JP2005034543A - Monitoring device for blood flow condition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a monitoring device for blood flow conditions capable of reducing the burden to a subject to be tested, detecting a blood pressure stably, and displaying a blood flow rate in an artery and the distribution. <P>SOLUTION: This monitoring device 100 for blood flow conditions is equipped with a transmitter 1 and a receiver 3 for transmitting an ultrasonic pulse to a blood vessel in vivo and receiving ultrasonic echo reflected by the blood vessel to change into ultrasonic echo signal, a calculation part 5 of the blood vessel diameter for analyzing the phase of ultrasonic echo signal and calculating temporal change in the blood vessel diameter, a cuff-type blood-pressure meter 7 for measuring the maximum and the minimum blood pressure flowing in the blood vessel, and a calibration operating part 6 for calculating a blood pressure wave showing the temporal change of blood pressure flowing in the blood vessel based on the maximum and the minimum blood pressure measured by the cuff-type blood pressure meter 7 and the temporal change of the blood vessel diameter which is calculated by the calculation part 5 for blood vessel diameter. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the field of medical instruments, the present invention uses ultrasound to non-invasively measure the in-vivo blood vessel diameter caused by blood pressure pulsation to obtain a continuous blood pressure value, and to perform blood flow by Doppler analysis of ultrasonic echoes. The present invention relates to a blood flow state monitoring device capable of obtaining a speed.

Conventionally, as this type of blood flow state monitoring device, a configuration for measuring blood pressure non-invasively in real time has been proposed as disclosed in Japanese Patent Laid-Open No. 5-3858. According to this configuration, a pulse wave waveform is detected by a pressure sensor pressed against an artery near the body surface from the outside of the subject's skin, and the maximum blood pressure measured by a cuff sphygmomanometer separately attached to the same subject and Based on the average blood pressure, the pulse wave waveform is associated with the blood pressure value, and the blood pressure waveform is monitored in real time.
JP-A-5-3858

  However, in the configuration of the conventional blood flow state monitoring device described above, it is necessary to press the pressure sensor against the artery with a certain pressure in order to obtain a blood pressure waveform in real time. For this reason, it is necessary to provide components such as a diaphragm in order to precisely control the magnitude and direction of the force applied to the pressure sensor. As a result, it is difficult to downsize the pressure sensor itself, and there is a problem that the burden on the subject increases.

  In addition, in the configuration of the conventional blood flow state monitoring device described above, only blood pressure can be measured, and blood flow velocity of an ultrasonic diagnostic device or the like is measured when trying to measure blood flow velocity flowing in an artery. There is a problem that it is necessary to separately provide a device for this purpose.

  An object of the present invention is to reduce a burden on a subject, to stably detect a blood pressure, and to display a blood flow velocity flowing in an artery and its distribution. To provide an apparatus.

  The blood flow state monitoring device according to the present invention transmits an ultrasonic signal to a blood vessel in a subject, receives an ultrasonic echo reflected by the blood vessel, and converts it into an ultrasonic echo signal; and A blood vessel diameter calculating unit that analyzes an ultrasonic echo signal and calculates a temporal change in the blood vessel diameter representing the diameter of the blood vessel, and stores a pre-acquired maximum blood pressure value and minimum blood pressure value of the blood flowing through the blood vessel Based on the temporal change of the blood vessel diameter calculated by the blood vessel diameter calculating means and the maximum blood pressure and the minimum blood pressure stored in the storage means, And a calibration calculation means for calculating a blood pressure waveform representing a change in the blood pressure.

  Another blood flow state monitoring apparatus according to the present invention includes an ultrasonic transmission / reception unit that transmits an ultrasonic signal to a blood vessel in a subject, receives an ultrasonic echo reflected by the blood vessel, and converts the ultrasonic echo into an ultrasonic echo signal. Blood vessel diameter calculating means for analyzing the ultrasonic echo signal and calculating a temporal change in the blood vessel diameter representing the diameter of the blood vessel, and a maximum blood pressure value and an average blood pressure value of the blood flowing through the blood vessel acquired in advance. Blood pressure of blood flowing through the blood vessel based on the temporal change of the blood vessel diameter calculated by the blood vessel diameter calculating means and the maximum blood pressure and the average blood pressure stored in the storage means And a calibration calculation means for calculating a blood pressure waveform representing a temporal change of the blood pressure.

  In the blood flow state monitoring device according to the present invention, based on the temporal change of the blood vessel diameter calculated by the blood vessel diameter calculating means and the highest blood pressure and the lowest blood pressure measured by the cuff sphygmomanometer, the blood flowing through the blood vessel is measured. A calibration calculation means calculates a blood pressure waveform representing a temporal change in blood pressure. For this reason, the temporal change of the blood pressure of the blood flowing through the blood vessel can be accurately obtained.

  The blood flow state monitoring apparatus according to the present invention further includes a blood flow velocity calculating means for calculating a blood flow velocity of the blood flowing through the blood vessel based on the ultrasonic echo signal. With this configuration, the blood flow velocity of the blood flowing through the blood vessel can also be measured, so that more information can be provided as a circulatory system biological information monitor.

  In the blood flow state monitoring apparatus according to the present invention, the calibration calculation means includes the maximum blood pressure measured by the cuff sphygmomanometer with a maximum value of the temporal change in the blood vessel diameter calculated by the blood vessel diameter calculation means. The temporal change of the blood vessel diameter calculated by the blood vessel diameter calculating means is made to correspond to the minimum blood pressure measured by the cuff type sphygmomanometer. Correlate with blood pressure value. With this configuration, it is possible to associate a temporal change in blood vessel diameter with a blood pressure value with a simple configuration.

  In the blood flow state monitoring device according to the present invention, each heart rate is calculated based on the temporal change in the blood vessel diameter calculated by the blood vessel diameter calculating means and the blood flow velocity calculated by the blood flow velocity calculating means. Blood flow volume calculating means for calculating a blood flow volume representing the volume of blood flowing through the blood vessel in the period is further provided. With this configuration, the blood flow volume during each heartbeat period can be measured in real time, and more information can be acquired as a circulatory system biological condition monitor.

  The blood flow state monitoring apparatus according to the present invention further includes display means for displaying the blood pressure waveform calculated by the calibration calculation means. With this configuration, the blood pressure waveform can be displayed in real time, and more information can be displayed as a circulatory system biological condition monitor.

  The blood flow state monitoring device according to the present invention preferably further comprises display means for displaying the blood flow velocity calculated by the blood flow velocity calculating means. This is because the blood flow velocity can be displayed in real time by this configuration, and more information can be displayed as a biological state monitor of the circulatory system.

  In the blood flow state monitoring apparatus according to the present invention, the ultrasonic transmission / reception means includes an ultrasonic probe provided so as to face the surface of the skin of the living body. This is because, with this configuration, an ultrasonic pulse is transmitted to a blood vessel in the living body, and an ultrasonic echo reflected by the blood vessel is received and converted into an ultrasonic echo signal.

  In the blood flow state monitoring apparatus according to the present invention, the ultrasonic probe transmits a blood vessel diameter detection beam for detecting the blood vessel diameter along a direction substantially perpendicular to a blood vessel wall constituting the blood vessel. A first element and a blood flow velocity detection beam for detecting the blood flow velocity are transmitted so as to intersect with the blood vessel diameter detection beam transmitted from the first element substantially at the center of the lumen of the blood vessel. 2 elements are included. With this configuration, the blood flow velocity along the axial direction of the blood vessel can be detected.

  In the blood flow state monitoring apparatus according to the present invention, the blood vessel diameter detection beam and the blood flow velocity detection beam are transmitted alternately. This is to prevent mutual interference of transmission ultrasonic waves.

  The ultrasonic probe further includes tilting means provided to tilt the second element with respect to the blood vessel. With this configuration, both the first element and the second element can be configured by a single transducer, so that the ultrasonic probe can be reduced in size.

  ADVANTAGE OF THE INVENTION According to this invention, the blood-flow state monitor which can reduce the burden on a test subject, can detect a blood pressure stably, and can display the blood flow velocity and its distribution which flow through an artery. An apparatus can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing a configuration of a blood flow state monitoring apparatus 100 according to the first embodiment. The blood flow state monitoring device 100 includes a transmission unit 1. The transmission unit 1 generates an ultrasonic pulse for transmission to a blood vessel in a living body and supplies the ultrasonic pulse to an ultrasonic probe 2 that is an ultrasonic transmission / reception unit.

  FIG. 2 is a cross-sectional view for explaining the configuration of the ultrasonic probe 2. The ultrasonic probe 2 has an ultrasonic coupling material 35 disposed on the body surface 31 of the subject. The ultrasonic coupling material 35 is preferably composed of a gel or the like whose main component is water. More preferably, it is a gel in the form of a sheet, and is composed of an adhesive gel so that the close contact with the body surface 31 is maintained.

  The ultrasonic probe 2 is a linear array probe, and is an aggregate of transducers in which a plurality of micro transducers are arranged in a one-dimensional direction in order to control the position and direction of the ultrasonic beam. In the example shown in FIG. 2, the transducers are arranged along the lateral direction shown in FIG. 2 parallel to the axial direction of the blood vessel constituted by the anterior wall 32 of the artery, the posterior wall 33 of the artery, and the artery blood vessel lumen 34. The ultrasonic probe 2 is disposed on the side.

  On the ultrasonic coupling material 35, the probe partial element 36a and the probe partial element 36b are provided adjacent to each other. The probe partial element 36a irradiates a blood vessel diameter detecting ultrasonic beam 37 along a direction substantially perpendicular to the anterior wall 32 and the posterior wall 33 of the artery. The probe sub-element 36b controls the phase of the transmission signal, and irradiates the velocity detection ultrasonic beam 38 so as to intersect the blood vessel diameter detection ultrasonic beam 37 at the approximate center of the arterial blood vessel lumen 34 by a beam forming technique. Thus, the velocity detecting ultrasonic beam 38 is irradiated along a direction obliquely intersecting with the axial direction of the blood vessel, so that the blood flow velocity along the axial direction of the blood vessel can be detected.

  The blood vessel diameter detecting ultrasonic beam 37 and the velocity detecting ultrasonic beam 38 are alternately irradiated in order to prevent mutual interference of transmission ultrasonic waves. The blood vessel diameter detection ultrasonic beam 37 reflected by the blood vessel is converted into an electric signal by the ultrasonic probe 2, and signals from each element are delayed and added, amplified by the receiving unit 3, converted into a digital signal, and phase-converted. A phase detection process is performed by the detection unit 4, converted into a complex baseband signal of the in-phase component I and the quadrature component Q, and supplied to the blood vessel diameter calculation unit 5.

  The blood vessel diameter calculating unit 5 performs tracking calculation of echo signals of the blood vessel front wall 32 and the blood vessel rear wall 33 based on the blood vessel diameter detecting ultrasonic beam 37, and the blood vessel representing the diameter of the blood vessel based on the distance difference therebetween. Calculate the change in diameter over time.

  The blood flow state monitoring device 100 has a storage unit 11, stores the measured values of the highest blood pressure and the lowest blood pressure of the subject acquired in advance with a cuff sphygmomanometer, and supplies the measured values to the calibration calculation unit 6. .

  The calibration calculation unit 6 associates the maximum blood vessel diameter value with the maximum blood pressure value read from the storage unit 11 for one heartbeat of the blood vessel diameter waveform, and associates the minimum blood vessel diameter value with the minimum blood pressure value and displays the display unit 8. To supply. The display unit 8 displays a blood vessel diameter waveform converted into a blood pressure value as a blood pressure waveform.

  The velocity detection ultrasonic beam 38 reflected by the blood vessel is converted into an electric signal by the ultrasonic probe 2, amplified by the receiving unit 3, converted into a digital signal, subjected to phase detection processing by the phase detection unit 4, and an in-phase component It is converted into a complex baseband signal of I and a quadrature component Q and supplied to the wall filter 9.

  The wall filter 9 performs a high-pass filtering process to extract only the reflection component from the blood flow from the velocity detection ultrasonic beam 38 and supplies the output signal to the FFT calculation unit 10. The FFT calculation unit 10 performs frequency analysis of the output from the wall filter 9 by fast Fourier transform calculation. The frequency analysis result by the FFT calculation unit 10 is sent to the display unit 8, and the blood flow velocity waveform is displayed together with the blood pressure output from the calibration calculation unit 6. The phase detection unit 4 may be provided individually because there are one post-process (wall filter 9 side, blood vessel diameter calculation unit 5 side). In this case, since the amount of calculation is reduced, the size and cost can be reduced.

  FIGS. 3A and 3B are waveform diagrams showing blood pressure and blood flow velocity measured by the blood flow state monitoring apparatus 100 according to the first embodiment. Referring to FIG. 3A, a waveform 21 displayed on the display unit 8 is a blood pressure waveform from the calibration calculation unit 6 and represents a temporal change in blood pressure value. Referring to FIG. 3 (b), the waveform 22 displayed on the display unit 8 shows the blood flow velocity waveform from the FFT calculation unit 10, and the frequency of the fast Fourier transform calculation result is taken on the vertical axis, and the fast Fourier transform is performed. The power of the conversion calculation result is displayed as shading as luminance, and the temporal change of the image is shown. In this way, the blood pressure waveform and the blood flow velocity waveform can be displayed in synchronization on the same screen.

  As described above, according to the blood flow state monitoring apparatus according to the first embodiment of the present invention, blood pressure can be measured in real time in a non-invasive manner by measuring a blood vessel diameter using an ultrasonic echo. At the same time, blood flow velocity information flowing in the same blood vessel can be measured using ultrasonic echoes. For example, when the blood pressure of the subject decreases, it can be determined whether or not sufficient blood is being sent to the periphery by looking at the blood flow velocity waveform, so that more accurate treatment is possible.

  Moreover, since both blood pressure and blood flow velocity are measured based on ultrasound, the ultrasound transmitter, receiver, and phase detector can be shared. Therefore, it is possible to easily reduce the size of the ultrasonic sensor attached to the subject and the size of the blood flow state monitoring device. Although the ultrasonic probe 2 is a linear array probe, it may be a convex array, a concave shape, or a two-dimensional array. Furthermore, in the present embodiment, the calibration is based on the maximum blood pressure value and the minimum blood pressure value stored in the storage means, but the measured value from the cuff type sphygmomanometer is transferred online almost in real time. You may make it do.

(Second Embodiment)
FIG. 4 is a block diagram showing a configuration of a blood flow state monitoring apparatus 100A according to the second embodiment. In the first embodiment, the same constituent elements as those of the blood flow state monitoring apparatus 100 described above with reference to FIG. Therefore, detailed description of these components is omitted. The difference from the blood flow state monitoring apparatus 100 described above is that an ultrasonic probe 2 </ b> A is provided instead of the ultrasonic probe 2.

  FIG. 5 is a cross-sectional view for explaining the configuration of the ultrasonic probe 2A. In the first embodiment, the same components as those described above with reference to FIG. 2 are denoted by the same reference numerals. Therefore, detailed description of these components is omitted.

  The ultrasonic probe 2A includes a blood vessel diameter measuring transducer 43a provided on the ultrasonic coupling material 35 and a standoff 40c that is an inclination means provided next to the blood vessel diameter measuring transducer 43a. is doing. A slope is formed on the standoff 40c on the side opposite to the blood vessel diameter measuring transducer 43a. The angle of the slope of the standoff 40c may be about 10 ° at the acute angle portion (α), but about 30 ° is preferable in order to measure blood flow more accurately. On the slope formed in the standoff 40c, a blood flow velocity measuring transducer 40b is provided. The standoff 40c is made of a material whose main component is a gel whose main component is water that does not attenuate ultrasonic waves, or a (butadiene) rubber material.

  The blood vessel diameter measuring transducer 43a irradiates a blood vessel diameter detecting ultrasonic beam 37 along a direction substantially perpendicular to the anterior wall 32 and the posterior wall 33 of the artery. The blood flow velocity measurement transducer 40 b irradiates the velocity detection ultrasonic beam 38 so as to intersect the blood vessel diameter detection ultrasonic beam 37 at the approximate center of the arterial blood vessel lumen 34.

  The blood flow velocity measuring transducer 40b provided on the slope formed in the standoff 40c is perpendicular to the surface thereof, similarly to the blood vessel diameter measuring transducer 43a provided on the ultrasonic coupling material 35. Irradiate an ultrasonic beam along the direction. For this reason, both the blood vessel diameter measuring transducer 43a and the blood flow velocity measuring transducer 40b can be configured by a single transducer. Therefore, in the blood vessel diameter measuring transducer 43a and the blood flow velocity measuring transducer 40b, the circuit configurations of the ultrasonic beam transmitting unit and the receiving unit can be simplified.

  By providing the standoff 40c in this manner, the velocity detecting ultrasonic beam 38 is irradiated along a direction obliquely intersecting with the axial direction of the blood vessel, so that the blood flow velocity along the axial direction of the blood vessel is increased. Can be detected.

  As described above, according to the second embodiment, an ultrasonic probe can be configured by two single transducers and a standoff. For this reason, an ultrasonic probe can be reduced in size. Furthermore, it is possible to simplify the circuit configuration of the ultrasonic beam transmitter and receiver. Therefore, the blood flow state monitoring device can be reduced in size and price.

(Third embodiment)
FIG. 6 is a block diagram showing a configuration of a blood flow state monitoring apparatus 100B according to the third embodiment. In the first embodiment, the same constituent elements as those of the blood flow state monitoring apparatus 100 described above with reference to FIG. Therefore, detailed description of these components is omitted. The difference from the blood flow state monitoring apparatus 100 described above is that an FFT calculation unit 10B is provided instead of the FFT calculation unit 10.

  FIG. 7 is a cross-sectional view for explaining a method of calculating a blood flow volume using ultrasonic waves transmitted from the ultrasonic probe 2 provided in the blood flow state monitoring apparatus 100B. The blood vessel diameter obtained by tracking is D, and the angle at which the blood vessel diameter detecting ultrasonic beam 37 and the velocity detecting ultrasonic beam 38 intersect is θ.

  Assuming that the blood flow velocity at the position separated from the blood vessel center by the distance R along the traveling direction of the velocity detection ultrasonic beam 38 is v (R, t), the flow rate F (t) per unit time is as follows. It can be calculated by the following (Equation 1).

  In order to obtain the blood flow velocity v (R, t), a plurality of echoes based on the velocity detecting ultrasonic beam 38 are sampled along the depth direction, and FFT calculation is performed at each sampling point.

  Furthermore, by integrating the flow rate F (t) per unit time with the heartbeat time, the blood flow volume Vol for each heartbeat can be obtained.

  FIGS. 8A, 8B, and 8C are waveform diagrams showing blood pressure, blood flow, and blood flow velocity measured by the blood flow state monitoring device 100B. The blood pressure waveform 21, the blood flow waveform 61 for each heartbeat, and the blood flow velocity waveform 22 are displayed on the same screen. Since the blood flow volume for each heartbeat is calculated once for each heartbeat, the blood flow waveform 61 is displayed as a straight line for each heartbeat period as shown in FIG.

  The heartbeat period can be obtained from a separately installed electrocardiogram. Further, it is possible to capture the systolic timing of the heart by detecting a sudden rise in the blood vessel diameter waveform or the blood flow velocity waveform, and it is also possible to obtain the heartbeat period based on these waveforms.

  As described above, according to the blood flow state monitoring apparatus according to the third embodiment of the present invention, blood pressure and blood flow volume can be displayed, and the blood flow state of the subject can be monitored in more detail.

  The present invention can be applied to a medical device for obtaining a blood flow velocity.

1 is a block diagram showing a configuration of a blood flow state monitoring device according to Embodiment 1. FIG. Sectional drawing for demonstrating the structure of the ultrasonic probe provided in the blood-flow state monitoring apparatus which concerns on Embodiment 1. FIG. Waveform diagram showing blood pressure and blood flow velocity measured by the blood flow state monitoring apparatus according to Embodiment 1 A block diagram showing a configuration of a blood flow state monitoring apparatus according to a second embodiment. Sectional drawing for demonstrating the structure of the ultrasonic probe provided in the blood-flow state monitoring apparatus which concerns on Embodiment 2. FIG. A block diagram showing a configuration of a blood flow state monitoring apparatus according to a third embodiment. Sectional drawing for demonstrating the path | route of the ultrasonic wave transmitted from the ultrasonic probe provided in the blood-flow state monitoring apparatus which concerns on Embodiment 3. FIG. Waveform diagram showing blood pressure, blood flow volume and blood flow velocity measured by the blood flow state monitoring apparatus according to the third embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmission part 2 Ultrasonic probe 3 Reception part 4 Phase detection part 5 Blood vessel diameter calculation part 6 Calibration calculation part 7 Cuff type sphygmomanometer 8 Display part 9 Wall filter 10 FFT calculation part 100 Blood flow state monitoring apparatus

Claims (11)

An ultrasonic transmission / reception means for transmitting an ultrasonic signal to a blood vessel in a subject, receiving an ultrasonic echo reflected by the blood vessel, and converting it into an ultrasonic echo signal;
A blood vessel diameter calculating means for analyzing the ultrasonic echo signal and calculating a temporal change in the blood vessel diameter representing the diameter of the blood vessel;
Storage means for storing a maximum blood pressure value and a minimum blood pressure value of blood flowing through the blood vessel acquired in advance;
A blood pressure representing a temporal change in the blood pressure of the blood flowing through the blood vessel based on the temporal change in the blood vessel diameter calculated by the blood vessel diameter calculating means and the highest blood pressure and the lowest blood pressure stored in the storage means. A blood flow state monitoring apparatus comprising calibration calculation means for calculating a waveform.   The blood flow state monitoring device according to claim 1, further comprising blood flow velocity calculation means for calculating a blood flow velocity of blood flowing through the blood vessel based on the ultrasonic echo signal.   The calibration calculating means associates the maximum value of the temporal change of the blood vessel diameter calculated by the blood vessel diameter calculating means with the maximum blood pressure measured by the cuff sphygmomanometer, and changes the temporal change of the blood vessel diameter. 2. The blood flow according to claim 1, wherein a temporal change of the blood vessel diameter calculated by the blood vessel diameter calculating means is associated with a blood pressure value by associating the minimum value of the blood vessel with the minimum blood pressure stored by the storage means. Condition monitoring device.   Based on the temporal change of the blood vessel diameter calculated by the blood vessel diameter calculating means and the blood flow velocity calculated by the blood flow velocity calculating means, the volume of blood flowing through the blood vessel in each heartbeat period is calculated. The blood flow state monitoring device according to claim 2, further comprising blood flow volume calculating means for calculating a blood flow volume to be expressed.   The blood flow state monitoring apparatus according to claim 1, further comprising display means for displaying the blood pressure waveform calculated by the calibration calculating means.   The blood flow state monitoring device according to claim 2, further comprising display means for displaying the blood flow velocity calculated by the blood flow velocity calculating means.   The blood flow state monitoring apparatus according to claim 1, wherein the ultrasonic transmission / reception means includes an ultrasonic transmission / reception element unit provided to face the surface of the skin of the subject. The ultrasonic probe transmits a blood vessel diameter detection beam for detecting the blood vessel diameter along a direction substantially perpendicular to a blood vessel wall constituting the blood vessel,
A blood flow velocity detection beam for detecting the blood flow velocity, and a second element that transmits the blood vessel diameter detection beam transmitted from the first element so as to intersect at a substantial center of the lumen of the blood vessel. The blood flow state monitoring device according to claim 2.   The blood flow state monitoring device according to claim 8, wherein the blood vessel diameter detection beam and the blood flow velocity detection beam are transmitted alternately.   The blood flow state monitoring device according to claim 8, wherein the ultrasonic probe further includes a tilting means provided to tilt the second element with respect to the blood vessel. An ultrasonic transmission / reception means for transmitting an ultrasonic signal to a blood vessel of a subject, receiving an ultrasonic echo reflected by the blood vessel, and converting it into an ultrasonic echo signal;
A blood vessel diameter calculating means for analyzing the ultrasonic echo signal and calculating a temporal change in the blood vessel diameter representing the diameter of the blood vessel;
Storage means for storing a maximum blood pressure value and an average blood pressure value of blood flowing through the blood vessel acquired in advance;
A blood pressure waveform representing a temporal change in the blood pressure of the blood flowing through the blood vessel based on the temporal change in the blood vessel diameter calculated by the blood vessel diameter calculating means and the maximum blood pressure and the average blood pressure stored in the storage means. A blood flow state monitoring apparatus comprising calibration calculation means for calculating the blood flow.

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