JP5139143B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus that observes eddy currents in a bloodstream.

  In the ultrasonic diagnostic apparatus, for example, Doppler information (velocity information) is acquired from each point in the blood flow in the heart, and a two-dimensional blood flow image is constructed by two-dimensional mapping them. This is called a color Doppler method or a color flow mapping method. In general, velocity information displayed by the color Doppler method is not a true velocity of blood flow but a velocity component along the beam direction.

  Patent Document 1 describes a method for estimating a two-dimensional velocity vector from the velocity (beam direction velocity component) calculated at each point on the scanning plane. In this method, on the premise that the entire blood flow is composed of “vortex flow” and other “basic flow”, first, the observed beam direction velocity component is converted into the vortex flow component and the basic flow component. Disassembled. Next, for the vortex flow, the orthogonal velocity component is obtained by using a predetermined flow function, and for the basic flow, the orthogonal component is obtained by drawing a predetermined streamline. According to experiments by the present inventors, it has been confirmed that this method can obtain a clinically valuable two-dimensional velocity vector for the blood flow of the heart. According to this method, since the velocity component in the beam direction and the velocity component in the orthogonal direction for the vortex are obtained during the calculation, the two-dimensional velocity vector is displayed only for the vortex and the streamlines such as multiple rings are displayed. Is possible.

  When the velocity component of the vortex in the heart (for example, the left ventricle) is calculated using the method described in the above-mentioned Patent Document 1 and discriminated, the vortex is displayed two-dimensionally. When streamline display is performed, one or more vortex flows appear in the heart. For example, in the left ventricle, one or more eddy currents tend to appear near the apex or mitral valve. Moreover, it has been found that the appearance (number, size, position, etc.) of vortices in the heart differs depending on the content and degree of the disease. It is expected that this very interesting research result will be useful for cardiovascular medicine and others in the present or future.

JP 2005-110939 A

  The objective of evaluating eddy current visualization techniques in clinical practice is the objective evaluation of eddy currents. In other words, quantification of vortex flow. A technique for quantifying the eddy current estimated from the beam direction velocity component at each point on the scanning plane has not been provided.

  An object of the present invention is to provide an ultrasonic diagnostic apparatus capable of providing quantified information about eddy currents estimated from beam direction velocity components at each point on the observation surface of a subject.

  The present invention provides a function calculation means for obtaining a flow state function indicating a state of eddy currents existing on the observation surface based on Doppler information obtained by transmitting and receiving ultrasonic waves to the observation surface in the living body, and a flow state function The present invention relates to an ultrasonic diagnostic apparatus comprising: a specifying means for specifying a peak of the current and an index value calculating means for calculating a quantitative index value of the eddy current corresponding to the peak based on the value of the flow state function for the specified peak.

  Here, a flow function in hydrodynamics can be used as the flow state function, but is not limited to this. For example, it is conceivable that the two-dimensional velocity of each point in the observation plane is obtained by a two-direction ultrasonic beam, and the flow vortex is specified from the two-dimensional velocity of each point. Is an example of the flow state function.

  In one aspect, the index value calculation means uses a vortex maximum flow rate that is a value of the flow state function for the peak as the quantitative index value of the vortex flow corresponding to the peak, and the vortex maximum flow rate in the flow state function. Calculate at least one of an area of a closed curve connecting points having a predetermined flow rate value, a diameter or radius of a circle having the area, and a vortex intensity obtained by dividing the vortex flow rate by the area. To do.

  In a further aspect, the ultrasonic diagnostic apparatus superimposes and displays the means for obtaining an isoflow line of the flow state function and the quantitative index value of the eddy current corresponding to the isoflow line and the peak, with the Doppler information. Display means.

  In the above configuration, the function calculation means divides the integration path into a range in which the Doppler information is positive and a range in which the Doppler information is negative for each of the plurality of integration paths set on the observation surface. Determining means for determining the smaller absolute value of the integration result of the Doppler information as a range corresponding to the vortex flow not including the basic flow, and for each of a plurality of integration paths, the determination means among the integration paths includes the vortex flow. And a second calculation unit that calculates the flow state function based on Doppler information in a range determined to correspond to.

  In addition, the second calculation means, for each of the plurality of integration paths, converts the Doppler information in the range determined by the determination means to correspond to the eddy current among the integration paths, to the beam of the eddy current in the range. The beam direction velocity component of the eddy current in the part other than the range in the integration path is the directional velocity component, and the integration result of the beam direction velocity component in the part other than the range is the beam direction velocity component within the range. The flow state function for the eddy current may be calculated based on the beam direction velocity component in the determined range and the portion other than the determined range.

  According to the present invention, the quantitative index value of the eddy current in the observation surface can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In this embodiment, the flow function of the eddy current component in the observation surface is obtained by the same method as in Patent Document 1, and the quantitative index value of the eddy current is calculated from the flow function. Hereinafter, an example of the calculation method will be described.
[Estimation of eddy current components]
[1] Blood flow velocity vector in the observation plane

  First, the velocity component of the flow will be described with reference to FIG. In this figure, a linear scanning method is assumed, and the x direction indicates the ultrasonic beam direction, and the xy plane indicates a linear scanning tomographic plane.

ここで、ｅzは観測面に垂直方向の単位ベクトルである。 The actual blood flow velocity V (x, y, z) is a three-dimensional vector, and this vector V is a tomographic plane of a color Doppler image (hereinafter referred to as an observation plane) as shown in the following equation (1). Can be decomposed into a two-dimensional vector U (x, y) and a velocity component w perpendicular to the observation plane (z direction).

Here, ez is a unit vector perpendicular to the observation surface.

ここで、ｅ_ｘは超音波ビーム方向の単位ベクトルであり、ｅ_ｙはビームに直交する方向の単位ベクトルである。 The two-dimensional velocity vector U (x, y) in the observation plane is further divided into a component u (x, y) in the beam direction and a component v (x in the direction perpendicular to the beam, as shown in the following equation (2). , y).

Here, e _x is a unit vector in the ultrasonic beam direction, and e _y is a unit vector in the direction orthogonal to the beam.

Hereinafter, a method for estimating the two-dimensional blood flow velocity vector U in the observation surface area will be described. The “observation surface region” described below is not an infinite plane, but a finite surface region that is the scanning range of the ultrasonic beam.
[2] Flow separation in the observation area: Eddy current and basic flow

  As shown in FIG. 2, in this embodiment, the flow in the observation surface region 100 includes a “vortex” 110 that is a flow only in the finite observation surface region 100 and a region outside the region 100 through the observation surface region 100. Assume that there is an outflow and an inflow to and from a “basic flow” 120.

  In this flow decomposition, it is assumed that the flow in the observation plane region 100 includes a component of the flow that is closed and circulated in the region 100, and such a component of the in-plane circulation flow is named “vortex flow” 110. . Thus, it should be noted that the “vortex flow” 110 of the present embodiment is a completely independent concept from the “vortex” in fluid dynamics. The remainder obtained by removing the vortex 110 from the entire flow in the observation surface region 100 is referred to as a “basic flow” 120. Therefore, the basic flow 120 includes a component that flows in and out three-dimensionally into the observation surface region 100 and a component that flows in and out between the observation surface region 100 and the outside of the region 100 in the same plane. Contains.

In this way, when the flow in the observation surface region 100 is decomposed into the vortex flow 110 and the basic flow 120, the velocity component u (x, y) in the beam direction of the equation (2) is expressed by the following equation (3): It is represented by the sum of the velocity component u _s (x, y) carried by the vortex flow 110 and the velocity component u _b (x, y) carried by the basic flow 120.

Similarly, the velocity component v (x, y) in the direction orthogonal to the beam in the equation (2) is also the component v _s (x, y) due to the vortex 110 and the component due to the basic flow 120 as in the following equation (4). It is expressed as the sum of v _b (x, y).

Only the velocity component u (x, y) in the beam direction can be observed directly by the ultrasonic Doppler method. In the present embodiment, the velocity component u _s (x, y) of the vortex 110 in the beam direction is estimated based on the information on the beam direction velocity component u (x, y). Then, by using the obtained velocity component u _s (x, y) of the vortex flow 110, the component v _s (x, y) of the vortex flow 110 and the component of the basic flow 120 among the velocity components orthogonal to the beam are used. Estimate v _b (x, y). An estimation method for each of these components will be described below.
[3] Estimation of flow function of eddy current component a) Flow function

したがって、渦流１１０のビーム方向の速度成分ｕ_ｓが分かれば（ｕ_ｓの推定法は次に述べる）、流れ関数Ｓは次式（７）から求められる。

ロ）流量関数と距離流量関数 A two-dimensional incompressible fluid can describe a flow state using a flow function. Now vortex flow 110 in the observation plane is assumed to be the flow of a two-dimensional non-compressible fluid, and velocity components u _s beam direction of the vortex flow 110, the velocity component v _s in the orthogonal direction to the beam, the stream function S Using (x, y), it can be expressed by the following equations (5) and (6) (see FIG. 3).

Thus, knowing the beam direction velocity component u _s vortex 110 (Estimation of u _s is described below), the stream function S is determined from the following equation (7).

B) Flow function and distance flow function

The flow function S (x, y) described above relates to a two-dimensional flow. In the present embodiment, a flow function F (x, y) is used in which the concept of the flow function S is extended to the flow in the observation plane in the three-dimensional flow. The flow rate function F (x, y) is the beam direction velocity component u (x, y) that can be obtained by the Doppler method in the same direction (y direction) as the equation (7). Calculate by integrating. That is, the flow rate function F (x, y) is defined by the following equation (8).

Here, as shown in FIG. 4A, the observation surface region 100 has an x axis parallel to the beam direction and a y axis perpendicular to the beam direction. The beam scanning range is a range indicated by [y ₁ , y ₂ ]. The integration of Expression (8) is a process of integrating u (x, y) from y = 0 to y = y along a straight integration path 200 whose distance from the y-axis is x in (a). is there. In the numerical calculation, this integration is performed by adding the value of the beam direction velocity component u of each point (x, y) obtained by the Doppler method from y = 0 to y = y along the integration path 200. . If the distribution of the beam direction velocity component u at each point (x, y) along the integration path 200 is a curve 210, the flow function F (x, y) along the integration path 200 is shown in FIG. ).

距離流量関数Ｆ_ｒ(x)は、距離ｘの位置でのビーム方向に垂直な直線を横切る流量（ただしビーム方向速度成分ｕのみによるもの）の総計を示す。図４の（ｃ）は、距離流量関数Ｆ_ｒ(x)の曲線２３０の例を示している。
ハ）渦流成分の流量の推定 Further, in the integration path 200 located at a distance x along the beam direction, a value obtained by integrating the velocity component u in the beam direction over the beam scanning range [y ₁ , y ₂ ] is obtained as a distance flow function F _r ( x). That is, the distance flow function F _r (x) can be expressed by the following equation (9).

The distance flow rate function F _r (x) represents the total of the flow rate (only due to the beam direction velocity component u) crossing a straight line perpendicular to the beam direction at the position of the distance x. FIG. 4C shows an example of the curve 230 of the distance flow rate function F _r (x).
C) Estimating the flow rate of eddy current components

Next, the flow rate due to the vortex component is calculated from the distance flow rate function F _r (x) thus obtained. For this purpose, the distance flow function F _r (x) is calculated from the contribution F _{r +} from u ₊ which is a positive component of u and u ₋ which is a negative component of u, as shown in the following equation (10). To F _r− .

Here, when determining the stream function S of the vortex 110, the contribution _{S +} from the positive component _{u s +} a _{u s,} contributions from the negative components _{u s-of u s} S _- decomposes and. The eddy current 110 in the observation surface region 100 is considered to be a two-dimensional flow, and by definition, there is no inflow / outflow from the outside via the boundary line on the outer periphery of the observation surface region 100. If u _s is integrated from one end point to the other end point, the result is zero ((b) in FIG. 3). Therefore, the relationship of following Formula (11) is formed.

Here, it is assumed that the component of the vortex 110 is the largest in the flow in the observation surface region 100. That is, here, in the curve of the flow rate function F (x, y) on the path 200 at the distance x as viewed from the y axis, the total flow rate (that is, the distance flow rate F _r (x)) in the entire path 200 is opposite. It is assumed that the flow rate in the section of the flow is all due to the vortex flow 110.

This assumption will be described with reference to FIG. Assuming that the distribution of the beam direction velocity component u on the path 200 is as shown by the curve 300 in (a), the flow crossing the path 200 is the positive direction of the x-axis in the entire path. I can say that. Here, in this flow, the flow rate component due to the vortex flow 110 circulating in the observation surface region 100 becomes zero if totaled over the entire path 200, so that the total flow rate F _r (x) is due to the basic flow 120. I can say that. Then, it is assumed that the flow direction of the basic flow 120 is the same direction (that is, the direction of the total flow rate) over the entire path 200, and that the flow in the opposite direction is caused by the vortex flow 110. That is, in FIG. 5A, the flow rate in the section where u is negative is assumed to be due to the vortex 110.

  In this case, the flow rate due to the “reverse flow” component is inevitably smaller than the flow rate due to the flow component in the same direction as the total flow rate.

Therefore, under this assumption, the following relational expression (12) is established.

If the distance flow function F _r (x) is positive as in the example of FIG. 5 (see (b)), the value of −F _r− is smaller than the value of F _{r +} (here, absolute values are Therefore, the following equations (13) and (14) hold.

This is the case where the negative flow is considered to be due to the vortex 110. That is, in this case, as shown in FIG. 5B, the flow rate F _r− due to the negative flow becomes equal to the contribution S ₋ due to the negative component u _s− of the vortex 110. Here, in one example, the ratio k ₊ of the positive flow rate S ₊ of the vortex flow to the positive flow rate F _{r +} is defined by the following equation (15).

Here, since F _{r +} and F _r− are known, the value of S ₊ is determined from Equation (13), and the value of the ratio k ₊ is determined from Equation (15).

On the other hand, when F _r (x) is negative or zero, since F _{r +} is smaller than or equal to −F _r− , the following equations (16) and (17) hold.

ニ）流れ関数の推定 This is the case where the forward flow is considered to be due to the vortex 110. In this case, the flow rate F _{r +} due to the flow in the positive direction is equal to the contribution S ₊ due to the component u _{s + in} the positive direction of the vortex flow 110. Here, in one example, the ratio k ₋ of the negative flow rate S ₋ of the vortex flow to the negative flow rate F _r− is defined by the following equation (18). The value of this ratio k ₋ can also be obtained in the same way as the value of the ratio k ₊ described above.

D) Estimation of flow function

  Here, for the sake of estimation, it is assumed as an example that the springs and the suction are uniformly generated in the observation surface region 100.

First, as shown in FIG. 5, the case where the distance flow rate function F _r (x) is positive will be described. In this case, under the above assumptions, the ratio k ₊ is of the formula (15), the ratio of the vortex velocity component u _s in the case of a positive relative velocity component u in the beam direction. That is, the following equation (19) is established.

Thus from the above equation (3), the velocity components _{u b} of the beam direction of the base stream 120 is represented by the following formula (20).

  In the above calculation, as shown in FIG. 5C, the beam direction velocity component u in the positive range is proportionally distributed between the component due to the vortex 110 and the component due to the basic flow 120. That is, in FIG. 5C, the broken curve 305 indicates the component of the vortex flow 110, and the difference between the curve 300 and the curve 305 indicates the component of the basic flow 120.

Although the distance flow function F _{r (x)} has been described for the case of positive, it is possible to distance flow function F _{r (x)} is considered similarly for negative or zero. That is, the negative flow rate S of the vortex for negative flow _{F r- -} ratio of k _- from velocity components _{u s} and _{u b} of the vortex and the basic flow of the beam direction, the following equation (21) and (22) expressed.

By using the u _s obtained by equation (19) or (21) can be obtained an expression for the vortex component from (7) the stream function S (x, y).

  As described above, the case of linear scanning has been described as an example. However, in the case of sector scanning or convex scanning, the flow function of the eddy current component in the observation plane region is obtained by performing the same calculation as described above in the polar coordinate system. Can do. In the polar coordinate system, the beam direction is the radial direction, and the direction orthogonal to the beam is the circumferential direction. Regardless of the scanning method, the flow function F of a certain point (assumed to be point A) is a “path perpendicular to the beam direction” (that is, the distance in the beam direction is the same). (In the case of sector scanning, an arc perpendicular to the radius), the beam direction of each point on the path from the point on the path on the predetermined edge of the observation surface area to the point A It can be obtained by sequentially adding velocity components. The distance flow rate function represents the total flow rate (that is, the integration result over the entire section of the path) as a function of distance in each integration path having different beam direction distances.

  The example of the method for obtaining the flow function S representing the flow rate of the “vortex” component that is closed and circulated in the observation plane from the velocity component in the beam direction obtained by the ultrasonic beam operation has been described.

In the above example, the range considered to correspond to the eddy current component in the integration path (that is, the reverse direction to the direction of the total flow along the integration path (this is referred to as “forward direction”). The flow rate equal to the flow rate in the section) is proportionally distributed by the ratio k for the portion outside the range, and the beam direction velocity component of the eddy current component in the portion outside the range is defined. However, this is only an example and is not limited to this.
[Quantification of eddy current components]

In this embodiment, a quantitative index value of the eddy current is calculated based on the flow function of the eddy current thus obtained. Examples of index values to be calculated include the following.
(1) Maximum flow of vortex

The peak value (peak flow rate value) of the flow function S is defined as the maximum flow rate of the vortex centered on the peak. If the flow function S is calculated, the peak value can be obtained by searching for the peak of the function S. When there are a plurality of eddy currents in the observation surface region, the peak value can be obtained for each eddy current. Note that the flow rate here is for a flow in the two-dimensional observation plane, and therefore the value of the dimension of (length) ² / time (for example, the unit is cm ² / s).
(2) Half-value area of vortex

  A surface having a flow rate ½ of the maximum flow rate of the vortex (that is, the peak value of the flow function S) is obtained from the flow function S, and the area of the surface is defined as the half-value area of the vortex. In other words, among the iso-level lines of the flow function S surrounding the peak of the flow function S (that is, the iso-flow lines), the area surrounded by the iso-level line corresponding to the flow value half the flow value of the peak is The half value area. This can also be calculated if the flow function S is known. This index value quantifies the spatial extent of the eddy current.

The “half value” is merely an example. If generalized, the area of the surface of the flow rate at a predetermined ratio with respect to the peak value can be used as an index. You may obtain | require and use the value of the ratio suitable for the characteristic of object by experiment etc. This also applies to the following (3) and (4).
(3) Diameter or radius of half-value area of vortex

The diameter or radius of a circle having the same area as the half-value area of the vortex described above. This represents the spatial extent of the eddy current when the shape of the eddy current is assumed to be a circle.
(4) Eddy strength of vortex

The value obtained by dividing the maximum flow rate of the vortex by the half-value area of the vortex is defined as the vortex strength of the vortex. This indicates the flow rate per unit area, and the larger this value, the stronger the vortex. That is, as the vortex strength increases, the gradient of the flow function becomes steeper (in other words, the interval between the vortex flow rate isolevel lines is closer), and the vortex flow rate per area increases. Since the dimension of the maximum flow rate is (length) ² / hour and the dimension of the half-value area is (length) ² , the dimension of the vortex strength is 1 / hour.
[Example of device configuration]

  FIG. 6 shows an example of the configuration of an ultrasonic diagnostic apparatus that implements the above method. In the apparatus configuration shown in FIG. 6, the eddy current calculation unit 416 is a functional module that calculates the vortex flow function and the index value by the above method. The other components may be the same as those of a conventional general ultrasonic diagnostic apparatus.

  In this apparatus, a transmission signal is generated by the transmission unit 404 in accordance with control from the control unit 402 according to an operation from the input device 400, and the transducer array in the probe 406 is driven by this transmission signal, so that the subject 500 A beam of ultrasonic pulses is transmitted inside. The echo of the beam from within the subject 500 is received by the probe 406, and an electrical reception signal is generated. The received signal is subjected to predetermined signal processing by the receiving unit 408 to become beam data, and is input to the B-mode calculating unit 410, the color Doppler calculating unit 412, and the spectral Doppler calculating unit 414. These calculate B-mode data, color Doppler data (ie, beam direction velocity components at each point), and spectral Doppler data, respectively.

  For example, the B mode calculation unit 410 executes detection, logarithmic compression processing, and the like on the beam data. Further, the color Doppler calculation unit 412 performs a quadrature detection process by mixing a reference signal with a received signal as beam data, for example, by a quadrature detection circuit, and obtains a complex signal as a result. Then, an autocorrelation operation is performed on the complex signal, and a speed is calculated by performing an arctangent operation on the complex signal that is the operation result. The velocity is a velocity component along the ultrasonic beam direction.

  The region-of-interest setting unit 422 sets a region of interest (ROI) in which the eddy current calculation unit 416 performs calculation in the ultrasonic beam scanning region (observation surface region). The region of interest is set by, for example, specifying a control point that defines the outer peripheral line of the region of interest on the tomographic image displayed on the display unit 420 using the input device 400 including a pointing device such as a trackball. This can be done by operation. In this case, the position information of each control point input to the input device 400 is input to the region-of-interest setting unit 422 via the control unit 402, and the region-of-interest setting unit 422 is, for example, an inside of a closed curve that can sequentially connect these control points. To the region of interest. Information on the set region of interest (for example, information on a closed curve that defines the outer periphery of the region of interest) is input to the eddy current calculation unit 416. For example, when viewing the flow in the ventricle, a closed curve surrounding the ventricle is set as the region of interest.

  The eddy current calculation unit 416 calculates a flow function by executing calculation processing according to the above-described method from the value of the beam direction velocity component at each point in the observation plane obtained by the color Doppler calculation unit 412. Further, the above-described index value is calculated from the calculated flow function. In the calculation of the flow function or the index value, the calculation range may be limited to the region of interest set by the region of interest setting unit 422. That is, in the configuration of FIG. 6, at least one frame of line data output from the color Doppler calculation unit 412 is stored, and this is processed by the eddy current calculation unit 416 based on the above-described method.

  FIG. 7 shows an example of a functional configuration of the eddy current calculation unit 416. In this example, first, the flow function calculation unit 600 calculates a vortex flow function in the observation plane based on the beam direction velocity component at each point in the observation plane by a program or circuit in which the above-described method is implemented.

  The equal flow line calculation unit 602 calculates an equal level line for each predetermined flow interval, that is, an equal flow line in the flow function. The equiflow rate line can be calculated by obtaining a point (coordinate) having a flow rate value for each flow rate interval in the flow function.

  The peak calculation unit 604 obtains the coordinates of the point (maximum value) of the flow function and the value (flow rate value) of the flow function at the peak from the value of the flow function at each point on the observation surface. There may be multiple peaks in the observation plane. It can be assumed that there are as many eddies as the number of peaks. Each peak coordinate and flow value pair obtained by the peak calculation unit 604 is stored in the peak database 606.

  The index value calculation unit 608 calculates the eddy current index value corresponding to each peak based on the information on each peak stored in the peak database 606. For example, as the maximum flow rate of the eddy current, the flow rate value of each peak read from the peak database 606 may be used as it is. The half-value area may be calculated by causing the iso-flow line calculation unit 602 to calculate an iso-flow line having a flow rate that is half the maximum flow rate, and calculating the area of the region surrounded by the iso-flow line obtained by the calculation. The radius (or diameter) corresponding to the half-value area may be obtained by dividing the square root of the half-value area by the circumference ratio (or 1/2 of the circumference ratio). Further, the vortex intensity may be obtained by dividing the maximum flow rate by the half-value area.

  The eddy current image generation unit 610 corresponds to each equal flow line calculated by the equal flow line calculation unit 602 (for each predetermined flow rate interval and half value of the maximum flow rate) and each peak calculated by the index value calculation unit 608. An image representing the eddy current index value to be generated is generated.

  FIG. 8 schematically shows an example of an image generated by the eddy current image generation unit 610. In this example, the flow function isoflow line 700 is shown in the image. The peaks 710-1 and 710-2 of the flow function are the centers of the vortices. In this example, the peak 710-1 has a larger number of isoflow lines surrounding the peak than the peak 710-2, and thus it can be seen that the former has a larger maximum flow rate. In the illustrated example, the peak position is not clearly shown in the image, but an image in which the peak position is clearly indicated may be generated. In this example, an index value display column 720 is displayed in association with the peak that is the center of the eddy current, and one or more index values for the eddy current are displayed in the column 720. Further, in this example, only the peak 710-1 with the larger maximum flow rate is displayed with the equal flow rate line 705 corresponding to the half-value area and the index value display column 720. In this example, the maximum flow rate and vortex intensity of the vortex are displayed, but the present invention is not limited to this. In this example, the index value display field 720 and the peak position of the eddy current are linked on the display, but the correlation is not limited to this.

  The eddy current calculation unit 416 can be realized by software processing, but by realizing the calculation processing based on the above method as a DSP (digital signal processor), processing with higher real-time characteristics is possible. Become.

  An example of the processing procedure of the eddy current calculation unit 416 is shown in FIG. In this example, first, the flow function calculation unit 600 obtains a flow function S (x, y) from the Doppler velocity component in the tomographic plane obtained by the color Doppler calculation unit 412 (S1). Next, the peak calculation unit 604 obtains the position and value (flow rate value) of the peak of the flow function (S2), and registers the position and value of each peak in the region of interest in the peak database 606 (S3). Here, as an example, in the peak database 606, it is assumed that the position and value pairs of each peak are sorted in descending order of the peak value. Then, the counter i is initialized to 1 (S4), the i-th peak (vortex) information is selected from the peak database 606, the vortex index value is calculated based on the information, and the position of the selected peak is calculated. The index value is displayed, for example, on an image showing the equal flow line calculated by the equal flow line calculation unit 602 (S5). For example, displaying the index values for all vortices in the region of interest complicates the image, so the index values may be displayed only for up to a predetermined number of vortices in descending order of maximum flow rate. In this case, after step S5, it is determined whether or not the processes up to the predetermined number have been completed (S6). If not completed, i is incremented by 1 (S7), and the process of step S5 is repeated.

  Note that the configuration and processing procedure of the eddy current calculation unit 416 shown in FIGS. 7 and 9 are merely examples, and other configurations and procedures may be used as long as the above-described method is implemented.

  The biological signal measuring instrument 424 is a device that generates a biological signal such as an electrocardiogram signal by measuring a living body, for example. The generated biological signal is input to the image display processing unit 418.

  The image display processing unit 418 forms a display image for diagnosis using the B-mode data, color Doppler data, spectral Doppler data, eddy current image (equal flow line and index value) and biological signal thus obtained. In this image forming process, B-mode data, color Doppler data, and the like may be subjected to scan conversion corresponding to various ultrasonic beam scanning formats such as sector scanning. Various images adapted to the image format of the display unit 420 by scan conversion are appropriately combined according to the setting of the diagnostic image mode, whereby a display image is formed and displayed on the display unit 420.

  For example, in the example of the display image schematically shown in FIG. 10, an eddy current equiflow line 700 included in the flow in the ventricular wall 800 and an electrocardiogram waveform 750 are displayed.

  As described above, the flow in the observation surface region is assumed to be a superposition of the closed vortex flow circulating in the region and the other basic flow, and the vortex flow is calculated from the flow function F (x, y). Ingredients can be extracted. Since the eddy current component is a flow that is closed in the two-dimensional observation surface region, the concept of a two-dimensional flow function can be applied, thereby obtaining a two-dimensional flow for the eddy current. Then, a quantitative index of eddy current can be calculated from the information on the flow of eddy current.

  If the apparatus of this embodiment is utilized, the characteristic of abnormal blood flow can be objectively and quantitatively evaluated from the flow velocity vector distribution in the heart, for example. In myocardial disease, it is effective for determining the quality of myocardial function.

It is a figure for demonstrating decomposition | disassembly of a three-dimensional blood-flow velocity vector. It is a figure for demonstrating decomposition | disassembly of the flow in an observation surface area | region. It is a figure for demonstrating the relationship between the eddy current in an observation surface area | region, and a flow function. It is a figure for demonstrating a flow rate function and a distance flow rate function. It is a figure for demonstrating decomposition | disassembly into a vortex | eddy_current component and a basic flow component. It is a figure which shows an example of a structure of the ultrasound diagnosing device using the method of embodiment. It is a figure which shows the structural example of an eddy current calculating part. It is a figure which shows typically an example of the image which an eddy current calculating part produces | generates. It is a figure which shows an example of the process sequence of an eddy current calculating part. It is a figure which shows typically an example of the display image which an image display process part produces | generates.

Explanation of symbols

  100 observation surface area, 110 vortex flow, 120 basic flow, 400 input device, 402 control unit, 404 transmission unit, 406 probe, 408 reception unit, 410 B mode calculation unit, 412 color Doppler calculation unit, 414 spectral Doppler calculation unit, 416 Eddy current calculation unit, 418 image display processing unit, 420 display unit, 600 flow function calculation unit, 602 isoflow line calculation unit, 604 peak calculation unit, 606 peak database, 608 index value calculation unit, 610 eddy current image generation unit.

Claims (3)

Function calculation means for obtaining a flow state function indicating the state of eddy current existing on the observation surface based on Doppler information obtained by transmitting and receiving ultrasonic waves to the observation surface in the living body;
A specific means for identifying the peak of the flow state function;
Based on the value of the flow state function for the identified peak, an index value calculating means for calculating a quantitative index value of the eddy current corresponding to the peak;
An ultrasonic diagnostic apparatus comprising:   The index value calculation means, as a quantitative index value of the eddy current corresponding to the peak, a vortex maximum flow rate that is a value of the flow state function for the peak, and a predetermined ratio with respect to the vortex maximum flow rate in the flow state function. Calculating at least one of an area of a closed curve connecting points having a flow rate value, a diameter or radius of a circle having the area, and a vortex intensity obtained by dividing the vortex flow rate by the area. The ultrasonic diagnostic apparatus according to claim 1. Means for obtaining an isoflow line of the flow state function;
Display means for displaying the quantitative index value of the eddy current corresponding to the isoflow line and the peak superimposed on the Doppler information;
The ultrasonic diagnostic apparatus according to claim 1, further comprising:

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