Blood flow image diagnosing device

• US 9,028,421 B2
• Filed: 04/20/2010
• Issued: 05/12/2015
• 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
• Primary Examiner(s): Kahelin, Michael
• Assistant Examiner(s): Alter, Mitchell E
• Application Number:
  US13/254,754
• Publication Number:
  US 20110319775A1
• Time in Patent Office: 1,848 Days
• Field of Search: None
• 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

A blood flow image diagnosis device which diagnoses a blood flow map by separating, on the basis of a plurality of blood flow maps covering a specified time including one or more cardiac beats, a blood flow of a surface layer blood vessel observed in a surface layer in an observation region of a body tissue from a background blood flow of a peripheral background region. The device distinguishably displays a first blood flow map of the surface layer blood vessel and a second blood flow map of the background blood flow. The device calculates and compares information on a blood flow including blood flow value, blood flow waveform, or blood vessel diameter in the first and second blood flow maps, and displays the calculated information.

Claims

1. A blood flow image diagnosis device comprising:

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

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

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

an image storage section that stores the plurality of images;

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

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

wherein

the arithmetic section separates, based on a plurality of blood flow maps covering the specified time including one or more cardiac beats, a blood flow of a surface layer blood vessel observed in a surface layer in the observation region of the body tissue from a background blood flow of a peripheral background region,

the display section distinguishably displays a first blood flow map of the surface layer blood vessel and a second blood flow map of the background blood flow,

the arithmetic section calculates and compares information on a blood flow including blood flow value, blood flow waveform, or blood vessel diameter in said first and second blood flow maps, and

the display section displays the calculated information,

wherein the arithmetic section;

calculates an amount of position-disparity, generated by movement of a measuring object, regarding said plurality of blood flow maps,

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

obtains a mask image based on the average blood flow map by distinguishing a range with higher blood flow from a range with lower blood flow based on a threshold and excluding isolated points on the average blood flow map,

superimposes the mask image on each of the plurality of blood flow maps,

independently extracts the blood flow on the surface layer blood vessel and the background blood flow in a first region of the plurality of blood flow maps, respectively, and

obtains information on the blood flow of the surface layer blood vessel and the background blood flow.

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

wherein the arithmetic section:

obtains blood flow waveforms for the surface layer blood vessel and the background blood flow in one or more regions of the blood flow map, and

quantifies a feature of one of the blood flow waveforms appearing upon either an increase or decrease of blood flow variation by heart beat or features of the blood flow waveforms, and

the display section displays and compares the quantified feature with respect to the one or more regions of the blood flow map.

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

wherein the arithmetic section

obtains skewness of blood flow waveforms for the surface layer blood vessel and the background blood flow in one or more regions of the blood flow map, and

the display section displays and compares the skewness of the blood flow waveforms with respect to the one or more regions of the blood flow map.

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

wherein the arithmetic section:

determines blood flow waveforms for the surface layer blood vessel and the background blood flow in one or more regions of the blood flow map,

integrates a blood flow value in a time in which one of the blood flow waveforms goes to a bottom from a peak,

integrates a constant blood flow value, indicated as a difference between a peak value and a minimum value, in the same time, and

quantifies a feature of one of the blood flow waveforms by obtaining a ratio of the integrated blood flow value and the integrated constant blood flow value, and

the display section displays and compares the quantified feature with respect to the one or more regions of the blood flow map.

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

wherein the arithmetic section:

obtains blood flow waveforms for the surface layer blood vessel and the background blood flow in one or more regions of the blood flow map,

obtains respective amplitude values of the blood flow waveforms, and

quantifies a feature of one of the blood flow waveforms by calculating a ratio of the corresponding amplitude value to an average blood flow value, and

the display section displays and compares the quantified feature with respect to the one or more regions of the blood flow map.

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

wherein the calculating and comparing information on a blood flow includes the blood flow value, and

wherein the arithmetic section:

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

separates, based on the specified one or more regions containing the surface layer blood vessel in the first blood flow map, the blood flow of the surface layer blood vessel from the background blood flow,

extracts the blood flow value in the one or more regions, and

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

the display section displays and compares the respective average value with respect to the one or more regions of the blood flow map.

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

wherein the arithmetic section:

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

separates, based on the specified one or more regions containing the surface layer blood vessel in the first blood flow map, the blood flow of the surface layer blood vessel from the background blood flow,

calculates a 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

the display section displays and compares the numerical value.

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

wherein the arithmetic section:

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

separates, based on the specified one or more regions containing the surface layer blood vessel in the first blood flow map, the blood flow of the surface layer blood vessel from the background blood flow,

specifies borderlines between the surface layer blood vessel and the background blood flow existing on both sides of the surface layer blood vessel, and

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

the display section displays and compares the calculated diameter.

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

wherein the blood flow image diagnosis device:

compares the calculated information with second information calculated by the arithmetic section on another blood flow image data with a different measurement date or time,

calculates an increase-decrease rate of the calculated information based on the second information, and

displays and compares the increase-decrease rate.

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

wherein the blood flow image diagnosis device:

makes a mask, for separating the blood flow of the surface layer blood vessel from the background blood flow, 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 the plurality of the blood flow maps, and

obtains information on blood flow at a surface layer site and a background site on each of the blood flow maps to which the mask is applied.

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

wherein the arithmetic section:

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

separates, based on the specified one or more rectangular regions, the blood flow of the surface layer blood vessel from the background blood flow,

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, and

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

the display section displays the obtained value, and

compares the value in each of the specified one or more rectangular regions mutually or with a value measured at a different time.

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

wherein the blood flow image diagnosis device:

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

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

analyzes and quantifies a feature of the waveform.

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

wherein the arithmetic section:

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

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

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

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

wherein the arithmetic section

calculates, in a region containing a number of retina vessels extending from an optic nerve head to all sides, 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 each total blood flow volume or compares the total blood flow volume with one measured on a different date.

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

wherein the arithmetic section:

calculates, in a region containing a number of retina vessels extending from an optic nerve head to all sides, a ratio of blood flow volume to a blood vessel diameter with respect to blood vessels passing through the region, and

the display section displays the calculated ratio using a figure or color.

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

wherein the arithmetic section:

analyzes, in surface layer blood vessels crossing mutually or a piece of the surface layer blood vessel with branched vessels in the blood flow map, a blood flow volume or a blood flow waveform of each blood vessel, and

the display section displays analysis results near each surface layer blood vessel, saves the results as data files or compares the results with results measured on a different date.

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

wherein the calculating and comparing information on a blood flow includes the blood flow value, and

wherein the arithmetic section:

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

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

displays the calculated difference using a figure or color.

18. A blood flow image diagnosis method comprising:

irradiating, with a laser beam, an observation region of a body tissue having a blood cell;

detecting reflected light from the observation region of the body tissue;

capturing, on the basis of the detected reflected light, a plurality of images for a specified time including one or more cardiac beats, each of the plurality of images comprising pixels;

storing the plurality of images;

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

displaying a two-dimensional distribution of the calculated blood flow rate as a blood flow map;

wherein

the calculating comprises separating, on the basis of a plurality of blood flow maps covering the specified time including one or more cardiac beats, a blood flow of a surface layer blood vessel observed in a surface layer in the observation region of the body tissue from a background blood flow of a peripheral background region,

the displaying comprises distinguishably displaying a first blood flow map of the surface layer blood vessel and a second blood flow map of the background blood flow,

the calculating further comprises calculating and comparing information on a blood flow including blood flow value, blood flow waveform, or blood vessel diameter in said first and second blood flow maps, and

the displaying further comprises displaying the calculated information,

wherein the calculating the information on the blood flow comprises;

calculating an amount of position-disparity, generated by movement of a measuring object, regarding said plurality of blood flow maps,

obtaining an average blood flow map by compensating the plurality of the blood flow maps with the amount of position-disparity and superimposing the compensated plurality of the blood flow maps,

obtaining a mask image based on the average blood flow map by distinguishing a range with higher blood flow from a range with lower blood flow based on a threshold and excluding isolated points on the average blood flow map,

superimposing the mask image on each of the plurality of blood flow maps,

independently extracting the blood flow on the surface layer blood vessel and the background blood flow in a first region of the plurality of blood flow maps, respectively, and

obtaining information on the blood flow of the surface layer blood vessel and the background blood flow.