information on a blood flow including blood flow value, blood flow waveform or blood vessel diameter in said portions, and

the display section has a function that displays the calculation result obtained in the arithmetic section.

2. The blood flow image diagnosis device according to claim 1,

wherein the arithmetic section has a function that

calculates an amount of position-disparity between each map generated by movement of measuring object regarding said plural blood flow map data,

obtains an average blood flow map by compensating the amount of position-disparity and superimposing,

distinguishes a range with higher blood flow from a range with lower blood flow than a predetermined threshold level,

excludes isolated points,

separates a series of high value points regarded as a blood flow of blood vessel in a surface layer from the others regarded as a background blood flow,

reflects thus-obtained information in each map,

extracts independently a blood flow on a surface layer blood vessel appeared on the surface layer site and a background blood flow existing in a background site in a predetermined region of a map, and

obtains information on the above blood flow in each site.

3. The blood flow image diagnosis device according to claim 1,

wherein the arithmetic section has a function that

obtains each blood flow waveform for the blood vessel in a surface layer and the background blood flow separated by the above function in one or more predetermined regions of a blood flow map,

quantifies a feature of a blood flow waveform which appeared upon either an increase or decrease of blood flow variation by heart beat or features of both blood flow waveforms and displays and compares thus-obtained values with respect to each region.

4. The blood flow image diagnosis device according to claim 1,

wherein the arithmetic section has a function that

obtains each skewness of blood flow waveform for the blood vessel in a surface layer and the background blood flow separated by the above function in one or more predetermined regions of a blood flow map, and

displays and compares thus-obtained values with respect to each region.

5. The blood flow image diagnosis device according to claim 1,

wherein the arithmetic section has a function that

determines each blood flow waveform for the blood vessel in a surface layer and the background blood flow separated by the above function in one or more predetermined regions of a blood flow map,

integrates a blood flow value in a time in which a waveform goes to a bottom from a peak,

integrates a constant blood flow value indicated as (peak value−

minimum value) in the same time,

quantifies a feature of a blood flow waveform by obtaining a ratio of both integrated blood flow values,

displays and compares thus-obtained values with respect to each region.

6. The blood flow image diagnosis device according to claim 1,

wherein the arithmetic section has a function that

obtains each blood flow waveform for the blood vessel in a surface layer and the background blood flow separated by the above function in one or more predetermined regions of a blood flow map,

obtains an amplitude value of each blood flow waveform,

quantifies a feature of a blood flow waveform by calculating a ratio of the amplitude to the average blood flow value, and

displays and compares thus-obtained values with respect to each region.

7. The blood flow image diagnosis device according to claim 1,

wherein the arithmetic section has a function that

specifies one or more regions containing a surface layer blood vessel in a blood flow map,

separates a blood flow of the surface layer blood vessel from a background blood flow by the above function,

extracts a blood flow value in each region, and

calculates independently each average value for the surface layer blood vessel and the background blood flow, and

a function that displays and compares thus-obtained values with respect to each region.

8. The blood flow image diagnosis device according to claim 1,

wherein the arithmetic section has a function that

specifies one or more regions containing a surface layer blood vessel in a blood flow map,

separates a blood flow of the surface layer blood vessel from a background blood flow by the above function,

calculates the total number of pixels in a region corresponding to the surface layer blood vessel, thereby calculates a numerical value proportional to a diameter of the surface layer blood vessel, and

displays and compares the numerical value.

9. The blood flow image diagnosis device according to claim 1,

wherein the arithmetic section has a function that

specifies one or more regions containing a surface layer blood vessel in a blood flow map,

separates a blood flow of the surface layer blood vessel from a background blood flow by the above function,

specifies borderlines between the surface layer blood vessel and the background blood flow existing in both sides thereof,

calculates a diameter of the surface layer blood vessel on the basis of the interval of the borderlines, and

displays and compares the thus-obtained value.

10. The blood flow image diagnosis device according to claim 1,

wherein the blood flow image diagnosis device has a function that

compares results calculated according to claim 1 with results calculated in the same manner based on other blood flow image data with a different measurement date or time,

calculates an increase-decrease rate of the former based on the latter, and

displays and compares the thus-obtained value.

11. The blood flow image diagnosis device according to claim 1,

wherein the device has a function that,

when a mask is made to separate a surface layer blood vessel from a background blood flow,

makes the mask by utilizing light and dark parts of a retina image which is obtained by irradiating an incoherent light to an eye ground,

applies the mask to each blood flow map, and

obtains information on said blood flow in each site.

12. The blood flow image diagnosis device according to claim 1,

wherein the arithmetic section has a function that

specifies one or more rectangular regions containing a surface layer blood vessel in a blood flow map so as to have a longer direction along a course of the blood vessel,

separates a blood flow of a surface layer blood vessel from a background blood flow by the function set forth above,

totals a value that is obtained by subtracting a background blood flow value from a blood flow value in each pixel in a region corresponding to the surface layer blood vessel,

obtains a value proportional to a blood flow volume of the surface layer blood vessel by dividing the sum by a longitudinal pixel count of the rectangular region,

displays the thus-obtained value, and

compares the value in each region mutually or with a value measured at a different time.

13. The blood flow image diagnosis device according to claim 12,

wherein the device has a function that

analyzes an appearance that the value proportional to a blood flow volume obtained by the arithmetic section changes during the measurement,

displays analysis results as a waveform of blood flow volume, and

analyzes and quantifies a feature of the waveform.

14. The blood flow image diagnosis device according to claim 1,

wherein the arithmetic section has a function that,

in a region containing a number of retina vessels extending from an optic nerve head to all sides, distinguishes an artery and a vein by analyzing a blood flow waveform in a blood vessel crossing a borderline of the region,

analyzes a blood flow volume and/or a blood flow waveform, respectively, and

displays analysis results near each blood vessel, saves them as data files or compares them with those measured on a different date.

15. The blood flow image diagnosis device according to claim 1,

wherein the arithmetic section has a function that,

in a region containing a number of retina vessels extending from an optic nerve head to all sides,

calculates each total blood flow volume of an artery and a vein going in and out through a boundary of the region, and

compares a value of a ratio of both total blood flow volumes or compares the total blood flow volume with one measured on a different date.

16. The blood flow image diagnosis device according to claim 1,

wherein the arithmetic section has a function that,

in a region containing a number of retina vessels extending from an optic nerve head to all sides,

calculates a ratio of blood flow volume to a blood vessel diameter with respect to blood vessels passing through the region, and

displays results thus calculated using a figure or color.

17. The blood flow image diagnosis device according to claim 1,

wherein the arithmetic section has a function that,

in surface layer blood vessels crossing mutually or a piece of a surface layer blood vessel with branched vessels in a blood flow map,

analyzes a blood flow volume or a blood flow waveform of each blood vessel, and

displays analysis results near each blood vessel, saves them as data files or compares them with those measured on a different date.

18. The blood flow image diagnosis device according to claim 1,

wherein the arithmetic section has a function that,

in a surface layer blood vessel in a blood flow map,

analyzes each time variation of waveforms regarding a blood flow volume and a blood flow value of the surface layer blood vessel,

calculates a difference of a peak position between these waveforms, and

displays results thus calculated using a figure or color.