JP2008173177A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic apparatus capable of detecting a blood flow-intima boundary position on the anterior wall of an arterial blood vessel. <P>SOLUTION: The ultrasonic diagnostic apparatus includes a transmission part 1 for driving an ultrasonic probe for transmitting ultrasonic transmission waves to a living body including a blood vessel; a reception part 2 for receiving ultrasonic reflected waves obtained by the reflection of the ultrasonic transmission waves inside the living body by using the ultrasonic probe and generating reception signals; a phase information processing part 6 for calculating at least one feature amount among a feature amount relating to the moving amount of body tissue in a fixed period at a plurality of measurement positions inside the living body, a feature amount relating to a moving speed and a feature amount relating to an acceleration by processing the phase information of the reception signals; and a blood flow-intima boundary position detection part 7 for detecting the boundary position of a blood flow region and the intima on the anterior wall of the blood vessel of the living body on the basis of the at least one feature amount. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus that diagnoses a state of a blood vessel using ultrasonic waves.

  In recent years, an increasing number of people suffer from cardiovascular diseases such as myocardial infarction and cerebral infarction, and it has become a major issue to prevent and treat such diseases. Since arteriosclerosis is closely related to the onset of myocardial infarction and cerebral infarction, early diagnosis of arteriosclerosis is important in preventing such cardiovascular diseases.

  The diagnosis of arteriosclerosis is performed by measuring the intima-media thickness (hereinafter abbreviated as IMT) of the blood vessel. Among the arteries, the carotid artery has a larger IMT value from the initial stage of arteriosclerosis than other sites. Therefore, measurement of IMT in the carotid artery is effective for diagnosis of arteriosclerosis. In addition, since the carotid artery is located at a relatively shallow depth of 2 to 3 cm from the skin surface, it is possible to measure with higher accuracy than other arteries. Is suitable.

  Conventionally, a method for measuring an IMT value of a vascular wall of a carotid artery by ultrasonic waves is known. For example, Patent Document 1 discloses a method for measuring an IMT value of a blood vessel wall based on a maximum peak value and a second peak value in a luminance signal for a B-mode image generated based on an ultrasonic wave reflected by a blood vessel. Disclosure.

  However, since this method uses echo intensity, if the intima brightness of the blood vessel wall to be measured is low, or if the luminance information contains a lot of noise, the blood flow-intima boundary position or the intima-outer membrane There is a problem that the boundary position cannot be accurately detected, and the accurate IMT value of the blood vessel wall cannot be measured. The above-described method is based on the assumption that the structure of the blood vessel wall to be measured is in a normal state. For this reason, there is a problem that the boundary position cannot be accurately measured if a atheroma (atheroma), which is a local lesion associated with arteriosclerosis, is present in the blood vessel to be measured.

  In order to solve this problem, for example, Patent Document 2 detects the blood flow-intima boundary position and the medial position based on the tissue hardness calculated from the phase change of the ultrasonic echo, and A method for measuring the IMT value is proposed.

  When a cross section parallel to the axial direction of a blood vessel is observed by these conventional ultrasonic diagnostic apparatuses, each blood vessel wall is depicted on the side closer to and far from the skin surface of the subject with respect to one blood vessel. The vessel walls near and far from the skin surface are called the anterior and posterior walls.

In general, an ultrasonic echo from the front wall near the ultrasonic probe is easily affected by noise such as multiple reflection of ultrasonic waves, and the contour of the front wall tends to be unclear in the obtained B-mode image. Further, the tissue hardness value used in the method of Patent Document 2 does not have a clear feature that is recognized on the rear wall near the blood flow-intima boundary position, and the accurate boundary position is automatically determined. It was difficult to detect. For this reason, in the IMT measurement by the conventional ultrasonic diagnostic apparatus, the rear wall is the measurement object.
Japanese Patent Laid-Open No. 11-318896 International Publication No. 2004/112568 Pamphlet Japanese Laid-Open Patent Publication No. 2004-357892

  However, atheroma is generated with arteriosclerosis, and when a lesion such as atheroma is present on the blood vessel wall of the front wall, it is necessary to measure blood vessels on the front wall. In this case, it is difficult to automatically detect the exact boundary position of the blood flow-intima boundary on the front wall for the reason described above, and it is ultimately necessary for the operator to make a determination from the B-mode image. As a result, when the B-mode image is unclear, it is difficult to determine the blood flow-intima boundary. Further, depending on the skill level of the operator, there are problems that an accurate boundary position cannot be determined and a measurement error is large.

  An object of the present invention is to solve such a problem of the prior art and to provide an ultrasonic diagnostic apparatus capable of detecting at least a blood flow-intima boundary position of an anterior wall of an arterial blood vessel. It is another object of the present invention to provide an ultrasonic diagnostic apparatus that can measure an accurate IMT value.

  The ultrasonic diagnostic apparatus according to the present invention includes a transmitter that drives an ultrasonic probe for transmitting an ultrasonic transmission wave to a living body including a blood vessel, and an ultrasonic wave obtained by reflecting the ultrasonic transmission wave in the living body. A reception unit that receives a reflected sound wave using the ultrasonic probe and generates a reception signal; and processing phase information of the reception signal, thereby providing a living body for a certain period at a plurality of measurement positions in the living body. A phase information processing unit that calculates at least one of the feature amount related to the movement amount of the tissue, the feature amount related to the moving speed, and the feature amount related to the acceleration, and the front of the blood vessel of the living body based on the at least one feature amount. A blood flow-intima boundary position detection unit that detects a boundary position between the blood flow region and the intima in the wall;

  In a preferred embodiment, the feature amount represents a magnitude of a noise component superimposed on the movement amount, movement speed, and acceleration.

  In a preferred embodiment, the plurality of measurement positions are arranged on an acoustic line of the received signal, and the blood flow-intima boundary position detection unit compares feature amounts at each measurement position on the acoustic line. Thus, the boundary position is detected on the acoustic line.

  In a preferred embodiment, the feature amount is a ratio of high-frequency components of the calculated movement amount, movement speed, and acceleration, respectively.

  In a preferred embodiment, the feature amount is a value obtained by integrating the absolute values of the calculated movement amount, movement speed, and acceleration over the predetermined period.

  In a preferred embodiment, the feature amount is a mean square value of the calculated movement amount, movement speed, and acceleration for the predetermined period.

  In a preferred embodiment, the predetermined period is a cardiac cycle of the living body.

  In a preferred embodiment, the blood flow-intima boundary position detection unit selects two selected from a feature amount related to the moving amount, a feature amount related to a moving speed, and a feature amount related to acceleration, and one of them is the other. Based on the divided value, a boundary position between the blood flow region and the intima in the front wall of the blood vessel of the living body is detected.

  In a preferred embodiment, a media-epicardium boundary position detection unit for detecting a boundary position between the media and the adventitia on the anterior wall of the blood vessel from the characteristics of the received signal, and a boundary position between the media and the adventitia And an IMT value calculation unit that calculates an IMT value of the anterior wall of the blood vessel from a boundary position between the blood flow region and the intima.

  In a preferred embodiment, the ultrasonic diagnostic apparatus further includes a B-mode processing unit that generates a tomographic image in the measurement region of the living body based on the received signal, and a display unit that displays the tomographic image, and the display The unit superimposes and displays the boundary position between the blood flow region and the intima on the tomographic image.

  According to the present invention, the phase information processing unit calculates at least one feature amount among the feature amounts related to the movement amount, movement speed, and acceleration of the living tissue. This feature value reflects the noise component superimposed on the movement amount, movement speed, and acceleration. The feature value obtained from the blood flow region has a large noise component, and the feature value obtained from the vascular wall tissue has a noise component. Therefore, the position of the blood flow-intima boundary on the front wall can be determined based on the feature amount. Therefore, the position of the blood flow-intima boundary on the front wall, which is unclear in the B-mode image and difficult when focusing on the intensity of the ultrasound echo signal and the tissue hardness value, is automatically and clearly defined. It can be detected. In addition, since it is not necessary to set a special region of interest for detecting the boundary, measurement can be performed more quickly than in the prior art.

  Hereinafter, embodiments of an ultrasonic diagnostic apparatus according to the present invention will be described. FIG. 1 shows a block diagram of an embodiment of an ultrasonic diagnostic apparatus according to the present invention. The ultrasonic diagnostic apparatus includes a transmission unit 1, a reception unit 2, a delay synthesis unit 3, a B-mode processing unit 4, a phase information processing unit 6, and a blood flow-intima boundary position detection unit 7. Each component block of the ultrasonic diagnostic apparatus is controlled by a control unit including a CPU (not shown). In addition, a user interface including a keyboard, a trackball, a switch, and a button (not shown) is connected to the control unit, and the user interface inputs an operator command regarding the operation of the ultrasonic diagnostic apparatus to the control unit 100.

  The transmission unit 1 generates a high-voltage signal that drives the ultrasonic probe 101 at a designated timing under the control of the control unit. The ultrasonic probe 101 converts the transmission signal generated by the transmission unit 1 into an ultrasonic wave and irradiates the ultrasonic wave from the surface 20 of the living body 40 into the living body 40.

  As shown in FIG. 1, the living body 40 includes an arterial blood vessel 30. The ultrasonic probe 101 is arranged on the living body 40 so that the ultrasonic wave is scanned in parallel with the axial direction of the arterial blood vessel. The measurement region of the living body 40 is scanned by a plurality of ultrasonic waves in parallel with the axial direction of the arterial blood vessel 30.

  The front wall 31 is located on the side close to the surface of the living body 40 and the rear wall 34 is located on the far side. A region between the front wall 31 and the rear wall 34 is a blood flow region 33. The front wall 31 includes an outer membrane 301 and an inner-media membrane 302, and a media-outer membrane boundary 310 is located between the outer membrane 301 and the inner-media membrane 302. A blood flow-intima boundary 311 is located between the intima 302 and the blood flow region 33.

  Similarly, the rear wall 32 is constituted by an outer membrane 304 and an inner-media membrane 303, and a media-outer membrane boundary 313 is located between the outer membrane 304 and the inner-media membrane 303. A blood flow-intima boundary 312 is located between the intima 303 and the blood flow region 33. An atheroma 36 is generated on the front wall 31.

  The receiving unit 2 detects the ultrasonic wave reflected from the inside of the living body 40 by the ultrasonic probe 101 and converts it into an electric reception signal. A plurality of electroacoustic transducers are arranged in the ultrasonic probe 101, and the deflection angle of the ultrasonic wave to be transmitted by selecting the electroacoustic transducer to be used for transmission and reception and adjusting the timing for applying a voltage to the electroacoustic transducer. And control the focus. The delay synthesizing unit 3 detects only ultrasonic waves from a specific position (focus) or direction (deflection angle) by giving a predetermined delay to the reception signals received by the electroacoustic transducers and adding them. .

  The B-mode processing unit 4 includes a filter, a detector, a logarithmic amplifier, and the like, analyzes mainly the amplitude of the received signal, and images the internal structure of the subject as a tomographic image.

  As will be described in detail below, the phase information processing unit 6 processes the phase information of the received signal, thereby performing the feature amount and movement related to the movement amount of the living tissue at a plurality of measurement positions in the living body 40 for a certain period. At least one feature value is calculated from the feature value related to speed and the feature value related to acceleration. This feature amount reflects a noise component superimposed on the movement amount, the movement speed, and the acceleration.

  The blood flow-intima boundary position detection unit 7 receives at least one feature amount from the phase information processing unit 6, and based on the received feature amount, the blood flow-intima boundary 311 on the front wall of the blood vessel of the living body 40. Detect position. The boundary detection method will be described in detail below.

  The ultrasonic diagnostic apparatus preferably further includes a media-exterior membrane boundary position detection unit 5, an IMT calculation unit 9, and an image synthesis unit 10.

  The media-exterior membrane boundary position detection unit 5 detects the location of the media-exterior membrane boundary 310 of the front wall 31 from the characteristics of the received signal. The boundary detection method is not particularly limited, and a known boundary detection method for blood vessels can be used. In the present embodiment, for example, it can be determined based on the peak of the luminance signal of the B-mode image disclosed in Patent Document 1.

  The IMT value calculation unit 9 obtains information on the position of the blood flow-intima boundary 311 and the position of the media-outer membrane boundary 310 from the blood flow-intima boundary position detection unit 7 and the media-intima boundary position detection unit 5. Respectively, and the IMT value of the anterior wall 31 of the arterial blood vessel 30 is calculated. For example, the IMT value at the cursor position shown on the display unit 11 is calculated. The position of the cursor can be designated by the operator through the user interface.

  The blood flow-intima boundary position detection unit 7 and the media-endocardium boundary position detection unit 5 are the same as the detection of the blood flow-intima boundary 311 position and the media-outer membrane boundary 310 position of the front wall 31. In this manner, the position of the blood flow-intima boundary 312 and the position of the media-epicardium boundary 313 of the rear wall 32 may be detected. In this case, the IMT value calculation unit 9 also calculates the IMT value of the rear wall 32.

  The image synthesizing unit 10 includes the position of the blood flow-intima boundary 311 on the front wall 31 output from the blood flow-intima boundary position detection unit 7 and the media-epicardium boundary position detection unit 5 and the media-outer membrane. Information on the position of the boundary 310 and information on the position of the blood flow-intima boundary 312 and the position of the intima-outer membrane boundary 313 on the rear wall 32 are received, and these boundaries are imaged and output from the B-mode processing unit 4. And is output to the display unit 11. Further, the image data is created so that the IMT values of the front wall 31 and the rear wall 32 output from the IMT value calculation unit 9 are also displayed on the display unit 11.

  The display unit 11 displays an image synthesized based on the output of the image synthesis unit 10. An image in which the blood flow-intima boundary 311, the media-exterior membrane boundary 310, the blood flow-intima boundary 312, and the media-exterior membrane boundary 313 are superimposed on the tomographic image is displayed on the display unit 11. An IMT value is also displayed. When a slight shift occurs between the tomographic image displayed on the display unit 11 and the detected boundary position, a predetermined offset value is added to or subtracted from the detected boundary to adjust the boundary position. An offset value may be set in the membrane-outer membrane boundary position detection unit 5 and the blood flow-intima boundary position detection unit 7.

  Next, operations of the phase information processing unit 6 and the blood flow-intima boundary position detection unit 7 will be described in detail. As described above, the ultrasonic probe 101 scans the measurement region of the living body 40 in parallel with the axial direction using a plurality of ultrasonic transmission waves. A reception signal for one frame is obtained by one scan of the measurement region. Usually, since ten to several tens of scans are performed during one cardiac cycle of the living body 40, ten to several tens of frames are included in one cardiac cycle. Each ultrasonic transmission wave to be scanned generates an ultrasonic wave (echo) reflected by the living body 40 from measurement positions set at predetermined intervals on the acoustic line.

  The phase information processing unit 6 receives the received signal and generates phase information of the received signal by performing quadrature detection on the received signal. In order to calculate the movement amount, movement speed, and acceleration of the living tissue with high accuracy, for example, a phase difference tracking method is used. Specifically, at the measurement position set on the acoustic line of each ultrasonic transmission wave to be scanned, the amplitude of the received signal does not change between two temporally adjacent frames, and only the phase and reflection position change. Under the constraint, the phase difference between the two received signals is obtained by the least square method so that the waveform matching error between the two received signals is minimized. From this phase difference, the moving speed of the measurement position is obtained, and by integrating this, the moving amount can be obtained. Further, the acceleration is obtained by dividing the moving speed obtained corresponding to two adjacent frames by the interval between the two frames.

  FIG. 2A shows a tomographic image of the measurement region generated by the B mode processing unit 4. In the tomographic image of FIG. 2A, the position of the ultrasonic acoustic line that has scanned the measurement region is shown in the horizontal direction. The measurement position is shown in the vertical direction. In the tomographic image of FIG. 2A, the blood flow region is expressed in dark black, the front wall is located above the blood flow region, and the rear wall is located below. The boundary between the blood flow region and the rear wall is clearly shown, but the boundary between the blood flow region and the front wall is unclear.

  FIG. 2B shows the calculation results of the movement amount x, the movement speed v, and the acceleration α for one cardiac cycle at the measurement positions located at the depths 15 and 60 on the 15th acoustic line in the tomographic image shown in FIG. To FIG. 2 (g). 2 (b), (c), and (d) are the movement amount x, the movement speed v, and the acceleration α for one cardiac cycle at the measurement position located at the depth 15, and FIG. 2 (e), (f), (G) is the movement amount x, movement speed v, and acceleration α for one cardiac cycle at the measurement position located at the depth 60.

  As is clear from these drawings, the movement amount x, the movement speed v, and the acceleration α shown in FIGS. 2B, 2C, and 2D have few noise components, but FIGS. It can be seen that many noise components are superimposed on the movement amount x, the movement speed v, and the acceleration α shown in FIGS. This is because, in general, the intensity of a received signal obtained from a living tissue such as a blood vessel wall is always larger than that of a received signal obtained from a blood flow region, and the S / N ratio is excellent.

  Therefore, it is determined whether or not the biological tissue is a blood vessel wall by determining whether or not a large amount of noise component is superimposed on the moving amount x, moving speed v or acceleration α of the living tissue at each measurement position on each acoustic line. It is possible to determine whether the region is a flow region, and by detecting the boundary between the blood vessel wall region and the blood flow region based on the determination, the position of the blood flow-intima boundary can be determined.

  The phase information processing unit 6 uses the movement amount x, the movement speed v as an index indicating the magnitude of the noise component superimposed on the movement amount x, movement speed v, or acceleration α of the living tissue at each measurement position on each acoustic line. Alternatively, it is generated as a feature quantity of acceleration α.

  The feature amount may be obtained, for example, by determining the proportion of the high-frequency component of the movement amount x, the movement speed v, or the acceleration α. Alternatively, it may be a mean square value during one cardiac cycle of the movement amount x, the movement speed v, or the acceleration α. Alternatively, the feature amount may be a value obtained by time-integrating the absolute value of the movement amount x, the movement speed v, or the acceleration α over one cardiac cycle. Hereinafter, an example in which the phase information processing unit 6 calculates a value obtained by time-integrating the absolute value of the movement amount x, the movement speed v, or the acceleration α over one cardiac cycle as the feature amount will be described.

  The position of the acoustic line in the measurement region is H, and the measurement position on each acoustic line is D. Also, let time be t. At this time, the moving amount x, the moving speed v, and the acceleration α of the measurement position D of the acoustic line H are x (H, D, t), v (H, D, t), α (H, D, t, respectively. ).

  As shown in equations (1) and (2), the phase information processing unit 6 is a single heartbeat cycle of absolute values of the moving speed v (H, D, t) and the acceleration α (H, D, t) as feature quantities. The time integral values of are respectively calculated. Tc is one cardiac cycle.

  When many noise components are superimposed on the moving speed and acceleration, these values are increased by obtaining the integral value of the absolute value. However, when the moving speed and acceleration itself differ due to different measurement positions on the same acoustic line, the value increases due to the large number of noise components just by comparing the feature values obtained by Equation (1) and Equation (2). Since it cannot be distinguished whether the movement speed or acceleration itself is large, there is a possibility that the position of the boundary cannot be automatically obtained from the feature amount obtained by the equations (1) and (2). For this reason, in order to eliminate the influence of the values of the moving speed and the acceleration itself, the phase information processing unit 6, as shown by the equation (3), the ratio K of the feature amount obtained by the equations (1) and (2). It is preferable to further obtain (H, D).

  The blood flow-intima boundary position detection unit 7 receives the ratio K (H, D) from the phase information processing unit 6 and examines the change in the ratio K (H, D) on the same acoustic line (H: constant). .

  FIG. 3A shows a graph in which the ratio K (H, D) is plotted in the entire measurement region. In the graph of FIG. 3A, a measurement position where the value of the ratio K (H, D) is large indicates that there are many noise components. As is clear from FIG. 3A, the value of K (H, D) is large near the center of the measurement position. A region where the value of the ratio K (H, D) is large is a blood flow region.

  FIG. 3B is a graph in which the ratio K (H, D) on the 15th acoustic line is plotted in the depth direction. As is apparent from the graph of FIG. 3B, the portion where the ratio K (H, D) is large is the blood flow region 33, and both sides sandwiching the blood flow region are the front wall and the rear wall of the blood vessel. A procedure in which the blood flow-intima boundary position detection unit 7 automatically detects the blood flow-intima boundary will be described with reference to the graph of FIG.

  First, the depth at which K (H, D) takes the maximum value Kmax is detected, and the depth is set to D = Dmax. Next, a depth Dhf at which K (H, D) rapidly changes from D = Dmax in a direction farther from the body surface of the living body is detected. This depth is the position of the blood flow-intima boundary 312 on the rear wall.

  Next, in the direction close to the living body surface from D = Dmax, a depth Dhn below which K (H, D) falls below a certain threshold Th is detected. This depth is the position of the blood flow-intima boundary 311 on the front wall. The threshold value Th is set from the outside by an operator or the like. Alternatively, a threshold Th corresponding to the shape of the K (H, D) graph is set in the ultrasonic diagnostic apparatus in advance, and the threshold Th set according to the shape of the K (H, D) graph is selected. May be.

  For each acoustic line H, the position of the blood flow-intima boundary 311 of the front wall and the blood flow-intima boundary 312 of the rear wall is determined in this procedure, thereby blood flow of the blood vessel included in the measurement region. All membrane boundaries can be detected and determined. Since the position of the boundary is determined for each acoustic line, the blood flow-intima boundary 311 can be detected and determined along the atheroma 36 even when the atheroma 36 shown in FIG. 1 is included in the measurement region. it can.

  As described above, according to the ultrasonic diagnostic apparatus of the present invention, the blood flow in the front wall, which is unclear in the B-mode image and difficult when focusing on the intensity of the ultrasonic echo signal and the hardness value of the tissue, The position of the intima boundary can be detected automatically and clearly. In addition, since it is not necessary to set a special region of interest for detecting the boundary, measurement can be performed more quickly than in the prior art.

  Furthermore, by superimposing the detected boundary on the tomographic image and displaying it on the display unit, the operator can visually recognize the boundary position, which can be used for grasping the blood vessel properties.

  In the above description, the ratio K (H, D) is defined from the moving speed and acceleration of the tissue, but the same effect can be obtained by defining it from the moving amount and moving speed as shown in the following equation (4). Is obtained.

  Moreover, in the said embodiment, although the received signal obtained during one cardiac cycle is integrated, as long as the same predetermined period is used in the calculation of the numerator and denominator shown by Formula (3), it may be shorter than one cardiac cycle. .

  In addition, the ultrasonic diagnostic apparatus of this embodiment may further determine the inner diameter of the blood vessel from the position of the blood flow-intima boundary 311 on the front wall and the position of the blood flow-intima boundary 312 on the rear wall.

  The present invention is preferably used for a medical ultrasonic diagnostic apparatus, and in particular, is preferably used for an ultrasonic diagnostic apparatus used for vascular property image display or diagnosis.

It is a block diagram which shows the structure of position embodiment of the ultrasonic diagnosing device by this invention. (A) has shown the acoustic line and measurement position on the tomographic image in measurement. (B) to (d) show the calculated moving amount, moving speed and acceleration of the blood vessel wall tissue, and (e) to (g) show the calculated moving amount, moving speed and acceleration of the blood flow region. Show. (A) is a graph which shows distribution of ratio K in the measurement area | region calculated | required in a phase information processing part, (b) is a graph which shows distribution of ratio K on a certain acoustic line.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmission part 2 Reception part 3 Delay synthetic | combination part 4 B mode process part 5 Media-outer membrane boundary position detection part 6 Phase information processing part 7 Blood flow-intima boundary position detection part 9 ITM value calculation part 10 Image composition part 11 Display unit 20 Surface 30 Blood vessel 31 Blood vessel front wall 32 Blood vessel rear wall 33 Blood flow region 40 Living body 101 Probe 301 Front wall outer membrane 302 Inner membrane of front wall 303 Inner membrane of rear wall 304 Outer membrane of rear wall 310 blood flow-intima boundary 311 in front wall 311 media-outer membrane boundary in front wall 312 blood flow-intima boundary in back wall 313 media-outer membrane boundary in back wall

Claims (10)

A transmitter that drives an ultrasonic probe for transmitting an ultrasonic transmission wave to a living body including a blood vessel;
A reception unit that receives an ultrasonic reflected wave obtained by reflecting the ultrasonic transmission wave in the living body using the ultrasonic probe, and generates a reception signal;
By processing the phase information of the received signal, at least one of the feature amount related to the movement amount of the living tissue, the feature amount related to the moving speed, and the feature amount related to the acceleration at a plurality of measurement positions in the living body for a certain period. A phase information processing unit for calculating a feature amount;
A blood flow-intima boundary position detection unit that detects a boundary position between a blood flow region and an intima in a front wall of the blood vessel of the living body based on the at least one feature amount;
An ultrasonic diagnostic apparatus comprising:   The ultrasonic diagnostic apparatus according to claim 1, wherein the feature amount represents a magnitude of a noise component superimposed on the movement amount, movement speed, and acceleration. The plurality of measurement positions are arranged on an acoustic line of the reception signal,
The ultrasonic diagnostic apparatus according to claim 1, wherein the blood flow-intima boundary position detection unit detects a boundary position on the acoustic line by comparing feature amounts at each measurement position on the acoustic line.   The ultrasonic diagnostic apparatus according to claim 2, wherein the feature amount is a ratio of high-frequency components of the calculated movement amount, movement speed, and acceleration.   The ultrasonic diagnostic apparatus according to claim 2, wherein the feature amount is a value obtained by integrating the absolute values of the calculated movement amount, movement speed, and acceleration over the predetermined period.   The ultrasonic diagnostic apparatus according to claim 2, wherein the feature amount is a mean square value of the predetermined period of the calculated movement amount, movement speed, and acceleration.   The ultrasonic diagnostic apparatus according to claim 2, wherein the predetermined period is a cardiac cycle of the living body.   The blood flow-intima boundary position detection unit selects two selected from the feature amount related to the moving amount, the feature amount related to the moving speed, and the feature amount related to acceleration, and based on a value obtained by dividing one by the other, The ultrasonic diagnostic apparatus according to claim 2, wherein a boundary position between a blood flow region and an intima in a front wall of a blood vessel of the living body is detected. A media-endocardium boundary position detection unit for detecting a boundary position between the media and the adventitia in the front wall of the blood vessel from the characteristics of the received signal;
An IMT value calculation unit that calculates an IMT value of the anterior wall of the blood vessel from the boundary position between the media and outer membrane and the boundary position between the blood flow region and the intima,
The ultrasonic diagnostic apparatus according to claim 2, further comprising: A B-mode processing unit that generates a tomographic image in the measurement region of the living body based on the received signal;
A display unit for displaying the tomographic image;
In addition,
The ultrasonic diagnostic apparatus according to claim 1, wherein the display unit displays a boundary position between the blood flow region and the intima so as to be superimposed on the tomographic image.

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