ULTRASONIC DIAGNOSTIC APPARATUS, IMT MEASUREMENT METHOD, AND IMT MEASUREMENT PROGRAM

• US 20080171939A1
• Filed: 01/03/2008
• Published: 07/17/2008
• Est. Priority Date: 01/15/2007
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: ISHIHARA, Keitarou
• Granted Patent: US 7,959,572 B2
• Time in Patent Office: Days
• US Class Current: 600/449
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 8/0858 involving measuring tissue layers, e.g. skin, interfaces
• CPC Class Codes: G01S 7/52026 Extracting wanted echo signals Doppler systems G01S15/50; Doppler short range imaging systems G01S15/8979
• CPC Class Codes: G06T 2207/10132 Ultrasound image
• CPC Class Codes: G06T 2207/20104 Interactive definition of region of interest [ROI]
• CPC Class Codes: G06T 2207/30101 Blood vessel; Artery; Vein; Vascular
• CPC Class Codes: G06T 7/12 Edge-based segmentation
• CPC Class Codes: G06T 7/60 Analysis of geometric attributes

Abstract

An ultrasonic diagnostic apparatus by which highly quantitative IMT (intima media thickness) measurement with little variations depending on examiners can be performed. The ultrasonic diagnostic apparatus includes: an ultrasonic probe for transmitting ultrasonic waves to an object to be inspected and receiving ultrasonic echoes generated by reflection of the ultrasonic waves in the object to output reception signals; a signal processing unit for performing at least envelope detection processing on the reception signals outputted from the ultrasonic probe to generate envelope data; a boundary detecting unit for detecting two boundaries representing intima media of a blood vessel based on difference or differential of values of the envelope data and amounts of change in the values of the envelope data; and an IMT calculating unit for calculating an IMT of the blood vessel based on the two boundaries detected by the boundary detecting unit.

Claims

1. An ultrasonic diagnostic apparatus comprising:

an ultrasonic probe for transmitting ultrasonic waves to an object to be inspected and receiving ultrasonic echoes generated by reflection of the ultrasonic waves in the object to output reception signals;

signal processing means for performing at least envelope detection processing on the reception signals outputted from said ultrasonic probe to generate envelope data;

boundary detecting means for detecting two boundaries representing intima media of a blood vessel based on one of difference and differential of values of the envelope data and amounts of change in the values of the envelope data; and

IMT (intima media thickness) calculating means for calculating an IMT of the blood vessel based on the two boundaries detected by said boundary detecting means.

2. The ultrasonic diagnostic apparatus according to claim 1, further comprising:

threshold value setting means for setting a threshold value to be compared with the amounts of change in the values of the envelope data;

wherein said boundary detecting means detects as a boundary a region in which an amount of change in the values of the envelope data is larger than the threshold value set by said threshold value setting means.

3. The ultrasonic diagnostic apparatus according to claim 2, wherein said threshold value setting means resets the threshold value to a smaller value in a case where at least one of the two boundaries is not detected.

4. The ultrasonic diagnostic apparatus according to claim 1, further comprising:

search range setting means for setting a search range for a boundary;

wherein said boundary detecting means searches for a boundary based on the envelope data corresponding to the search range set by said search range setting means.

5. The ultrasonic diagnostic apparatus according to claim 4, wherein said search range setting means resets, when only one boundary is detected by said boundary detecting means, a search range for searching for the other boundary based on a position of the one boundary.

6. The ultrasonic diagnostic apparatus according to claim 1, further comprising:

error detecting means for detecting a detection error of a boundary based on a position relationship among boundaries in an azimuth direction with respect to the boundary detected by said boundary detecting means.

7. The ultrasonic diagnostic apparatus according to claim 6, wherein said error detecting means determines whether or not there is a detection error of a boundary based on a difference between a coordinate value of a boundary of interest and an average value of coordinate values of neighboring boundaries in the azimuth direction of the boundary.

8. The ultrasonic diagnostic apparatus according to claim 6, wherein said search range setting means resets, when a detection error of a boundary is detected by said error detecting means, a search range based on one of (i) positions of neighboring boundaries in the azimuth direction of the boundary that has been erroneously detected and (ii) a position of another boundary existing in a depth direction of the boundary that has been erroneously detected;

and

said boundary detecting means searches for a boundary within the reset search range to detect a true boundary.

9. The ultrasonic diagnostic apparatus according to claim 1, wherein said IMT calculating means obtains a maximum value of the IMT and a position where the IMT is largest based on IMTs calculated in plural measurement lines, respectively.

10. An IMT (intima media thickness) measurement method of measuring an IMT of a blood vessel based on envelope data in an ultrasonic diagnostic apparatus for transmitting ultrasonic waves to an object to be inspected and receiving ultrasonic echoes generated by reflection of the ultrasonic waves in the object to obtain reception signals, and performing at least envelope detection processing on the reception signals to generate the envelope data, said method comprising the steps of:

(a) detecting two boundaries representing intima media of the blood vessel based on one of difference and differential of values of the envelope data and amounts of change in the values of the envelope data; and

(b) calculating the IMT of the blood vessel based on the two boundaries detected at step (a).

11. The IMT measurement method according to claim 10, further comprising the step of:

(c) setting a threshold value to be compared with the amounts of change in the values of the envelope data;

wherein step (a) includes detecting as a boundary a region in which an amount of change in the values of the envelope data is larger than the threshold value set at step (c).

12. The IMT measurement method according to claim 10, further comprising the step of:

(d) setting a search range for a boundary;

wherein step (a) includes searching for a boundary based on the envelope data corresponding to the search range set at step (d).

13. The IMT measurement method according to claim 10, further comprising the step of:

(e) detecting a detection error of a boundary based on a position relationship among boundaries in an azimuth direction with respect to the boundary detected at step (a).

14. The IMT measurement method according to claim 13, wherein step (d) includes resetting, when a detection error of a boundary is detected at procedure (e), a search range based on one of (i) positions of neighboring boundaries in the azimuth direction of the boundary that has been erroneously detected and (ii) a position of another boundary existing in a depth direction of the boundary that has been erroneously detected;

and

step (a) includes searching for a boundary within the reset search range to detect a true boundary.

15. The IMT measurement method according to claim 10, wherein step (b) includes obtaining a maximum value of the IMT and a position where the IMT is largest based on IMTs calculated in plural measurement lines, respectively.

16. An IMT (intima media thickness) measurement program embodied on a computer readable medium, for measuring an IMT of a blood vessel based on envelope data in an ultrasonic diagnostic apparatus for transmitting ultrasonic waves to an object to be inspected and receiving ultrasonic echoes generated by reflection of the ultrasonic waves in the object to obtain reception signals, and performing at least envelope detection processing on the reception signals to generate the envelope data, said program activating a CPU to execute the procedures of:

(a) detecting two boundaries representing intima media of the blood vessel based on one of difference and differential of values of the envelope data and amounts of change in the values of the envelope data; and

(b) calculating the IMT of the blood vessel based on the two boundaries detected at procedure (a).

17. The IMT measurement program according to claim 16, wherein procedure (a) includes detecting as a boundary a region in which the amount of change in the values of the envelope data is larger than a preset threshold value.

18. The IMT measurement program according to claim 16, further activating the CPU to execute the procedure of:

(e) detecting a detection error of a boundary based on a position relationship among boundaries in an azimuth direction with respect to the boundary detected at procedure (a).

19. The IMT measurement program according to claim 18, wherein procedure (d) includes resetting, when a detection error of a boundary is detected at procedure (e), a search range based on one of (i) positions of neighboring boundaries in the azimuth direction of the boundary that has been erroneously detected and (ii) a position of another boundary existing in a depth direction of the boundary that has been erroneously detected;

and

procedure (a) includes searching for a boundary within the reset search range to detect a true boundary.

20. The IMT measurement program according to claim 16, wherein procedure (b) includes obtaining a maximum value of the IMT and a position where the IMT is largest based on IMTs calculated in plural measurement lines, respectively.