JP2002238903A - Blood vessel wall tracking method, blood vessel diameter measuring method and ultrasonic diagnostic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately track a blood vessel wall and accurately measure a blood vessel diameter by simple computation. SOLUTION: An ultrasonic diagnostic apparatus 100 is equipped with an ultrasonic image generation section (ultrasonic probe 1, transmission and reception section 2, a B-mode processing section 3, DSC 4), a display 5, a VTR 6 recording an ultrasonic image G obtained in time series, a control section 12, a computation processing section 10 for measuring a blood vessel diameter ϕ(an early wall specification section 101 specifying an anterior wall portion and a posterior wall portion being the reference through an operator, an ROI setting section 102 setting interesting areas including each wall portion, an image storage section 103 storing the ultrasonic image G, a correlation computation section 104 computing a correlation in the nearly vertical direction for interesting areas of ultrasonic images G0, G1 different in time series, a blood vessel wall tracking section 105 tracking positions of wall portions on the basis of the correlation, a blood vessel diameter computation section 106 computing a blood vessel diameter ϕ). The necessity of making an operator specify wall portions being the reference alone helps reduce burden on a worker.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blood vessel wall tracking method and an ultrasonic diagnostic apparatus, and more particularly, to a blood vessel wall tracking method capable of accurately tracking a blood vessel wall with a simple calculation and a blood vessel with a simple calculation. The present invention relates to a blood vessel diameter measuring method capable of accurately measuring a diameter and an ultrasonic diagnostic apparatus for performing each method.

[0002]

2. Description of the Related Art In order to perform a test for judging arteriosclerosis or the like, the diameter of a blood vessel (for example, a brachial artery or a carotid artery) or a change thereof may be measured from an ultrasonic image displayed on a screen. For example, one of the ultrasonic images recorded in time series on a VTR (VideoTape Recorder) or the like is displayed on the screen as a still image, and the operator applies a scale to the screen to measure the diameter of a blood vessel, The operator adjusted the cursor to the position facing the front wall portion and the rear wall portion and measured the distance between the cursors, that is, the blood vessel diameter using the measurement function of the ultrasonic diagnostic apparatus, by advancing the imaging time by several tens of seconds. This is repeatedly performed on a still image to observe a change in blood vessel diameter.

[0003]

As described above, conventionally, every time the diameter of a blood vessel is measured, it is necessary for the operator to apply a scale or to position a cursor. There is a problem that it depends on the degree and takes time and effort. Therefore, a first object of the present invention is to provide a blood vessel wall tracking method and an ultrasonic diagnostic apparatus which enable accurate tracking of a blood vessel wall by a simple calculation.
It is a second object of the present invention to provide a blood vessel diameter measuring method and an ultrasonic diagnostic apparatus capable of accurately measuring a blood vessel diameter by a simple calculation.

[0004]

According to a first aspect, the present invention displays on a screen one of a plurality of ultrasonic images obtained in time series by scanning an object with ultrasonic waves, When the operator specifies a wall portion of a blood vessel on the ultrasonic image, a region of interest including the wall portion is set, and the region of interest of the ultrasonic image different in time series is substantially perpendicular to the wall portion. There is provided a blood vessel wall tracking method, wherein a position of the wall portion is tracked by taking a correlation. In the blood vessel wall tracking method according to the first aspect, attention is paid to the fact that the movement of the wall portion due to blood pressure fluctuation in the cardiac cycle is limited to a direction substantially perpendicular to the wall portion (radial direction of the short-axis cross section of the blood vessel). The position of the wall portion is tracked by correlating the region of interest including the wall portion designated by the operator in a direction substantially perpendicular to the wall portion. That is, the position of the blood vessel wall in the ultrasonic images that are different in time series can be obtained by the fact that the correlation becomes maximum. For example, when blood vessels are drawn in the horizontal direction of the screen, it is sufficient to calculate the correlation only in the vertical direction of the screen.
Thus, the blood vessel wall can be accurately tracked by a simple correlation operation. Further, since the operator only has to specify the wall portion for only the first ultrasonic image, it does not take much trouble.

According to a second aspect, the present invention displays one of a plurality of ultrasonic images obtained in time series by scanning an object with ultrasonic waves on a screen, and displays the ultrasonic images on the ultrasonic images. When the operator designates a pair of a front wall portion and a rear wall portion of a blood vessel, a region of interest including each of the wall portions is set, and a blood vessel diameter corresponding to the wall portion is calculated. A blood vessel diameter measuring method is provided, wherein a correlation in a direction substantially perpendicular to each wall portion is calculated for each region of interest in an image to track the position of each wall portion and calculate a blood vessel diameter. In the blood vessel diameter measuring method according to the second aspect, attention is paid to the fact that movement of a wall portion due to blood pressure fluctuation in a cardiac cycle is limited to a direction substantially perpendicular to the wall portion (radial direction of a short-axis cross section of the blood vessel). The position of each wall portion is tracked by calculating a correlation in a direction substantially perpendicular to each wall portion with respect to the region of interest including the front wall portion and the rear wall portion designated by the operator, and the blood vessel diameter is calculated. That is, the position of the blood vessel wall in the ultrasonic images that are different in time series can be obtained based on the maximum correlation, and the blood vessel diameter can be calculated accordingly. Thus, the blood vessel wall can be accurately tracked by a simple correlation operation, and the blood vessel diameter can be accurately calculated.

In a third aspect, the present invention is an ultrasonic diagnostic apparatus for transmitting an ultrasonic pulse, receiving an ultrasonic echo, and generating a plurality of ultrasonic images in time series, wherein the ultrasonic diagnostic apparatus comprises: A wall part designating means for receiving designation of a wall part of a blood vessel from an operator on a screen displaying one of the blood vessels, an ROI setting means for setting a region of interest including the wall part, An ultrasonic diagnostic apparatus, comprising: a blood vessel wall tracking means for tracking the position of the wall portion by correlating the region of interest in a direction substantially perpendicular to the wall portion. According to the ultrasonic diagnostic apparatus of the third aspect, the blood vessel wall tracking method of the first aspect can be suitably implemented.

According to a fourth aspect, the present invention is an ultrasonic diagnostic apparatus for transmitting ultrasonic pulses, receiving ultrasonic echoes, and generating a plurality of ultrasonic images in time series, Wall portion designating means for accepting a designation of a pair of a front wall portion and a rear wall portion of a blood vessel from an operator on a screen displaying one;
ROI for setting each region of interest including each wall portion
Setting means, a blood vessel diameter calculating means for calculating a blood vessel diameter corresponding to the wall portion, and a correlation in a direction substantially perpendicular to each wall portion for each region of interest of the ultrasonic image different in time series. An ultrasonic diagnostic apparatus comprising: a blood vessel wall tracking / blood vessel diameter calculating means for tracking a position of a wall portion and calculating a blood vessel diameter. According to the ultrasonic diagnostic apparatus of the fourth aspect, the blood vessel diameter measuring method of the second aspect can be suitably implemented.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to this. FIG. 1 is a configuration diagram showing an ultrasonic diagnostic apparatus according to one embodiment of the present invention. The ultrasonic diagnostic apparatus 100 includes an ultrasonic probe 1 and a transmission / reception unit 2 which outputs a sound ray signal a by repeatedly transmitting an ultrasonic pulse into a subject and receiving an ultrasonic echo corresponding thereto. A B-mode processing unit 3 for generating B-mode sound ray data from the sound ray signal; and a DSC (Digital Scan Converter) 4 for generating a B-mode ultrasonic image G from the B-mode sound ray data.
And a display 5 such as a CRT (Cathode Ray Tube), and a VTR 6 for recording the ultrasonic images G obtained in time series.
And an arithmetic processing unit 10 for performing arithmetic processing necessary for measuring the blood vessel diameter φ, and an operation unit 12 having a pointing device 11 such as a trackball or a mouse.

The arithmetic processing unit 10 includes an initial wall specifying unit 101 for specifying a wall portion serving as a reference for measuring a blood vessel diameter φ;
RO for setting region of interest (ROI)
An I setting unit 102, an image storage unit 103 that stores the ultrasonic image G, and a correlation operation unit 10 that calculates a correlation between the images.
4, and the movement amount L of the front wall and the rear wall (Wf, Wb in FIG. 3 etc.)
The apparatus includes a blood vessel wall tracking unit 105 that calculates f and Lb to track the position of a wall portion, and a blood vessel diameter calculation unit 106 that calculates a blood vessel diameter φ.

FIG. 2 is a flowchart showing a blood vessel diameter measuring process by the ultrasonic diagnostic apparatus 100 of FIG. Note that V
It is assumed that an ultrasonic image G obtained by adjusting the sound ray direction so as to be as vertical as possible to the traveling direction of the blood vessel for diameter measurement (for example, the brachial artery or the carotid artery) is recorded in the TR 6 in advance. In step ST1, an ultrasonic image G0 obtained by reproducing one of the ultrasonic images G recorded on the VTR 6 is displayed as a still image. For example, as shown in FIG.
Is displayed. The front wall Wf is a blood vessel wall on the near side when viewed from the ultrasound probe 1. The rear wall Wb
This is a blood vessel wall on the far side as viewed from the ultrasonic probe 1. The x direction is the horizontal direction of the screen. The y direction is the vertical direction of the screen (the depth direction as viewed from the ultrasonic probe 1).

The following steps F2 to F6 (processing corresponding to the front wall) and steps B2 to B6 (processing corresponding to the rear wall)
Are processes performed in parallel. However, after the end of one process, the process may shift to the other process.

In step F2, the operator operates the operation unit 12
Then, the front wall of the blood vessel T is specified as an initial wall using the initial wall specifying unit 101. For example, as shown in FIG.
By operating the pointing device 11, the trace mark C is aligned with a plurality of points along the inner wall of the front wall Wf, and the front wall Wf is traced.

In step F3, the operator operates the operation unit 12
And an ROI setting unit 102 for setting a region of interest ROI including the blood vessel T. For example, as shown in FIG. 5, a section extended from the designated front wall Wf in the y direction by an arbitrary area length α is set as a region of interest ROI. The region of interest ROI may be automatically set. In step F4, the ultrasound image G0 in the region of interest ROI is stored in the image storage unit 103.

In step FB5, the arithmetic processing unit 10
Next, the ultrasonic image G1 after the elapse of the diameter measurement time (for example, several tens of seconds) is fetched from the VTR 6.

In step F6, as shown in FIGS. 6 (a) and 6 (b), the blood vessel wall tracking section 105
The pixel value P0 (x, x) in the ultrasonic image G0 in the OI
y) and the ultrasonic image G in the region of interest ROI.
1 is the integrated value D of the difference d from the pixel value P1 (x, y + τ)
(Τ) for various τ It is calculated by: However, in the above equation, x1 is the minimum x coordinate in the region of interest ROI. x2 is the maximum x coordinate in the region of interest ROI. y1 is
The y-coordinate corresponding to each x-coordinate of the initial wall. β is an empirically determined y-direction area length in the range of β <α so that even when the initial wall moves, the pixels corresponding to the same position in the subject can perform a correlation operation. .Tau.max which gives the minimum of the integrated value D (.tau.), That is, the maximum of the correlation.
Is obtained as the movement amount Lf of the front wall Wf.

In step B2 performed in parallel with step F2, for example, as shown in FIG. 7, the rear wall Wb of the blood vessel T is designated. Thereby, the blood vessel diameter φ0 with respect to the initial wall is calculated by φ0 = | yf−yb | × sin {θ}. However, yf, yb is the front wall Wf,
The x coordinate of the middle point of the trace range of the rear wall Wb, that is, (x
It is the y coordinate of each wall corresponding to (1 + x2) / 2. θ is
The angle on the acute angle side formed by the rear wall Wb with the y direction.

In steps B3 to B6, the same processing as in steps F3 to F6 is performed on the rear wall Wb.
The movement amount Lb of b is obtained. In general, in an ultrasonic image, the effects of acoustic shading, multiple reflections, and attenuation appear asymmetrically near the front wall Wf and near the rear wall Wb, and therefore, the appearance of the two differs. Therefore, by separately performing the correlation calculation processing on the region of interest including the front wall Wf and the region of interest including the rear wall Wb, it is possible to accurately calculate the movement amounts Lf and Lb.

In step ST7, the blood vessel diameter calculator 1
06 is a blood vessel diameter φ based on the movement amounts Lf and Lb.
Is calculated by φ1 = φ0 + Lf−Lb. FIG. 8 shows the blood vessel diameter φ1 and the movement amount Lf,
The relationship of Lb is schematically shown. The dotted line is the initial wall. If the angle θ (see FIG. 7) is close to 90 °, since sinｓθ｝ ≒ 1, the movement amounts Lf, Lb in the y direction
The error due to considering as a diameter change amount can be ignored.

In step ST8, when all necessary blood vessel diameters φ1 have been calculated, the blood vessel diameter measurement processing is terminated according to the instruction of the operator. Otherwise, the flow returns to step F5 and step B5. Thereafter, the blood vessel diameter φ (= φ
0, φ1) or a graph showing the change in the blood vessel diameter φ with respect to time.

In the flow of FIG. 2, the first ultrasonic image G0 is stored in the image storage unit 103, but is updated and stored in the ultrasonic image G1, and the front wall and the rear wall of the ultrasonic image G1 are stored. As the reference, the movement amounts Lf and Lb may be calculated. Further, instead of specifying the inner walls of the front wall Wf and the rear wall Wb as the initial wall, the outer diameter of the blood vessel T may be measured by specifying the outer wall.

According to the ultrasonic diagnostic apparatus 100 described above, for the region of interest ROI including the initial wall designated by the operator,
Calculating the movement amounts Lf and Lb that maximize the correlation in the vertical direction of the screen (generally a direction substantially perpendicular to the wall portion of the blood vessel), and calculating the blood vessel diameter φ of the blood vessel T based on the movement amounts Lf and Lb; Can be done.

[0022]

According to the blood vessel wall tracking method, the blood vessel diameter measuring method and the ultrasonic diagnostic apparatus of the present invention, the blood vessel wall can be tracked based on the result of correlation calculation in a direction substantially perpendicular to the blood vessel wall. In addition, since the diameter of the blood vessel is measured, the speed of the arithmetic processing can be increased. Also, since the operator only needs to specify the reference wall portion, the work load can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an ultrasonic diagnostic apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a blood vessel diameter measuring process by the ultrasonic diagnostic apparatus of FIG. 1;

FIG. 3 is an explanatory diagram showing a first ultrasonic image.

FIG. 4 is an explanatory diagram showing a state where a front wall of a blood vessel is designated.

FIG. 5 is an explanatory diagram showing a state in which a region of interest is set.

FIG. 6 is an explanatory diagram illustrating a principle of calculating a difference between pixel values.

FIG. 7 is an explanatory diagram showing a state in which a rear wall of a blood vessel is designated.

FIG. 8 is an explanatory diagram showing a calculation principle of a blood vessel diameter.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 ultrasonic probe 2 transmission / reception unit 3 B-mode processing unit 4 DSC 5 display 6 VTR 10 calculation processing unit 11 pointing device 12 operation unit 101 initial wall designation unit 102 ROI setting unit 103 image storage unit 104 correlation operation unit 105 blood vessel Wall tracking unit 106 Blood vessel diameter calculation unit a Sound ray signal G Ultrasound image Lf, Lb Movement amount T Blood vessel Wf Front wall Wb Back wall φ Blood vessel diameter

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Hashimoto 127 Gee Yokogawa Medical System Co., Ltd. 4-7, Asahigaoka, Hino-shi, Tokyo F term (reference) 4C301 DD21 EE11 EE13 JB28 KK30 5J083 AA02 AB17 AC29 AC30 AD04 AE10 BA01 BE08 EA14 EB05

Claims (4)

[Claims] 1. A plurality of ultrasonic images obtained in time series by scanning an object with ultrasonic waves are displayed on a screen.
When the operator specifies a wall portion of a blood vessel on the ultrasonic image, a region of interest including the wall portion is set, and the region of interest of the ultrasonic image different in time series is substantially perpendicular to the wall portion. A method for tracking a blood vessel wall, wherein the position of the wall portion is tracked by taking a correlation. 2. One of a plurality of ultrasonic images obtained in time series by scanning an object with ultrasonic waves is displayed on a screen.
When the operator specifies a pair of a front wall portion and a rear wall portion of a blood vessel on the ultrasonic image, a region of interest including each of the wall portions is set, and a blood vessel diameter corresponding to the wall portion is calculated. A blood vessel diameter measuring method for calculating a blood vessel diameter and calculating a blood vessel diameter by correlating a region of interest in the ultrasonic image that is substantially different from each other in a direction substantially perpendicular to the wall portions. 3. An ultrasonic diagnostic apparatus for transmitting an ultrasonic pulse, receiving an ultrasonic echo, and generating a plurality of ultrasonic images in a time series, wherein an ultrasonic image is displayed on a screen displaying one of the ultrasonic images. A wall portion designating unit that receives designation of a wall portion of a blood vessel from an operator, an ROI setting unit that sets a region of interest including the wall portion, and a region of interest of the ultrasonic image that differs in time series. An ultrasonic diagnostic apparatus comprising: a blood vessel wall tracking means for tracking a position of the wall portion by taking a correlation in a substantially vertical direction. 4. An ultrasonic diagnostic apparatus which transmits an ultrasonic pulse, receives an ultrasonic echo, and generates a plurality of ultrasonic images in a time series, wherein an ultrasonic image is displayed on a screen displaying one of the ultrasonic images. A wall portion designating unit for receiving a designation of a pair of a front wall portion and a rear wall portion of a blood vessel from an operator, an ROI setting unit for setting a region of interest including each of the wall portions, and a blood vessel diameter corresponding to the wall portion. A blood vessel diameter calculating means for calculating, and for each region of interest of the ultrasonic image different in time series, a correlation in a direction substantially perpendicular to the respective wall portions is tracked to track a position of each wall portion and calculate a blood vessel diameter. An ultrasonic diagnostic apparatus comprising: a blood vessel wall tracking / blood vessel diameter calculating means.