Ultrasound diagnostic device and method for measuring umbilical cord length

Abstract

Ultrasound diagnostic device that features: an image former (24) which generates an ultrasound image based on data obtained by sending and receiving ultrasound a template generator (30) which, based on the data, generates a template (70) representing a fluctuation of a pulse at a first end of a blood vessel of interest running in an umbilical cord (56); a graph generator (34) that, based on the data, generates a graph (72) representing a fluctuation of a pulse at a second end of the blood vessel of interest; a computer (36) that calculates a reproductive time of the blood between the first end and the second end by identifying in the graph (72) a section (72A) corresponding to the template (70); and an estimator (38) that estimates the length of the umbilical cord (56) based on the reproductive time of the blood; wherein the template generator (30) generates the template (70) based on a temporal change in brightness information in the ultrasound image at the first end, and The graph generator (34) generates the graph (72) based on a temporal change of brightness information in the ultrasound image at the second end.

Description

CROSS-REFERENCE TO RELATED REGISTRATION

[0001] This application claims priority over Japanese patent application No. 2020-080111, which was filed on April 30, 2020. TECHNICAL AREA

[0002] The present disclosure relates to an ultrasound diagnostic device and a method for measuring the length of an umbilical cord and, in particular, a technique for observing the pulse of a blood vessel. BACKGROUND

[0003] Ultrasound diagnostic devices are used in various medical fields. An ultrasound diagnostic device is a tool that creates an ultrasound image based on data obtained by sending and receiving ultrasound waves to and from an object. In obstetrics, ultrasound examinations are performed to assess a mother's health or the growth of a fetus.

[0004] During ultrasound examinations in obstetrics, various measurements are performed. Currently, these measurements do not include measuring the length of the umbilical cord. The umbilical cord is an important tissue that connects the placenta and the fetus. If the umbilical cord is too long or too short, problems for both the fetus and the mother are more likely to occur. Measuring the length of the umbilical cord during ultrasound examinations is desirable, but this measurement is not currently performed. Similarly, measuring the length of other tissues during ultrasound examinations is also desirable.

[0005] JP H6-261898 A discloses an ultrasound diagnostic device that measures pulse wave propagation velocity. In this ultrasound diagnostic device, Doppler information is observed at two points of a blood vessel, and a pulse wave propagation time is calculated based on the acquired Doppler information. The pulse wave propagation velocity is then calculated by dividing the distance between the two points by the pulse wave propagation time. The distance between the two points is a known piece of information.

[0006] As described, measuring the length of a tissue of interest is desirable during ultrasound examination. The length of the tissue of interest can be calculated by multiplying the average velocity of blood flowing in a blood vessel of interest within the tissue of interest by the time (time difference) of blood movement between the respective ends of the blood vessel of interest. In this case, a configuration can be considered in which the time difference is determined by comparing a blood velocity distribution or a Doppler waveform between the ends of the blood vessel of interest. However, since the blood velocity distribution and the Doppler waveform are information that changes instantaneously and drastically, determining the time difference in the manner described above is not realistic.

[0007] An advantage of the present disclosure lies in the measurement of the length of a tissue of interest using ultrasound diagnostics. Alternatively, an advantage of the present disclosure lies in the realization of a new method for accurately measuring a reproductive time or blood flow time. A further alternative advantage of the present disclosure lies in the realization of a new method for measuring the length of an umbilical cord.

[0008] An ultrasound probe that enables the determination of the propagation speed of pulse waves between stationary transducer elements of the probe is disclosed in US 2017 / 0143309A1. Relevant considerations regarding the significance and challenges of measuring umbilical cord lengths using ultrasound in fetuses can be found in Krzyzanowski, Arkadiusz et al., Modern Ultrasonography of the Umbilical Cord: Prenatal Diagnosis of Umbilical Cord Abnormalities and Assessment of Fetal Wellbeing, Medical Science Monitor, Vol. 25, 2019, pp. 3170–3180, ISSN 1643-3750, https: / / doi.org / 10.1.12659 / MSM.913762. OVERVIEW

[0009] According to the present disclosure, an ultrasound diagnostic device according to the invention, a method according to the invention for measuring the length of an umbilical cord, and a program according to the invention executed by an information processor are provided, each of which is defined in the corresponding independent claims. Further advantageous embodiments are specified in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The embodiment(s) of the present disclosure is / are described with reference to the following figures, wherein: Fig. 1 a block diagram showing an ultrasound diagnostic device according to an embodiment of the present disclosure; Fig. 2 a representation showing an upstream end (first end) and a downstream end (second end) of a blood vessel of interest; Fig. 3 a representation that shows a first area of ​​interest and a second area of ​​interest; Fig. 4. A diagram illustrating a comparison between a template and a graph; Fig. 5 is a representation that shows an example display of a measurement result; Fig. 6 is a flowchart showing an example operation; Fig. 7 is a block diagram showing an ultrasound diagnostic device according to an alternative configuration; and Fig. Figure 8 is a diagram that shows another method for comparing a template and a graph. DESCRIPTION OF EXECUTION FORMS

[0011] One embodiment of the present disclosure will now be described with reference to the drawings. (1) Overview of embodiment

[0012] An ultrasound diagnostic device according to an embodiment of the present disclosure comprises a template generator, a graph generator, a computer, and an estimator. The template generator, based on data acquired by transmitting and receiving ultrasound, generates a template representing a pulse oscillation at the first end of a blood vessel of interest running through a tissue of interest. Based on the data, the graph generator generates a graph representing a pulse oscillation at the second end of the blood vessel of interest. The computer calculates the blood propagation time between the first and second ends by identifying a segment in the graph that corresponds to the template. The estimator estimates the length of the tissue of interest based on the blood propagation time.

[0013] Pulse variability is a change over the time of a pulse period (also known as pulse rate). This change is a long-period variation and occurs gradually over time, unlike the velocity distribution of blood flow and the Doppler waveform, which change significantly over time. Therefore, by comparing the template and the graph representing pulse variability at two points, it becomes possible to calculate the propagation time of the blood flowing between these two points with relative accuracy. Based on the configuration described above, the length of the tissue of interest can be estimated, and the accuracy of this estimate can be improved.

[0014] The ends to be measured are positioned within the tissue of interest or within another tissue that extends from the tissue of interest. In cases where a spatial discrepancy arises between the end of the tissue of interest and the end of the blood vessel of interest, the length of the tissue of interest can be corrected to resolve the discrepancy. In some cases, if the discrepancy is small, it can be ignored.

[0015] In another configuration of this disclosure, the tissue of interest is an umbilical cord, and the estimator estimates the length of the umbilical cord as the length of the tissue of interest. Two arteries and one vein run within the umbilical cord. A phenomenon can be observed for the blood flow in these blood vessels in which the pulse period changes over time within a relatively long period (for example, a period of a few seconds). Such a phenomenon is reflected in the template. In another configuration of this disclosure, the blood vessel of interest to be measured is selected from among the three blood vessels. Alternatively, an individual measurement can be performed on each individual blood vessel, and the three measurement results obtained based on these measurements can be integrated.

[0016] In another configuration of the present disclosure, the estimator estimates the length of the tissue of interest by multiplying the blood's propagation time by an average blood velocity. In yet another configuration of the present disclosure, the ultrasound diagnostic device further comprises a velocity calculator that calculates the average blood velocity based on the Doppler information contained in the data. Various methods can be used to calculate the average velocity. Alternatively, the calculated velocity can be corrected based on an angle between an ultrasound beam and the direction of blood flow.

[0017] In another configuration of this disclosure, the average blood velocity is specified by a user or determined based on fetal information. According to this configuration, the average velocity can be determined without the use of an ultrasound Doppler procedure, that is, without increasing the amount of ultrasound radiation directed at the fetus. For example, the average velocity can be specified by the user based on a past measurement. Alternatively, the average velocity can be determined automatically based on the weeks of pregnancy.

[0018] In a further configuration of the present disclosure, the ultrasound diagnostic device further comprises an image shaper that generates an ultrasound image based on the data. The template generator creates the template based on a temporal change in brightness information in the ultrasound image at the first end. The graph generator creates the graph based on a temporal change in brightness information in the ultrasound image at the second end.

[0019] The brightness information of the blood vessel (and of parts within and outside of it) changes with the pulse of the blood vessel. In the configuration described above, such a temporal change in brightness information is used to generate the template and the graph. Alternatively, other information, such as a change in the diameter of the blood vessel and a shift of a tracking point within the blood vessel, can also be used.

[0020] In a further configuration of the present disclosure, a first area of ​​interest is defined on the ultrasound image, containing the first endpoint and serving to observe the temporal change of the brightness information at the first endpoint. Additionally, a second area of ​​interest is defined on the ultrasound image, containing the second endpoint and serving to observe the temporal change of the brightness information at the second endpoint. The first and second areas of interest can be set by the user or automatically by image analysis.

[0021] In a further embodiment of the present disclosure, two markers are displayed on the ultrasound image, indicating the first and second areas of interest, respectively. In addition, the blood flow propagation time and the length of the tissue of interest are displayed along with the ultrasound image.

[0022] A method for measuring the length of an umbilical cord according to an embodiment of the present disclosure comprises: a template generation step; a graph generation step; a computation step; and an estimation step. In the template generation step, a template is generated based on data obtained by sending and receiving ultrasound, representing a pulse oscillation at an upstream end of a blood vessel of interest running in the umbilical cord. In the graph generation step, a graph representing a pulse oscillation at a downstream end of the blood vessel of interest is generated based on the data. In the computation step, the blood transmission time from the upstream end to the downstream end is calculated by comparing the template with the graph.In this estimation step, the length of the umbilical cord is estimated based on the reproductive time of the blood.

[0023] In another configuration of the present disclosure, the blood vessel of interest is an artery. In this case, the upstream end is located within or near a fetus, and the downstream end is located within or near a placenta. Alternatively, the blood vessel of interest is a vein. In this case, the upstream end is located within or near a placenta, and the downstream end is located within or near a fetus.

[0024] A program according to an embodiment of the present disclosure is a program executed by an information processor which, when executed, causes the information processor to implement: a template generation function; a graph generation function; and a computation function. The template generation function is a function to generate a template representing the time-dependent change of an upstream end of a blood vessel of interest running in an umbilical cord, based on data obtained by sending and receiving ultrasound to and from a mother. The graph generation function is a function to generate a graph representing the time-dependent change of a downstream end of the blood vessel of interest, based on the data.The calculation function is a function to calculate a reproduction time of blood from the upstream end to the downstream end by identifying a section in the graph that corresponds to the template.

[0025] The program is installed in the information processor via a recording medium or a network. The recording medium can be, for example, a medium that stores the program non-volatilely. The concept of a recording medium includes a portable recording medium. The information processor is a device with a processor that executes a program, and the concept of an information processor includes an ultrasound diagnostic device, an ultrasound diagnostic system, a computer, and the like. (2) Detail of the embodiment

[0026] Fig. Figure 1 shows an ultrasound diagnostic device according to an embodiment of the present disclosure. The ultrasound diagnostic device is a device installed in a medical facility, such as a hospital, which generates and displays an ultrasound image based on a received signal obtained by sending and receiving ultrasound to and from a subject. The structure and operation of the ultrasound diagnostic device are now described using an ultrasound examination of pregnant women in obstetrics as an example.

[0027] A probe 10 is a portable transducer / receiver. The probe 10 is held by an examiner (a physician, examination technician, etc.) who is the user. A transducer / receiver surface of the probe 10 is positioned to make contact with a surface of the mother's (pregnant) abdomen. The probe 10 contains a transducer array. The transducer array consists of several transducers arranged in a one-dimensional plane. An ultrasound beam 12 is generated by the transducer array and electronically scanned. This process creates a scan plane 14. The position and orientation of the probe 10 are adjusted by the examiner so that one or more observation points in the fetus are included in the scan plane 14.

[0028] Examples of electronic scanning methods for the ultrasound beam 12 include electronic linear scanning, electronic sector scanning, and similar methods. A scan plane 14 has a coordinate system defined by a depth direction r and a scan direction θ. Alternatively, a two-dimensional transducer array can be provided in the probe 10. This means that volume data can be acquired from a three-dimensional space by two-dimensional scanning of the ultrasound beam.

[0029] When a B-mode, in which a tomographic image is displayed, is selected, the ultrasound beam 12 is electronically scanned as described above. When a PW mode (or a CW mode), in which Doppler information is observed, is selected, an ultrasound beam 16 is repeatedly generated in a specific viewing direction. In the present embodiment, a composite mode is selected in which the B-mode and the PW mode are executed in a temporally separated manner as needed.

[0030] A transmitting circuit 18 is an electronic circuit that functions as a transmitting beam shaper. A receiving circuit 20 is an electronic circuit that functions as a receiving beam shaper. During transmission, several transmit signals are delivered in parallel to each other by the transmitting circuit 18 to the transducer array. In this process, a transmitting beam is formed. When a reflected wave from the interior of a living body is received by the transducer array during reception, several received signals are output in parallel to each other by the multiple transducer elements.

[0031] For the multiple received signals, phase alignment and summation (i.e., delay and summation) are performed in the receiving circuit 20 so that beam data corresponding to the received beam is generated. During the execution of B-mode, a set of received frame data is generated for each electronic scan of the ultrasonic beam 12 at a given time. A set of received frame data is formed from several beam data arranged in the scan direction. A set of beam data is formed from several sets of echo data arranged in a depth direction. During the execution of PW-mode, the ultrasonic beam is generated repeatedly in a specific direction. During the execution of composite mode, for example, sending and receiving multiple times for B-mode and sending and receiving once for PW-mode are performed alternately.

[0032] Downstream of the receiving circuit 20, a beam data processor, not shown in the figures, is provided. A Doppler processor 22 is a circuit that extracts Doppler information from each set of beam data acquired by transmitting and receiving according to the PW mode. Specifically, information from a sampling port is extracted from each set of beam data, and a spectrum, which is a frequency analysis result of the Doppler information, is generated based on a frequency analysis of this information. Data displaying the spectrum are sent by the Doppler processor 22 to a display processor 26. Additionally, this data is also sent to an umbilical cord length calculator 38. The umbilical cord length calculator 38 calculates an average velocity based on the spectrum. Alternatively, the calculation of the average velocity can also be performed in the Doppler processor 22.

[0033] A tomography image former 24 is a module that generates a display frame data array from a receive frame data array. The tomography image former 24 has a digital scan converter (DSC). The DSC has a coordinate conversion function, an interpolation function, a frame rate setting function, or the like. Each set of generated display frame data corresponds to a tomography image. Alternatively, other ultrasound images, such as a two-dimensional blood flow image, can also be generated. Alternatively, the average velocity can be calculated from such other ultrasound images. The display frame data array (that is, a tomography image array in a temporally sequential order) is sent to the display processor 26 and a pulse period calculator 28.

[0034] The display processor 26 has an image compositing function, a color calculation function, and the like. The data from the tomography image are sent by the display processor 26 to a display 40. The display 40 consists of an LCD, an organic electroluminescence (EL) device, or the like. A tomography image is displayed as an ultrasound image on the screen of the display 40, and two markers indicating two areas of interest, a blood transfusion time, an estimated umbilical cord length, and the like are also displayed, as described later.

[0035] The ultrasound diagnostic device according to the present embodiment comprises the pulse period calculator 28, a template generator 30, a template memory 32, a graph generator 34, a time difference calculator 36, and the umbilical cord length calculator 38. These structures correspond, for example, to several functions that are implemented by a processor (which, as will be described later, can be a CPU). Before these structures are described, some assumptions will be outlined.

[0036] By setting the position and orientation of probe 10, a tomographic image containing a fetal image and a placental image is displayed. During this process, the position and orientation of probe 10 are adjusted so that two ends of the umbilical cord appear in the tomographic image; more precisely, a first end (in the present embodiment, an upstream end) of a blood vessel of interest running in the umbilical cord and a second end (in the present embodiment, a downstream end) of the blood vessel of interest appear in the tomographic image. Alternatively, if the pattern matching described later can be performed, the position and orientation of probe 10 can be adjusted so that the ends appear sequentially in the tomographic image.

[0037] Two arteries and one vein run through the umbilical cord, and one of these blood vessels is selected by the user as the vessel of interest. Alternatively, the selection can be automated. The umbilical cord has a serpentine shape within the amniotic fluid, and normally the tomography image does not include the entire cord; only a portion of it appears on the scan.

[0038] In the present embodiment, after the position and orientation of the probe 10 have been set, a first region of interest (ROI), surrounding the first end of the blood vessel of interest, is manually defined on the tomography image, and a second region of interest (ROI), surrounding the second end of the blood vessel of interest, is also manually defined. Alternatively, the two regions of interest can be automatically defined by analyzing the tomography image. The position, size, shape, and other characteristics of each region of interest are appropriately defined to exclude other blood vessels.

[0039] The Pulse Period Calculator 28 successively calculates the pulse period from temporal changes in brightness information in each area of ​​interest. The pulse period can be calculated as the number of pulses per unit of time. The ends of the blood vessel of interest periodically expand and contract on the tomography image, or the shapes or positions of the ends change periodically. This causes a corresponding section to become periodically brighter or darker. From the change in the tomography image, the pulse period can be calculated at each individual point in time. In fetuses, the period changes with respect to time with a significantly long interval (for example, a period of 4.5 seconds), and therefore there is a fluctuation in the pulse. In some cases, such a fluctuation in a pulse can be observed in an adult.

[0040] The pulse period calculator 28 outputs a period array calculated from the brightness information in the first area of ​​interest to the template generator 30 and a period array calculated from the brightness information in the second area of ​​interest to the graph generator 34.

[0041] The template generator 30 generates a template as an input period array or as part of an input period array. In the present embodiment, the template is a waveform that shows a temporal change in the pulse period over a specific period. The specific period is set, for example, in a range from 1 second to 10 seconds. It should be noted that the numerical values ​​described here are only exemplary and not limiting. The template generated from the brightness information at the first end is stored in the template memory 32.

[0042] Graph generator 34 produces a graph showing the temporal change of the pulse based on the period array generated from the brightness information at the second end. The graph is a waveform. Template generation and graph generation are performed simultaneously. Alternatively, template and graph generation can be performed at different times, provided the pattern matching described below can be carried out appropriately.

[0043] The time difference calculator 36 operates as a matching unit. This means that a portion of the generated graph corresponding to the template is identified. In this process, for example, while a template position is being changed relative to the graph, a correlation calculation is performed at each template position. A match is determined if a correlation value meets a specific condition.

[0044] The time difference calculator 36 calculates a difference (time difference) between the time of template creation and the time of the corresponding result. This time difference can also be referred to as the template propagation time. That is, the time difference corresponds to the time it takes for blood to move within the blood vessel of interest from one end to the other. The present embodiment utilizes the fact that the pulse variability changes with a long period and determines the propagation time, or transit time, of the blood by matching the pattern of variability between the ends.

[0045] The umbilical cord length calculator 38 multiplies the gestational age by an average velocity (average flow rate) to estimate the length of the umbilical cord. The average velocity is determined based on Doppler information. Alternatively, the average velocity can be determined based on gestational weeks or similar parameters. A table can also be created that lists the average velocity based on information such as gestational weeks. The Doppler information is normally obtained from the first end. Alternatively, the Doppler information can be obtained from the second end or from another location. Data indicating the umbilical cord length is sent to the display processor 26.

[0046] Alternatively, data showing the template or data showing the graph can be sent to the display processor 26. In other words, the template and the graph can be displayed on the screen of the display 40. In the present embodiment, the gestation period and the umbilical cord length, measured in real time, are displayed as numerical values ​​along with the tomography image, which is a video image.

[0047] A controller 42 controls operations of different, in Fig. The structures shown in Figure 1. The controller 42, for example, is a CPU that executes a program. A control panel 44 is connected to the controller 42. The control panel 44 is an input device with multiple buttons, a trackball, a keyboard, or the like. The two areas of interest and a sample gate are set using the control panel 44. The start of template acquisition is initiated via the control panel 44. The average speed can be specified using the control panel 44, or the weeks of pregnancy can be entered using the control panel 44.

[0048] Fig. Figure 2 shows a tomography image 46. Fig. Figure 2 is a schematic representation to illustrate the present embodiment. In the Fig. In the example configuration shown in Figure 2, a cross-section 48 of a uterus appears in the tomography image 46. Reference numeral 50 indicates the amniotic fluid, and reference numeral 52 indicates a uterine wall. A placenta 54 and a fetus 57 are connected by an umbilical cord 56. The umbilical cord 56 contains two arteries and one vein, which are present in that order from the fetal side. Normally, the entire umbilical cord 56 does not appear in the tomography image 46, but in Fig. Figure 2 shows the entire umbilical cord 56 schematically to facilitate understanding of the present embodiment.

[0049] At the in Fig. In the example configuration shown in Figure 2, the blood vessel of interest is a specific artery. An upstream end a of the artery serves as the first end, which is a measurement target for template creation, and a downstream end b of the artery serves as the second end, which is a measurement target for graph creation.

[0050] Based on the understanding that one end and the other end of the umbilical cord 56 extend to an interior of the fetus 57 and an interior of the placenta 54, respectively, the upstream end a belongs to the one end of the umbilical cord 56 and the downstream end b belongs to the other end of the umbilical cord 56. On the other hand, based on the understanding that the one end and the other end of the umbilical cord 56 do not extend into the interior of the fetus 57 and the interior of the placenta 54, respectively, the upstream end a is located near the one end of the umbilical cord 56 and within the fetus 57, and the downstream end b is located near the other end of the umbilical cord 56 and within the placenta 54. In either understanding, there is no significant difference in the length of the umbilical cord.

[0051] In Fig. Direction 58 is set for observing Doppler information such that it passes through the upstream end a. A sample port 60 is set in direction 58 such that it contains the upstream end a. The Doppler information is acquired from within sample port 60. The acquisition of the Doppler information can be performed before the template and graph are generated, during the generation of the template and graph, or after the generation of the template and graph. When the average velocity is calculated from the Doppler information, a velocity correction corresponding to an angle between a blood flow direction and a beam direction can be applied.

[0052] Fig. Figure 3 shows two areas of interest, 62 and 64. In the tomography image 46, the first area of ​​interest, 62, is positioned around the upstream end, and the second area of ​​interest, 64, is positioned around the downstream end. Elements identical to those already described are given the same reference symbols, and their descriptions are not repeated. This applies to all drawings from [reference number] onwards. Fig. 4 likewise. Alternatively, one of the settings of the first area of ​​interest 62 and the sample gate can also function as the other setting.

[0053] Fig. Figure 4 shows a template 70 and a graph 72. A horizontal axis t represents time, and a vertical axis D represents a pulse period. The pulse period changes with a long period. That is, there is a fluctuation in the pulse period. A template period tw is set so that all or part of a period of the fluctuation is contained within the template period. For example, a period in the range of 0.5 seconds to 10 seconds can be set as the template period tw. Alternatively, a period in the range of 2 seconds to 8 seconds can be set. In the Fig. In the example configuration shown in section 4, the midpoint of the template period tw is represented by t1.

[0054] Graph 72 grows over time. At each point in time, template 70 is compared with graph 72 (see, for example, reference 70A). A correlation calculation is performed for this comparison. If a correlation value meets a certain condition, a correspondence is established. In the Fig. In the example configuration shown in Figure 4, a section represented by reference symbol 72A in graph 72 corresponds to template 70 (see reference symbol 70B). The midpoint of section 72A is represented by reference symbol t2. A time difference dt from t1 to t2 can be considered the respiration time of the blood in the blood vessel of interest. The length of the blood vessel of interest can be estimated by multiplying the respiration time of the blood by the average velocity of the blood, and the length of the umbilical cord can be estimated from the length of the blood vessel of interest. Various corrections can be applied to this procedure as needed.

[0055] Fig. Figure 5 shows an example of a display. A tomography image 76 is displayed on a screen 74. The tomography image 76 contains a marker 62A, which shows the first area of ​​interest, set relative to the first end, and a marker 64A, which shows the second area of ​​interest, set relative to the second end. In a lower part of the tomography image 76, a numerical value 78, which indicates the calculated gestational age, and a numerical value, which indicates the estimated length of the umbilical cord, are displayed. These numerical values ​​make it possible to diagnose an abnormality of an umbilical cord that is too long or too short.

[0056] In the configuration described above, the artery is set as the observation target, but alternatively, a vein can also be set as the observation target. In this case, the upstream end is set on the placental side and the downstream end on the fetal side.

[0057] Fig. Figure 6 shows an example operation as a flowchart. In section 10, the first region of interest (ROI) and the second region of interest (ROI), which contain the first and second ends of the blood vessel of interest, respectively, are set on the tomography image. In section 12, the average blood velocity is determined. Doppler information can be used in this process. Alternatively, the average velocity can be determined based on the gestational age. In section 14, the template is generated based on the brightness information in the first region of interest.

[0058] In page 16, the template is successively compared with the graph generated based on the brightness information in the second area of ​​interest. The comparison is repeated until a match is found in page 18. Once a match is found, the time difference, i.e., the reproductive time, is calculated in page 20. In page 22, the reproductive time of the blood is multiplied by the average blood velocity to estimate the length of the umbilical cord. The estimated length of the umbilical cord is displayed in page 24.

[0059] Alternatively, the lengths of the umbilical cord can be determined for two or three blood vessels in the cord using a procedure similar to the one described above, and an average value can be calculated. Alternatively, the procedure described above can be applied to a recorded tomography image array. Alternatively, instead of changing the brightness information, reference can be made to a change in blood vessel diameter, a shift in a tracking point, or the like. Alternatively, the length of the umbilical cord can be calculated using the procedure described above based on volume data. In this case, stress during probe position and orientation adjustment can be reduced, and the first and second areas of interest can be set more appropriately. Alternatively, a similar procedure can be applied to other tissues, including blood vessels.

[0060] Fig. Figure 7 shows an alternative configuration. Two probes, 10A and 10B, are connected to the transmitting circuit 18 and the receiving circuit 20, operating simultaneously. For example, the first end of the blood vessel of interest is observed by probe 10A, and the second end of the blood vessel of interest is observed by probe 10B. If the in Fig. The structure shown in Figure 7 can be used, two parallel transmitting systems and two parallel receiving systems can be provided, or one transmitting system and one receiving system can each be operated in a time-split manner.

[0061] Fig. Figure 8 shows another matching method. Averaging process is applied to a waveform 82, which shows the fluctuation of the pulse period at the first end, to generate an average curve 86. A difference 82A between the average curve 86 and the waveform 82 forms a template. The difference 82A is a fluctuation component that is taken into account in the present embodiment. The template period is represented by tw1.

[0062] Additionally, a similar process is applied to a waveform 84, which shows the fluctuation of the pulse period at the second end, to generate an average curve 88. A difference 84A between the average curve 88 and the waveform 84 forms a graph. Similar to the difference 82A, the difference 84A is a fluctuation component that is taken into account in the present embodiment.

[0063] The template (see reference 82A) is continuously compared with the graph (see reference 84A). When a section matching the template is found, a time difference dt1 is determined. The time difference dt1 is the reproductive time of the blood. According to the procedure of Fig. 8. Even if there is a change in the duration of a longer period, the influence of this can be reduced. That is, the accuracy of the calculation of the reproductive period can be improved.

Claims

[1] Ultrasound diagnostic device which features: an image former (24) which generates an ultrasound image based on data obtained by sending and receiving ultrasound a template generator (30) which, based on the data, generates a template (70) representing a fluctuation of a pulse at a first end of a blood vessel of interest running in an umbilical cord (56); a graph generator (34) that, based on the data, generates a graph (72) representing a fluctuation of a pulse at a second end of the blood vessel of interest; a computer (36) that calculates a reproductive time of the blood between the first end and the second end by identifying in the graph (72) a section (72A) corresponding to the template (70); and an estimator (38) that estimates the length of the umbilical cord (56) based on the reproductive time of the blood; wherein the template generator (30) generates the template (70) based on a temporal change in brightness information in the ultrasound image at the first end, and The graph generator (34) generates the graph (72) based on a temporal change of brightness information in the ultrasound image at the second end. [2] Ultrasound diagnostic device according to claim 1, wherein the estimator (38) estimates the length of the umbilical cord (56) by multiplying the reproductive time of the blood by an average velocity of the blood. [3] Ultrasound diagnostic device according to claim 2, further comprising: a velocity calculator (38) which calculates the average velocity of the blood based on the Doppler information contained in the data. [4] Ultrasound diagnostic device according to claim 2, wherein the average velocity of the blood is determined by a user or is determined based on fetal information. [5] Ultrasound diagnostic device according to claim 1, wherein On the ultrasound image, a first area of ​​interest (62, 62A), which contains the first end and serves to observe the temporal change of the brightness information at the first end, is set, and A second area of ​​interest (64, 64A) is set on the ultrasound image, which contains the second end and serves to observe the temporal change of the brightness information at the second end. [6] Method for measuring the length of an umbilical cord (56), wherein the method comprises: Generating an ultrasound image from data obtained by sending and receiving ultrasound, Generating (S14) a template (70) representing a fluctuation of a pulse at an upstream end of a blood vessel of interest running in an umbilical cord (56), based on the data; Generating (S16) a graph (72) representing a fluctuation of a pulse at a downstream end of the blood vessel of interest, based on the data; Calculating (S16-S20) a reproduction time of the blood from the upstream end to the downstream end by comparing the template (70) with the graph (72); and Estimating (S22) the length of the umbilical cord (56) based on the reproductive time of the blood, wherein the template (70) is generated based on a temporal change of brightness information in the ultrasound image at the first end, and The graph (72) is generated based on a temporal change of brightness information in the ultrasound image at the second end. [7] Method for measuring the length of the umbilical cord according to claim 6, wherein the blood vessel of interest is an artery, the upstream end is located inside or near a fetus, and the downstream end is located within or near a placenta. [8] Method for measuring the length of the umbilical cord according to claim 6, wherein the blood vessel in question is a vein, the upstream end is located within or near a placenta, and the downstream end is located inside or near a fetus. [9] Non-volatile recording medium that stores a program executed by an information processor, the program containing the following functions: Generating an ultrasound image from data obtained by sending and receiving ultrasound to and from a mother; Generating (30) a template (70) representing a temporal change of a pulse of an upstream end of a blood vessel of interest running in an umbilical cord (56) based on the data; Generating (34) a graph (72) representing a temporal change of a pulse of a downstream end of the blood vessel of interest, based on the data; Calculating (36) a reproduction time of the blood from the upstream end to the downstream end by identifying a section (72A) in the graph (72) that corresponds to the template (70), and Estimating (38) the length of the umbilical cord (56) based on the reproductive time of the blood, wherein the template (70) is generated based on a temporal change of brightness information in the ultrasound image at the first end, and The graph (72) is generated based on a temporal change of brightness information in the ultrasound image at the second end.

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