Device and method for assessing cardiovascular activity

Abstract

Cardiovascular Activity Assessment Device and Method This description relates to a portable electronic device for assessing human cardiovascular activity, comprising first and second probes substantially parallel to each other and situated on either side of a third probe (101C), substantially perpendicular to the first and second probes, each probe having an array of ultrasonic transducers (103A, 103B, 103C), and a control circuit configured to: a) estimate, by a first ultrasonic beam emitted by the first probe (101A), the position of a blood vessel (150) relative to the device; and b) adjust a second ultrasonic beam (201; 201′), emitted by the third probe (101C), according to the estimated position of the blood vessel (150). Figure for the abstract: Fig. 3

Description

Title of the invention: Device and method for evaluating cardiovascular activity Technical field

[0001] The present description relates generally to electronic devices, and more particularly to devices and methods for evaluating cardiovascular activity by ultrasound. Prior art

[0002] Electronic devices and methods for evaluating cardiovascular activity are known, making it possible, for example, to detect malfunctions likely to affect a cardiovascular system of a human being, to monitor a clinical condition of a patient suffering from cardiovascular disease or to follow a change in cardiovascular parameters of an athlete during a sporting performance. Summary of the invention

[0003] An object of an embodiment is to overcome all or part of the drawbacks of known devices and methods for evaluating cardiovascular activity. More particularly, an object of an embodiment is to provide a portable electronic device for evaluating cardiovascular activity, for example having external dimensions compatible with being worn on a user's wrist.

[0004] For this, one embodiment provides a portable electronic device for evaluating human cardiovascular activity, comprising first and second probes substantially parallel to each other and located on either side of a third probe, substantially perpendicular to the first and second probes, each probe comprising a strip of ultrasonic transducers, and a control circuit configured to: a) estimating, by a first ultrasound beam emitted by the first probe, a position of a blood vessel relative to the device; and b) adjust a second ultrasound beam, emitted by the third probe, according to the estimated position of the blood vessel.

[0005] According to one embodiment, an emission direction of the second ultrasound beam is adjusted according to the estimated position of the blood vessel.

[0006] According to one embodiment, a focal length of the second ultrasound beam is further adjusted according to the estimated position of the blood vessel.

[0007] According to one embodiment, the first ultrasound beam emitted by the first probe is adjusted according to the estimated position of the blood vessel.

[0008] According to one embodiment, the second probe is configured to emit a third ultrasonic beam.

[0009] According to one embodiment, during step a), the position of the blood vessel relative to the device is further estimated by the third ultrasound beam emitted by the second probe.

[0010] According to one embodiment, a pulse wave velocity inside the blood vessel is estimated from the first and third ultrasound beams emitted respectively by the first and second probes.

[0011] According to one embodiment, the blood flow inside the blood vessel is further estimated, from the second ultrasound beam, by Doppler effect.

[0012] According to one embodiment, the blood vessel is the ulnar artery.

[0013] According to one embodiment, the control circuit comprises a first ge pulse generator connected to the ultrasonic transducers of the arrays of the first and second probes and a second pulse generator connected to the ultrasonic transducers of the array of the third probe.

[0014] According to one embodiment, the control circuit comprises a single pulse generator connected, via a multiplexer, to the ultrasonic transducers of the arrays of the first, second and third probes.

[0015] According to one embodiment, the array of ultrasonic transducers of the third probe comprises twice as many ultrasonic transducers as each of the arrays of ultrasonic transducers of the first and second probes, the multiplexer being a 1 to 2 multiplexer.

[0016] One embodiment provides a connected watch or bracelet comprising a device as described.

[0017] One embodiment provides a method for evaluating human cardiovascular activity, by a portable electronic device comprising first and second probes substantially parallel to each other and located on either side of a third probe, substantially perpendicular to the first and second probes, each probe comprising a strip of ultrasonic transducers, and a control circuit, the method comprising the following steps: a) estimating, by a first ultrasound beam emitted by the first probe, a position of a blood vessel relative to the device; and b) adjust a second ultrasound beam, emitted by the third probe, according to the estimated position of the blood vessel.

[0018] According to one embodiment, in step a), the position of the blood vessel relative to the device is further estimated by a third ultrasound beam emitted by the second probe. Brief description of the drawings

[0019] These characteristics and advantages, as well as others, will be explained in detail in the following description of particular embodiments given without limitation in relation to the attached figures among which:

[0020] [Fig.l] is a top view illustrating, schematically and partially, an example of a portable electronic device for evaluating cardiovascular activity according to one embodiment;

[0021] [Fig.2] is a sectional view, along plane AA of [Fig.l], of the device of [Fig.l] in a first configuration of use;

[0022] [Fig.3] is a sectional view, along plane AA of [Fig.l], of the device of [Fig.l] in a second configuration of use;

[0023] [Fig.4] represents, schematically and partially, an example of embodiment of a control circuit of the device of [Fig.l];

[0024] [Fig.5] represents, schematically and partially, another example of embodiment of the control circuit of the device of [Fig.l]; and

[0025] [Fig.6] illustrates an example of integration of the device of [Fig.l] into a smart watch worn on a user's wrist. Description of the embodiments

[0026] The same elements have been designated by the same references in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same references and may have identical structural, dimensional and material properties.

[0027] For the sake of clarity, only the steps and elements useful for understanding the described embodiments have been shown and are detailed. In particular, the various applications of the devices and methods described have not been detailed, the described embodiments being compatible with all or most of the applications likely to benefit from a device or method for estimating cardiovascular activity. In addition, the ultrasonic transducers of the probes of the device have not been detailed, the production and practical implementation of these transducers being within the scope of the person skilled in the art from the indications of the present description.

[0028] Unless otherwise specified, when referring to two elements connected to each other, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") to each other, this means that these two elements can be connected or be connected by means of one or more other elements.

[0029] In the following description, when referring to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "upper", "lower", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made, unless otherwise specified, to the orientation of the figures.

[0030] Unless otherwise specified, the expressions "about", "approximately", "substantially", and "of the order of" mean to within 10%, preferably to within 5% or, when it is an angular value, to within 10°, preferably to within 5°.

[0031] [Fig.l] is a top view illustrating, schematically and partially, an example of a portable electronic device 100 for evaluating cardiovascular activity by ultrasound according to one embodiment.

[0032] In the example shown, the device 100 comprises first, second and third probes 101A, 101B, 101C each comprising a strip of ultrasonic transducers 103A, respectively 103B, respectively 103C. In the example shown, the strips of transducers 103A, 103B and 103C are substantially linear. As a variant, each strip of transducers 103A, 103B and 103C may have a non-rectilinear shape, for example curved. Furthermore, [Fig.l] illustrates an example in which the transducers 103A, 103B, 103C of the same strip have substantially identical external dimensions, apart from manufacturing variations, and are regularly spaced. However, as a variant, the transducers 103A, 103B, 103C of the same strip may have different dimensions from each other and variable spacing.

[0033] The first and second ultrasonic probes 101A, 101B are located on either side of the third ultrasonic probe 101C and are substantially parallel to each other. The third probe 101C is substantially perpendicular to the first and second probes 101A, 101B. In this example, the first, second and third probes 101A, 101B, 101C have, in top view, a general H shape, the first and second probes 101A, 101B respectively forming the two vertical bars of the H and the third probe 101C forming the horizontal bar of the H.

[0034] In the example illustrated in [Fig.l], the probes 101A, 101B each comprise eight ultrasonic transducers 103A, 103B and the probe 10IC comprises sixteen ultrasonic transducers 103C. However, the probes 101A, 101B, 10IC may comprise numbers of ultrasonic transducers 103A, 103B, 103C different from those shown. For example, the number of ultrasonic transducers 103A, 103B, 103C of each strip corresponds to a power of two and the number of ultrasonic transducers 103C of the central probe 101C is twice as large as the number of ultrasonic transducers 103A, 103B of each of the two lateral probes 101A, 101B. The ultrasonic transducers 103A, 103B, 103C each have, for example, a substantially rectangular shape. In addition, the transducers 103C may be narrower than the transducers 103A, 103B so that the probe 101C has a greater lateral resolution than the probes 101A, 101B. 10 IB, for example in a case where probe 101C is used in mode B, or to perform an electronically deflected Doppler shot, and probes 101 A, 101B are used in mode A as will be explained in more detail later.

[0035] In the example shown, the portable electronic device 100 is arranged above a blood vessel 150, for example an artery, one wall of which is symbolized, in [Fig. 1], by two dotted lines. For the purposes of simplification, the thickness of the blood vessel 150 is neglected, the two dotted lines of [Fig. 1] thus being able to symbolize indifferently the internal or external walls of the blood vessel 150. In this example, the arrays of ultrasonic transducers 103A, 103B of the first and second probes 101A, 101B are oriented transversely relative to the blood vessel 150, and the array of ultrasonic transducers 103C of the third probe 101C is oriented longitudinally relative to the blood vessel 150.More specifically, in the illustrated example, the array of ultrasonic transducers 103C is substantially parallel to an axis Ox, along which the blood vessel 150 extends laterally, while the arrays of ultrasonic transducers 103A, 103B are substantially parallel to an axis Oy, perpendicular to the axis Ox. For example, in a case where the device 100 is worn on the arm or wrist of a user, the blood vessel 150 is the ulnar artery.

[0036] For the purposes of simplification, [Fig. 1] shows an example in which the blood vessel 150 is substantially rectilinear and has a cross-section of shape, for example circular, and of substantially constant dimensions over its entire length. However, in practice, the blood vessel 150 may have any shape, for example a curved shape, and a cross-section of variable shape and dimensions over all or part of its length. Furthermore, [Fig. 1] shows an example in which the arrays of ultrasonic transducers 103A, 103B, 103C are substantially centered relative to the blood vessel 150. This example is however not limiting, the arrays of ultrasonic transducers 103A, 103B, 103C being able to be off-centered, for example offset along the axis Oy, relative to the blood vessel 150.

[0037] For the purposes of legibility of the drawing, [Fig.l] illustrates an example in which the blood vessel 150 has a diameter greater than the length (dimension taken along the Oy axis) of the transducers 103C. The blood vessel 150 may, however, have different proportions relative to the transducers 103C, for example a diameter substantially equal to the length of the transducers 103C, or a diameter less than the length of the transducers 103C.

[0038] [Fig.2] is a sectional view, along plane AA of [Fig.1], of the portable electronic device 100 for evaluating human cardiovascular activity in a first configuration of use.

[0039] In this configuration of use, the blood vessel 150 is substantially parallel to a substantially planar lower face 1001 of the device 100. More precisely, the blood vessel 150 has a median axis 150M parallel to the axis Ox, the lower face 1001 of the device 100 being parallel to the plane Oxy. In the example shown, the ultrasonic transducers 103A, 103B, 103C are substantially equidistant from the median axis 150M of the blood vessel 150. In other words, in this example, the blood vessel 150 extends laterally under the ultrasonic transducers 103A, 103B, 103C at a substantially constant depth P. In the orientation of [Fig.2], the depth P corresponds to a distance, measured along the vertical axis Oz, between the lower face 1001 of the device 100 and the median axis 150M of the blood vessel 150. By way of example, the lower face 1001 of the device 100 is placed on and in contact with the skin of an arm 151 of the user.

[0040] The ultrasonic transducers 103A, 103B of the probes 101A, 101B of the device 100 make it possible, for example, to estimate a volume flow rate Dv of blood circulating inside a portion of the blood vessel 150 located under the device 100, for example by a method for determining pulse wave velocity (PWV). The pulse wave velocity, denoted VOP, is for example calculated from a measurement of pulse wave propagation time (PTT), produced at each heartbeat, between the ultrasonic transducers 103A and 103B.

[0041] For this, the device 100 records, for example, time changes DA(t), DB(t) of a diameter D of the blood vessel 150 evaluated in two distinct locations separated by a distance L, for example directly above the probes 101A and 101B. A phase shift measurement At between the time changes DA(t), DB(t) of the diameter D, recorded respectively using the probes 101A and 101B following the same heartbeat, makes it possible to estimate the pulse wave propagation time between these probes. Knowing the distance L separating the probes 101A and 101B, it is then possible to calculate the pulse wave propagation speed VOP inside the blood vessel 150 (VOP = L / At).

[0042] As an example, the temporal variations DA(t), DB(t) of the diameter D of the blood vessel 150 are evaluated in mode A. In this mode, an amplitude of a returned echo signal is measured as a function of the depth. As a variant, the temporal variations DA(t), DB(t) of the diameter D of the blood vessel 150 can be evaluated from images produced in mode B. In this mode, two-dimensional ultrasound images composed of light points representing ultrasonic echoes are produced, the brightness of each point being determined by the amplitude of the returned echo signal.

[0043] Furthermore, the ultrasonic transducers 103C of the third probe 101C can make it possible to estimate the volume flow rate Dv of the blood circulating inside the portion of the blood vessel 150 located under the device 100. The estimation of the flow rate Dv by the probe 101C is for example carried out by Doppler effect.

[0044] In this case, the ultrasonic transducers 103C are for example controlled to emit an incident ultrasonic beam 201 in the direction of the blood vessel 150, and to receive an ultrasonic beam reflected by the blood circulating inside the blood vessel 150. The incident ultrasonic beam 201 corresponds for example to a pulse signal of frequency f; and the reflected ultrasonic beam corresponds for example to a pulse signal of frequency fr. By measuring a frequency shift between the incident and reflected signals, that is to say by measuring a difference between the frequencies fr and fi5, it is possible to determine the speed v of movement of the blood inside the blood vessel 150. Furthermore, the measurements of the diameter D make it possible to estimate a section S of the blood vessel 150 under the device 100. The section S corresponds for example to a surface of a cross-section of the blood vessel 150.By multiplying the section S of the blood vessel 150 by the speed v of blood flow through this section, we can then go back to the volume flow rate Dv of the blood inside the blood vessel 150 (Dv = S*v).

[0045] As an example, the diameter D of the blood vessel 150 is evaluated, in mode A or in mode B, by the ultrasonic transducers 103C of the probe 101C. Alternatively, the diameter D of the blood vessel can be evaluated, in mode A or in mode B, by the ultrasonic transducers 103A of the probe 101A and / or by the ultrasonic transducers 103B of the probe 101B as previously explained.

[0046] When estimating the blood flow rate Dv by Doppler effect, the incident ultrasound beam 201 emitted by the array of ultrasound transducers 103C has an emission direction forming for example an angle α, called the deflection angle ("steering angle", in English), relative to a normal to the lower surface 1001 of the device 100. To obtain optimal measurement accuracy of the speed v, the angle α is for example adjusted so that the ultrasound beam 201 reaches the blood vessel 150 at a low angle of incidence θ, called the Doppler angle. For example, the angle θ is between 30° and 60°.

[0047] Furthermore, the incident ultrasound beam 201 is for example focused at the median axis 150M of the blood vessel 150, i.e. at the depth P under the device 100, in this example. This makes it possible for example to measure the speed v at the center of the flow and not near the walls of the blood vessel 150. This results in better measurement accuracy.

[0048] Alternatively, the probe 101C can be used to perform B-mode ultrasound imaging, more precisely high-frequency Plane Wave Imaging (PWI). From the images thus obtained, the diameter D of the blood vessel 150 and the blood circulation velocity v can for example be estimated by a technique called Vector Flow Imaging (VFI).

[0049] [Fig. 3] is a sectional view, along plane AA of [Fig. 1], of the electrical device 100 portable human cardiovascular activity assessment electronics in a second use configuration.

[0050] In this configuration of use, the blood vessel 150 is inclined relative to the device 100. More precisely, the blood vessel 150 is, in this example, parallel to the plane Oxz and inclined at an angle q> relative to the horizontal axis Ox, the lower face 1001 of the device 100 being parallel to the plane Oxy. In this example, the ultrasonic transducers 103B of the second probe 10IB are further from the median axis 150M of the blood vessel 150 than the ultrasonic transducers 103A of the first probe 101A. More precisely, in the example illustrated in [Fig.3], the median axis 150M of the blood vessel 150 is located at a depth PA under the ultrasonic transducers 103A and at another depth PB, greater than the depth PA, under the ultrasonic transducers 103B. In the orientation of [Fig.3], the depths PA, PB correspond to distance measurements along the vertical axis Oz.

[0051] In the example illustrated in [Fig.3], the inclination of the blood vessel 150 modifies the angle of incidence of the incident ultrasound beam 201 emitted by the probe 101C in the direction of the blood vessel 150. More precisely, in this example, the beam 201 reaches the blood vessel 150 at an angle of incidence 0' less than the angle 0 (0' = 0 + q>). This tends to degrade the accuracy of the measurement of the speed v, therefore the estimation of the volume flow rate Dv of the blood inside the blood vessel 150.

[0052] Furthermore, in the example illustrated in [Fig. 3], the angle q> of inclination of the blood vessel 150 tends to cause a focusing of the incident ultrasound beam 201 emitted by the probe 101C in an area far from the median axis 150M, that is to say closer to the walls of the blood vessel 150M than in the example illustrated in [Fig. 2]. This also tends to degrade the accuracy of the measurement of the speed v, therefore of the flow rate Dv.

[0053] According to one embodiment, advantage is taken of the lateral arrays of ultrasonic transducers 103A, 103B located on either side of the central array of ultrasonic transducers 103C to emit ultrasonic beams making it possible to estimate the position of the blood vessel 150 relative to the device 100. Depending on the estimated position of the blood vessel 150, the ultrasonic beam 201 emitted by the third probe 101C is then adjusted.

[0054] More precisely, the ultrasonic transducers 103A emit for example a first ultrasonic beam making it possible to estimate the position, for example the depth PA along the axis Oz, at which the blood vessel 150 is located directly above the probe 101 A. Similarly, the ultrasonic transducers 103B emit for example a second ultrasound beam making it possible to determine the position, for example the depth DB along the Oz axis, at which the blood vessel 150 is located directly above the probe 101B. From the depths PA and PB, and knowing the distance L separating the probes 101A and 101B, it is possible to work out the angle q> of inclination of the blood vessel 150 relative to the Ox axis, for example by considering that the portion of the blood vessel 150 located under the device 100 is substantially rectilinear. The estimation of the angle q> thus obtained makes it possible for example to advantageously compensate for the inclination of the blood vessel 150 when measuring the speed v by Doppler effect, for example by emitting with the central probe 101C an incident ultrasound beam 201' forming an angle a' with the normal to the lower surface 1001 of the device 100.The angle a' is for example adjusted so that the ultrasound beam 201' reaches the blood vessel 150 at an angle of incidence as close as possible to the angle 0 (equal to the angle 0, in the example illustrated in [Fig.3]).

[0055] Estimating the angle q>, using the lateral probes 101A, 101B of the device 100, also makes it possible to modify a focal distance of the incident ultrasound beam emitted by the central probe 10IC. In the example shown, the incident ultrasound beam 201' is focused in the vicinity of the median axis 150M of the blood vessel 150, which again makes it possible to compensate for the inclination of the blood vessel 150 relative to the device 100 and to advantageously obtain more precise measurements than if the probe 10IC emitted the ultrasound beam 201.

[0056] Furthermore, the ultrasonic beams emitted by the lateral probes 101A, 101B can be adjusted as a function of the estimated position of the blood vessel 150. More precisely, an emission direction and a focal distance of the ultrasonic beams respectively emitted by the arrays of ultrasonic transducers 103A, 103B can be adjusted as a function of the estimated position of the blood vessel 150. As a variant, once the position of the blood vessel 150 has been detected by the probes 101A, 101B, only a portion of the ultrasonic transducers 103A, 103B, for example the ultrasonic transducer 130A, 103B of each array closest to the median axis 150M, can be used to monitor the temporal evolution of the diameter D.

[0057] In the case where the probes 101A, 101B implement the method for determining pulse wave velocity by measuring pulse transit time previously described in relation to [Fig. 2], the estimation of the position of the blood vessel 150 relative to the device 100 can furthermore be advantageously used to compensate for a distance error between the diameter measurement zones D directly above the ultrasonic transducers 103A, 103B. In the example of [Fig. 3], these zones are in fact separated by a distance L' not equal to the distance L between the probes 101A and 101B, as in the example illustrated in [Fig. 2], but equal to L*cos(q>).

[0058] An example is illustrated in [Fig.3] in which the median axis 150M of the vessel blood vessel 150 is inclined at a negative angle q> relative to the Ox axis and in which the ultrasound beam 201' is directed downstream of the blood vessel 150 (to the right, in the orientation of [Fig. 3]). Alternatively, the blood vessel 150 could be inclined at a positive angle q> relative to the Ox axis, the depth PA being in this case greater than the depth PB. Compensation for the inclination of the blood vessel 150 would then be achieved, for example, by adjusting the angle a' so that the ultrasound beam 201' reaches the blood vessel 150 at an angle of incidence of between 120 and 150°. In this case, the ultrasound beam 201' would be directed upstream of the blood vessel 150 (to the left, in the orientation of [Fig. 3]).

[0059] Although an example has been described above in which the blood vessel 150 is parallel to the plane Oxz and inclined with respect to the angle Ox, the described embodiments also apply to cases in which the blood vessel 150 has any orientation in space. By way of example, the described embodiments can be transposed by the person skilled in the art to cases in which the blood vessel 150 is parallel to the plane Oxy and inclined with respect to the axis Ox and to cases in which the blood vessel 150 is parallel neither to the plane Oxz nor to the plane Oxy.

[0060] Furthermore, embodiments have been described above in which the direction and / or focal length of the ultrasound beams emitted by the arrays of ultrasound transducers 103A, 103B, 103C can be adjusted as a function of the estimated position of the blood vessel 150. However, it would also be possible to take advantage of the estimation of the position of the blood vessel 150 relative to the device 100 to compensate for measurements made by the probes 101A, 101B, 101C without modifying the direction and / or focal length of the ultrasound beams that they emit, or in addition to such modifications.

[0061] Furthermore, although an example has been described in which the two lateral transducer arrays 103A and 103B are used to estimate the position of the blood vessel 150, it could, as a variant, be provided to use a single lateral transducer array, for example the transducers 103A of the probe 101A or the transducers 103B of the probe 101B, to estimate the position of the blood vessel 150. This variant is within the ability of the person skilled in the art based on the indications of the present description.

[0062] [Fig.4] schematically and partially represents an example of embodiment of a control circuit 400 of the device 100 of [Fig.1].

[0063] In the example shown, the circuit 400 comprises two pulse generators 401AB, 401C (“pulse”, in English), also called transmission circuits. The pulse generator 401AB is for example connected to the ultrasonic transducers 103A, 103B of the lateral probes 101A, 10IB and the pulse generator 40IC is for example connected to the ultrasonic transducers 103C of the central probe 10IC. In this example, each pulse generator 401 AB, 40IC comprises, for each ultrasonic transducer 103A, 103B, 103C to which it is connected, a channel 403. For example, in the case where the strips of the lateral probes 101A, 101B each comprise eight ultrasonic transducers 103A, 103B and where the strip of the central probe 10IC comprises sixteen ultrasonic transducers 103C, each pulse generator 401AB, 401C comprises sixteen identical channels 403, apart from manufacturing dispersions. For example, the pulse generators 401 AB and 401C are identical, apart from manufacturing dispersions.

[0064] In the example shown, each channel 403 more precisely comprises an amplifier 405 (HV), for example a high voltage amplifier, a transmission beamformer 407 (TX BF) and a transmission-reception switch 409. In the example illustrated in [Fig. 4], the transmission beamformer 407 comprises an input connected to an output of a processing unit 411 (PU), for example a programmable pre-diffused matrix ("Field-Programmable Gate Array" - FPGA, in English), and an output connected to an input of the high-voltage amplifier 405. The amplifier 405 comprises an output connected to one of the terminals of the switch 409 and to one of the ultrasonic transducers 103A, 103B, 103C. In this example, the other terminal of each switch 409 is connected to an analog front end 421, also called a receiving circuit.

[0065] The reception circuit 421 comprises a plurality of reception channels 423. In this example, the circuit 421 comprises a number of reception channels 423 equal to half the number of ultrasonic transducers 103A, 103B, 103C of the device 100. For example, in the case where the bars of the lateral probes 101A, 101B each comprise eight ultrasonic transducers 103A, 103B and where the bar of the central probe 101C comprises sixteen ultrasonic transducers, the circuit 421 comprises sixteen identical channels 423, apart from manufacturing variations.

[0066] In the example shown, each channel 423 more precisely comprises an amplifier 425 (LNA), for example a low noise amplifier, an amplifier 427 (PGA), for example a programmable gain amplifier, a low pass filter 429 (LPF), an analog-digital converter 431 (ADC) and a serial converter 433 (LVDS), for example a converter capable of operating in low voltage differential signaling. In this example, the amplifier 425 of each channel 423 has an input connected to one of the channels 403 of the pulse generator 401 AB and to one of the channels 403 of the pulse generator 40IC, and an output connected to an input of the amplifier 427. The amplifier 427 has an output connected to an input of the filter 429. The converter 431 includes an input connected to the filter 429 and an output connected to an input of the series converter 433. In the example shown, the amplifiers 425 and 427, the filter 429 and the converter 431 each comprises a control input connected to an output of the processing unit 411. In addition, each channel 423 of the circuit 421 comprises an output, corresponding to an output of the serial converter 433, connected to the processing unit 411.

[0067] An example of operation of the device 100 associated with the circuit 400 will now be described in relation to [Fig.4].

[0068] During a first transmission step, the switches 409 of the pulse generator 401 AB are for example all in the open state and ultrasonic beams are emitted by the lateral probes 101A and 101B. During the first transmission step, the processing unit 411 is for example configured not to transmit any signal to the transmission beam formers 407 of the pulse generator 401C, the probe 101C then emitting for example no ultrasonic beam. Then, during a first reception step after the first transmission step, all the switches 409 of the pulse generator 401 AB are for example closed in order to allow the lateral probes 101A, 101B to pick up ultrasonic echoes. In this example, the position of the blood vessel 150 relative to the device 100 is for example estimated at the end of the first reception step.

[0069] Then, during a second transmission step subsequent to the first reception step, all the switches 409 of the pulse generator 40IC are in the open state and ultrasonic beams are emitted by the central probe 101C. During the second transmission step, the processing unit 411 is for example configured not to transmit any signal to the transmission beamformers 407 of the pulse generator 401AB, the probes 101A and 101B then emitting for example no ultrasonic beam. Finally, during a second reception step subsequent to the second transmission step, all the switches 409 of the pulse generator 40IC are closed for example in order to allow the central probe 101C to pick up ultrasonic echoes. The measurement of the flow rate Dv is for example carried out at the end of the second reception step.

[0070] Once the second reception step is completed, the emission parameters of the beam emitted by the central probe 101C and / or the beams emitted by the probes 101A, 101B are adjusted, for example, as a function of the position of the blood vessel 150 relative to the device 100 as estimated during the first reception step. The transmission and reception steps previously described can then, for example, be repeated using the modified emission parameters.

[0071] By way of example, the position of the blood vessel 150 is estimated and the emission parameters of the probe 10IC and / or the probes 101 A, 101B are modified at the start of a phase of evaluation of the cardiovascular activity of a patient, the emission parameters of the probe 10IC and / or the probes 101 A, 101B remaining thereafter unchanged until the next evaluation phase, for example carried out on another patient. Alternatively, it may be provided that the operations of estimating the position of the blood vessel 150 and adjusting the emission parameters of the probe 10IC and / or the probes 101 A, 101B are repeated during the same phase of evaluation of the patient's cardiovascular activity.

[0072] [Fig. 5] schematically and partially represents an example of embodiment of a control circuit 500 of the device 100 of [Fig. 1]. The circuit 500 of [Fig. 5] comprises elements in common with the circuit 400 of [Fig. 4].

[0073] The circuit 500 of [Fig. 5] differs from the circuit 400 of [Fig. 4] mainly in that, in the example shown, the circuit 500 comprises a single pulse generator, for example the pulse generator 401 AB previously described in relation to [Fig. 4]. Furthermore, the circuit 500 differs from the circuit 400 in that it comprises a multiplexer 501 (MUX) connecting the ultrasonic transducer arrays 103A, 103B, 103C of the probes 101A, 101B, 101C of the device 100 to the pulse generator 401 AB. In the example shown where the device comprises thirty-two ultrasonic transducers 103A, 103B, 103C, the multiplexer 501 more precisely comprises sixteen channels and is of type 1 to 2.

[0074] By way of example, each channel of the multiplexer 501 comprises, as in the example illustrated in [Fig. 5], a switch 503 of the single-pole double-throw (SPDT) type, one input terminal of which is connected to one of the channels 403 of the pulse generator 401 AB, a first output terminal of which is, for example, connected to one of the ultrasonic transducers 103A, 103B of the lateral probes 101 A, 101 B, and a second output terminal of which is, for example, connected to one of the ultrasonic transducers 103C of the central probe 101 C. The multiplexer 501 further comprises a control input connected to the processing unit 411 and making it possible, for example, to switch all the switches 503 between their first and second output terminals, for example substantially simultaneously.For example, the control input receives from the processing unit 411 a control signal, a first level of which places all the switches 503 in a state where their input terminal is connected to their first output terminal and a second level of which places all the switches 503 in another state where their input terminal is connected to their second output terminal.

[0075] An example of operation of the device 100 associated with the circuit 500 will now be described in relation to [Fig.5].

[0076] During a first transmission step, the switches 409 of the pulse generator 401AB are for example all in the open state, the switches 503 of the multiplexer 501 are for example placed in the state in which their input terminal is connected to their first output terminal, connected to the ultrasonic transducers 103A, 103B in this example, and ultrasonic beams are emitted by the lateral probes 101A and 101B. Then, during a first reception step subsequent to the first transmission step, for example, all the switches 409 of the pulse generator 401AB are closed in order to allow the lateral probes 101A, 101B to pick up ultrasonic echoes, the switches 503 of the multiplexer 501 remaining in the state where their input terminal is connected to their first output terminal. In this example, the position of the blood vessel 150 relative to the device 100 is for example estimated at the end of the first reception step.

[0077] Then, during a second transmission step subsequent to the first reception step, the switches 409 of the pulse generator 401 AB are for example opened, the switches 503 of the multiplexer 501 are for example switched to the state in which their input terminal is connected to their second output terminal, connected to the ultrasonic transducers 103C in this example, and ultrasonic beams are emitted by the central probe 10IC. Finally, during a second reception step subsequent to the second transmission step, for example, all the switches 409 of the pulse generator 401 AB are closed in order to allow the central probe 101C to pick up ultrasonic echoes, the switches 503 of the multiplexer 501 remaining in the state where their input terminal is connected to their second output terminal, in order to allow the central probe 101C to pick up ultrasonic echoes.The measurement of the Dv flow rate is for example carried out at the end of the second reception stage.

[0078] Once the second reception step is completed, the emission parameters of the beam emitted by the central probe 101C and / or the beams emitted by the probes 101A, 101B are adjusted, for example, as a function of the estimated position of the blood vessel 150 relative to the device 100. The emission and reception steps previously described can then, for example, be repeated using the modified emission parameters.

[0079] An advantage of the circuits 400, 500 previously described is that they have a low number of electronic components and channels, which makes the circuits 400, 500 and the device 100 compatible with integration into a portable device and having a low acquisition cost.

[0080] [Fig. 6] illustrates an example of integration of the device 100 of [Fig. 1] in a device 600 of the bracelet type worn on the arm 151 of a user, for example a smart watch. In the example shown, the device 600 further integrates the control circuit 500 of the device 100. The device 100 is for example located in an area of ​​the device 600 intended to be placed substantially opposite the ulnar artery 150 of the arm 151 of the user. By way of example, the device 100 is integrated into a bracelet 601 of the device 600.

[0081] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will occur to those skilled in the art. In particular, those skilled in the art are able to substitute the control circuit 500 of the device 600 of [Fig. 6] with the control circuit 400 previously described in relation to [Fig. 4].

[0082] Finally, the practical implementation of the embodiments and variants described is within the reach of the person skilled in the art from the functional indications given above. In particular, the practical realization of the device 100, in particular the geometry, the positioning and the control of the ultrasonic transducers 103A, 103B, 103C of the probes 101A, 101B, 101C of the device 100, and the control of the elements of the circuits 400, 500 by the processing unit 411 are within the reach of the person skilled in the art from the indications of the present description.

Claims

Claims

1. Portable electronic device for evaluating human cardiovascular activity, comprising first and second probes (101 A, 101B) substantially parallel to each other and located on either side of a third probe (101C), substantially perpendicular to the first and second probes, each probe (101 A, 101B, 101C) comprising a strip of ultrasonic transducers (103A, 103B, 103C), and a control circuit (400; 500) configured to: a) estimate, by a first ultrasonic beam emitted by the first probe (101A), a position of a blood vessel (150) relative to the device; and b) adjust a second ultrasonic beam (201; 201'), emitted by the third probe (101C), as a function of the estimated position of the blood vessel (150).

2. Device according to claim 1, wherein the control circuit is configured to, in step b), adjust an emission direction of the second ultrasound beam (201; 201') as a function of the estimated position of the blood vessel (150).

3. Device according to claim 1 or 2, wherein the control circuit is further configured to, in step b), adjust a focal length of the second ultrasound beam (201; 201') as a function of the estimated position of the blood vessel (150).

4. A device according to any one of claims 1 to 3, wherein the control circuit is configured to adjust the first ultrasound beam emitted by the first probe (101A) as a function of the estimated position of the blood vessel (150).

5. A device according to any one of claims 1 to 4, wherein the second probe (101B) is configured to emit a third ultrasonic beam.

6. Device according to claim 5, wherein the control circuit is further configured to, during step a), estimate the position of the blood vessel (150) relative to the device by means of the third ultrasound beam emitted by the second probe (101B).

7. The device of claim 5 or 6, wherein the control circuit is configured to estimate a pulse wave velocity within the blood vessel (150) from the first and third ultrasound beams emitted respectively by the first and second probes (101A, 101B).

8. Device according to any one of claims 1 to 7, wherein the control circuit is further configured to estimate the blood flow rate inside the blood vessel (150), from the second ultrasound beam (201; 201'), by Doppler effect.

9. A device according to any one of claims 1 to 8, wherein the blood vessel (150) is the ulnar artery.

10. A device according to any one of claims 1 to 9, wherein the control circuit (400) comprises a first pulse generator (401AB) connected to the ultrasonic transducers (103A, 103B) of the arrays of the first and second probes (101A, 101B) and a second pulse generator (40IC) connected to the ultrasonic transducers (103C) of the array of the third probe (101C).

11. Device according to any one of claims 1 to 9, in which the control circuit (500) comprises a single pulse generator (401AB) connected, via a multiplexer (501), to the ultrasonic transducers (103A, 103B, 103C) of the arrays of the first, second and third probes (101A, 101B, 101C).

12. The device of claim 11, wherein the ultrasonic transducer array (103C) of the third probe (101C) comprises twice as many ultrasonic transducers (103C) as each of the ultrasonic transducer arrays (103A, 103B) of the first and second probes (101A, 101B), the multiplexer (501) being a 1 to 2 multiplexer.

13. Watch (600) or connected bracelet comprising a device according to any one of claims 1 to 12.

14. Method for evaluating human cardiovascular activity, by a portable electronic device comprising first and second probes (101A, 101B) substantially parallel to each other and located on either side of a third probe (101C), substantially perpendicular to the first and second probes, each probe (101A, 101B, 101C) comprising a strip of ultrasonic transducers (103A, 103B, 103C), and a control circuit (400; 500), the method comprising the following steps, implemented by the control circuit: a) estimating, by a first ultrasonic beam emitted by the first probe (101A), a position of a blood vessel (150) relative to the device; and b) adjusting a second ultrasound beam (201; 201'), emitted by the third probe (10IC), according to the estimated position of the blood vessel (150).

15. The method of claim 14, wherein, in step a), the position of the blood vessel (150) relative to the device is further estimated by a third ultrasound beam emitted by the second probe (101B).

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