Ultrasound diagnostic device and storage medium

Abstract

To provide techniques that can reduce the time required in analysis of ultrasound images.SOLUTION: An ultrasound diagnostic device is configured to: compare, with a threshold value Th, a pixel value of each pixel included in an ultrasound image Ui acquired at a current time point ti, so as to count the total number ai of pixels having a pixel value greater than the threshold value Th; if the total number ai of pixels is less than or equal to the maximum value amax of the total number of pixels obtained in the past, perform a peak hold for holding a peak value bi-1 at a time point ti-1 immediately preceding the current time point ti as a peak value bi at the current time point ti; set a time window W including the peak value bi of the current time point ti and a past peak value, and calculate a change amount ci at the current time point ti in the peak value based on a plurality of peak values included in the time window W; calculate an index value di of the current time point ti representative of the change amount ci at the current time point ti with respect to the peak value bi of the current time point ti; and determine whether the current time point ti is an initial arrival time TA of a contrast agent based on the index value di of the current time point ti and the maximum value dmax of the index values obtained in the past.SELECTED DRAWING: Figure 20

Description

[Technical Field]

[0001] The present invention relates to an ultrasound diagnostic apparatus that performs contrast imaging, and a storage medium that includes instructions that can be executed by the ultrasound diagnostic apparatus. [Background technology]

[0002] In ultrasound contrast examinations, a contrast agent is administered to the subject. There is a certain time difference between the time it takes for the contrast agent to reach tumors and normal tissue, and this time difference provides useful information for differential diagnosis. For example, portal vein blood flow is dominant in normal liver, but arterial blood is dominant in typical hepatocellular carcinoma (HCC). Therefore, when a contrast agent is administered, it reaches the HCC first, and the liver parenchyma is stained after the contrast agent reaches the HCC. A method for quantitatively presenting this time difference is known to use a time intensity curve (TIC) and parametric images. Parametric images are often used to display the arrival time of the contrast agent in color. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-094220 Summary of the Invention [Problem to be solved by the invention]

[0004] During a contrast-enhanced examination, the examiner scans the patient and acquires a series of ultrasound images in time sequence. After completing the contrast-enhanced examination, the examiner analyzes the acquired ultrasound images to determine the initial arrival time, which represents the time when the contrast agent first enters the examination area. Parametric images are then created based on the initial arrival time.

[0005] However, when determining the initial arrival time of the contrast agent, the user needs to carefully examine a series of ultrasound images acquired in the contrast examination, which poses a problem of time-consuming analysis of the ultrasound images.

[0006] Therefore, there is a demand for a technique that can reduce the time required to analyze ultrasound images. [Means for solving the problem]

[0007] A first aspect of the present invention is to compare a pixel value of each pixel included in a currently acquired ultrasound image with a threshold value, and count the total number of pixels having a pixel value greater than the threshold value; When the total number of pixels obtained for the current ultrasound image is greater than the maximum value of the total number of pixels obtained in the past, the total number of pixels obtained for the current ultrasound image is determined as a peak value, and when the total number of pixels obtained for the current ultrasound image is equal to or less than the maximum value of the total number of pixels obtained in the past, a peak hold is performed to hold the peak value at the time point immediately before the current time as the peak value at the current time point; setting a time window including the current peak value and past peak values, and calculating the current amount of change in the peak value based on the multiple peak values ​​included in the time window; calculating a current index value representing a current change from a current peak value; determining whether the current time is the initial arrival time of the contrast agent based on the current index value and the maximum index value obtained in the past; repeatedly performing the steps of counting the total number of pixels, performing the peak hold, calculating the amount of change, calculating the index value, and making the determination, and updating the initial arrival time of the contrast agent every time it is determined that the current time is the initial arrival time of the contrast agent; The ultrasound diagnostic device includes one or more processors that execute the above.

[0008] A second aspect of the present invention is a non-transitory computer-readable storage medium having instructions stored thereon, the non-transitory computer-readable storage medium comprising: The instructions, when executed by one or more processors, cause the one or more processors to: comparing the pixel value of each pixel included in the currently acquired ultrasound image with a threshold value, and counting the total number of pixels having a pixel value greater than the threshold value; When the total number of pixels obtained for the current ultrasound image is greater than the maximum value of the total number of pixels obtained in the past, the total number of pixels obtained for the current ultrasound image is determined as a peak value, and when the total number of pixels obtained for the current ultrasound image is equal to or less than the maximum value of the total number of pixels obtained in the past, a peak hold is performed to hold the peak value at the time point immediately before the current time as the peak value at the current time point; setting a time window including the current peak value and past peak values, and calculating the current amount of change in the peak value based on the multiple peak values ​​included in the time window; calculating a current index value representing a current change from a current peak value; determining whether the current time is the initial arrival time of the contrast agent based on the current index value and the maximum index value obtained in the past; repeatedly performing the steps of counting the total number of pixels, performing the peak hold, calculating the amount of change, calculating the index value, and making the determination, and updating the initial arrival time of the contrast agent every time it is determined that the current time is the initial arrival time of the contrast agent; A non-transitory computer-readable storage medium that causes the computer to execute the method. [Effects of the Invention]

[0009] In the present invention, an index value is calculated each time an ultrasound image is acquired, and it is determined whether the current time is the initial arrival time of the contrast agent based on the current index value and the maximum value of the past index values. Therefore, the initial arrival time of the contrast agent can be automatically detected in real time while a contrast examination of a subject is being performed. This eliminates the need for a user to analyze acquired ultrasound images to determine the initial arrival time of the contrast agent, thereby reducing the workload on the user during a contrast examination and shortening the time required to analyze ultrasound images. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram of an ultrasonic diagnostic device 1. [Figure 2] FIG. 10 is a diagram showing a curve G1 representing the total number of pixels stained with a contrast agent. [Figure 3] FIG. 10 is a diagram showing a peak hold curve G2 obtained by performing peak hold on the total number of pixels of the curve G1. [Figure 4] FIG. 10 is a diagram showing a change amount curve G3 representing the change amount of the peak value. [Figure 5] FIG. 10 is an explanatory diagram of a method for calculating a change amount c. [Figure 6] FIG. 10 is a diagram showing a curve G4 representing an index value. [Figure 7] FIG. 10 is a flowchart of a process for detecting the initial arrival time of a contrast agent. [Figure 8] FIG. 10 is an explanatory diagram of steps ST41 to ST47 when detecting the arrival time of a contrast agent based on an ultrasound image U1 at the current time t1. [Figure 9] FIG. 10 is an explanatory diagram of step ST41. [Figure 10] FIG. 10 is an explanatory diagram of steps ST41 to ST47 when detecting the arrival time of the contrast agent based on an ultrasound image U2 at the current time t2. [Figure 11] FIG. 10 is an explanatory diagram of a method for creating a parametric image E2 at time t2. [Figure 12] FIG. 10 is an explanatory diagram of step ST40 at the current time t3. [Figure 13] FIG. 10 is an explanatory diagram of a method for creating a parametric image E3 at time t3. [Figure 14] FIG. 10 is an explanatory diagram of step ST40 at time t4. [Figure 15] FIG. 10 is an explanatory diagram of step ST48. [Figure 16] FIG. 10 is an explanatory diagram of step ST40 at time t5. [Figure 17] FIG. 10 is an explanatory diagram of a method for creating a parametric image E5 at time t5. [Figure 18] FIG. 10 is an explanatory diagram of step ST40 at time t6. [Figure 19] FIG. 10 is an explanatory diagram of a method for creating a parametric image E6 at time t6. [Figure 20] FIG. 10 is an explanatory diagram of step ST40 at time t7. [Figure 21] FIG. 10 is an explanatory diagram of step ST48. [Figure 22] FIG. 10 is an explanatory diagram of step ST40 at time t8. [Figure 23] FIG. 10 is an explanatory diagram of a method for creating a parametric image E8 at time t8. [Figure 24] FIG. 10 is an explanatory diagram of step ST40 at time t9. [Figure 25] FIG. 10 is an explanatory diagram of a method for creating a parametric image E9 at time t9. [Figure 26] FIG. 10 is an explanatory diagram of step ST40 at time t10. [Figure 27] FIG. 10 is an explanatory diagram of a method for creating a parametric image E10 at time t10. [Figure 28] FIG. 10 is an explanatory diagram of step ST40 at time t11. [Figure 29] FIG. 10 is an explanatory diagram of a method for creating a parametric image E11 at time point t11. [Figure 30] FIG. 1 shows data obtained between time points t1 and t25. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a description will be given of an embodiment of the invention, but the present invention is not limited to the following embodiment.

[0012] FIG. 1 is a block diagram of an ultrasonic diagnostic device 1.

[0013] The ultrasound diagnostic device 1 includes an ultrasound probe 2, a transmit beamformer 3, a transmitter 4, a receiver 5, a receive beamformer 6, a processor 7, a display unit 8, a memory 9, and a user interface 10.

[0014] The ultrasound probe 2 has a plurality of transducer elements 2a arranged in an array. A transmit beamformer 3 and a transmitter 4 drive the plurality of transducer elements 2a arranged in the ultrasound probe 2, and ultrasound waves are transmitted from the transducer elements 2a. The ultrasound waves transmitted from the transducer elements 2a are reflected inside the subject, and the reflected echoes are received by the transducer elements 2a. The transducer elements 2a convert the received echoes into electrical signals and output these electrical signals as echo signals to the receiver 5. The receiver 5 performs predetermined processing on the echo signals and outputs them to the receive beamformer 6. The receive beamformer 6 performs receive beamforming on the signals received from the receiver 5 and outputs echo data.

[0015] The receive beamformer 6 may be a hardware beamformer or a software beamformer. If the receive beamformer 6 is a software beamformer, the receive beamformer 6 may include one or more processors, including one or more of: i) a graphics processing unit (GPU), ii) a microprocessor, iii) a central processing unit (CPU), iv) a digital signal processor (DSP), or v) another type of processor capable of performing logical operations. The processor(s) constituting the receive beamformer 6 may be separate from or comprised within the processor 7.

[0016] The ultrasound probe 2 may include electrical circuitry for performing all or part of the transmit beamforming and / or receive beamforming. For example, all or part of the transmit beamformer 3, transmitter 4, receiver 5, and receive beamformer 6 may be provided within the ultrasound probe 2.

[0017] The processor 7 controls the transmit beamformer 3, the transmitter 4, the receiver 5, and the receive beamformer 6. The processor 7 is also in electronic communication with the ultrasound probe 2. The processor 7 controls which transducer elements 2a are active and the shape of the ultrasound beam transmitted from the ultrasound probe 2. The processor 7 is also in electronic communication with the display 8. The processor 7 can process the echo data to generate an ultrasound image. The term "electronic communication" can be defined to include both wired and wireless communication. According to one embodiment, the processor 7 can include a central processing unit (CPU). According to other embodiments, the processor 7 can include one or more processors or other electronic components capable of performing processing functions, such as a digital signal processor, a field programmable gate array (FPGA), a graphics processing unit (GPU), or other types of processors. According to other embodiments, the processor 7 can include multiple electronic components capable of performing processing functions. For example, the processor 7 can include two or more electronic components selected from the list of electronic components including a central processing unit, a digital signal processor, a field programmable gate array, and a graphics processing unit.

[0018] The processor 7 may also include a complex demodulator (not shown) for demodulating the RF data. In alternative embodiments, the demodulation may be performed earlier in the processing chain.

[0019] The processor 7 can also generate various ultrasound images (e.g., B-mode images, color Doppler images, M-mode images, color M-mode images, spectral Doppler images, elastography images, TVI images, strain images, strain velocity images, etc.) based on data obtained by processing by the receive beamformer 6. One or more modules can also generate these ultrasound images.

[0020] The image beams and / or image frames may be stored and timing information indicating when the data was acquired in memory. The modules may include, for example, a scan conversion module that performs a scan conversion operation to convert the image frames from coordinate beam space to display space coordinates. A video processor module may be provided that reads the image frames from memory and displays the image frames in real time while a procedure is being performed on the subject. The video processor module may store the image frames in an image memory, and the ultrasound images may be read from the image memory and displayed on a display 8.

[0021] As used herein, the term "image" may broadly refer to both a visible image and data representing a visible image, and the term "data" may include raw data, which is ultrasound data before a scan conversion operation, and image data, which is data after a scan conversion operation.

[0022] The above-mentioned processing tasks handled by the processor 7 may be executed by a plurality of processors.

[0023] Furthermore, when the receive beamformer 6 is a software beamformer, the processing executed by the beamformer may be executed by a single processor or by multiple processors.

[0024] The display unit 8 is, for example, an LED (Light Emitting Diode) display unit, an LCD (Liquid Crystal Display), or an organic EL (Electro-Luminescence) display unit. The display unit 8 displays an ultrasound image.

[0025] The memory 9 is any known data storage medium. In one example, the ultrasound image display system includes a non-transitory storage medium and a transitory storage medium as memory. The ultrasound image display system may also include multiple memories. The non-transitory storage medium is a non-volatile storage medium such as a hard disk drive (HDD) or a read-only memory (ROM). The non-transitory storage medium may include a portable storage medium such as a compact disk (CD) or a digital versatile disk (DVD). The program executed by the processor 7 is stored in the non-transitory storage medium. The transitory storage medium is a volatile storage medium such as a random access memory (RAM).

[0026] The memory 9 stores one or more instructions executable by the processor 7. The one or more instructions cause the processor 7 to perform various operations.

[0027] The processor 7 can also be configured to be connected to an external storage device via a wired or wireless connection. In this case, the instructions to be executed by the processor 7 can be stored in both the memory 9 and the external storage device.

[0028] The user interface 10 can accept input from a user (e.g., an operator). For example, the user interface 10 accepts input of instructions and information from the user. The user interface 10 includes a keyboard, hard keys, a trackball, a rotary control, soft keys, etc. The user interface 10 may also include a touch screen that displays soft keys, etc.

[0029] The ultrasonic diagnostic apparatus 1 is configured as described above.

[0030] Before specifically describing the embodiment of the ultrasound diagnostic apparatus 1, the basic principle of the method for detecting the arrival time of the contrast agent in this embodiment will be described.

[0031] 2 to 6 are explanatory diagrams of the basic principle of a method for detecting the arrival time of a contrast agent.

[0032] 2 shows a curve G1. The horizontal axis represents time, and the vertical axis represents the total number of pixels stained with contrast agent among the multiple pixels included in the ultrasound image. Therefore, the curve G1 roughly represents how the total number of pixels stained with contrast agent changes over time.

[0033] The time t0 represents the start of the scan. The contrast agent can be administered immediately before the scan start time t0, simultaneously with the scan start time t0, or immediately after the scan start time t0. Immediately after the start of the scan, the contrast agent has not yet flowed into the examination area, so the total number of pixels stained by the contrast agent, a, is zero. However, as the contrast agent begins to flow into the examination area over time, the total number of pixels stained by the contrast agent increases rapidly, causing the curve to rise sharply. The time t at which this curve begins to rise sharply 10 represents the initial arrival time TA of the contrast agent. After the initial arrival time TA of the contrast agent has elapsed, the total number a of pixels stained by the contrast agent increases, and at the time t40 At time t, the curve G1 reaches a peak, and the contrast agent gradually flows out of the examination region, so the total number of pixels stained by the contrast agent decreases over time.

[0034] As described above, when the contrast agent starts to flow into the examination region, the total number of pixels stained by the contrast agent increases rapidly. Therefore, the time t 10 If we can identify the time t 10 can be considered as the initial arrival time TA of the contrast agent.

[0035] However, even after the initial arrival time TA of the contrast agent has passed, the total number of pixels a continues to increase and decrease. Therefore, even after the initial arrival time TA has passed, there appears a time point at which the total number of pixels a stained by the contrast agent suddenly increases. For example, at time t 40 ~Time t 60 Referring to the time t 40 Since the following represents the time phase in which the contrast agent flows out of the examination area, the total number of pixels a decreases with time. However, the total number of pixels a does not decrease monotonically, but rather decreases while repeatedly increasing and decreasing, so at time t 40 ~Time t 60 During this time, the total number of pixels stained by the contrast agent increases rapidly (for example, at time t 50 ) appears.

[0036] Therefore, in order to determine the initial arrival time TA of the contrast agent, a sudden increase in the total number of pixels occurring at the initial arrival time TA of the contrast agent and a time point t 40 ~Time t 60 Therefore, in order to make this distinction, the inventors of the present application came up with the idea of ​​performing peak hold on the total number a of pixels of curve G1 (see FIG. 3).

[0037] FIG. 3 is a diagram showing a peak hold curve G2 obtained by performing peak hold on the total number of pixels of the curve G1 (note that details of peak hold will be explained later in FIG. 10 and the like).

[0038] The peak hold curve G2 is the initial arrival time TA of the contrast agent (time t 10 ), there is a steep rise, but at time t 40 After the total number of pixels a reaches its maximum value at time t, the value is maintained at the same value regardless of whether the total number of pixels a increases or decreases. 10 and the change in the peak value in the vicinity, and the time t 40 ~t 60 A clear difference appears in the amount of change in peak value at . To make this difference easier to understand, a change curve G3 that represents the amount of change in peak value is shown in Figure 4.

[0039] The change amount c of the change amount curve G3 can be calculated based on the peak hold curve G2. Fig. 5 is an explanatory diagram of a method for calculating the change amount c. For example, i The change in c i Let us consider the case where the change c i When calculating the peak hold curve G2, a time window W having a predetermined time width is set. This time window W is set at the time t i-k ~t i The (k+1) peak values ​​b i-k ~b i At time t i The change in c i is the (k+1) peak value b i-k ~b i It can be calculated as the change (slope) of

[0040] Returning to Figure 4, the explanation continues.

[0041] Therefore, referring to the change curve G3, at time t 10 The change at time t 40 After that, the amount of change becomes zero. Therefore, by analyzing the value of the change amount curve G3, the initial arrival time TA(t 10 ) at time t 40 ~t 60It is possible to distinguish between

[0042] However, in the change curve G3, the initial arrival time TA(t 10 ) as well as at time t 20 and time t 30 Therefore, the initial arrival time TA(t 10 ) is determined by the initial arrival time TA(t 10 ) and time t 20 and time t 30 It is necessary to distinguish between the peak value b and the amount of change c. Therefore, in order to make this distinction, the inventors of the present application came up with the idea of ​​calculating an index value that reflects both the peak value b and the amount of change c. Figure 6 shows a curve G4 that represents the index value. This index value can be calculated using the following formula (1). d i =c i / b i (1) where d i is the time t i The index value at c i is the time t i The change in b i is the time t i Therefore, the peak value b i The larger the index value d i The initial arrival time of the contrast agent TA(t 10 ) is the time phase when the contrast agent starts to flow into the examination area, so the initial arrival time TA(t 10 ) the peak value b i Therefore, the initial arrival time of the contrast agent TA(t 10 ) the index value d i On the other hand, at time t 20 and time t 30 In this case, the area stained by the contrast agent is expanded, so the peak value b i Therefore, the index value d i is the initial arrival time of the contrast agent TA(t 10) and reaches a maximum value at the initial arrival time TA(t 10 ) and thereafter, the index value d i By calculating the initial arrival time of the contrast agent TA(t 10 ) at time t 20 and time t 30 can be distinguished from.

[0043] It should be noted that even before the contrast agent arrives, there are pixels with high brightness due to the properties of the tissue. These pixels with high brightness exhibit the same behavior as if they were stained with a contrast agent, even if they are not stained with a contrast agent. Therefore, referring to the index value curve G4, before the contrast agent arrives (at time t 10 (before) time t 100 and t 200 In this case, the index value d 100 and d 200 However, the contrast agent has not yet arrived at the time t 100 and t 200 The index value d 100 and d 200 is the initial arrival time of the contrast agent TA(t 10 ) index value d 10 Therefore, the initial arrival time of the contrast agent TA(t 10 ) index value d 10 The index value d 100 and d 200 can be distinguished from

[0044] Therefore, as mentioned above, the index value d i By calculating the above index value d, it is possible to identify the initial arrival time of the contrast agent. i This paper describes a method for detecting the initial arrival time of a contrast agent using the method.

[0045] FIG. 7 is a flow diagram of the process for detecting the initial arrival time of the contrast agent.

[0046] Please note that in the following explanation, priority is given to making the characteristics of the embodiment easier to understand, and the number of data and the values ​​of each data are different from the number of data and data values ​​of an actual contrast examination.

[0047] In step ST10, a contrast agent is administered to the subject.

[0048] In step ST20, i is set to an initial value (i=1). i is set to a time t i , ultrasound image U i , the total number of pixels a i , peak value b i , change amount c i , and the index value d i After setting i to i=1, the process proceeds to step ST30.

[0049] In step ST30, the processor i In ultrasound image U i In this case, since i=1, it is determined whether an ultrasound image U1 has been acquired at the current time t1. If it is determined that an ultrasound image U1 has been acquired at the current time t1, the process proceeds to step ST40.

[0050] In step ST40, a process of detecting the arrival time of the contrast agent is executed based on the ultrasound image U1 at the current time t1.

[0051] Since step ST40 includes steps ST41 to ST47, each step will be explained in order.

[0052] FIG. 8 is an explanatory diagram of steps ST41 to ST47 when detecting the arrival time of the contrast agent based on the ultrasound image U1 at the current time t1.

[0053] In step ST41, the processor counts the total number a1 of pixels whose pixel values ​​exceed a threshold value TH among the plurality of pixels included in the ultrasound image U1 acquired at the current time t1 (see FIG. 9).

[0054] FIG. 9 is an explanatory diagram of step ST41.

[0055] The processor compares the pixel values of each of the plurality of pixels P1 to P included in the ultrasonic image U1 with the threshold value Th. If the pixel value exceeds the threshold value Th, it is determined that the pixel is shaded by the contrast agent. On the other hand, if the pixel value is less than or equal to the threshold value Th, it is determined that the pixel is not shaded by the contrast agent. In the present embodiment, the threshold value Th is determined based on the maximum value M of the pixel values that each pixel can display. Specifically, the threshold value Th is determined based on the following equation. z の各々の画素値を閾値Thと比較し、画素値が閾値Thを超えている画素は、造影剤により染影されていると判断し、一方、画素値が閾値Th以下である画素は、造影剤により染影されていないと判断する。本実施形態では、各画素が表示できる画素値の最大値Mに基づいて、閾値Thを決定している。具体的には、以下の式に基づいて、閾値Thを決定している。

[0056] Th = k·M Here, k is a coefficient that takes a value within the range of 0 < k < 1.

[0057] The value of k can be determined based on the actual pixel value of the pixel when the pixel is shaded by the contrast agent. For example, k can be set to k = 0.3. Assuming that the maximum value M is M = 255 and k = 0.3, the threshold value Th can be set to Th = 76.5.

[0058] Therefore, when the pixel value is smaller than the threshold value Th, the processor can determine that the contrast agent has not reached the pixel, and when the pixel value exceeds the threshold value Th, the processor can determine that the contrast agent has reached the pixel. For this reason, the processor can obtain the total number of pixels considered to have been reached by the contrast agent by counting the total number of pixels having pixel values greater than the threshold value Th among the pixels P1 to P. Here, it is assumed that all pixels of the ultrasonic image U1 have pixel values smaller than the threshold value Th. Therefore, with respect to the ultrasonic image U1, the processor determines that the total number a1 of pixels exceeding the threshold value Th is a1 = 0. FIG. 8 shows the total number a1 (= 0) of pixels at the time point t1 determined in step ST41. When the total number a1 of pixels is determined, the process proceeds to step ST42. z のうち、閾値Thより大きい画素値を有する画素の総数をカウントすることにより、造影剤が到達したと考えられる画素の総数を求めることができる。ここでは、超音波画像U1のどの画素も閾値Thより小さい画素値を有しているとする。したがって、超音波画像U1に関しては、プロセッサは、閾値Thを超えた画素の総数a1を、a1=0と決定する。図8に、ステップST41で決定された時点t1における画素の総数a1(=0)を示す。画素の総数a1が決定されると、ステップST42に進む。

[0059] In step ST42, the processor performs peak hold on the total number of pixels a1 at the current time t1 to determine a peak value b1. Since there is no data on the total number of pixels obtained at past times at the current time t1, the processor sets the total number of pixels a1 at the current time t1 as the peak value b1 at the current time t1. In other words, it determines b1 = a1. Once the peak value b1 has been determined, the process proceeds to step ST43.

[0060] At time t1, only one peak value data point (peak value b1) has been acquired. In this case, the process of step ST43 cannot be performed, so the process proceeds to step ST47 without proceeding to step ST43.

[0061] In step ST47, the processor determines an initial value of the initial arrival time TA of the contrast agent. Here, the initial value of the initial arrival time TA of the contrast agent is determined to be TA=t1. After determining TA=t1, the process proceeds to step ST48.

[0062] In step ST48, the processor increments i from i = 1 to i = 2. After incrementing i, the process returns to step ST30.

[0063] In step ST30, the processor i In ultrasound image U i Here, since i has been incremented to i=2, it is determined whether an ultrasound image U2 has been acquired at the current time t2. If it is determined that an ultrasound image U2 has been acquired at the current time t2, the process proceeds to step ST40.

[0064] In step ST40, a process of detecting the arrival time of the contrast agent is executed based on the ultrasound image U2 at the current time t2.

[0065] FIG. 10 is an explanatory diagram of steps ST41 to ST47 when detecting the arrival time of the contrast agent based on the ultrasound image U2 at the current time t2.

[0066] In step ST41, the processor determines the total number a2 of pixels at time point t2. The method for calculating the total number of pixels is the same as the method described with reference to Fig. 9. Here, it is assumed that a2 = 0, as at time point t1. Once the total number a2 of pixels has been calculated, the process proceeds to step ST42.

[0067] In step ST42, the processor performs peak hold on the total number a2 of pixels at the current time t2 to determine a peak value b2. Specifically, the processor determines the peak value b2 as follows.

[0068] The processor calculates the total number a2 of pixels obtained for the ultrasound image U2 at the current time t2 and the maximum value a2 of the total number of pixels obtained in the past. max Then, the total number a2 of pixels obtained for the ultrasound image U2 at the current time t2 is compared with the maximum value a of the total number of pixels obtained in the past. max If a2>a max ), the processor determines the total number a2 of pixels obtained for the ultrasound image U2 at the current time t2 as the peak value b2. On the other hand, if the total number a2 of pixels obtained for the ultrasound image U2 at the current time t2 is smaller than the maximum value a of the total number of pixels obtained in the past, max In the following case (a2≦a max ), the peak value b1 at time t1 is held as the peak value b2 at the current time t2.

[0069] Here, the total number of pixels a2 at time t2 is the maximum value a of the total number of pixels obtained in the past. max (i.e., it is the same as a1). Therefore, a2≦a max Therefore, the processor holds the peak value b1 at time t1 as the peak value b2 at the current time t2. Therefore, the peak value b2 is determined as b2 = b1 = 0. After determining the peak value b2, the process proceeds to step ST43.

[0070] In step ST43, the change amount c2 of the peak value at time t2 is calculated. As explained with reference to FIG. 5, the change amount is calculated by dividing the (k+1) peak values ​​b included in the time window W having a predetermined time width.i-k ~b i Here, for convenience of explanation, k is set to 1. That is, in this embodiment, the time window W is calculated based on two peak values ​​(i.e., the current time t i Peak value b at i and the current time t i The previous time point t i-1 Peak value b at i-1 ) and has a time span including the

[0071] Therefore, when calculating the amount of change c2 at time t2, the processor sets a time window W including two data points (i.e., a time window including peak value b2 at the current time t2 and peak value b1 at the time t1 immediately before the current time t2), and calculates the amount of change c2 between the two data points b1 and b2 included in the time window W. Here, b2=b1, so the amount of change c2 is c2=0. After calculating the amount of change c2, the processor proceeds to step ST44.

[0072] In step ST44, the index value d2 at the current time t2 is calculated. i The index value d i is d i =c i / b i Therefore, the index value d2 at the current time t2 can be calculated as d2=c2 / b2. Here, c2=0, so d2=0. After calculating the index value d2, the process proceeds to step ST45.

[0073] In step ST45, the processor i The index value d i and the maximum value of the past index value d max Whether to update the initial arrival time of the contrast agent is determined based on the above. Here, since only one index value (index value d2) has been calculated so far, no past index values ​​exist. In this case, the process proceeds to step ST50.

[0074] In step ST50, the processor creates a parametric image at time t2. A parametric image is an image in which pixels reached by the contrast agent are assigned a color corresponding to the arrival time of the contrast agent. FIG. 11 is an explanatory diagram of a method for creating a parametric image E2 at time t2. At time t2, the total number a2 of pixels exceeding the threshold value TH is a2=0. In this case, since there are no pixels stained with the contrast agent, the ultrasound image U1 at time t1 is displayed as is as the parametric image E2 at the current time t2. After displaying the parametric image E2, the process proceeds to step ST60.

[0075] In step ST60, it is determined whether the test has been completed. Here, since the test has not been completed yet, the process proceeds to step ST49.

[0076] In step ST49, the processor increments i. Here, since i=2, it increments i to 3. Then, the process returns to step ST30.

[0077] In step ST30, the processor i In ultrasound image U i Here, since i has been incremented to i=3, it is determined whether an ultrasound image U3 has been acquired at the current time t3. If it is determined that an ultrasound image U3 has been acquired at the current time t3, the process proceeds to step ST40.

[0078] In step ST40, a process of detecting the arrival time of the contrast agent is executed based on the ultrasound image U3 at the current time t3.

[0079] FIG. 12 is an explanatory diagram of step ST40 (steps ST41 to ST47) at the current time t3.

[0080] In step ST41, the processor determines the total number of pixels a3 at time point t3. The method for calculating the total number of pixels is the same as the method described with reference to Fig. 9. Here, it is assumed that a3 = 0, as at time point t2. Once the total number of pixels a3 has been calculated, the process proceeds to step ST42.

[0081] In step ST42, the processor performs peak hold on the total number a3 of pixels at the current time t3 to determine a peak value b3. Specifically, the processor determines the peak value b3 as follows.

[0082] The processor calculates the total number a3 of pixels obtained for the ultrasound image U3 at the current time t3 and the maximum value a3 of the total number of pixels obtained in the past. max Then, the total number a3 of pixels obtained for the ultrasound image U3 at the current time t3 is compared with the maximum value a of the total number of pixels obtained in the past. max If a3>a max ), the processor determines the total number a3 of pixels obtained for the ultrasound image U3 at the current time t3 as the peak value b3. On the other hand, if the total number a3 of pixels obtained for the ultrasound image U3 at the current time t3 is smaller than the maximum value a of the total number of pixels obtained in the past, max In the following case (a3≦a max ), the peak value b2 at time t2 is held as the peak value b3 at the current time t3.

[0083] Here, the total number of pixels a3 at time t3 is the maximum value a of the total number of pixels obtained in the past. max (i.e., a1 and a2 are the same). Therefore, a3≦a max Therefore, the processor stores the peak value b2 at time t2 as the peak value b3 of the total number of pixels at the current time t3. Therefore, the peak value b3 is determined as b3 = b2 = 0. After determining the peak value b3, the process proceeds to step ST43.

[0084] In step ST43, the change amount c3 of the peak value at time t3 is calculated. Specifically, the processor sets a time window W including the number of data points at two points (i.e., a time window including the peak value b3 at the current time t3 and the peak value b2 at the time t2 immediately before the current time t3), and calculates the change amount c3 of the two points of data b2 and b3 included in the time window W. Here, since b2=b3, the change amount c3 of the peak value is c3=0. After calculating the change amount c3 of the peak value, the process proceeds to step ST44.

[0085] In step ST44, an index value d3 at the current time t3 is calculated. The index value d3 at the current time t3 can be calculated as d3=c3 / b3. Here, c3=0, so d3=0. After calculating the index value d3, the process proceeds to step ST45.

[0086] In step ST45, the processor i The index value d i and the maximum value of the past index value d max Based on the current time t i Here, we determine whether the current time t i is the time t3, the processor calculates the index value d3 at the current time t3 and the maximum value d max Specifically, the processor determines whether the current time t3 is the initial arrival time of the contrast agent based on the index value d3 at the current time t3 and the maximum value d max Then, the processor compares the index value d3 at the current time t3 with the maximum value d max If it exceeds (d3>d max ), it is determined that the current time t3 is the initial arrival time of the contrast agent, and the process proceeds to step ST46, where the initial arrival time TA of the contrast agent is updated from time t1 to time t3. On the other hand, if the index value d3 at the current time t3 is equal to the maximum value d max If it does not exceed (d3≦d max ), the processor determines that the current time t3 is not the initial arrival time of the contrast agent, and proceeds to step ST50 without updating the initial arrival time TA of the contrast agent.

[0087] Here, d3=d2=0, so d3≦d max Therefore, the processor determines that the number of pixels stained by the contrast agent has not increased rapidly, and proceeds to step ST50 without updating the initial arrival time TA of the contrast agent.

[0088] In step ST50, the processor creates a parametric image at time t3. FIG. 13 is an explanatory diagram of a method for creating a parametric image E3 at time t3. At time t3, the total number a3 of pixels exceeding the threshold TH is a3=0. In this case, since there are no pixels stained with contrast agent, the parametric image E2 at time t2 is displayed as is as the parametric image E3 at the current time t3. After displaying the parametric image E3, the process proceeds to step ST60.

[0089] In step ST60, it is determined whether the test has been completed. Here, since the test has not been completed yet, the process proceeds to step ST49.

[0090] In step ST49, the processor increments i. Here, since i=3, it increments i to 4. Then, the process returns to step ST30.

[0091] In step ST30, the processor i In ultrasound image U i In this case, since i has been incremented to i=4, it is determined whether an ultrasound image U4 has been acquired at the current time t4. If it is determined that an ultrasound image U4 has been acquired at the current time t4, the process proceeds to step ST40.

[0092] In step ST40, a process of detecting the arrival time of the contrast agent is executed based on the ultrasound image U4 at the current time t4.

[0093] FIG. 14 is an explanatory diagram of step ST40 (steps ST41 to ST47) at time point t4.

[0094] In step ST41, the processor determines the total number of pixels a4 at time t4. The method for calculating the total number of pixels is the same as the method described with reference to FIG. 9. Here, it is assumed that a4>a1 to a3. Therefore, the ultrasound image U4 at time t4 includes pixels whose pixel values ​​exceed the threshold value Th. Once the total number of pixels a4 is calculated, the process proceeds to step ST42.

[0095] In step ST42, the processor performs peak hold on the total number a4 of pixels at the current time t4 to determine a peak value b4. Specifically, the processor determines the peak value b4 as follows.

[0096] The processor calculates the total number a4 of pixels obtained for the ultrasound image U4 at the current time t4 and the maximum value a4 of the total number of pixels obtained in the past. max Then, the total number a4 of pixels obtained for the ultrasound image U4 at the current time t4 is compared with the maximum value a of the total number of pixels obtained in the past. max If a4>a max ), the processor determines the total number a4 of pixels obtained for the ultrasound image U4 at the current time t4 as the peak value b4. On the other hand, if the total number a4 of pixels obtained for the ultrasound image U4 at the current time t4 is smaller than the maximum value a4 of the total number of pixels obtained in the past, max In the following case (a4≦a max ), the peak value b3 at time t3 is held as the peak value b4 at the current time t4.

[0097] Here, the total number of pixels a4 at time t4 is the maximum value a of the total number of pixels obtained in the past. max (i.e., greater than a1 to a3). Therefore, a4>a max Therefore, the processor determines the total number a4 of pixels obtained for the ultrasound image U4 at the current time t4 as the peak value b4. Therefore, the peak value b4 is determined as b4=a4(>0). After determining the peak value b4, the process proceeds to step ST43.

[0098] In step ST43, the processor calculates the amount of change c4 in the peak value at time t4. Specifically, the processor sets a time window W including the number of data points for two points (i.e., a time window including the peak value b4 at the current time t4 and the peak value b3 at the time t3 immediately before the current time t4), and calculates the amount of change c4 between the two data points b3 and b4 included in the time window W. The amount of change c4 can be calculated using the following formula.

[0099] c4=(b4-b3) / (t4-t3) After calculating the amount of change c4 at time t4, the process proceeds to step ST44.

[0100] In step ST44, an index value d4 at the current time t4 is calculated. The index value d4 at the current time t4 can be calculated by d4=c4 / b4. After calculating the index value d4, the process proceeds to step ST45.

[0101] In step ST45, the processor calculates the index value d4 at the current time t4 and the maximum value d max Specifically, the processor determines whether the current time t4 is the initial arrival time of the contrast agent based on the index value d4 at the current time t4 and the maximum value d max Then, the processor compares the index value d4 at the current time t4 with the maximum value d max If it exceeds (d4>d max ), it is determined that the current time t4 is the initial arrival time of the contrast agent, and the process proceeds to step ST46, where the initial arrival time TA of the contrast agent is updated from time t1 to time t4. On the other hand, if the index value d4 at the current time t4 is equal to the maximum value d max If it does not exceed (d4≦d max ), the processor determines that the current time t3 is not the initial arrival time of the contrast agent, and proceeds to step ST50 without updating the initial arrival time TA of the contrast agent.

[0102] Here, d4>d maxTherefore, the process proceeds to step ST46, where the processor discards the previously determined initial arrival time TA (=t1) and updates the initial arrival time TA of the contrast agent from time t1 to time t4, and then proceeds to step ST48.

[0103] FIG. 15 is an explanatory diagram of step ST48.

[0104] The processor discards the parametric image E3 and sets the ultrasound image U4 at time t4 as the initial image of the parametric image. After setting the initial image of the parametric image, the process proceeds to step ST49.

[0105] In step ST49, the processor increments i. Here, since i=4, it increments i to 5. Then, the process returns to step ST30.

[0106] In step ST30, the processor i In ultrasound image U i Here, since i has been incremented to i=5, it is determined whether an ultrasound image U5 has been acquired at the current time t5. If it is determined that an ultrasound image U5 has been acquired at the current time t5, the process proceeds to step ST40.

[0107] In step ST40, a process of detecting the arrival time of the contrast agent is executed based on the ultrasound image U5 at the current time t5.

[0108] FIG. 16 is an explanatory diagram of step ST40 (steps ST41 to ST47) at time t5.

[0109] In step ST41, the processor determines the total number of pixels a5 at time t5. The method for calculating the total number of pixels is the same as the method described with reference to Fig. 9. Here, it is assumed that a5 = 0. Once the total number of pixels a5 has been calculated, the process proceeds to step ST42.

[0110] In step ST42, the processor performs peak hold on the total number a5 of pixels at the current time t5 to determine a peak value b5. Specifically, the processor determines the peak value b5 as follows.

[0111] The processor calculates the total number a5 of pixels obtained for the ultrasound image U5 at the current time t5 and the maximum value a5 of the total number of pixels obtained in the past. max Then, the total number a5 of pixels obtained for the ultrasound image U5 at the current time t5 is compared with the maximum value a of the total number of pixels obtained in the past. max If a5>a max ), the processor determines the total number a5 of pixels obtained for the ultrasound image U5 at the current time t5 as the peak value b5. On the other hand, if the total number a5 of pixels obtained for the ultrasound image U5 at the current time t5 is smaller than the maximum value a of the total number of pixels obtained in the past, max In the following case (a5≦a max ), the peak value b4 at the previous time point t4 is held as the peak value b5 at the current time point t5.

[0112] Here, the maximum value of the total number of pixels obtained in the past a max is a max = a4, and the total number of pixels a5 at time t5 is a5 = 0. Therefore, a5 ≦ a max Therefore, the processor holds the peak value b4 at the immediately previous time point t4 as the peak value b5 at the current time point t5, that is, determines that b5 = b4. After determining the peak value b5, the process proceeds to step ST43.

[0113] In step ST43, the processor calculates the amount of change c5 in the peak value at time t5. Specifically, the processor sets a time window W including two data points (i.e., a time window including the peak value b5 at the current time t5 and the peak value b4 at the time t4 immediately before the current time t5), and calculates the amount of change c5 between the two data points b4 and b5 included in the time window W. The amount of change c4 can be calculated using the following formula.

[0114] c5=(b5-b4) / (t5-t4) Since b5=b4, the calculation is c5=0. After calculating the amount of change c5 at time t5, the process proceeds to step ST44.

[0115] In step ST44, an index value d5 at the current time t5 is calculated. The index value d5 at the current time t5 can be calculated as d5=c5 / b5. Since c5=0, the calculation is d5=0. After calculating the index value d5, the process proceeds to step ST45.

[0116] In step ST45, the processor calculates the index value d5 at the current time t5 and the maximum value d max Specifically, the processor determines whether the current time t5 is the initial arrival time of the contrast agent based on the index value d5 at the current time t5 and the maximum value d max Then, the processor compares the index value d5 at the current time t5 with the maximum value d max If it exceeds (d5>d max ), it is determined that the current time t5 is the initial arrival time of the contrast agent, and the process proceeds to step ST46, where the initial arrival time TA of the contrast agent is updated from time t4 to time t5. On the other hand, if the index value d5 at the current time t5 is equal to the maximum value d max If it does not exceed (d5≦d max ), the processor determines that the current time t5 is not the initial arrival time of the contrast agent, and proceeds to step ST50 without updating the initial arrival time TA of the contrast agent.

[0117] Here, the maximum value of the past index value d max is d max = d4, and the index value d5 at time t5 is d5 = 0. Therefore, d5 ≦ d max Therefore, the processor determines not to update the initial arrival time TA of the contrast agent, but to maintain the previously determined initial arrival time TA (=t4), and proceeds to step ST50.

[0118] In step ST50, the processor creates a parametric image at time t5. FIG. 17 is an explanatory diagram of a method for creating a parametric image E5 at time t5. At time t5, the total number a5 of pixels exceeding the threshold TH is a5=0. In this case, since there are no pixels stained with contrast agent, the ultrasound image U4 at time t4 is displayed as is as the parametric image E5 at the current time t5. After displaying the parametric image E5, the process proceeds to step ST60.

[0119] In step ST60, it is determined whether the test has been completed. Here, since the test has not been completed yet, the process proceeds to step ST49.

[0120] In step ST49, the processor increments i. Here, since i=5, it increments i to 6. Then, the process returns to step ST30.

[0121] In step ST30, the processor i In ultrasound image U i In this case, since i has been incremented to i=6, it is determined whether an ultrasound image U6 has been acquired at the current time t6. If it is determined that an ultrasound image U3 has been acquired at the current time t6, the process proceeds to step ST40.

[0122] In step ST40, a process of detecting the arrival time of the contrast agent is executed based on the ultrasound image U3 at the current time t6.

[0123] FIG. 18 is an explanatory diagram of step ST40 (steps ST41 to ST47) at time t6.

[0124] In step ST41, the processor determines the total number a6 of pixels at time t6. The method for calculating the total number of pixels is the same as the method described with reference to Fig. 9. Here, it is assumed that a6 = 0. Once the total number a6 of pixels has been calculated, the process proceeds to step ST42.

[0125] In step ST42, the processor performs peak hold on the total number a6 of pixels at the current time t6 to determine a peak value b6. Specifically, the peak value b6 is determined as follows.

[0126] The processor calculates the total number a6 of pixels obtained for the ultrasound image U6 at the current time t6 and the maximum value a6 of the total number of pixels obtained in the past. max Then, the total number a6 of pixels obtained for the ultrasound image U6 at the current time t6 is compared with the maximum value a6 of the total number of pixels obtained in the past. max If a6>a max ), the processor determines the total number a6 of pixels obtained for the ultrasound image U6 at the current time t6 as the peak value b6. On the other hand, if the total number a6 of pixels obtained for the ultrasound image U6 at the current time t6 is smaller than the maximum value a6 of the total number of pixels obtained in the past, max In the following case (a6≦a max ), the peak value b5 at the previous time point t5 is held as the peak value b6 at the current time point t6.

[0127] Here, the maximum value of the total number of pixels obtained in the past a max is a max = a4, and the total number of pixels a6 at the current time t6 is a6 = 0. Therefore, a6 ≦ a max Therefore, the processor holds the peak value b5 at the immediately previous time point t5 as the peak value b6 at the current time point t6, that is, determines that b6=b6. After determining the peak value b6, the process proceeds to step ST43.

[0128] In step ST43, the processor calculates the amount of change c6 in the peak value at time t6. Specifically, the processor sets a time window W including the number of data points for two points (i.e., a time window including the peak value b6 at the current time t6 and the peak value b5 at the time t5 immediately before the current time t6), and calculates the amount of change c6 between the two data points b5 and b6 included in the time window. Here, since b5=b6, the amount of change c6 is c6=0. After calculating the amount of change c6, the processor proceeds to step ST44.

[0129] In step ST44, an index value d6 at the current time t6 is calculated. The index value d6 at the current time t6 can be calculated as d6=c6 / b6. Here, c6=0, so d6=0. After calculating the index value d6, the process proceeds to step ST45.

[0130] In step ST45, the processor calculates the index value d6 at the current time t6 and the maximum value d max Specifically, the processor determines whether the current time t6 is the initial arrival time of the contrast agent based on the index value d6 at the current time t6 and the maximum value d max Then, the processor compares the index value d6 at the current time t6 with the maximum value d max If it exceeds (d6>d max ), it is determined that the current time t6 is the initial arrival time of the contrast agent, and the process proceeds to step ST46, where the initial arrival time TA of the contrast agent is updated from time t4 to time t6. On the other hand, if the index value d6 at the current time t6 is equal to the maximum value d max If it does not exceed (d6≦d max ), the processor determines that the current time t6 is not the initial arrival time of the contrast agent, and proceeds to step ST50 without updating the initial arrival time TA of the contrast agent.

[0131] Here, the maximum value of the past index value d max is d max = d4, and the index value d6 at the current time t6 is d6 = 0. Therefore, d6 ≦ d max Therefore, the processor determines not to update the initial arrival time TA of the contrast agent, but to maintain the previously determined initial arrival time TA (=t4), and proceeds to step ST50.

[0132] In step ST50, the processor creates a parametric image at time t6. FIG. 19 is an explanatory diagram of a method for creating a parametric image E6 at time t6. At time t6, the total number a6 of pixels exceeding the threshold TH is a6=0. In this case, since there are no pixels stained with contrast agent, the parametric image E5 at time t5 is displayed as is as the parametric image E6 at the current time t6. After displaying the parametric image E6, the process proceeds to step ST60.

[0133] In step ST60, it is determined whether the test has been completed. Here, since the test has not been completed yet, the process proceeds to step ST48.

[0134] In step ST48, the processor increments i. Here, since i=6, it increments i to 7. Then, the process returns to step ST30.

[0135] In step ST30, the processor i In ultrasound image U i Here, since i has been incremented to i=7, it is determined whether an ultrasound image U7 has been acquired at the current time t7. If it is determined that an ultrasound image U7 has been acquired at the current time t7, the process proceeds to step ST40.

[0136] In step ST40, a process of detecting the arrival time of the contrast agent is executed based on the ultrasound image U7 at the current time t7.

[0137] FIG. 20 is an explanatory diagram of step ST40 (steps ST41 to ST47) at time t7.

[0138] In step ST41, the processor determines the total number of pixels a7 at time t7. The method for calculating the total number of pixels is the same as the method described with reference to Fig. 9. Here, a7 is assumed to be a larger value than a1 to a6. Once the total number of pixels a7 has been calculated, the process proceeds to step ST42.

[0139] In step ST42, the processor performs peak hold on the total number a7 of pixels at the current time t7 to determine a peak value b7. Specifically, the processor determines the peak value b7 as follows.

[0140] The processor calculates the total number a7 of pixels obtained for the ultrasound image U7 at the current time t7 and the maximum value a7 of the total number of pixels obtained in the past. max Then, the total number a7 of pixels obtained for the ultrasound image U7 at the current time t7 is compared with the maximum value a of the total number of pixels obtained in the past. max If a7>a max ), the processor determines the total number a7 of pixels obtained for the ultrasound image U7 at the current time t7 as the peak value b7. On the other hand, if the total number a7 of pixels obtained for the ultrasound image U7 at the current time t7 is smaller than the maximum value a7 of the total number of pixels obtained in the past, max In the following case (a7≦a max ), the peak value b6 at time t6 is held as the peak value b7 at the current time t7.

[0141] Here, the maximum value of the total number of pixels obtained in the past a max is a max = a4, and the total number of pixels a7 at the current time t7 is a7>a4. max Therefore, the processor determines the total number a7 of pixels obtained for the ultrasound image U7 at the current time t7 as the peak value b7. Therefore, the peak value b7 is determined as b7=a7. b7 is a value greater than b6 (b7>b6). After determining the peak value b7, the process proceeds to step ST43.

[0142] In step ST43, the processor calculates the amount of change c7 of the peak value at time t7. Specifically, the processor sets a time window W including the number of data points for two points (i.e., a time window including the peak value b7 at the current time t7 and the peak value b6 at the time t6 immediately before the current time t7), and calculates the amount of change c7 between the two data points b6 and b7 included in the time window. The amount of change c7 can be expressed by the following formula:

[0143] c7=(b7-b6) / (t7-t6) After calculating the peak value change amount c7, the process proceeds to step ST44.

[0144] In step ST44, an index value d7 at the current time t7 is calculated. The index value d7 at the current time t7 can be calculated by d7=c7 / b7. After calculating the index value d4, the process proceeds to step ST45.

[0145] In step ST45, the processor calculates the index value d7 at the current time t7 and the maximum value d max Specifically, the processor determines whether the current time t7 is the initial arrival time of the contrast agent based on the index value d7 at the current time t7 and the maximum value d max Then, the processor compares the index value d7 at the current time t7 with the maximum value d max If it exceeds (d7>d max ), it is determined that the current time t7 is the initial arrival time of the contrast agent, and the process proceeds to step ST46, where the initial arrival time TA of the contrast agent is updated from time t4 to time t7. On the other hand, if the index value d7 at the current time t7 is equal to the maximum value d of the past index values, max If it does not exceed (d7≦d max ), the processor determines that the current time t7 is not the initial arrival time of the contrast agent, and proceeds to step ST50 without updating the initial arrival time TA of the contrast agent.

[0146] Here, the maximum value of the past index value d max is d max = d4, and the index value d7 at the current time t7 is d7>d4. Therefore, d7>d max Therefore, the process proceeds to step ST46, where the processor discards the previously determined initial arrival time TA (=t4), updates the initial arrival time TA of the contrast agent from time t4 to time t7, and then proceeds to step ST48.

[0147] FIG. 21 is an explanatory diagram of step ST48.

[0148] The processor discards the parametric image E6 and sets the ultrasonic image U7 at time t7 as the initial image of the parametric image. After setting the initial image of the parametric image, it proceeds to step ST49.

[0149] In step ST49, the processor increments i. Here, since i = 7, i is incremented to 8. Then, it returns to step ST30.

[0150] In step ST30, the processor determines whether the ultrasonic image U i is acquired at the current time t i . Here, since i has been incremented to i = 8, it determines whether the ultrasonic image U8 is acquired at the current time t8. If it is determined that the ultrasonic image U8 is acquired at the current time t8, it proceeds to step ST40.

[0151] In step ST40, based on the ultrasonic image U8 at the current time t8, a detection process for the arrival time of the contrast agent is executed.

[0152] FIG. 22 is an explanatory diagram of step ST40 (steps ST41 to ST47) at time t8.

[0153] In step ST41, the processor determines the total number of pixels a8 at time t8. The calculation method of the total number of pixels is the same as the method described while referring to FIG. 9. Here, it is assumed that a8 < a7. When the total number of pixels a8 is calculated, it proceeds to step ST42.

[0154] In step ST42, the processor performs peak hold on the total number of pixels a8 at the current time t8 and determines the peak value b8. Specifically, the peak value b8 is determined as follows.

[0155] The processor compares the total number of pixels a8 obtained for the ultrasonic image U8 at the current time t8 with the maximum value a of the total number of pixels obtained previouslymax Then, the total number a8 of pixels obtained for the ultrasound image U8 at the current time t8 is compared with the maximum value a of the total number of pixels obtained in the past. max If a8>a max ), the processor determines the total number a8 of pixels obtained for the ultrasound image U8 at the current time t8 as the peak value b8. On the other hand, if the total number a8 of pixels obtained for the ultrasound image U8 at the current time t8 is smaller than the maximum value a8 of the total number of pixels obtained in the past, max In the following case (a8≦a max ), the peak value b7 at the immediately previous time point t7 is held as the peak value b8 at the current time point t8.

[0156] Here, the maximum value of the total number of pixels obtained in the past a max is a max = a7, and the total number of pixels a8 at time t8 is a8 <a7である。したがって、a8≦a max Therefore, the processor holds the peak value b7 at the immediately previous time point t7 as the peak value b8 at the current time point t8, that is, determines that b8=b7. After determining the peak value b8, the process proceeds to step ST43.

[0157] In step ST43, the processor calculates the amount of change c8 of the peak value at time t8. Specifically, the processor sets a time window W including the number of data points for two points (i.e., a time window including the peak value b8 at the current time t8 and the peak value b7 at the time t7 immediately before the current time t8), and calculates the amount of change c8 of the two data points b8 and b7 included in the time window W. The amount of change c8 can be expressed by the following equation.

[0158] c8=(b8-b7) / (t8-t7) Since b8=b7, the calculation is c8=0. After calculating the amount of change c8 at time t8, the process proceeds to step ST44.

[0159] In step ST44, an index value d8 at the current time t8 is calculated. The index value d8 at the current time t8 can be calculated as d8=c8 / b8. Since c8=0, the calculation is d8=0. After calculating the index value d8, the process proceeds to step ST45.

[0160] In step ST45, the processor calculates the index value d8 at the current time t8 and the maximum value d max Specifically, the processor determines whether the current time t8 is the initial arrival time of the contrast agent based on the index value d8 at the current time t8 and the maximum value d max Then, the processor compares the index value d8 at the current time t8 with the maximum value d max If it exceeds (d8>d max ), it is determined that the current time t8 is the initial arrival time of the contrast agent, and the process proceeds to step ST46, where the initial arrival time TA of the contrast agent is updated from time t7 to time t8. On the other hand, if the index value d8 at the current time t8 is equal to the maximum value d max If it does not exceed (d8≦d max ), the processor determines that the current time t8 is not the initial arrival time of the contrast agent, and proceeds to step ST50 without updating the initial arrival time TA of the contrast agent.

[0161] Here, the maximum value of the past index value d max is d max = d7, and the index value d8 at time t8 is d8 <d7である。したがって、d8≦d max Therefore, the processor determines not to update the initial arrival time TA of the contrast agent, but to maintain the previously determined initial arrival time TA (=t7), and proceeds to step ST50.

[0162] In step ST50, the processor creates a parametric image at time t8. FIG. 23 is an explanatory diagram of a method for creating a parametric image E8 at time t8. At time t8, the total number of pixels exceeding the threshold value TH is a8>0. For ease of explanation, in FIG. 23, it is assumed that the pixels exceeding the threshold value TH (total number of pixels a8) at time t8 appear concentrated in a region R8 of the ultrasound image U8. Therefore, the processor identifies a region R80 corresponding to region R8 from the ultrasound image U7, which is the reference image of the parametric image, and calculates the time difference Δt between time t7 (the initial arrival time TA of the contrast agent) and time t8 for the pixels in region R80. 78 A color corresponding to the value of the color is assigned to the image to create a parametric image E8 at time point t8. After the parametric image E8 is displayed, the process proceeds to step ST60.

[0163] In step ST60, it is determined whether the test has been completed. Here, since the test has not been completed yet, the process proceeds to step ST48.

[0164] In step ST48, the processor increments i. Here, since i=8, it increments i to 9. Then, the process returns to step ST30.

[0165] In step ST30, the processor i In ultrasound image U i Here, since i has been incremented to i=9, it is determined whether an ultrasound image U9 has been acquired at the current time t9. If it is determined that an ultrasound image U9 has been acquired at the current time t9, the process proceeds to step ST40.

[0166] In step ST40, a process of detecting the arrival time of the contrast agent is executed based on the ultrasound image U9 at the current time t9.

[0167] FIG. 24 is an explanatory diagram of step ST40 (steps ST41 to ST47) at time t9.

[0168] In step ST41, the processor determines the total number a9 of pixels at time t9. The method for calculating the total number of pixels is the same as the method described with reference to Fig. 9. Here, it is assumed that a9>a1 to a8. Once the total number a9 of pixels is calculated, the process proceeds to step ST42.

[0169] In step ST42, the processor performs peak hold on the total number a9 of pixels at the current time t9 to determine a peak value b9. Specifically, the peak value b9 is determined as follows.

[0170] The processor calculates the total number a9 of pixels obtained for the ultrasound image U9 at the current time t9 and the maximum value a9 of the total number of pixels obtained in the past. max Then, the total number a9 of pixels obtained for the ultrasound image U9 at the current time t9 is compared with the maximum value a of the total number of pixels obtained in the past. max If a9>a max ), the processor determines the total number a9 of pixels obtained for the ultrasound image U9 at the current time t9 as the peak value b9. On the other hand, if the total number a9 of pixels obtained for the ultrasound image U9 at the current time t9 is smaller than the maximum value a of the total number of pixels obtained in the past, max In the following case (a9≦a max ), the peak value b8 at the previous time point t8 is held as the peak value b9 at the current time point t9.

[0171] Here, the maximum value of the total number of pixels obtained in the past a max is a max = a7, and the total number of pixels a9 at the current time t9 is a9>a7. Therefore, a9>a max Therefore, the processor determines the total number a9 of pixels at the current time t9 as the peak value b9 of the total number of pixels at the current time t9. Therefore, the peak value b9 is determined as b9=a9(>b8). After determining the peak value b9, the process proceeds to step ST43.

[0172] In step ST43, the processor calculates the amount of change c9 in the peak value at time t9. Specifically, the processor sets a time window W including two data points (i.e., a time window including the peak value b9 at the current time t9 and the peak value b8 at the time t8 immediately before the current time t9), and calculates the amount of change c9 between the two data points b8 and b9 included in the time window W. The amount of change c9 can be expressed by the following equation.

[0173] c9=(b9-b8) / (t9-t8) Here, c9 is a value greater than c7 (c9>c7). After calculating the amount of change c9, the process proceeds to step ST44.

[0174] In step ST44, an index value d9 at the current time t9 is calculated. The index value d9 at the current time t9 can be calculated by d9=c9 / b9. After calculating the index value d9, the process proceeds to step ST45.

[0175] In step ST45, the processor calculates the index value d9 at the current time t9 and the maximum value d max Specifically, the processor determines whether the current time t9 is the initial arrival time of the contrast agent based on the index value d9 at the current time t9 and the maximum value d max Then, the processor compares the index value d9 at the current time t9 with the maximum value d max If it exceeds (d9>d max ), it is determined that the current time t9 is the initial arrival time of the contrast agent, and the process proceeds to step ST46, where the initial arrival time TA of the contrast agent is updated from time t7 to time t9. On the other hand, if the index value d9 at the current time t9 is equal to the maximum value d max If it does not exceed (d9≦d max ), the processor determines that the current time t9 is not the initial arrival time of the contrast agent, and proceeds to step ST50 without updating the initial arrival time TA of the contrast agent.

[0176] Here, the maximum index value obtained in the past, d max is d max= d7, and the index value d9 at time t9 is d9 <d7である。したがって、d9≦d max Therefore, the processor determines not to update the initial arrival time TA of the contrast agent, but to maintain the previously determined initial arrival time TA (=t7), and proceeds to step ST50.

[0177] In step ST50, the processor creates a parametric image at time t9. FIG. 25 is an explanatory diagram of a method for creating a parametric image E9 at time t9. At time t9, the total number of pixels exceeding the threshold value TH is a9>0. For ease of explanation, in FIG. 25, it is assumed that the pixels exceeding the threshold value TH (total number of pixels a9) at time t9 appear concentrated in a region R9 of the ultrasound image U9. Therefore, the processor identifies a region R90 corresponding to region R9 from the parametric image E8, and calculates the time difference Δt between time t7 (the initial arrival time TA of the contrast agent) and time t9 for the pixels in region R90. 79 A parametric image E9 at time t9 is created by assigning a color corresponding to the image to the image. After the parametric image E9 is displayed, the process proceeds to step ST60.

[0178] In step ST60, it is determined whether the test has been completed. Here, since the test has not been completed yet, the process proceeds to step ST48.

[0179] In step ST48, the processor increments i. Here, since i=9, it increments i to 10. Then, the process returns to step ST30.

[0180] In step ST30, the processor i In ultrasound image U i Here, i is incremented to i=10, so the current time t 10 In ultrasound image U 10 Determine whether the current time t 10 In ultrasound image U 10 If it is determined that the value has been acquired, the process proceeds to step ST40.

[0181] In step ST40, at the current time point t 10 of the ultrasonic image U 10 based on, the detection process of the arrival time of the contrast agent is executed.

[0182] FIG. 26 is an explanatory diagram of step ST40 (steps ST41 to ST47) at time point t 10 .

[0183] In step ST41, the processor determines the total number a 10 of the pixels at time point t 10 . The calculation method of the total number of pixels is the same as the method described while referring to FIG. 9. Here, it is assumed that a 10 <a9. When the total number a 10 of the pixels is calculated, the process proceeds to step ST42.

[0184] In step ST42, the processor performs peak hold on the total number a 10 of the pixels at the current time point t 10 and determines the peak value b 10 . Specifically, the peak value b 10 is determined as follows.

[0185] The processor compares the total number a 10 of the pixels obtained for the ultrasonic image U 10 at the current time point t 10 with the maximum value a max of the total number of past pixels. Then, when the total number a 10 of the pixels obtained for the ultrasonic image U 10 at the current time point t 10 is greater than the maximum value a max of the total number of past pixels (a 10 >a max ), the processor determines the total number a 10 of the pixels obtained for the ultrasonic image U 10 at the current time point t 10 as the peak value b 10 . On the other hand, for the ultrasonic image U 10 at the current time point t 10The total number of pixels obtained for a 10 is the maximum number of pixels obtained in the past, a max In the following cases (a 10 ≦a max ), the peak value b9 at the previous time point t9 is 10 Peak value b at 10 Retain as.

[0186] Here, the maximum value of the total number of pixels obtained in the past a max is a max = a9, and at time t 10 The total number of pixels in a 10 is a 10 <a9である。したがって、a 10 ≦a max Therefore, the processor calculates the peak value b9 at time t9 as 10 The peak value of the total number of pixels in b 10 Therefore, the peak value b 10 is b 10 = b9. Peak value b 10 After determining the above, the process proceeds to step ST43.

[0187] In step ST43, the processor calculates the time t 10 The change in c 10 Specifically, the processor calculates a time window W (i.e., the current time t 10 Peak value b at 10 and the current time t 10 A time window W is set that includes the peak value b9 at the time t9 immediately before the peak value b9. 10 The change in c 10 Calculate the change c 10 can be expressed by the following formula:

[0188] c 10 =(b 10 -b9) / (t 10 -t9) Here, b 10 =b9, so c 10= 0. Peak value change c 10 After calculating, the process proceeds to step ST44.

[0189] In step ST44, the current time t 10 The index value d 10 Calculate at the current time t 10 The index value d 10 is d 10 =c 10 / b 10 It can be calculated as follows: c 10 = 0, so d 10 = 0. The index value d 10 After calculating, the process proceeds to step ST45.

[0190] In step ST45, the processor 10 The index value d 10 and the maximum value of the past index value d max Based on the current time t 10 Specifically, the processor determines whether the current time t 10 The index value d 10 and the maximum value of the past index value d max Then, the processor compares the current time t 10 The index value d 10 is the maximum value of the index in the past d max If it exceeds (d 10 >d max ), at the current time t 10 is the initial arrival time of the contrast agent, the process proceeds to step ST46, and the initial arrival time TA of the contrast agent is calculated from the time point t7 to the time point t 10 On the other hand, at the current time t 10 The index value d 10 is the maximum value of the index in the past d max If it does not exceed (d 10 ≦d max ), the processor is currently 10 is not the initial arrival time of the contrast agent, and the process proceeds to step ST50 without updating the initial arrival time TA of the contrast agent.

[0191] Here, the maximum index value obtained in the past, dmax is d max = d7, and at time t 10 The index value d 10 is d 10 <d7である。したがって、d 10 ≦d max Therefore, the processor determines not to update the initial arrival time TA of the contrast agent, but to maintain the previously determined initial arrival time TA (=t7), and proceeds to step ST50.

[0192] In step ST50, the processor 10 A parametric image is created at time t 10 Parametric image E in 10 27 is an explanatory diagram of a method for creating the time t 10 In this case, the number of pixels that exceed the threshold TH (total number of pixels a 10 ) is the ultrasound image U 10 Therefore, the processor identifies a region R100 corresponding to the region R10 from the parametric image E9, and calculates the time t7 (the initial arrival time TA of the contrast agent) and the time t 10 The time difference Δt 710 and assign a color corresponding to time t 10 Parametric image E in 10 Create a parametric image E 10 When this is displayed, proceed to step ST60.

[0193] In step ST60, it is determined whether the test has been completed. Here, since the test has not been completed yet, the process proceeds to step ST48.

[0194] In step ST48, the processor increments i. Here, since i=10, it increments i to 11. Then, the process returns to step ST30.

[0195] In step ST30, the processor i In ultrasound image U iHere, i is incremented to i=11, so the current time t 11 In ultrasound image U 11 Determine whether the current time t 11 In ultrasound image U 11 If it is determined that the value has been acquired, the process proceeds to step ST40.

[0196] In step ST40, the current time t 11 Ultrasound image of U 11 Based on this, a process of detecting the arrival time of the contrast agent is performed.

[0197] Figure 28 shows the time t 11 10 is an explanatory diagram of step ST40 (steps ST41 to ST47) in the flowchart of FIG.

[0198] In step ST41, the processor 11 The total number of pixels in a 11 Determine the total number of pixels a 11 Once calculated, the process proceeds to step ST42.

[0199] In step ST42, the processor 11 The total number of pixels in a 11 Peak hold is performed on the peak value b 11 Specifically, the peak value b is determined as follows: 11 Determine.

[0200] The processor is currently 11 Ultrasound image of U 11 The total number of pixels obtained for a 11 and the maximum value of the total number of past pixels a max And compare it with the current time t 11 Ultrasound image of U 11 The total number of pixels obtained for a 11 is the maximum value of the total number of past pixels a max If it is greater than (a 11 >a max ), the processor is currently 11 Ultrasound image of U11 The total number of pixels obtained for a 11 The peak value b 11 On the other hand, at the current time t 11 Ultrasound image of U 11 The total number of pixels obtained for a 11 is the maximum number of pixels obtained in the past, a max In the following cases (a 11 ≦a max ), the previous time point t 10 Peak value b at 10 At the current time t 11 Peak value b at 11 Retain as.

[0201] Here, the maximum value of the total number of pixels obtained in the past a max is a max = a9, and at time t 11 The total number of pixels in a 11 is a 11 > a9. Therefore, a 11 >a max Therefore, the processor 11 The total number of pixels in a 11 At the current time t 11 Peak value b at 11 Therefore, the peak value b 11 is b 11 =a 11 (>b 10 ) is determined. Peak value b 11 After determining the above, the process proceeds to step ST43.

[0202] In step ST43, the processor calculates the time t 11 The change in c 11 Specifically, the processor calculates a time window W (i.e., the current time t 11 Peak value b at 11 and the current time t 11 The previous time point t 10 Peak value b at 10 A time window including W is set, and two data points b 10 and b 11The change in c 11 Calculate the change c 11 can be expressed by the following formula:

[0203] c 11 =(b 11 -b 10 ) / (t 11 -t 10 ) Change c 11 After calculating, the process proceeds to step ST44.

[0204] In step ST44, the current time t 11 The index value d 11 Calculate at the current time t 11 The index value d 11 is d 11 =c 11 / b 11 The index value d can be calculated as follows: 11 After calculating, the process proceeds to step ST45.

[0205] In step ST45, the processor 11 The index value d 11 and the maximum value of the past index value d max Based on the current time t 11 Specifically, the processor determines whether the current time t 11 The index value d 11 and the maximum value of the past index value d max Then, the processor compares the current time t 11 The index value d 11 is the maximum value of the index in the past d max If it exceeds (d 11 >d max ), at the current time t 11 is the initial arrival time of the contrast agent, the process proceeds to step ST46, and the initial arrival time TA of the contrast agent is calculated from the time point t7 to the time point t 11 On the other hand, at the current time t 11 The index value d 11 is the maximum value of the index in the past d max If it does not exceed (d 11 ≦d max), the processor is currently 11 is not the initial arrival time of the contrast agent, and the process proceeds to step ST50 without updating the initial arrival time TA of the contrast agent.

[0206] Here, the maximum index value obtained in the past, d max is d max = d7, and at time t 11 The index value d 11 is d 11 <d7である。したがって、d 11 ≦d max Therefore, the processor determines not to update the initial arrival time TA of the contrast agent, but to maintain the previously determined initial arrival time TA (=t7), and proceeds to step ST50.

[0207] In step ST50, the processor 11 A parametric image is created at time t 11 Parametric image E in 11 29 is an explanatory diagram of a method for creating the time t 11 In this case, the number of pixels that exceed the threshold TH (total number of pixels a 11 ) is the ultrasound image U 11 Therefore, the processor generates the parametric image E 10 From the above, a region R110 corresponding to the region R11 is identified, and the time t7 (initial arrival time TA of the contrast agent) and the current time t 11 The time difference Δt 711 and assign a color corresponding to the current time t 11 Parametric image E in 11 Create a parametric image E 11 When this is displayed, proceed to step ST60.

[0208] In step ST60, it is determined whether the test has been completed. Here, since the test has not been completed yet, the process proceeds to step ST48.

[0209] In step ST48, the processor increments i. Here, since i=11, it increments i to 12. Then, the process returns to step ST30.

[0210] The flow is repeated in the same manner. 25 The figure shows the data obtained during the total number of pixels a i is the time t 11 The maximum value a 11 However, at time t 11 From here on, the maximum value a 11 Therefore, the peak value b i is the time t 11 The index value d is maintained at the same value thereafter. 12 ~d 25 is zero, so the index value d 12 ~d 25は、 Since the index value does not exceed the maximum value d7, the final updated value of the initial arrival time TA of the contrast agent is TA = t7. Therefore, after time t7, the parametric image is repeatedly updated with the initial arrival time TA = t7 of the contrast agent as the reference time, and the contrast examination is completed.

[0211] In this embodiment, in a contrast examination of a subject, an index value d i Calculate the current time t i The index value d i exceeds the maximum value of the past index value, the initial arrival time TA of the contrast agent is updated. Therefore, the initial arrival time TA of the contrast agent can be automatically detected in real time while a contrast examination of the subject is being performed. This eliminates the need for the user to analyze acquired ultrasound images to determine the initial arrival time of the contrast agent, thereby reducing the user's workload during the contrast examination. Furthermore, since the initial arrival time of the contrast agent can be detected during the contrast examination, a parametric image can also be created in parallel with the contrast examination. Therefore, the time required for analyzing ultrasound images can be reduced.

[0212] In this embodiment, at time ti The index value d i Calculate the current time t i The index value d i is the maximum value of the index in the past d max If the initial arrival time of the contrast agent is exceeded, the initial arrival time of the contrast agent is updated. Therefore, as shown in FIG. 28, between the time points t1 and t6, the initial arrival time of the contrast agent is updated. i The index value of is the maximum value of the past index value d max If the time exceeds the initial arrival time TA, it may be determined to be the initial arrival time of the contrast agent even if it is between time points t1 and t6. In this embodiment, time point t4 is determined to be the initial arrival time of the contrast agent. However, since the contrast agent has not yet arrived at the examination region between time points t1 and t6, the index value d4 at time point t4 is a sufficiently small value. On the other hand, since the contrast agent flows into the examination region at time point t7, the index value d7 at time point t7 becomes a large value. Therefore, the index value d7 at time point t7 exceeds the index value d4 at time point t4, and the initial arrival time TA of the contrast agent can be updated from time point t4 to time point t7. This makes it possible to avoid continuing to create parametric images based on time point t4 after the initial arrival time TA (= t7) of the contrast agent has passed.

[0213] Furthermore, in this embodiment, the total number of pixels exceeding the threshold value Th increases rapidly at time t9 after time t7. However, the index value d9 at time t9 is affected by the peak value b9 and becomes smaller than the index value d7 at time t7, so it is possible to avoid the possibility that time t9 will be determined to be the initial arrival time TA of the contrast agent.

[0214] In this embodiment, the time t 11 Hereafter, the peak value b 11 ~b 25 Since the value remains the same, the change in c 12 ~c 25 is zero. Therefore, at time t 12 Hereafter, the index value d 12 ~d 25 Since the value of is zero (or a sufficiently small value), at time t 12 The following index value d 12 ~d 25However, it is avoided that the index value d7 at the time t7 is exceeded. 11 ~t 25 This also avoids the possibility that the time is determined to be the initial arrival time of the contrast agent.

[0215] In this embodiment, the initial arrival time TA of the contrast agent is automatically detected in real time while the subject is undergoing a contrast examination. However, the initial arrival time TA of the contrast agent may be automatically detected in real time after the contrast examination is completed. [Explanation of symbols]

[0216] 1. Ultrasound diagnostic equipment 2 Ultrasound probes 2a Vibration element 3 Transmit beamformer 4 Transmitters 5 Receiver 6 Receive beamformer 7 processors 8 Display 9. Memory 10 User Interface

Claims

1. comparing the pixel value of each pixel included in the currently acquired ultrasound image with a threshold value, and counting the total number of pixels having a pixel value greater than the threshold value; When the total number of pixels obtained for the current ultrasound image is greater than the maximum value of the total number of pixels obtained in the past, the total number of pixels obtained for the current ultrasound image is determined as a peak value, and when the total number of pixels obtained for the current ultrasound image is equal to or less than the maximum value of the total number of pixels obtained in the past, a peak hold is performed to hold the peak value at the time point immediately before the current time as the peak value at the current time point; setting a time window including the current peak value and past peak values, and calculating the current amount of change in the peak value based on the multiple peak values ​​included in the time window; calculating a current index value representing a current change from a current peak value; determining whether the current time is the initial arrival time of the contrast agent based on the current index value and the maximum index value obtained in the past; repeatedly performing the steps of counting the total number of pixels, performing the peak hold, calculating the amount of change, calculating the index value, and making the determination, and updating the initial arrival time of the contrast agent every time it is determined that the current time is the initial arrival time of the contrast agent; 1. An ultrasound diagnostic device comprising: one or more processors that execute the

2. the one or more processors 2. The ultrasound diagnostic device according to claim 1, wherein the steps of counting the total number of pixels, performing the peak hold, calculating the amount of change, calculating the index value, and making the determination are performed each time an ultrasound image is acquired.

3. the one or more processors 10. The ultrasound diagnostic apparatus according to claim 1, wherein processing for detecting an initial arrival time of a contrast agent is performed based on an ultrasound image currently acquired.

4. 4. The ultrasound diagnostic apparatus of claim 3, wherein determining whether the current time is the initial arrival time of the contrast agent includes determining whether the current index value exceeds a maximum index value obtained in the past.

5. the one or more processors 5. The ultrasonic diagnostic apparatus according to claim 4, wherein when it is determined that the initial arrival time of the contrast agent is to be updated, the ultrasonic image acquired at the current time is set as a reference image for the parametric image.

6. the one or more processors 6. The ultrasonic diagnostic apparatus according to claim 5, wherein a parametric image is created when the current index value does not exceed the maximum index value obtained in the past.

7. the one or more processors To determine whether the inspection is complete; and If it is determined that the examination has not been completed, it is determined whether an ultrasound image has been acquired, and a process of detecting the initial arrival time of the contrast agent is performed on the acquired ultrasound image. The ultrasonic diagnostic apparatus according to claim 6, wherein the ultrasonic diagnostic apparatus executes the above.

8. the one or more processors 7. The ultrasonic diagnostic apparatus of claim 6, wherein after a reference image of the parametric image is set, the parametric image is updated each time it is determined that the current index value does not exceed the maximum index value obtained in the past.

9. The ultrasonic diagnostic apparatus according to claim 1 , wherein the threshold value is determined based on a maximum value of a pixel value that can be displayed by each pixel.

10. A non-transitory computer-readable storage medium having instructions stored thereon, comprising: The instructions, when executed by one or more processors, cause the one or more processors to: comparing the pixel value of each pixel included in the currently acquired ultrasound image with a threshold value, and counting the total number of pixels having a pixel value greater than the threshold value; When the total number of pixels obtained for the current ultrasound image is greater than the maximum value of the total number of pixels obtained in the past, the total number of pixels obtained for the current ultrasound image is determined as a peak value, and when the total number of pixels obtained for the current ultrasound image is equal to or less than the maximum value of the total number of pixels obtained in the past, a peak hold is performed to hold the peak value at the time point immediately before the current time as the peak value at the current time point; setting a time window including the current peak value and past peak values, and calculating the current amount of change in the peak value based on the multiple peak values ​​included in the time window; calculating a current index value representing a current change from a current peak value; determining whether the current time is the initial arrival time of the contrast agent based on the current index value and the maximum index value obtained in the past; repeatedly performing the steps of counting the total number of pixels, performing the peak hold, calculating the amount of change, calculating the index value, and making the determination, and updating the initial arrival time of the contrast agent every time it is determined that the current time is the initial arrival time of the contrast agent; A non-transitory computer-readable storage medium that causes the

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