JP2008100094A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic apparatus by which three-dimensional information of a scanning cross-section is effectively utilized in various forms while displaying a two-dimensional image regarding real-time performance as important. <P>SOLUTION: The ultrasonic diagnostic apparatus is equipped with a transmission part 2 and a reception part 3 to collect echo signals by scanning the cross-section inside an examinee by an ultrasonic beam, a receiver part 4 to generate a two-dimensional image on the basis of the echo signals, an image memory unit 8 to retain three-dimensional volume data, a position detector 24 to detect a position of the cross-section to be scanned by the ultrasonic beam, a DSC 33 to generate the two-dimensional image of a cross-section same as the cross-section to be scanned by the ultrasonic beam on the basis of the detected cross-section, and a display part 7 to simultaneously display the two-dimensional image generated from the echo signals and the two-dimensional image generated from the volume data. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is mainly applied for the purpose of administering an ultrasound contrast agent to a subject, observing blood flow dynamics of blood vessels, hemodynamics at the organ parenchyma level by detecting perfusion, and quantitative evaluation thereof. The present invention relates to an ultrasonic diagnostic apparatus having various image processing functions.

  There are various types of medical applications of ultrasound, but the mainstream is an ultrasound diagnostic apparatus that obtains a tomographic image of a soft tissue of a living body using an ultrasonic pulse reflection method. This ultrasonic diagnostic apparatus is a non-invasive examination method that displays a tomographic image of a tissue. An X-ray diagnostic apparatus, an X-ray computed tomography apparatus (X-ray CT), a magnetic resonance imaging apparatus (MRI), and nuclear medicine Compared to other diagnostic devices such as diagnostic devices (gamma camera, SPECT, etc.), real-time display is possible, the device is small and inexpensive, high safety without exposure to X-rays, etc., and blood flow by ultrasonic Doppler method It has features such as imaging.

  For this reason, ultrasonic diagnosis is widely performed in the heart, abdomen, mammary gland, urology, and gynecology. In particular, the heartbeat and fetal movement can be obtained in real time by simply operating the ultrasound probe from the surface of the body, and because it is highly safe, it can be repeatedly examined and moved to the bedside. Therefore, it is easy to carry out inspections.

  In addition, it is possible to display the velocity distribution of blood flow toward or away from the vibrator by the ultrasonic Doppler method and the power value distribution of the blood flow echo signal by the power Doppler method. In particular, the power Doppler method can detect perfusion of the vascular system with higher sensitivity, and is being used for diagnosis of abnormal blood flow at the peripheral level of the kidney, liver cancer, and the like.

  In such a field of ultrasonic diagnosis, the need for a three-dimensional image is increasing as in the case of X-ray CT and MRI. In addition to the planar information obtained from a two-dimensional tomographic image, the three-dimensional image takes into account the information in the depth direction, so that the shape of the tissue, the state of blood vessels, etc. can be known more clearly. It is expected.

  For obtaining three-dimensional information, position information and image information at that time are simultaneously captured by a position sensor attached to a probe, and then a three-dimensional image is reconstructed based on the position information. Many techniques have been proposed so far, but with the recent increase in CPU speed, three-dimensional images can be reconstructed and displayed in a very short time.

  However, regardless of how fast the CPU is, it is possible to reconstruct and display a 3D image in real time or a time close to it from 3D echo data captured by a 3D scan, as in 2D display. The current situation is that we have not yet reached the point where we can do it. Therefore, in practice, after taking the three-dimensional data and stopping the scanning, the three-dimensional image is reconstructed and then displayed and viewed. For this reason, in normal diagnosis, the conventional two-dimensional tomographic image is often observed in real time.

  An object of the present invention is to effectively utilize three-dimensional position information of a scanning section in various forms while displaying a two-dimensional image with an emphasis on real-time characteristics.

According to a first aspect of the present invention, there is provided means for collecting an echo signal by scanning a cross section inside a subject with an ultrasonic beam, means for generating a two-dimensional image based on the echo signal, and three-dimensional volume data. Holding means, means for detecting the position of the cross section scanned with the ultrasonic beam, and a two-dimensional image of the same cross section as the cross section scanned with the ultrasonic beam based on the position information of the detected cross section It comprises means for generating from the volume data, means for simultaneously displaying a two-dimensional image generated from the echo signal, and a two-dimensional image generated from the volume data.
According to a second aspect of the present invention, there is provided means for collecting echo signals by scanning a cross section inside a subject with an ultrasonic beam, means for generating a two-dimensional image based on the echo signals, and three-dimensional volume data. And a means for detecting the position of the cross section scanned with the ultrasonic beam, and a partial image in the same cross section as the cross section scanned with the ultrasonic beam based on the position information of the detected cross section. The apparatus includes: means for generating from the volume data; and means for combining and displaying a partial image generated from the volume data on a two-dimensional image generated from the echo signal.

  According to the present invention, it is possible to effectively utilize the three-dimensional position information of the scanning section in various forms while displaying a two-dimensional image with emphasis on real-time characteristics.

  Embodiments of the present invention will be described below with reference to the drawings. Although the present invention can be applied to any region of interest, the following description will be made assuming that an abnormal region is identified by observing a tumor or blood vessel such as a liver or pancreas.

(First embodiment)
FIG. 1 shows the configuration of the ultrasonic diagnostic apparatus according to the first embodiment. This apparatus includes an ultrasonic probe 1 responsible for transmission / reception of ultrasonic signals to / from a subject, and an apparatus main body 20 that drives the ultrasonic probe 1 and processes echo signals collected via the ultrasonic probe 1. And an operation panel 21 that is connected to the apparatus main body 20 and inputs various instruction information from the operator to the apparatus main body 20. Various input devices such as a trackball 22 and a keyboard 23 are connected to or installed on the operation panel 21. Via this operation panel 21, setting of scanning conditions, setting of a region of interest, and other various setting conditions related to the present invention are input.

  A plurality of micro vibrators such as piezoelectric ceramics are arranged at the tip of the ultrasonic probe 1. The form of the ultrasonic probe 1 may be any of sector correspondence, linear correspondence, convex correspondence, and the like. Here, a description will be given of the sector-corresponding ultrasonic probe 1.

  The apparatus main body 20 includes an ultrasonic transmitter 2, an ultrasonic receiver 3, a receiver 4, a B-mode digital scan converter 5, a memory synthesizer 6, a display unit 7, an image memory unit 8, and a Doppler unit 9. In addition to the components, a position detector 24, a coordinate memory unit 25, and a marker digital scan converter 26 according to the present invention are provided.

  The ultrasonic transmitter 2 includes a pulse generator 2A, a transmission delay circuit 2B, and a pulsar 2C. The ultrasonic transmitter 2 controls the delay time of each channel, shapes the ultrasonic wave into a beam shape, and transmits this as a pulse wave to the subject. In addition, it is provided to scan the cross section in the subject by changing the direction of the ultrasonic beam. The ultrasonic beam transmitted from the ultrasonic probe 1 by driving the ultrasonic transmission unit 2 is reflected by the discontinuous surface of the acoustic impedance in the subject and returns to the ultrasonic probe 1.

  A minute electric signal (echo signal) converted by each transducer of the ultrasonic probe 1 is taken into the ultrasonic receiver 3 for each channel, where it is first amplified by the preamplifier 3A and then received by the reception delay circuit 3B. Is given the same delay time as at the time of transmission, and finally added by the adder 3C. By this addition, a reception signal in which a reflection component from a specific direction is emphasized is generated.

  This received signal is taken into the receiver unit 4, where it is logarithmically amplified, envelope-detected, and output as a digital signal by an analog-digital converter. The output from the receiver unit 4 is converted by a B-mode digital scan converter (DSC) 5 from an ultrasonic scan raster signal sequence to a video format raster signal sequence. As a result, tomographic image data, so-called B-mode image data, is generated. This tomographic image data is sent to the display unit 7 via the memory synthesis unit 6 and displayed in grayscale.

  The reception signal generated by the ultrasonic wave receiving unit 3 is also taken into the Doppler unit 9, where it is first subjected to quadrature detection and then converted to a digital signal. The MTI filter removes the low frequency component (clutter component) that has undergone frequency shift due to reflection from a slow moving body such as a heart wall that is not subject to Doppler examination, and the fast moving body such as blood cell that is subject to Doppler examination. Only high frequency components (blood flow components) that have undergone frequency shift due to reflection are passed. Further, the blood flow component is subjected to frequency analysis by an autocorrelator, whereby the strength of each frequency is obtained. Based on the strength of each frequency, the average speed, its variance, and power are calculated. Thereby, blood flow image data representing a two-dimensional state of blood flow is generated. The blood flow image data is combined with the tomographic image data in the memory combining unit 6 and displayed in color on the display unit 7.

  The image memory 8 is provided to store and hold either one or both of the raster signal string data of the ultrasonic scan before conversion and the raster signal string data of the video format after conversion in the B-mode digital scan converter 5. These data can be displayed and reproduced by an operator arbitrarily calling after diagnosis, for example.

  Next, the position detector 24, the coordinate memory unit 25, and the marker digital scan converter 26, which are the main parts of the present embodiment, will be described together with the mechanism of the three-dimensional scan.

(3D scanning)
FIG. 2 shows an example of this three-dimensional scan. The three-dimensional scan is a scan in which the scanning plane is moved in the three-dimensional region of the subject P, and received signals are collected from each point in the three-dimensional region. Here, in the three-dimensional scan, the tip of the probe 1 is applied to the body surface of the subject, and the probe 1 is placed on the X axis (the body axis of the subject P) while this position (hereinafter referred to as the reference position P0) is fixed. Rotation α about the orthogonal axis perpendicular to the horizontal direction), rotation β about the Y axis of the probe 1 (orthogonal axis perpendicular to the body axis of the subject P), and the Z axis of the probe 1 This is performed by appropriately combining and moving the rotation γ around (the axis parallel to the body axis of the subject P).

(Cross-section position detection)
The position detection circuit 24 includes a reference position P0 (x0, y0, z0), an angle θα (a rotation angle about the X axis), an angle θβ (a rotation angle about the Y axis) in the three-dimensional scan. ), The angle θγ (rotational angle about the Z axis) is detected constantly or periodically. These detection signals (hereinafter referred to as position information) represent the position of the cross section scanned with the ultrasonic beam.

(Acquisition and storage of 3D position information of interest points)
As shown in FIG. 3A, when the operator operates the device panel 21 or the like to move the pointer on the screen and designates a point of interest such as a tumor on the tomographic image displayed on the display unit 7. Marker data is output from the coordinate memory unit 25. The marker data is combined with the tomographic image data by the memory combining unit 6 via the marker digital scan converter 26. Thereby, the marker P1 is superimposed on the point of interest of the tomographic image. Note that the shape of the marker is not limited to the x mark, and any shape such as a circle, a polygon, or an arrow may be used, and the number of markers is not limited to one, and a plurality (P2, P3,. be able to.

  In the coordinate memory unit 25, the position of the marker in the screen is obtained, and from this position and the cross-sectional position detected by the position detection circuit 24, the three-dimensional coordinates (position information) of the point of interest shown in FIG. Calculate and memorize this.

(Marker redisplay)
After a point of interest is specified on a tomographic image of a certain cross section and position information of the point of interest is stored, the scanning cross section may be changed for the purpose of observing a tumor or the like from another direction. The position information of the changed scanning section is detected by the position detection circuit 24 and supplied to the coordinate memory unit 25. The coordinate memory unit 25 determines whether or not the point of interest is included in the changed scanning section based on the stored position information of the point of interest and the position information of the changed scanning section. When the point of interest is not included in the scanning section, marker data is not output. Thereby, the marker is not displayed on the tomographic image of the changed scanning section. On the other hand, when the point of interest is included in the changed scanning section, the coordinate memory unit 25 outputs marker data. Thereby, the marker is superimposed and displayed on the tomographic image of the changed scanning section.

Therefore, the three-dimensional positional relationship between tomographic images having different scanning sections can be grasped to some extent through the marker. This
If you observe the tumor again from a different section, you can easily find it,
When observing the stenosis part of the blood vessel again from another cross section, it becomes easier to observe the positional relationship of the blood vessel running.
When counting the number of lesions in an organ, it can be accurately counted without duplication. For the operator, a 3D image does not appear, and diagnosis is performed with a conventional 2D tomographic image. The effect that it can be used comparatively easily in diagnosis can be produced.

(Another example of marker)
The marker may be a trace line (TL) of a region of interest such as a blood vessel cross section or a tumor contour as shown in FIG. As an example of superimposing and displaying such a mark on the tomographic image, the trace line TL is regarded as N points (P11, P12,... P1N), and the changed scanning section is the same as in the case of P1. It is determined whether or not it intersects with the trace line TL (FIG. 4B), and in the case of intersecting, markers CP1 and CP2 representing the intersection are superimposed and displayed on the tomographic image (FIG. 4C).

  Further, the trace line TL is projected onto the changed scanning section, and the projected trace line PTL is superimposed on the tomographic image.

(Expanding the area of interest)
When it is strictly determined whether or not the point of interest is included in the changed scanning section as described above, the marker is not displayed even if the point of interest is slightly deviated from the changed scanning section. It becomes very difficult to handle. So the point of interest
(P1) = (x1, y1, z1)
Instead of dealing with
Area (P1) = (x1 ± σ, y1 ± σ, z1 ± σ)
It is possible to gently determine whether or not the enlarged area intersects the changed scanning section. The enlargement parameter σ can be arbitrarily designated by the operator.

(Nearby display)
As an example of the above-described expansion of the point of interest, it can be shown that the scanning section is close to the point of interest. For example, with respect to the point of interest P1 designated by the operator, two types of regions centered on the position are represented as follows:
Area1 (P1) = (x1 ± σ1, y1 ± σ1, z1 ± σ1)
When,
Area2 (P1) = (x1 ± σ2, y1 ± σ2, z1 ± σ2)
And set. Note that σ <σ1 <σ2.

  When the area Area2 (P1) intersects with the changed scanning section, when the area Area1 (P1) intersects with the changed scanning section, the point of interest P1 is changed. By changing the display mode of the marker depending on the shape or color depending on when it is included in the scanning cross section, it is possible to recognize that the scanning cross section is approaching the mark and gradually approaching or moving away. Specifically, when the scanning section intersects with the area Area2 (P1), a relatively small marker is displayed, and when the scanning section intersects with the area Area1 (P1), a relatively large marker is displayed. This makes it relatively easy to find the previously noted points of interest from another scan section. Note that this method can be similarly realized for the color Doppler method.

(Modification of position detection circuit 24)
The position detection circuit 24 detects a relative position with respect to the probe 1. If the absolute position of the subject P moves, a position alignment error may occur, and the real-time image and the marker may shift. Therefore, as shown in FIG. 5, by attaching the position sensors 60 to at least three places of the subject P, the position detection circuit 24 detects the positions of both the subject P and the probe 1 at the same time, and always the subject-probe. It is possible to correct the positional relationship.

(Second Embodiment)
FIG. 6 shows the configuration of the ultrasonic diagnostic apparatus according to the second embodiment. In FIG. 6, the same parts as those in FIG. In the second embodiment, an external input device 31, a volume memory unit 32, and an internal data digital scan converter 33 are provided. The volume memory unit 32 stores volume data by ultrasonic waves such as the heart and the abdomen input via the external input device 31. This volume data is not limited to that obtained by an ultrasonic diagnostic apparatus, but may be data obtained by other modalities such as an X-ray computed tomography apparatus (CT scan) or a time resonance imaging apparatus (MRI). Good.

  The volume memory unit 32 selectively reads out the data in the cross section from the volume data according to the position information of the scanning cross section detected by the position detecting device 24, and the internal data digital scan converter 33 reads out the data from the read out data. The tomographic image data of the same cross section as the scanning cross section detected by the position detection device 24, that is, the cross section scanning in real time is reconstructed.

  At this time, since the position information is detected in real time by the position detection device 24, the tomographic image reconstructed based on the volume data also changes in accordance with the movement of the scanning section due to the movement of the probe 1.

  The tomographic image data reconstructed by the internal data digital scan converter 33 is combined with the real-time tomographic image data in parallel on one screen by the memory combining unit 6 and displayed on the display unit 7.

(Position alignment)
Since the tomographic image data having the same cross section as the cross section scanned in real time is reconstructed from the stored volume data as described above, it is necessary to achieve positional alignment. This procedure is shown in FIG. First, as shown in FIG. 8A, a real-time tomographic image 101 and a tomographic image 102 reconstructed with an appropriate cross section from volume data are simultaneously displayed. Next, the operator compares both images so that the reconstructed tomographic image becomes an image related to substantially the same cross section as the real-time tomographic image as shown in FIG. Then, the position of the cross section to be reconstructed from the volume data is rotated and translated with respect to the XYZ axes using the keyboard 23 or the trackball 22 or the like. Thereby, the position alignment (position adjustment) is completed, and the tomographic image reconstructed based on the volume data is changed in accordance with the movement of the scanning section due to the movement of the probe 1.

(Use of the second embodiment)
By changing the volume data stored in the volume memory unit 32 of the apparatus main body 20, it can be applied to various uses. If, for example, past data of the same patient is held as volume data, it becomes easier to grasp the transition of the lesion by comparing and comparing the tomogram before treatment and the tomogram after treatment of the same section. If, for example, the data of a healthy person is stored as volume data, a lesion can be easily found by comparing and comparing the tomogram of the patient having the same cross section with the tomogram of the healthy person.

(Modification of the second embodiment)
This embodiment can be modified as shown in FIG. That is, the volume memory unit 32 stores data generated by scanning immediately before the patient currently under examination. The tomographic image data is sent from the B-mode digital scan converter 5 to the volume memory unit 32 and stored together with position information from the position detection device 24.

  Thus, if data collected immediately before the same patient, for example, is stored as volume data, scanning of the same cross section can be easily reproduced. That is, when a small lesion is found during diagnosis and stored in an image, an accurate scanning section may be uncertain even if scanning is attempted to confirm again. In such a case, a desired lesion can be found again by performing an operation in conjunction with the image stored immediately before.

(Other modifications of the second embodiment)
In this modification, data recorded in the volume memory unit 32 is data on occupied disease areas such as primary liver cancer, metastatic liver cancer, gallstones, and hemangiomas, or fetal data. These data may be data obtained by recording volume data of a diseased organ from an actual case and partially extracting the site, or may be created using highly accurate three-dimensional computer graphics or the like. Good.

  From this volume data, based on the position information of the real-time scanning section detected by the position detection device 24, partial tomographic image data of only the diseased organ relating to the same section as the scanning section is reconstructed. The reconstructed partial tomographic image data is inserted into the corresponding part of the tomographic image obtained in real time by the memory synthesis unit 6. This fitting process is performed by replacing the tomographic image data obtained in real time with the reconstructed partial tomographic image data. In addition, it is important not only to replace but also to synthesize several pixels at the boundary as if they are inserted into the organ of the subject under examination in real time by performing superposition or smoothing processing.

  It is also important that the image quality condition of the partial tomographic image data to be reconstructed is linked with the panel operation of the diagnostic apparatus so as to eliminate a sense of incongruity with the real-time tomographic image. Normally, the gain and dynamic range of the diagnostic image are changed by the operator using the operation panel and set by the B-mode digital scan converter 5. This information is simultaneously transmitted to the internal data digital scan converter 33, and the image quality of both can be changed in conjunction with each other.

  Position matching between the volume data and the real-time tomographic image is as described above. However, the main purpose of this modification is to use it for training in which screening is performed as if a lesion exists while observing a healthy subject. Therefore, the operator's position correction only sets the rough coordinates of the liver, and then the position information of the volume data for the reconstructed image can be set randomly within a range that does not deviate from the liver. To do. The volume memory unit 32 also has a function of being randomly selected from a plurality of types of data having different sizes and disease names stored therein.

  This makes it possible to perform training for searching for lesions and performing diagnosis for healthy subjects as subjects. In other words, if data of another patient who has become ill, for example, is stored as volume data, an effect can be obtained that can be used as an educational simulation for ultrasonic examinations for healthy individuals.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 is a block diagram showing a configuration of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. The schematic diagram which shows the general three-dimensional scan performed by moving the probe 1 of FIG. (A) is a diagram showing a point marker P1 designated at an arbitrary position on the real-time image via the trackball 22 or the like in FIG. 1, and (b) is a diagram of the point marker P1 detected by the position detection device 24 in FIG. The figure which shows a position. (A) is a diagram showing a trace line marker T1 freely drawn on a real-time image via the trackball 22 or the like of FIG. 1, and (b) is a trace line T1 of (a) and when it is drawn. The figure which shows cross point CP1, CP2 with a different scanning cross section, (c) is the cross-line marker CP1, CP2 displayed on the image corresponding to the scanning cross section of (b), and the trace line marker projected on the said scanning cross section The figure which shows PT1. FIG. 6 is a diagram showing another configuration example of the position detection circuit 24 in FIG. 1. The block diagram which shows the structure of the ultrasonic diagnosing device which concerns on 2nd Embodiment of this invention. 7 is a flowchart showing a procedure for matching the coordinate system of the volume data of the volume memory unit of FIG. 6 with the coordinate system of the position detection device 24. It is a supplementary figure of the position alignment process in connection with 2nd Embodiment, (a) is a figure which shows the parallel display example of the real-time image before alignment, and the image cut out from volume data, (b) is the real-time image before alignment And FIG. 8 is a view showing a parallel display example of an image cut out from volume data. The block diagram which shows the structure of the ultrasonic diagnosing device which concerns on the modification of 2nd Embodiment of this invention. It is a supplementary figure of the partial synthetic | combination process in connection with the other modification of 2nd Embodiment, (a) is a figure which shows the example of a display of the real-time image before a synthesis | combination, (b) is a region of interest extracted from volume data. The figure which shows an example of a partial image, (c) is a figure which shows the example of a synthetic | combination display by inserting the partial image of the region of interest cut out from the volume data in the real-time image.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Ultrasonic probe, 2 ... Ultrasonic transmission part, 2A ... Pulse generator, 2B ... Transmission delay circuit, 2C ... Pulser, 3 ... Ultrasonic reception part, 3A ... Preamplifier, 3B ... Reception delay circuit, 3C ... Adder DESCRIPTION OF SYMBOLS 4 ... Receiver part, 5 ... B-mode digital scan converter, 6 ... Memory composition part, 7 ... Display part, 8 ... Image memory unit, 9 ... Doppler unit, 20 ... Apparatus main body, 21 ... Operation panel, 22 ... Trackball , 23 ... keyboard, 24 ... position detection device, 25 ... coordinate memory unit, 26 ... digital scan converter for marker.

Claims (2)

Means for collecting echo signals by scanning a cross section inside the subject with an ultrasonic beam;
Means for generating a two-dimensional image based on the echo signal;
Means for holding three-dimensional volume data;
Means for detecting a position of a cross-section scanned with the ultrasonic beam;
Means for generating, from the volume data, a two-dimensional image of the same cross section as the cross section scanned with the ultrasonic beam based on the position information of the detected cross section;
An ultrasonic diagnostic apparatus comprising: means for simultaneously displaying a two-dimensional image generated from the echo signal and a two-dimensional image generated from the volume data. Means for collecting echo signals by scanning a cross section inside the subject with an ultrasonic beam;
Means for generating a two-dimensional image based on the echo signal;
Means for holding three-dimensional volume data;
Means for detecting a position of a cross-section scanned with the ultrasonic beam;
Means for generating a partial image in the same cross section as the cross section scanned with the ultrasonic beam from the volume data based on the position information of the detected cross section;
An ultrasonic diagnostic apparatus comprising: means for combining and displaying a partial image generated from the volume data on a two-dimensional image generated from the echo signal.

Images