JP5276407B2 - Ultrasonic diagnostic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve accuracy of three-dimensional extraction of the left ventricle of the heart. <P>SOLUTION: A contour extraction part 20 sets a plurality of cross sections corresponding to the minor axis cross section between a cardiac apex and an annulus part inside a three-dimensional data space and extracts the contour of the left ventricle for each cross section. A sample point setting part 22 sets a plurality of sample points along the contour of the left ventricle inside each cross section. An interpolation processing part 24 forms a plurality of interpolation curves from the cardiac apex to the side of the annulus part by interpolation processing utilizing the plurality of sample points made to correspond to each other over the plurality of cross sections and a reference point corresponding to the cardiac apex, and extends the respective interpolation curves to a reference plane corresponding to the annulus part. In such a manner, the three-dimensional contour line of the left ventricle comprising the plurality of interpolation curves connecting the reference point corresponding to the cardiac apex of the left ventricle and the reference plane corresponding to the annulus part of the left ventricle is formed. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to a technique for extracting the left ventricle of the heart.

  By using the ultrasonic diagnostic apparatus, it is possible to diagnose the state of the target tissue based on the received signal obtained from the diagnostic region including the target tissue via the ultrasonic wave. For example, by measuring the volume of the heart (such as the volume in the left ventricle) using an ultrasonic diagnostic apparatus, it becomes possible to evaluate the motor function of the heart.

  When measuring the volume of the heart or the like, it is desirable to accurately extract the outline of the heart (the outline of the left ventricular cavity) and the like. Under such circumstances, several techniques for extracting the contour of a target tissue in an ultrasonic diagnostic apparatus have been proposed. For example, Patent Document 1 proposes a technique for detecting a boundary of an object such as a heart using two intersecting image planes.

Special table 2007-507248

  In three-dimensional data obtained via ultrasound, for example, the apex or annulus of the left ventricle cannot be accurately extracted by simple binarization processing, for example. For this reason, it has been difficult to accurately extract the left ventricle of the heart three-dimensionally in the three-dimensional data.

  The present invention has been made in such a situation, and an object thereof is to improve the accuracy of three-dimensional extraction of the left ventricle of the heart.

  In order to achieve the above object, an ultrasonic diagnostic apparatus according to a preferred embodiment of the present invention includes a probe that transmits and receives ultrasonic waves to and from a three-dimensional space including the heart, and transmission control of the probe from within the three-dimensional space. A transmitting / receiving unit that obtains a reception signal via ultrasound, a left ventricular extraction unit that extracts a left ventricle of a heart in a three-dimensional data space formed based on a reception signal obtained from the three-dimensional space, and the three-dimensional A reference point corresponding to the apex of the left ventricle in the data space, a reference setting unit for setting a reference plane corresponding to the annulus of the left ventricle, and the apex and the annulus in the three-dimensional data space. A plurality of cross-sections corresponding to the short-axis cross section of the left ventricle, and extracting a contour of the left ventricle for each cross section; and a plurality of samples along the contour of the left ventricle in each cross section A sample point setting unit for setting points, and the plurality of points A plurality of interpolation curves from the apex to the annulus are formed by an interpolation process using a plurality of sample points and the reference points that are associated with each other over a plane. A three-dimensional contour of the left ventricle comprising a plurality of interpolation curves connecting the reference point corresponding to the apex portion of the left ventricle to the reference plane corresponding to the annulus portion of the left ventricle Forming a line.

  In a preferred aspect, the sample points that are closest to each other among the adjacent cross sections of the plurality of cross sections are associated with each other.

  In a desirable mode, the sample point setting unit sets a plurality of sample points along the outline of the left ventricle in one representative section selected from the plurality of sections, and sets each sample point set in the representative section. For each sample point, a plurality of sample points associated with each other over a plurality of cross sections are set starting from each sample point.

  In a preferred aspect, the sample point setting unit selects, as the representative cross section, a cross section having a maximum perimeter of the left ventricular contour from the plurality of cross sections.

  In a preferred aspect, the reference setting unit sets the reference point at one apex position specified by the user, includes two annulus positions specified by the user, and passes through the apex position. The reference plane is set so as to be perpendicular to the long axis.

  In order to achieve the above object, a program according to a preferred aspect of the present invention is a program in which a heart is generated in a three-dimensional data space formed based on a received signal obtained from a three-dimensional space including the heart via ultrasonic waves. A left ventricular extraction function for extracting the left ventricle, a reference setting function for setting a reference point corresponding to the apex of the left ventricle and a reference plane corresponding to the valve annulus of the left ventricle in the three-dimensional data space, and In the three-dimensional data space, between the apex and the annulus, set a plurality of cross sections corresponding to the short axis cross section of the left ventricle, and extract the contour of the left ventricle for each cross section, Interpolation using a sample point setting function for setting a plurality of sample points along the outline of the left ventricle in each cross section, and a plurality of sample points and the reference points associated with each other over the plurality of cross sections By processing, the annulus from the apex An interpolation processing function that forms a plurality of interpolation curves toward the side and extends each interpolation curve to the reference plane, and realizes a computer to realize a left ventricular annulus from the reference point corresponding to the apex of the left ventricle A three-dimensional contour of the left ventricle is formed, which is composed of a plurality of interpolation curves connecting to the reference plane corresponding to.

  For example, the program of the above aspect is stored in a storage medium such as a disk or a memory, and is read into the computer via the storage medium. Alternatively, the program may be provided to the computer via a network or the like.

  The present invention increases the accuracy of three-dimensional extraction of the left ventricle of the heart.

  Hereinafter, preferred embodiments of the present invention will be described.

  FIG. 1 shows a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention, and FIG. 1 is a functional block diagram showing the overall configuration thereof.

  The probe 10 is an ultrasonic probe for acquiring three-dimensional echo data, and is used in contact with the body surface of a patient or inserted into a body cavity. The probe 10 transmits and receives ultrasonic waves in a three-dimensional space by mechanically scanning a 1D array transducer that transmits and receives ultrasonic waves in a two-dimensional plane by electronic scanning. The probe 10 may be one that transmits and receives ultrasonic waves in a three-dimensional space by electronically scanning a 2D array transducer in which transducers are two-dimensionally arranged.

  The transmission / reception unit 12 controls the probe 10 to transmit / receive ultrasonic waves in a three-dimensional space including the heart that is the target tissue, and obtains a reception signal from the three-dimensional space (diagnosis region) via the ultrasonic waves. That is, the transmission / reception unit 12 functions as a transmission beamformer and a reception beamformer, acquires voxel values (voxel data) for each voxel of a plurality of voxels constituting a three-dimensional space, and outputs them to the three-dimensional data memory 14.

  The ultrasonic diagnostic apparatus according to the present invention is suitable for heart diagnosis, for example. In general, in the ultrasound diagnosis of the heart, an ultrasound image is obtained in which the heart cavity portion is greatly projected and the heart muscle portion surrounds the heart cavity portion. That is, most of the formed ultrasound image is occupied by the myocardial part and the heart cavity part.

  In the three-dimensional data memory 14, each voxel value is recorded at an address corresponding to the coordinate value in the three-dimensional space. The coordinates in the three-dimensional space may be coordinate values of the rθφ polar coordinate system suitable for the sector scanning method of the ultrasonic beam, or may be coordinate values of an xyz orthogonal coordinate system suitable for the rectangular parallelepiped shape.

  The left ventricle extraction unit 16 extracts the left ventricle, which is a target tissue, in a three-dimensional data space composed of a plurality of voxel data stored in the three-dimensional data memory 14. In the extraction, first, a plurality of voxel data are binarized. In the present embodiment, an echo level is considered as a voxel value. In general, the heart cavity has a lower echo level than the myocardium. Therefore, by setting the threshold value to a level smaller than the level corresponding to the myocardial part and larger than the level corresponding to the cardiac chamber part, the myocardial part and the cardiac chamber part can be roughly classified based on the threshold value. it can. Note that it is desirable to perform a noise removal process or the like before the binarization process.

  Further, the left ventricular extraction unit 16 extracts the left ventricular heart chamber from the heart chamber identified by the binarization process. The left ventricular extraction unit 16 extracts a plurality of isolated sets of heart chamber voxels by, for example, labeling processing. The heart has four cavity portions corresponding to the left ventricle, left atrium, right ventricle, and right atrium. That is, each of the extracted isolated sets corresponds to four cavity portions. Since the cavity portion corresponding to the left ventricle has a larger volume than the other cavity portions, the left ventricle extraction unit 16 extracts the one with the maximum volume from a plurality of isolated sets as an isolated set corresponding to the left ventricle. . The volume of each isolated set is calculated based on the number of voxels included in each isolated set, for example.

  Note that there may be a case where each isolated set extracted by labeling processing or the like does not necessarily correspond to four cavity portions. For example, it may be extracted as a single isolated set in which the cavity portions corresponding to the left ventricle and the left atrium are connected. In such a case, the region of interest is set in the cavity corresponding to the left ventricle by the user, and the left chamber extracting unit 16 extracts the isolated set in the set region of interest as the isolated set corresponding to the left ventricle.

  When the heart chamber (isolated set) corresponding to the left ventricle is extracted, the apex annulus setting unit 18 in the three-dimensional data space, the reference point corresponding to the apex of the left ventricle and the left ventricular valve Set the reference plane corresponding to the ring part. The apex valve annulus setting unit 18 sets a reference point and a reference plane based on the apex position and the annulus position specified by the user. The user designates the apex position and the annulus position by using an operation device such as a trackball or a touch panel while referring to a display image such as a multi-plane image displayed on the display unit 30.

  FIG. 2 is a diagram illustrating an example of a display image that is referred to when designating the apex position and the annulus position. The display image shown in FIG. 2 is a multi-plane image including a long-axis section (A) of the left ventricle, a four-chamber section (B) of the heart, and a short-axis section (C) of the left ventricle. 3D image (D) is also included.

  The user appropriately adjusts the position of each cross section included in the multi-plane image shown in FIG. For example, the position of the long-axis cross section is adjusted so that the apex and the annulus of the left ventricle are projected in the long-axis cross section (A) of the left ventricle. Then, for example, one apex position 42 and two annulus positions 44 are designated in the long-axis cross section (A) of the left ventricle. For example, the user first designates one apex position 42 and further sets the long axis 43 of the left ventricle passing through the apex position 42. Then, for example, the user designates two valve annulus positions 44 on a straight line that intersects perpendicularly to the long axis 43 of the left ventricle.

  Returning to FIG. 1, when the apex position and the annulus position are designated by the user, the apex annulus setting part 18 is designated by the user with one apex position designated by the user as a reference point. The reference plane is set so as to be perpendicular to the long axis of the left ventricle including the two valve annulus positions and passing through the apex position. The apex annulus setting unit 18 includes, for example, two annulus positions 44 (FIG. 2) designated in the left ventricular long-axis cross section (A) (FIG. 2), and the left ventricular long-axis cross-section. A reference plane is set so as to intersect perpendicularly to (A).

  When the reference point and the reference plane are set, the contour extracting unit 20 sets a plurality of cross sections corresponding to the short-axis cross section of the left ventricle in the three-dimensional data space, and extracts the contour of the left ventricle for each cross section. . Further, the sample point setting unit 22 sets a plurality of sample points along the outline of the left ventricle in each cross section. Then, the interpolation processing unit 24 forms a plurality of interpolation curves from the apex to the annulus in the three-dimensional data space based on the set plurality of sample points.

  Therefore, processing in the contour extraction unit 20, the sample point setting unit 22, and the interpolation processing unit 24 will be described in detail. 1 is used in the following description for the portion (configuration) already shown in FIG.

  FIG. 3 is a diagram for explaining a contour extraction function, a sample point setting function, and an interpolation processing function in the present embodiment. 3A to 3C show specific examples of processing in the three-dimensional data space.

  The contour extracting unit 20 sets a plurality of cross sections corresponding to the short axis cross section of the left ventricle between the apex and the annulus in the three-dimensional data space, and the contour of the left ventricle is set for each cross section. To extract. For example, as illustrated in FIG. 3A, the contour extraction unit 20 sets a plurality of cross sections 52 at equal intervals between the apex position 42 and the annulus position 44. Each cross section 52 is set in parallel to the reference plane, for example. In FIG. 3A, five cross-sections 52 are set at an interval of L / 6 obtained by dividing the distance L from the apex position 42 to the plane (reference plane) including the valve annulus position 44 into six equal parts. . Note that the number of the cross sections 52 is not limited to five, and may be, for example, about several tens to several hundreds.

  The contour extracting unit 20 further extracts a left ventricular contour 54 for each cross section 52. The contour extraction unit 20 searches the boundary between the left ventricular heart chamber and the surrounding myocardium for each cross section 52 to form a contour 54 corresponding to the cross-sectional shape of the left ventricular heart chamber. It goes without saying that the shape and size of the contour 54 may differ depending on the position of each cross section. In addition, since the apex and the annulus are difficult to identify by a simple binarization process or the like, each cross-section 52 is desirably set so as not to include the apex and the annulus.

  When the contour 54 is formed in each of the plurality of cross sections 52, the sample point setting unit 22 sets a plurality of sample points 56 along the left ventricular contour 54 in each cross section 52. For example, as shown in FIG. 3B, the sample point setting unit 22 selects a cross section having the longest perimeter of the left ventricular contour 54 as the representative cross section 52T from among the plurality of cross sections 52, and within the representative cross section 52T. A plurality of sample points 56T are set along the contour 54T of the left ventricle. In the representative cross section 52T, the plurality of sample points 56T are set to, for example, about several hundred points at equal intervals.

  The sample point setting unit 22 further includes, for each sample point 56T set in the representative cross section 52T, a plurality of sample points 56 associated with each other over the plurality of cross sections 52, starting from the sample points 56T. Set.

  The sample point setting unit 22 searches for a point closest to each sample point 56T in the representative cross section 52T on the contour 54 'in the cross section 52' adjacent to the representative cross section 52T. And let the searched point be the sample point 56 'on the outline 54' in the adjacent cross section 52 '. The sample points 56T in the representative cross section 52T and the sample points 56 'in the adjacent cross section 52' thus set are associated with each other. When a sample point 56 ′ is set in the adjacent cross section 52 ′, the point closest to the sample point 56 ′ is located on the contour 54 ″ in the next cross section 52 ″ adjacent to the cross section 52 ′. Explored. Thus, the sample point setting unit 22 starts from each sample point 56T in the representative cross section 52T, and the adjacent cross section 52 'includes the sample points 56', 56 ", ... associated with the start sample point 56T. , 52 ″,... Are successively searched, and a plurality of sample points 56 associated with each other over a plurality of cross sections 52 are set.

  Thereby, for example, as shown in FIG. 3C, a plurality of cross-corresponding plural cross sections 52 along the vertical direction (the direction from the apex position 42 to the annulus position 44). A sample point 56 is set.

  Then, as shown in FIG. 3C, for example, the interpolation processing unit 24 uses a plurality of splines so as to connect the plurality of sample points 56 associated with each other based on the plurality of sample points 56 associated with each other. A curve 62 is formed. The interpolation processing unit 24 forms a plurality of spline curves 62 so as to include a reference point that is the apex position 42 in addition to a plurality of sample points 56 associated with each other.

  The interpolation processing unit 24 further expands each spline curve 62 to the reference plane 52B, thereby, as shown in FIG. 3C, a plurality of lines connecting the apex position 42 (reference point) to the reference plane 52B. A spline curve 62 is formed.

  In forming each spline curve 62, the interpolation processing unit 24 uses an interpolation method based on a plurality of sample points 56 and apex position 42 (reference point) associated with each other. For extending each spline curve 62 formed by the interpolation method to the reference plane 52B, for example, an extension process described below is used.

  FIG. 4 is a diagram for explaining the expansion process of each spline curve 62. FIG. 4A is a diagram showing an extension process using the extrapolation method. In the extrapolation method shown in FIG. 4A, the extension portion 62E is estimated using the already formed portion 62A of each spline curve 62. For example, the extension portion 62E is formed by using the coefficient of the curve in the portion 62A adjacent to the extension portion 62E.

  On the other hand, FIG. 4B is a diagram showing the decompression process using the virtual point 72. For example, the virtual point 72 is set to face the apex position 42 (reference point) across the reference plane 52B on the extension line of the long axis 43 of the left ventricle. The distance from the reference plane 52B to the virtual point 72 is determined based on the distance L from the reference plane 52B to the apex position 42, for example. In FIG. 4B, the distance from the reference plane 52B to the virtual point 72 is set to w × L (w is a coefficient determined empirically, for example). Then, a curve is formed by spline interpolation based on the plurality of sample points 56, the apex position 42, and the virtual point 72 that are associated with each other, and the formed curve is cut at the reference plane 52B to be expanded. A spline curve 62 is formed.

  A plurality of spline curves 62 as shown in FIG. 3C are formed by the contour extraction function, the sample point setting function, and the interpolation processing function described with reference to FIGS. 3 and 4, and the plurality of spline curves 62 are formed. Becomes the three-dimensional outline of the left ventricle. By increasing the number of the plurality of cross sections 52 and the number of sample points 56 in each cross section 52 in FIG. 3, the plurality of spline curves 62 (three-dimensional contour lines) become closer to the actual contour of the left ventricle. Further, based on the plurality of spline curves 62 and the plurality of sample points 56, for example, gaps between the plurality of spline curves 62 may be interpolated to form a curved surface showing a three-dimensional left ventricular contour.

  Returning to FIG. 1, when the left ventricular three-dimensional contour line (a plurality of spline curves 62 in FIG. 3) is formed in the interpolation processing unit 24, the volume calculation unit 26 determines whether the left ventricular three-dimensional contour line is left. Calculate the volume of the chamber. For example, the volume of the left ventricle is calculated from the number of voxels present inside the three-dimensional outline of the left ventricle and the volume of each voxel.

  The display image forming unit 28 forms an ultrasound image including the left ventricle based on a plurality of voxel data stored in the three-dimensional data memory 14. For example, the volume rendering method is used to form image data of an ultrasonic image that three-dimensionally displays the left ventricle of the heart. Further, the display image forming unit 28 may form a left ventricular contour image by a three-dimensional contour line of the left ventricle formed in the interpolation processing unit 24. For example, an outline image may be superimposed on an image obtained by the volume rendering method. Further, the display image forming unit 28 forms a display image indicating the volume of the left ventricular heart chamber obtained from the volume calculating unit 26 with a numerical value, a graph, or the like. An image corresponding to the image data formed in the display image forming unit 28 is displayed on a display unit 30 such as a monitor.

  In FIG. 1, the functions from the left ventricle extraction unit 16 to the interpolation processing unit 24 have been described as a part of the configuration in the ultrasonic diagnostic apparatus. However, these functions may be realized by a computer. For example, by causing a computer to read a program corresponding to each function from the left ventricular extraction unit 16 to the interpolation processing unit 24, hardware such as a CPU, a memory, and a hard disk included in the computer and the program (software) cooperate. Thus, the functions of the left ventricle extraction unit 16, the apex annulus setting unit 18, the contour extraction unit 20, the sample point setting unit 22, and the interpolation processing unit 24 described above may be realized.

  The preferred embodiments of the present invention have been described above, but in the above-described embodiments, for example, even when the apex portion or the annulus portion is difficult to identify by a simple binarization process or the like, the tertiary can be performed with relatively high accuracy. Originally, it becomes possible to extract the contour of the left ventricle, and for example, the measurement accuracy of the volume of the heart chamber is improved. The above-described embodiments are merely examples in all respects, and do not limit the scope of the present invention. The present invention includes various modifications without departing from the essence thereof.

1 is a functional block diagram showing an overall configuration of an ultrasonic diagnostic apparatus according to the present invention. It is a figure which shows the display image referred in the case of designation | designated of the apex position and the annulus position. It is a figure for demonstrating an outline extraction function, a sample point setting function, and an interpolation process function. It is a figure for demonstrating the expansion process of a spline curve.

Explanation of symbols

  10 probe, 12 transmission / reception unit, 16 left ventricular extraction unit, 18 apex annulus setting unit, 20 contour extraction unit, 22 sample point setting unit, 24 interpolation processing unit.

Claims (6)

A probe for transmitting and receiving ultrasonic waves to and from a three-dimensional space including the heart;
A transmission / reception unit that obtains a reception signal via ultrasonic waves from within a three-dimensional space by controlling transmission of the probe;
A left ventricular extraction unit for extracting the left ventricle of the heart in a three-dimensional data space formed based on a received signal obtained from the three-dimensional space;
A reference setting unit that sets a reference point corresponding to the apex portion of the left ventricle and a reference plane corresponding to the annulus portion of the left ventricle in the three-dimensional data space;
Within the three-dimensional data space, a plurality of cross sections not including the apex and annulus corresponding to the short axis cross section of the left ventricle are set between the apex and the annulus, and the left ventricle is set for each cross section. An outline extraction unit for extracting the outline of
A sample point setting unit for setting a plurality of sample points along the contour of the left ventricle in each cross section;
By interpolation processing using a plurality of sample points and the reference points associated with each other across the plurality of cross sections, a plurality of interpolation curves from the apex to the annulus are formed, An interpolation processing unit for extending the interpolation curve;
Have
Forming a three-dimensional contour of the left ventricle consisting of a plurality of interpolation curves connecting the reference point corresponding to the apex of the left ventricle to the reference plane corresponding to the annulus of the left ventricle,
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 1,
Sample points that are closest to each other between adjacent cross-sections of the plurality of cross-sections are associated with each other.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 2,
The sample point setting unit sets a plurality of sample points along the outline of the left ventricle in one representative section selected from the plurality of sections, and for each sample point set in the representative section , Setting each sample point as a starting point, a plurality of sample points associated with each other across a plurality of cross-sections,
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 3.
The sample point setting unit selects, as the representative cross section, the cross section having the maximum perimeter of the left ventricular contour from the plurality of cross sections.
An ultrasonic diagnostic apparatus. In the ultrasonic diagnostic apparatus according to any one of claims 1 to 4,
The reference setting unit sets the reference point at one apex position designated by the user, and includes two valve annulus positions designated by the user and with respect to the long axis of the left ventricle passing through the apex position. Set the reference plane to be vertical
An ultrasonic diagnostic apparatus. A left ventricular extraction function for extracting the left ventricle of the heart in a three-dimensional data space formed based on a received signal obtained via ultrasound from the three-dimensional space including the heart;
A reference setting function for setting a reference point corresponding to the apex of the left ventricle and a reference plane corresponding to the annulus of the left ventricle in the three-dimensional data space;
Within the three-dimensional data space, a plurality of cross sections not including the apex and annulus corresponding to the short axis cross section of the left ventricle are set between the apex and the annulus, and the left ventricle is set for each cross section. Contour extraction function to extract the contour of
A sample point setting function for setting a plurality of sample points along the contour of the left ventricle in each cross section;
By interpolation processing using a plurality of sample points and the reference points associated with each other across the plurality of cross sections, a plurality of interpolation curves from the apex to the annulus are formed, An interpolation processing function to extend the interpolation curve;
Is realized on a computer,
Forming a three-dimensional contour of the left ventricle consisting of a plurality of interpolation curves connecting the reference point corresponding to the apex of the left ventricle to the reference plane corresponding to the annulus of the left ventricle,
A program characterized by that.

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