Patent Publication Number: US-2021186464-A1

Title: Ultrasound diagnosis apparatus, method for displaying ultrasound image, and computer program product

Description:
TECHNICAL FIELD 
     The present invention relates to an ultrasound diagnosis apparatus, a method of displaying an ultrasonic image, and a computer program product. Further, the disclosed embodiments may relate to a method of generating and displaying an image representing microcalcified tissue in an ultrasound diagnosis apparatus. 
     BACKGROUND ART 
     Microcalcifications generated according to the accumulation of calcium in the human body cause disorders in organs or cardiovascular functions in the human body and manifest various diseases. In particular, it is known that microcalcified tissue present in the breast is highly likely to metastasize to malignant tumors, and thus a technique capable of detecting microcalcified tissue at an early stage is required to diagnose breast cancer early. 
     In microcalcification detection techniques according to the related art, X-ray images may be mainly used in consideration of the fact that calcareous materials absorb relatively little X-rays. However, this technique has disadvantages in that microcalcified tissue may not be detected in real time, user accessibility is degraded, and there is a potential risk (blood flow apoptosis, cancer expression, and DNA mutation) due to exposure of patients to radiation. Further, in clinically reading microcalcified tissue, evaluation of objectivity and standardized criterion are insufficient. 
     Meanwhile, an ultrasound diagnosis apparatus irradiates an object with an ultrasound signal generated from a transducer of a probe and receives information on the signal reflected from the object to obtain at least one image of a part (for example, soft tissue or blood flow) inside the object. 
     The ultrasound diagnosis apparatus has advantages in that the ultrasound diagnosis apparatus is harmless to the human body and may observe the internal structure and characteristics of the human body in a non-invasive manner. The ultrasound diagnosis apparatus may provide various types of clinical information (such as tissue shape, elasticity, blood flow rate, and the like). In particular, the ultrasound diagnosis apparatus may be used for observing microcalcifications or for real-time monitoring for a biopsy of the microcalcified tissue. In this case, a breast ultrasound or musculoskeletal ultrasound may be used. 
     DISCLOSURE 
     Technical Problem 
     Disclosed embodiments are for enabling an ultrasound diagnosis apparatus to display an image representing microcalcified tissue. 
     Technical Solution 
     One aspect of the present invention provides a method of displaying an ultrasonic image, the method including: acquiring first data by transmitting a first ultrasonic pulse to an object and by receiving an echo signal reflected from the object; acquiring second data by repeatedly performing, a plurality of times at predetermined time intervals, an operation of transmitting a second ultrasonic pulse different from the first ultrasonic pulse to the object and receiving an echo signal reflected from the object; detecting microcalcified tissue in the object by analyzing the second data; and displaying an ultrasonic image generated based on the first data and an image representing the detected microcalcified tissue. 
     Another aspect of the present invention provides an ultrasound diagnosis apparatus including: an ultrasonic transceiver configured to acquire first data by allowing a probe to transmit a first ultrasonic pulse to an object and receive an echo signal reflected from the object and configured to acquire second data by allowing the probe to repeatedly perform, a plurality of times at predetermined time intervals, an operation of transmitting a second ultrasonic pulse different from the first ultrasonic pulse to the object and receiving an echo signal reflected from the object; a controller configured to detect microcalcified tissue in the object by analyzing the second data; and a display unit configured to display an ultrasonic image generated based on the first data and an image representing the detected microcalcified tissue. 
     Still another aspect of the present invention provides a computer program product including a storage medium configured to store computer program code for performing the above-described method of displaying an ultrasonic image. 
     Advantageous Effects 
     According to the disclosed embodiments, an ultrasound diagnosis apparatus can accurately detect microcalcified tissue and can independently display only a microcalcification image or display an image representing a microcalcification by fusing the microcalcification image with an ultrasonic B mode image. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram illustrating a configuration of an ultrasound diagnosis apparatus according to an embodiment. 
         FIGS. 2A to 2C  are views illustrating ultrasound diagnosis apparatuses according to an embodiment. 
         FIG. 3  is a view illustrating a structure of an ultrasound diagnosis apparatus according to an embodiment. 
         FIG. 4  is a view illustrating a structure of a controller of the ultrasound diagnosis apparatus according to the embodiment. 
         FIGS. 5 to 7  are views for describing a pulse transmitted to detect a microcalcification according to the embodiment. 
         FIG. 8  is a view for describing spatiotemporal data generated according to the embodiment. 
         FIG. 9  is a view for describing characteristics of calcified tissue. 
         FIG. 10  is a view for describing a method of detecting microcalcified tissue according to the embodiment. 
         FIGS. 11 and 12  illustrate screens displayed on the ultrasound diagnosis apparatus according to the embodiment. 
         FIG. 13  is a flowchart illustrating a method of displaying an ultrasonic image according to the embodiment. 
     
    
    
     BEST MODE OF THE INVENTION 
     One aspect of the present invention provides a method of displaying an ultrasonic image, the method including: acquiring first data by transmitting a first ultrasonic pulse to an object and receiving an echo signal reflected from the object; acquiring second data by repeatedly performing, a plurality of times at predetermined time intervals, an operation of transmitting a second ultrasonic pulse different from the first ultrasonic pulse to the object and receiving an echo signal reflected from the object; detecting microcalcified tissue in the object by analyzing the second data; and displaying an ultrasonic image generated based on the first data and an image representing the detected microcalcified tissue. 
     Another aspect of the present invention provides an ultrasound diagnosis apparatus including: an ultrasonic transceiver configured to acquire first data by allowing a probe to transmit a first ultrasonic pulse to an object and receive an echo signal reflected from the object and configured to acquire second data by allowing the probe to repeatedly perform, a plurality of times at predetermined time intervals, an operation of transmitting a second ultrasonic pulse different from the first ultrasonic pulse to the object and receiving an echo signal reflected from the object; a controller configured to detect microcalcified tissue in the object by analyzing the second data; and a display unit configured to display an ultrasonic image generated based on the first data and an image representing the detected microcalcified tissue. 
     Still another aspect of the present invention provides a computer program product including a storage medium configured to store computer program code for performing the above-described method of displaying an ultrasonic image. 
     MODES OF THE INVENTION 
     The present specification describes the principles of the present invention and discloses embodiments such that the scope of the present invention may be clarified and those skilled in the art to which the present invention pertains may implement the present invention. The disclosed embodiments may be implemented in various forms. 
     Throughout the specification, the same reference numerals refer to the same components. The present specification does not describe all components of the embodiments, and general contents or duplicated contents between the embodiments in the technical field to which the present invention pertains will be omitted. Terms such as “part” or “portion” used in the specification may be implemented as software or hardware, and according to the embodiments, a plurality of “parts” or “portions” may be implemented as one unit or element, and one “part” or “portion” may include a plurality of units or elements. Hereinafter, the operating principles and embodiments of the present invention will be described with reference to the accompanying drawings. 
     In the present specification, an “image” may include a medical image obtained by a medical imaging apparatus such as a magnetic resonance imaging (MRI) device, a computed tomography (CT) device, an ultrasound imaging device, and an X-ray imaging device. 
     In the present specification, an “object” is to be photographed and may include a person, an animal, or a part thereof. For example, the object may include a part (organ) of a human body, a phantom, or the like. 
     Throughout the specification, an “ultrasonic image” means an image of the object, which is processed based on an ultrasonic signal transmitted to the object and reflected from the object. 
     Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a block diagram illustrating a configuration of an ultrasound diagnosis apparatus  100  according to an embodiment. The ultrasound diagnosis apparatus  100  may include a probe  20 , an ultrasonic transceiver  110 , a controller  120 , an image processing unit  130 , a display unit  140 , a storage unit  150 , a communication unit  160 , and an input unit  170 . 
     The ultrasound diagnosis apparatus  100  may be implemented as a portable type as well as a cart type. Examples of a portable ultrasound diagnosis apparatus may include a smart phone, a laptop computer, a personal digital assistant (PDA), a tablet personal computer (PC), and the like including a probe and an application, but the present invention is not limited thereto. 
     The probe  20  may include a plurality of transducers. The plurality of transducers may transmit ultrasonic signals to an object  10  according to a transmission signal applied from a transmission unit  113 . The plurality of transducers may receive ultrasonic signals reflected from the object  10  to form a reception signal. Further, the probe  20  may be implemented integrally with the ultrasound diagnosis apparatus  100  or may be implemented as a separate type in which the probe  20  is connected to the ultrasound diagnosis apparatus  100  in a wired or wireless manner. Further, the ultrasound diagnosis apparatus  100  may include one or more probes  20  according to an implementation form. 
     The controller  120  controls the transmission unit  113  to form a transmission signal to be applied to each of the plurality of transducers in consideration of the positions and focal points of the plurality of transducers included in the probe  20 . 
     The controller  120  controls a reception unit  115  to convert a reception signal received from the probe  20  in an analog-to-digital conversion manner and to sum the digitally converted reception signal in consideration of the positions and focal points of the plurality of transducers, thereby generating ultrasonic data. 
     The image processing unit  130  generates an ultrasonic image using the ultrasonic data generated by the ultrasonic reception unit  115 . 
     The display unit  140  may display the generated ultrasonic image and various pieces of information processed by the ultrasound diagnosis apparatus  100 . The ultrasound diagnosis apparatus  100  may include one or more display units  140  according to an implementation form. Further, the display unit  140  may be implemented as a touch screen in combination with a touch panel. 
     The controller  120  may control the overall operation of the ultrasound diagnosis apparatus  100  and a signal flow between internal components of the ultrasound diagnosis apparatus  100 . The controller  120  may include a memory that stores a program or data for performing a function of the ultrasound diagnosis apparatus  100  and a processor that processes the program or data. Further, the controller  120  may control the operation of the ultrasonic diagnosis device  100  by receiving a control signal from the input unit  170  or an external device. 
     The ultrasound diagnosis apparatus  100  may include the communication unit  160  and may be connected, through the communication unit  160 , to an external device (for example, a server, a medical device, a portable device (a smart phone, a tablet PC, a wearable device, and the like)). 
     The communication unit  160  may include one or more components enabling communication with the external device and may include, for example, at least one of a short-range communication module, a wired communication module, and a wireless communication module. 
     The communication unit  160  may transmit and receive the control signal to and from the external device. 
     The storage unit  150  may store various types of data or programs for driving and controlling the ultrasound diagnosis apparatus  100 , input/output ultrasonic data, acquired ultrasonic images, and the like. 
     The input unit  170  may receive a user&#39;s input for controlling the ultrasound diagnosis apparatus  100 . Although the user&#39;s input may include, for example, input obtained by manipulating a button, a keypad, a mouse, a trackball, a jog switch, a knob, and the like, input obtained by touching a touch panel or a touch screen, voice input, motion input, biometric information input (for example, iris recognition, fingerprint recognition, and the like), and the like, the present invention is not limited thereto. 
     Examples of the ultrasound diagnosis apparatus  100  according to the embodiment will be described through  FIGS. 2A to 2C . 
       FIGS. 2A to 2C  are views illustrating ultrasound diagnosis apparatuses according to an embodiment. 
     Referring to  FIGS. 2A and 2B , ultrasound diagnosis apparatuses  100   a  and  100   b  may each include a main display unit  121  and a sub display unit  122 . One of the main display unit  121  and the sub display unit  122  may be implemented as a touch screen. The main display unit  121  and the sub display unit  122  may display the ultrasonic image or various pieces of information processed by the ultrasound diagnosis apparatuses  100   a  and  100   b . Further, the main display unit  121  and the sub display unit  122  may be implemented as a touch screen and provide a graphical user interface (GUI) to receive data for controlling the ultrasound diagnosis apparatuses  100   a  and  100   b  from a user. For example, the main display unit  121  may display the ultrasonic image, and the sub display unit  122  may display a control panel for controlling the ultrasonic image in the form of the GUI. The sub display unit  122  may receive data for controlling the displaying of the image through the control panel displayed in the form of the GUI. The ultrasound diagnosis apparatuses  100   a  and  100   b  may control, using input control data, the displaying of the ultrasonic image displayed on the main display unit  121 . 
     Referring to  FIG. 2B , the ultrasound diagnosis apparatus  100   b  may further include a control panel  165  in addition to the main display unit  121  and the sub display unit  122 . The control panel  165  may include a button, a trackball, a jog switch, a knob, and the like, and may receive data for controlling the ultrasound diagnosis apparatus  100   b  from the user. For example, the control panel  165  may include a time gain compensation (TGC) button  171 , a freeze button  172 , and the like. The TGC button  171  is a button for setting a TGC value for each depth of the ultrasonic image. Further, when detecting the input of the freeze button  172  while scanning the ultrasonic image, the ultrasound diagnosis apparatus  100   b  may maintain a state in which a frame image at a corresponding time point is displayed. 
     Meanwhile, inputs of the button, the trackball, the jog switch, the knob, and the like included in the control panel  165  may be provided to the GUI in the main display unit  121  or the sub display unit  122 . 
     Referring to  FIG. 2C , the ultrasound diagnosis apparatus  100   c  may be implemented as a portable type. Examples of a portable ultrasound diagnosis apparatus  100   c  may include a smart phone, a laptop computer, a PDA, a tablet PC, and the like including a probe and an application, but the present invention is not limited thereto. 
     The ultrasound diagnosis apparatus  100   c  may include the probe  20  and a main body  40 , and the probe  20  may be connected to one side of the main body  40  in a wired or wireless manner. The main body  40  may include a touch screen  145 . The touch screen  145  may display the ultrasonic image, various pieces of information processed by the ultrasound diagnosis apparatus, the GUI, and the like. 
     Meanwhile, the ultrasound diagnosis apparatus according to the embodiment may provide various types of clinical information (such as tissue shape, elasticity, blood flow rate, and the like) including microcalcification. 
     The ultrasound diagnosis apparatus according to the embodiment may use a method of imaging the microcalcification using an image post-processing algorithm such as imaging the microcalcification using various channel data-based beamforming techniques or performing feature enhancement of only hyperechoic components. 
     However, when the ultrasound diagnosis apparatus uses a method of extracting a region suspected as the microcalcification through post-processing of the ultrasonic image, and when information (muscle, fat, blood flow, and the like) on various human tissues is mixed in a region of interest, there may be problems in that it is difficult to identify whether or not calcified tissue is present and it is impossible to independently detect only the microcalcified tissue. 
     When a user identifies the presence or absence of the calcified tissue in the object through images obtained by feature-enhancing the hyperechoic components and performs diagnosis, depending on the user who reads the ultrasonic image, the diagnosis agreement may be low, and it may be difficult to standardize the standard of diagnosis. Thus, a technique capable of automatically detecting the microcalcification quickly and accurately is required, and in particular, the development of a technique capable of independently detecting the microcalcification using an ultrasound diagnosis apparatus capable of obtaining an image in real time is required. 
       FIG. 3  is a view illustrating a structure of an ultrasound diagnosis apparatus capable of independently detecting microcalcification according to an embodiment. 
     An ultrasound diagnosis apparatus  300  according to the embodiment may include a probe  20 , an ultrasonic transceiver  310 , a controller  330 , and a display unit  340 . The description of the ultrasound diagnosis apparatus  100  of  FIG. 1  may be applied to each component of the ultrasound diagnosis apparatus  300  of  FIG. 3 . Thus, the duplicated description will be omitted. 
     The ultrasonic transceiver  310  transmits an ultrasonic pulse to the object through the probe  20  based on the control signal applied from the controller  330 , receives a radio frequency (RF) signal reflected from the object through the probe  20 , and outputs the RF signal to the controller  330 . 
     The ultrasonic transceiver  310  may acquire first data by allowing the probe  20  to transmit a first ultrasonic pulse to the object and receive an echo signal reflected from the object. The first ultrasonic pulse may be a pulse designed to acquire a B mode image. 
     The ultrasonic transceiver  310  may acquire second data by allowing the probe  20  to repeatedly perform, a plurality of times at predetermined time intervals, an operation of transmitting a second ultrasonic pulse different from the first ultrasonic pulse to the object and receiving an echo signal reflected from the object. 
     The second ultrasonic pulse may be a pulse designed based on characteristics of the microcalcified tissue. The second ultrasonic pulse may be a pulse having a sequence in which the magnitude of a waveform, the signal of a phase, a period, and the like are predefined to detect the microcalcification. 
     For example, the second ultrasonic pulse may be an asymmetric pulse in which a negative pressure component is dominant as compared to a positive pressure component and may be designed to have a wavelength longer than that of the first ultrasonic pulse. 
     The controller  330  may acquire, from the ultrasonic transceiver  310 , data including information on the echo signal reflected from the object. The controller  330  may acquire the first data and the second data from the ultrasonic transceiver  310 . The controller  330  may acquire RF channel data or complex baseband I/Q data that has passed through an analog-digital converter (ADC). 
     The controller  330  may detect the microcalcified tissue in the object by analyzing the second data. The controller  330  may reconstruct the second data into three-dimensional data including information on an axial depth, a lateral width, and a time, and analyze the three-dimensional data to extract the microcalcified tissue. The three-dimensional data may be spatiotemporal data using the axial depth, the lateral width, and time as axes. 
     For example, the controller  330  may estimate at least one of the intensity, the frequency, and the phase of the echo signal reflected from each region of the object by applying singular value decomposition (SVD) to the second data and may detect the microcalcified tissue in the object based on the estimated value. 
     The controller  330  may calculate, based on the second data, a variance of the phase change over time of the echo signal reflected from each region of the object and detect a region in which the variance of the phase change is larger than or equal to a predetermined value as the microcalcified tissue in the object. 
     The display unit  340  may display an ultrasonic image generated based on the first data and an image representing the detected microcalcified tissue. 
     The display unit  340  may independently display the ultrasonic image and the image representing the microcalcification in different regions. Further, the display unit  340  may display one image by fusing the B mode image of the cross-section of the object and the image representing the microcalcification. Further, the display unit  340  may display a region corresponding to the detected microcalcified tissue on the ultrasonic image that is the B mode image of the cross-section of the object. 
     The display unit  340  may display a color bar representing a plurality of colors corresponding to values representing the characteristics of the microcalcified tissue, select a color from the color bar based on a value representing the characteristics of the detected microcalcified tissue and may display the selected color on a region corresponding to the detected microcalcified tissue included in the ultrasonic image. For example, the values representing the characteristics of the microcalcified tissue may indicate the variance of the phase change over time of the echo signal reflected from the microcalcified tissue. 
       FIG. 4  is a view illustrating a controller  320  of the ultrasound diagnosis apparatus  300  according to the embodiment. 
     The controller  320  may include a pulse generation unit  410 , a spatiotemporal data acquisition unit  420 , an ultrasonic image generation unit  430 , a microcalcification detection unit  440 , and a microcalcification image generation unit  450 . Blocks  410 ,  420 ,  430 ,  440 , and  450  included in the controller  320  illustrated in  FIG. 4  may be individual hardware configurations or functional blocks implemented by the controller  320 . Thus, the operations of the blocks  410 ,  420 ,  430 ,  440 , and  450  described below may be performed by the controller  320 . 
     The pulse generation unit  410  may generate an ultrasonic pulse to be transmitted to the object through the probe  20 . The pulse generation unit  410  may control the ultrasonic transceiver  310  to form a transmission signal to be applied to each of the plurality of transducers in consideration of the positions and focal points of the plurality of transducers included in the probe  20 . The pulse generation unit  410  may control the ultrasonic transceiver  310  to transmit the ultrasonic pulse. 
     The pulse generation unit  410  may generate an ultrasonic pulse designed to acquire a Doppler image representing the motion of the object as well as a gray-scale ultrasonic image obtained by scanning the object according to an A mode (amplitude mode), a B mode (brightness mode), and an M mode (motion mode). 
     The pulse generation unit  410  according to the embodiment may generate a first ultrasonic pulse predesigned to acquire the B mode image. Further, the pulse generation unit  410  according to the embodiment may generate a second ultrasonic pulse predesigned to detect the microcalcification. The pulse generation unit  410  may generate a second ultrasonic pulse in which transmission parameters such as a sign, a magnitude, a phase, and a period of a waveform are determined in advance based on the characteristics of the microcalcification. 
     The second ultrasonic pulse transmitted by the ultrasound diagnosis apparatus  300  according to the embodiment to detect the microcalcification will be described in detail below with reference to  FIGS. 5 to 7 . 
     The pulse generation unit  410  according to the embodiment may generate, as the first ultrasonic pulse, an ultrasonic pulse having a positive pressure and a negative pressure which are symmetrical to each other and generate, as the second ultrasonic pulse, a pulse having a positive pressure and a negative pressure which are asymmetrical to each other. The pulse generation unit  410  according to the embodiment may improve microcalcification detection performance using the asymmetric ultrasonic pulse. 
     For example, as illustrated in  FIG. 5 , the asymmetric ultrasonic pulse may include a pulse having a dominant positive pressure as in a graph  510  or a pulse having a dominant negative pressure as in a graph  520 . The pulse illustrated in  FIG. 5  may be designed in the form in which a harmonic component is added to a transmission center frequency f 0  as in [Equation 1]. The harmonic component may be designed in the form in which a 2f 0  component is multiplied by the weight of a 0 . 
         f   n   =f   0 +2 f   0   a   0   [Equation 1]
 
     The ultrasonic pulse optimized for detection of the microcalcification may be designed based on experimental results of  FIGS. 6 and 7 . 
     A graph  600  of  FIG. 6  represents an average value of microcalcification signals received from the object when an ultrasonic pulse having a waveform illustrated in  FIG. 5  is applied to the object including a phantom simulating breast microcalcification. 
     The microcalcification signal may mean a signal of a microcalcification region extracted based on data obtained from the echo signal received from the object. According to the embodiment, the microcalcification signal may be obtained through a process illustrated in  FIGS. 8 and 10 , and a detailed method of obtaining the microcalcification signal will be described below. 
     A graph  610  of  FIG. 6  represents a change in the average value of the microcalcification signals received from the object when a transmission voltage of the ultrasonic pulse having a dominant positive pressure illustrated in the graph  510  of  FIG. 5  is increased. A graph  620  of  FIG. 6  represents a change in the average value of the microcalcification signals received from the object when a transmission voltage of the ultrasonic pulse having a dominant negative pressure illustrated in the graph  520  of  FIG. 5  is increased. 
     According to an experimental result illustrated in  FIG. 6 , it may be seen that when the ultrasonic pulse having a dominant negative pressure is used, a larger microcalcification signal is detected than in a case where the ultrasonic pulse having a dominant positive pressure. Thus, the pulse generation unit  410  according to the embodiment may preferably generate, as the second ultrasonic pulse, an ultrasonic pulse having a dominant negative pressure. 
     A graph  700  of  FIG. 7  represents an average value of the microcalcification signals received from the object when an ultrasonic pulse having a waveform illustrated in the graph  520  of  FIG. 5  is applied to the object including a phantom simulating breast microcalcification. 
     A graph  700  of  FIG. 7  represents a change in the average value of the microcalcification signals received from the object when the negative pressure of the ultrasonic pulse having a dominant negative pressure illustrated in the graph  520  of  FIG. 5  is increased. A graph  710  of  FIG. 7  represents a change in the average value of the microcalcification signals received from the object when the negative pressure of the ultrasonic pulse having a low frequency and a dominant negative pressure is increased. A graph  720  of  FIG. 7  represents a change in the average value of the microcalcification signals received from the object when the negative pressure of the ultrasonic pulse having a general frequency and a dominant negative pressure is increased. 
     According to an experimental result illustrated in  FIG. 7 , it may be seen that when the ultrasonic pulse having a low frequency (long wavelength), a larger microcalcification signal is detected than in a case where the ultrasonic pulse having a relatively high frequency (short wavelength) is used. Thus, the pulse generation unit  410  according to the embodiment may preferably generate, as the second ultrasonic pulse, an ultrasonic pulse having a wavelength that is longer than a predetermined value. Further, according to the experimental result illustrated in  FIG. 7 , it may be seen that as the negative pressure of the ultrasonic pulse increases, the average value of the microcalcification signals received from the object increases. Thus, the pulse generation unit  410  according to the embodiment may preferably generate, as the second ultrasonic pulse, an ultrasonic pulse having a negative pressure that is larger than a predetermined value. For example, the pulse generation unit  410  may generate, as the second ultrasonic pulse, an ultrasonic pulse having a negative pressure that is larger than the negative pressure of the first ultrasonic pulse. 
     Referring back to  FIG. 4 , a structure of the controller  320  of the ultrasound diagnosis apparatus  300  according to the embodiment will be described. 
     The spatiotemporal data acquisition unit  420  may reconstruct the ultrasonic data reflected from the object into spatiotemporal data including spatiotemporal information. The spatiotemporal data acquisition unit  420  may acquire the spatiotemporal data from the second data acquired from the echo signal reflected from the object in response to the second ultrasonic pulse. 
     The ultrasound diagnosis apparatus  300  may acquire the second data by repeatedly performing, a predefined number of times at predefined time intervals, an operation of transmitting the second ultrasonic pulse to the object  10  through the probe  20  and receiving the echo signal. The second data may include a plurality of pieces of image data acquired with respect to the cross-section of the object at a predetermined period, and each piece of image data may include spatial information on the cross-section of the object. 
     As illustrated in  FIG. 8 , the spatiotemporal data acquisition unit  420  may reconstruct three-dimensional data  801  including the information on the axial depth, the lateral width, and time by arranging, on a time axis, the plurality of pieces of image data included in the second data. Since the data acquired by the spatiotemporal data acquisition unit  420  includes both temporal information and spatial information, the data may be described as the spatiotemporal data. 
     The microcalcification detection unit  440  may independently detect the spatiotemporal data obtained from the spatiotemporal data acquisition unit  420  by distinguishing general tissue and the microcalcification from each other through spatiotemporal characteristic analysis. For example, the microcalcification detection unit  440  may independently detect the microcalcification signal by performing singular value decomposition on the spatiotemporal data. Further, the microcalcification detection unit  440  may perform independent microcalcification signal detection based on a power, an average frequency, a phase change, or the like of the microcalcification signal using an autocorrelation function. For example, the microcalcification detection unit  440  may use a microcalcification power estimation value based on the autocorrelation function. 
     The microcalcification detection unit  440  may separate and detect the microcalcification signal from the spatiotemporal data based on the characteristics of the microcalcification. For example, the microcalcification has a random phase change characteristic as compared to the general tissue. It is known that this is caused by the non-uniform nature of the surface of the calcified tissue. 
     A graph  910  of  FIG. 9  represents a phase change in signal of a blood flow region extracted based on the data acquired in response to the transmitted ultrasonic pulse when the ultrasonic pulse is transmitted to the object including a blood vessel a plurality of times. A graph  920  of  FIG. 9  represents a phase change in signal of a microcalcification region extracted based on the data acquired in response to the transmitted ultrasonic pulse when the ultrasonic pulse is transmitted to the object including a microcalcification a plurality of times. 
     As illustrated in  FIG. 9 , it may be seen that as compared to the general tissue such as blood flow, the phase change of the microcalcification is random (that is, distribution of the phase change is wide). The microcalcification detection unit  440  may separate and detect the microcalcification signal from the spatiotemporal data based on such phase change characteristics of the microcalcification. The microcalcification detection unit  440  may determine the microcalcified tissue when the variance of the phase change is larger than or equal to a predetermined value. 
       FIG. 10  is a view for describing a method of detecting microcalcified tissue by the microcalcification detection unit  440  according to the embodiment. 
     The microcalcification detection unit  440  may generate a Casorati matrix (x*Z, t) to arrange the data in a spatiotemporal manner based on the spatiotemporal data  1010  acquired by the spatiotemporal data acquisition unit  420  ( 1020 ). The microcalcification detection unit  440  may perform SVD on the generated Casorati matrix ( 1030 ). In this case, a U vector may denote data for spatial information, a V vector may denote data for temporal information, and a Σ vector may denote a rank of a singular value. 
     The microcalcification detection unit  440  may apply a spatiotemporal signal characteristic analysis function to an acquired singular value vector S. The spatiotemporal signal characteristic analysis function may include a covariance matrix analysis, an autocorrelation function, and the like. For example, the microcalcification detection unit  440  may acquire a spatiotemporal covariance matrix based on the acquired singular value vector S ( 1040 ). 
     The microcalcification detection unit  440  may separate and detect an independent microcalcification signal by analyzing spatiotemporal signal characteristics based on a result of applying the spatiotemporal signal characteristic analysis function. For example, the microcalcification detection unit  440  may detect, as the microcalcification signal, a signal in a region having a wide distribution of the phase change over time. 
     Referring back to  FIG. 4 , a structure of the controller  320  of the ultrasonic diagnosis apparatus  300  according to the embodiment will be described. 
     The ultrasonic image generation unit  430  may reconstruct an A mode image, a B mode image, an M mode image, a Doppler image, and the like, based on the data received in response to the ultrasonic pulse applied to the object. The ultrasonic image generation unit  430  according to the embodiment may generate the B mode image representing the cross-section of the object by reconstructing the first data received in response to the first ultrasonic pulse transmitted to the object. The ultrasonic image generation unit  430  may output the generated ultrasonic image to the display unit  340 . 
     The microcalcification image generation unit  450  may generate a microcalcification image by reconstructing, into a two-dimensional image, the microcalcification signal independently detected by the microcalcification detection unit  440 . The microcalcification image generation unit  450  may generate the microcalcification image on which a microcalcification region included in the cross-section of the object to which the ultrasonic pulse is transmitted is displayed. The microcalcification image generation unit  450  may apply various types of image post-processing to the generated microcalcification image. The microcalcification image generation unit  450  may output the generated microcalcification image to the display unit  340 . 
       FIGS. 11 and 12  illustrate screens displayed on the ultrasound diagnosis apparatus according to the embodiment. 
     As illustrated in  FIG. 11 , the display unit  340  may independently display an ultrasonic image  1110  generated by the controller  320  and an image  1130  representing the microcalcification in different regions on a screen  1100 . A region  1113  on the ultrasonic image  1110  is a region in which the microcalcification is concentrated in the object, and according to the diagnosis apparatus  300  according to the embodiment, the image  1130  on which only the microcalcification region is independently displayed may be generated and displayed. Similar to the ultrasonic image  1110 , it is identified that the microcalcifications are concentrated in a region  1133  on the image  1130 . 
     Meanwhile, the embodiments of the present disclosure are not limited to the embodiment illustrated in  FIG. 11 , and a screen in which the ultrasonic image and the image representing the microcalcification are fused may be displayed. 
     The display unit  340  may display an image, in which a region corresponding to the microcalcification is displayed on the ultrasonic image, by fusing the ultrasonic image and the image representing the microcalcification. For example, the region corresponding to the microcalcification may be displayed with any one of a predetermined color, a predetermined brightness, a predetermined figure, and a predetermined symbol on the ultrasonic image or may be displayed to flicker. 
     Further, the display unit  340  may further display a color bar representing a plurality of colors corresponding to the values representing the characteristics of the microcalcified tissue. The display unit  340  may select a color from the color bar based on a value representing the characteristics of the detected microcalcified tissue and may display the selected color in a region corresponding to the detected microcalcified tissue. However, the embodiments are not limited thereto, and various methods for representing the characteristics of the microcalcification in addition to the form of the color bar may be used. 
     For example, the values representing the characteristics of the microcalcified tissue may include the variance of the phase of the microcalcification signal acquired from the corresponding microcalcified tissue. In general, it is known that as the variance of the phase of the microcalcification signal increases, the probability of metastasis to a malignant tumor increases. Thus, the ultrasound diagnosis apparatus  300  according to the embodiment may increase breast cancer diagnosis accuracy by displaying the variance of the phase of the microcalcification signal corresponding to the microcalcified tissue together with the image representing the microcalcified tissue. 
       FIG. 12  illustrates an example of a screen on which the variance of the phase is displayed as a characteristic of the microcalcified tissue. 
     The display unit  340  may display, on the ultrasonic image, an image  1210  in which regions  1211 ,  1212 ,  1213 , and  1214  corresponding to the microcalcification are displayed. For example, the regions  1211 ,  1212 ,  1213 , and  1214  corresponding to the microcalcification may be displayed in predetermined colors on the ultrasonic image. 
     Further, the display unit  340  may further display a color bar  1230  representing the plurality of colors corresponding to the values representing the characteristics of the microcalcified tissue. A  FIG. 1220  of  FIG. 12  indicates that the variance of the phase of the microcalcification signal increases toward the top of the color bar  1230 . As illustrated in  FIG. 12 , the display unit  340  may display the region  1211 , the region  1212 , and the regions  1213  and  1214  using different colors selected from the color bar, based on a value representing the characteristics of the detected microcalcified tissue. 
       FIG. 13  is a flowchart illustrating a method of displaying an ultrasonic image according to the embodiment. 
     Operations of the method which will be described below may be performed by components of the ultrasound diagnosis apparatus  300  illustrated in  FIG. 3 . The above description related to the ultrasound diagnosis apparatus  300  will be also applied to each operation of the following method. 
     In operation  1310 , the ultrasound diagnosis apparatus  300  according to the embodiment may acquire the first data by transmitting the first ultrasonic pulse to the object and receiving the echo signal reflected from the object. 
     In operation  1320 , the ultrasonic diagnosis apparatus  300  according to the embodiment may acquire the second data by repeatedly performing, a plurality of times at predetermined time intervals, an operation of transmitting the second ultrasonic pulse different from the first ultrasonic pulse to the object and receiving the echo signal reflected from the object. 
     The second ultrasonic pulse may be a pulse designed based on characteristics of the microcalcified tissue. For example, the second ultrasonic pulse may be an asymmetric pulse in which a negative pressure component is dominant as compared to a positive pressure component and may have a wavelength longer than that of the first ultrasonic pulse. 
     In operation  1330 , the ultrasound diagnosis apparatus  300  according to the embodiment may detect the microcalcified tissue in the object by analyzing the second data. 
     The ultrasound diagnosis apparatus  300  may detect only the microcalcification signal, while independently distinguishing the microcalcification from the general tissue, by spatiotemporally analyzing a radio frequency (RF) signal or an I/Q signal received in response to the ultrasonic pulse transmitted to the object. a method of estimating a power, an average frequency, or a variance using the spatiotemporal signal characteristic analysis function (for example, the autocorrelation function) may be used as a method of detecting the microcalcification signal. 
     In detail, the ultrasound diagnosis apparatus  300  may reconstruct the second data acquired in operation S 1320  into the three-dimensional data including the information on the axial depth, the lateral width, and time. The ultrasound diagnosis apparatus  300  may extract the microcalcified tissue by analyzing the three-dimensional data. 
     The ultrasound diagnosis apparatus  300  may estimate at least one of the intensity, the frequency, and the phase of the echo signal reflected from each region of the object by applying the SVD to the second data and may detect the microcalcified tissue in the object based on the estimated value. 
     The ultrasound diagnosis apparatus  300  may calculate, based on the second data, the variance of the phase change over time of the echo signal reflected from each region of the object and detect a region in which the variance of the phase change is larger than or equal to a predetermined value as the microcalcified tissue in the object. 
     In operation  1340 , the ultrasound diagnosis apparatus  300  according to the embodiment may display the ultrasonic image generated based on the first data and the image representing the detected microcalcified tissue. 
     The ultrasound diagnosis apparatus  300  may generate the ultrasonic image by reconstructing the first data and generate the microcalcification image by reconstructing the microcalcification signal detected in operation  1330  for the purpose of displaying the microcalcification signal on a screen. 
     The ultrasound diagnosis apparatus  300  may individually display the ultrasonic image and the image representing the microcalcified tissue in different regions. Alternatively, the ultrasound diagnosis apparatus  300  may display one image by fusing the ultrasonic image and the image representing the microcalcified tissue. The ultrasound diagnosis apparatus  300  may display one image on which a region corresponding to the microcalcified tissue detected on the ultrasonic image is marked. 
     For example, the ultrasonic image generated based on the first data may be the B mode image representing the cross-section of the object, and the image representing the microcalcified tissue may be an image on which the location of the microcalcified tissue inside the cross-section is marked using color, contrast, a symbol, a figure, flickering, or the like. 
     The ultrasound diagnosis apparatus  300  may further display the color bar representing the plurality of colors corresponding to the values representing the characteristics of the microcalcified tissue. The ultrasound diagnosis apparatus  300  may select a color from the color bar based on a value representing the characteristics of the detected microcalcified tissue and may display the selected color in a region corresponding to the detected microcalcified tissue. For example, the values representing the characteristics of the microcalcified tissue may indicate the variance of the phase change over time of the echo signal reflected from the microcalcified tissue. 
     For example, the ultrasonic image generated based on the first data may be the B mode image representing the cross-section of the object, and the image representing the microcalcified tissue may be an image on which the location of the microcalcified tissue inside the cross-section is marked using color, contrast, a symbol, a figure, flickering, or the like. 
     The disclosed embodiments may be implemented as a software (S/W) program including a command stored in a computer-readable storage medium. 
     A computer, which is an apparatus capable of calling a stored command from a storage medium and operating according to the disclosed embodiments according to the called command, may include the ultrasound diagnosis apparatus according to the disclosed embodiments. 
     The computer-readable storage medium may be provided in the form of a non-transitory storage medium. Here, non-transitory means that the storage medium does not include a signal and is tangible but does not distinguish that data is semi-permanently or temporarily stored in the storage medium. 
     Further, the ultrasound diagnosis apparatus or method according to the disclosed embodiments may be included and provided in a computer program product. The computer program product may be traded between sellers and buyers as a product. 
     The computer program product may include a S/W program and a computer-readable storage medium in which the S/W program is stored. For example, the computer program product may include a product (for example, a downloadable application) in the form of a S/W program, which is electronically distributed through a manufacturer of the ultrasound diagnosis apparatus or an electronic market (for example, Google Play Store and App Store). For the electronic distribution, at least a part of the S/W program may be stored in the storage medium or may be temporarily generated. In this case, the storage medium may be a storage medium of a server of a manufacturer, a server of an electronic market, or a relay server temporarily storing the S/W program. 
     The computer program product may include a storage medium of a server or a storage medium of a terminal in a system including the server and the terminal (for example, the ultrasound diagnosis apparatus). Alternatively, when there is a third device (for example, a smartphone) that is communicatively connected to the server or terminal, the computer program product may include a storage medium of the third device. Alternatively, the computer program product may include the S/W program itself transmitted from the server to the terminal or the third device or transmitted from the third device to the terminal. 
     In this case, one of the server, the terminal, and the third device may execute the computer program product to perform the method according to the disclosed embodiments. Alternatively, two or more of the server, the terminal, and the third device may execute the computer program product to distribute and implement the method according to the disclosed embodiments. 
     For example, the server (for example, a cloud server, an artificial intelligence server, or the like) may execute the computer program product stored in the server to control the terminal communicatively connected to the server to perform the method according to the disclosed embodiments. 
     As another example, the third device may execute the computer program product to control the terminal communicatively connected to the third device to perform the method according to the disclosed embodiments. As a specific example, the third device may remotely control the ultrasound diagnosis apparatus to irradiate the object with the ultrasonic signal and generate an image of a part inside the object based on information on a signal reflected from the object. 
     As another example, the third device may execute the computer program product to directly perform the method according to the disclosed embodiment based on a value input from an auxiliary device (for example, a probe of a medical device). As a specific example, the auxiliary device may irradiate the object with the ultrasonic signal and acquire the ultrasonic signal reflected from the object. The third device may receive information on the reflected signal from the auxiliary device and may generate an image of a part inside the object based on the input information on the reflected signal. 
     When the third device executes the computer program product, the third device may download the computer program product from the server and execute the downloaded computer program product. Alternatively, the third device may execute the computer program product provided in a preloaded state to perform the method according to the disclosed embodiments.