Ultrasound imaging system

Abstract

The present specification relates to an ultrasound imaging system comprising a set of N ultrasound imaging probes (100) and a master device (110) external to the probes, where each ultrasound probe (100) comprises:-a set (201) of substantially ultrasound transducers; -an electronic transceiver circuit (203); -digital processing circuitry (205) adapted to control the electronic transceiver circuitry (203) of the probe; -a clock signal generator (207); and-communication circuitry (211) adapted to transmit data between the digital processing circuitry (205) of the probe and the master device (110), and wherein the master device (110) is adapted to synchronously control the transmission and / or reception of the ultrasound waves by the probe (100).

Description

[0001] This application is based on French patent application No. 23 / 09676, filed on September 14, 2023, entitled “Système d’imagerie ultrasonore” and claiming priority thereof, which is incorporated herein by reference in the extent permitted by law. TECHNICAL FIELD

[0002] The present disclosure relates generally to the field of ultrasound imaging systems. BACKGROUND

[0003] Portable ultrasound systems, commonly referred to as POC (Point Of Care) systems, have been provided, aimed at being taken close to the patient in non-essential medical treatment sites.

[0004] Such systems generally comprise a portable ultrasound probe and a smartphone or tablet type mobile terminal adapted to communicate with the probe. The probe is able to acquire ultrasound data relating to the patient's body, which are transmitted to the mobile terminal and processed to generate images displayed in real time on the mobile terminal screen, thus enabling the user to examine the patient.

[0005] It is desirable to improve at least partially certain aspects of known ultrasound systems. SUMMARY

[0006] For this purpose, embodiments provide an ultrasound imaging system comprising a set of N ultrasound imaging probes, where N is an integer greater than or equal to 2; and a master device external to the probes, wherein each ultrasound probe comprises: - a set of elementary ultrasound transducers; - an electronic transceiver circuit adapted to apply an electrical excitation signal to the elementary transducers of the probe and to read and digitize an electrical response signal of the elementary transducers of the probe; - a digital processing circuit adapted to control the electronic transceiver circuit of the probe; - a clock signal generator; and - a communication circuit adapted to transmit data between the digital processing circuit of the probe and the master device, and wherein the master device is adapted to control the transmission and / or reception of ultrasound waves by the probes in a synchronized manner, wherein the master device is configured to control P probes out of the N probes, where P is a positive integer smaller than N, to transmit ultrasound waves in a synchronized manner, and to control P' probes out of the (N-P) other probes, where P' is a positive integer smaller than or equal to N-P, to receive ultrasound waves scattered by the body to be analyzed.

[0007] According to embodiments, each ultrasound probe comprises a device for geolocating the probe.

[0008] According to embodiments, in each probe, the device for geolocating the probe is adapted to measure the position of the probe according to three translational mechanical degrees of freedom and according to three rotational mechanical degrees of freedom.

[0009] According to an embodiment, in each probe, the geolocation device comprises a satellite or an indoor geolocation chip, possibly coupled to an inertial sensor.

[0010] According to an embodiment, in each probe, the geolocation device is an ultrasonic geolocation system configured to control the transmission and reception of ultrasonic waves by the elementary ultrasonic transducers of the probe.

[0011] According to an embodiment, the master device is configured to spatially align the images acquired by the different probes with respect to the same fixed reference point, taking into account the probe positioning data measured by the geolocation device of each probe.

[0012] According to an embodiment, the master device is adapted to control the P probes to transmit ultrasonic waves in a synchronized manner so as to exert a push force on the body region to be analyzed by means of the acoustic radiation pressure, and to implement the function of imaging the region by the remaining N-P probes of the system.

[0013] According to an embodiment, the synchronization accuracy of the probes with respect to each other is less than 10 ms, or less than 10 , or less than 20 ns.

[0014] According to an embodiment, the communication circuit of each probe is a radio communication circuit.

[0015] According to an embodiment, the master device is adapted to control the P probes to transmit ultrasonic waves in a synchronized manner according to various scattering angles, and to control the other probes to receive the ultrasonic waves scattered by the body, so as to characterize the microscopic structure of the body under examination.

[0016] According to an embodiment, in each probe, the digital processing circuit of the probe is adapted to detect the glare of the probe caused by another probe, and to send an alarm signal to the master device, which is adapted to change the synchronization of the probes accordingly.

[0017] According to an embodiment: - during an initialization phase, each probe signals its presence and indicates to the master device an identification number peculiar to the probe, after which the master device communicates to each probe the sequence of the channels and initiates a clock synchronization sequence with each probe; and then - after the initialization phase, during an examination phase, each time a probe has completed a predefined operation, it sends to the other probes an operation end signal indicating its channel number, which forms an operation trigger signal for the probe with the next channel number. BRIEF DESCRIPTION OF DRAWINGS

[0018] In the following non-limiting description of specific embodiments, the above features and advantages, as well as other features and advantages, will be described in detail, with reference to the attached drawings, in which:

[0019] Figure 1 An example of an ultrasonic imaging system according to an embodiment is schematically shown;

[0020] Figure 2 An example of an ultrasound probe of an ultrasound imaging system according to an embodiment is shown in more detail in a block; and

[0021] Figure 3 An example of a mobile terminal of an ultrasound imaging system according to an embodiment is shown in more detail in a block. DETAILED DESCRIPTION

[0022] In the various drawings, identical features have been indicated by the same reference signs. In particular, structural and / or functional features common to the various embodiments can have the same reference and can have exactly the same structural, dimensional and material properties.

[0023] For the sake of clarity, only those steps and elements that are helpful for understanding the described embodiments are shown and described in detail. In particular, the formation of the various electronic circuits of the ultrasound transducers and of the ultrasound probes of the described system has not been described in detail, based on the indications of the present disclosure, the formation of these elements being within the capabilities of the person skilled in the art. Similarly, the formation of the external devices for controlling the ultrasound probes of the described system has not been described in detail, based on the indications of the present disclosure, the formation of such devices being within the capabilities of the person skilled in the art.

[0024] Unless otherwise stated, when referring to two elements connected to each other, this means a direct connection, without any intermediate elements other than conductors, and when referring to two elements coupled to each other, this indicates that the two elements can be connected or can be connected via one or more other elements.

[0025] Unless otherwise stated, the expressions "about", "approximately", "substantially" and "similar to" indicate plus or minus 10%, preferably plus or minus 5%.

[0026] According to an aspect of the described embodiments, there is provided a system comprising a plurality of ultrasound imaging probes controlled by a same master device external to the probes, the master device being adapted to control the transmission and / or reception of ultrasound waves by the probes synchronously. This enables to provide a wider range of examination scenarios. The ultrasound probes are preferably portable probes, such as POC type probes. The master device can be a portable terminal, such as a smartphone or a touch screen tablet. The master device can be configured to communicate with one or more, e.g. all, ultrasound imaging probes of the system.

[0027] Figure 1 An example of an ultrasound imaging system according to an embodiment is shown schematically.

[0028] Figure 1 The system of Fig. 1 comprises a plurality of portable ultrasound imaging probes 100, such as POC probes. In Figure 1In the example described, three ultrasound probes 100 have been shown. However, the described embodiments are not limited to this particular case, and more generally apply whatever the number N of ultrasound probes 100 in the system, with N being an integer greater than or equal to 2, for example greater than or equal to 3, for example in the range 3 to 20. The system also comprises a master device 110 external to the probes, which is adapted to control the probes 100 in a synchronized manner. In Figure 1 In the example described, three ultrasound probes 100 have been shown. However, the described embodiments are not limited to this particular case, and more generally apply whatever the number N of ultrasound probes 100 in the system, with N being an integer greater than or equal to 2, for example greater than or equal to 3, for example in the range 3 to 20. The system also comprises a master device 110 external to the probes, which is adapted to control the probes 100 in a synchronized manner. In

[0029] For example, the ultrasound probes 100 are identical within a manufacturing variation range. Each probe 100 comprises a set of elementary ultrasound transducers (not shown in detail in the figures), for example in a linear array or a matrix arrangement. Each probe also comprises electronic transceiver circuitry (not shown in the figures) adapted to apply electrical excitation signals to the elementary transducers of the probe, and to read and digitize electrical response signals from the transducers. Each probe 100 also comprises communication circuitry adapted to send and receive data via the communication link 120 coupling the probe to the master device 110. Each probe 100 can also comprise a battery to power the various electronic components of the probe.

[0030] An advantage of the system provided is the fact that it comprises a plurality of portable ultrasound probes controllable in a synchronized manner for scanning the same patient. In particular, this makes it possible to speed up the examination of a patient. This further allows to zoom in with respect to the field of view obtained with a single probe. Thus, it is possible to reconstruct a larger volume of investigation than with a single probe. This further makes it possible to obtain functions that are not usually accessible with a single portable probe, for example to implement decoupled push and imaging shear wave elastography analysis, or multi-scattering angle imaging functions.

[0031] For this purpose, according to an aspect of the described embodiments, each ultrasound probe 100 comprises a clock signal generator. The master device 110 is adapted to perform joint and synchronized programming of the transmission-reception sequences of the plurality of probes 100. The master device 110 is also adapted to pool the ultrasound imaging data acquired by all the different probes 100.

[0032] During the phase in which the probes 100 of the system acquire ultrasound images of the body to be analyzed, ultrasound waves are first transmitted to the body to be analyzed during a transmission phase, and then the return ultrasound waves backscattered by the anatomical structures of the body to be analyzed are measured during a reception phase.

[0033] During the transmission phase, also called ultrasound emission, the elementary transducers of the probe are controlled in parallel to emit ultrasound excitation pulses, for example in the form of converging waves or plane waves, or in the form of diverging waves, towards the body to be analyzed.

[0034] During the reception phase, the acoustic signals reflected by the surface or internal structures of the body to be analyzed are measured by each elementary transducer in the probe during an acquisition time window of determined duration. An image of the surface or internal structures of the body can thus be reconstructed. In practice, in order to obtain a high-quality image, a plurality of successive transmission-reception cycles can be repeated. In the following, M denotes the number of successive transmission-reception cycles performed to acquire an image, where M is an integer, for example in the range 1 to 300. Furthermore, an acquisition sequence can be repeated to obtain a video stream, for example 1 to 100 images per second. Thus, as an example, the acquisition of a video stream of 25 images per second, with an acquisition using M = 100 successive transmission-reception cycles per image, enables an ultrasound emission frequency of the order of 2.5 MHz.

[0035] As a non-limiting example of application, N portable probes 100 can be operated independently by N different users on different areas of a multiple trauma patient to speed up the examination time of the patient.

[0036] In this case, the master device can advantageously be configured to synchronize the N probes of the device so that only one ultrasound probe 100 transmits or receives ultrasound waves at any given time of the examination phase. In particular, this enables to avoid that multiple probes emit simultaneously. This further enables to avoid that a probe performs ultrasound emission during the reception phase of another probe. This can also enable to avoid that the return waves measured by an ultrasound probe are contaminated by the ultrasound waves emitted by another probe.

[0037] For example, if the N ultrasound probes of the system are denoted 1001...100N respectively, the master device 110 can be configured to control each probe 100 N successively to acquire an ultrasound image, where i is an integer ranging from 1 to N. At each acquisition of an image, the M transmission-reception cycles required to reconstruct the image are implemented successively, before starting another probe to acquire another image. The sequence of N successive acquisitions can then be repeated, for example periodically, for example at a rate enabling to obtain a video stream, for example 1 to 100 images per second per ultrasound probe. i i At each acquisition of an image, the M transmission-reception cycles required to reconstruct the image are implemented successively, before starting another probe to acquire another image. The sequence of N successive acquisitions can then be repeated, for example periodically, for example at a rate enabling to obtain a video stream, for example 1 to 100 images per second per ultrasound probe.

[0038] ​​As a variant, the N probes are controlled successively, each probe implementing a single transmission-reception cycle. For each probe, the transmission phase (ultrasound emission) is implemented after the end of the phase of reception of another ultrasound wave by the preceding probe. This sequence is repeated M times, so that each probe performs the M transmission-reception cycles necessary to reconstruct an image. The entire sequence can be repeated periodically, for example at a rate enabling a video stream to be obtained, for example 1 to 100 images per second per ultrasound probe.

[0039] As a variant for the case where M is greater than or equal to 3, the N probes are controlled successively to each implement L successive transmission-reception cycles, where L is an integer greater than 1 and less than M. When the N probes have each performed L transmission-reception cycles, the sequence is repeated until the M transmission-reception cycles necessary to reconstruct an image have been completed for each probe. The entire sequence can be repeated periodically, for example at a rate enabling a video stream to be obtained, for example 1 to 100 images per second per ultrasound probe.

[0040] As a variant, the N probes successively perform N ultrasound emissions, then, after the last emission, N corresponding reception phases are implemented successively by the N probes, so that each probe measures the echoes of the waves it has transmitted. This sequence is then repeated M times, so as to allow each probe to reconstruct an image. The entire sequence can be repeated periodically, for example at a rate enabling a video stream to be obtained, for example 1 to 100 images per second per ultrasound probe.

[0041] For example, the synchronization accuracy of the various ultrasound probes is less than 50 ms, preferably less than 10 ms, for example less than 1 ms. As a variant, the synchronization accuracy is about 1 ms, about 100 μβ, about 10 μβ, about 1 μβ, about 100 ns, about 10 ns, or about 1 ns. or about 10 ns.

[0042] In this mode of operation, each ultrasound probe can be coupled to a specific portable terminal, for example a smartphone or a tablet, to enable each operator to view in real time, that is to say during the examination, the images acquired by the probe they are operating. The master device can be one of the N portable terminals or an additional device, not necessarily portable, for example a computer or a remote server. The master device can then be configured to communicate with one or more of the N portable terminals associated with the probes, rather than directly with the corresponding probe(s).

[0043] The system can also be adapted to detect collisions, that is to say the dazzling of an active probe in reception mode caused by another probe in transmission mode. This detection can be performed by the processing circuit 205 (Figure 1) inside each probe, for example by comparing the amplitude of the received signal with a threshold value. Figure 2) are performed. For example, the detection of glare is based on a comparison of the echo signals read by the probe with a glare threshold. When the probe detects glare, the transmit-receive cycles affected by the glare are removed and are not taken into account when reconstructing the image.

[0044] If the repeated collisions and degrade the image quality, the clock signal of the probe can change due to a phase shift, a change in the clock frequency of the probe or both. These phase and / or frequency changes can be arbitrary according to predetermined values or random.

[0045] For example, the collisions detected by the probe are transmitted to the master device, which can decide to change the probe emission sequence.

[0046] Alternatively or in addition, the N image streams respectively acquired by the N probes can be transmitted to the master device, for example to create a patient file and / or to allow simultaneous viewing of all the images acquired by the physician or the nurse.

[0047] Advantageously, considering that the patient and the organ to be imaged are sufficiently static, the images respectively acquired by the plurality of probes 100 can be spatially aligned to each other to reconstruct a larger size investigation volume.

[0048] For this purpose, preferably each ultrasound probe 100 comprises a geolocation device able to measure the position of the probe according to six mechanical degrees of freedom (three translational and three rotational) and to store the temporal variations of said position. The temporal variations of the position of each probe can be transmitted to the master device 110 via the associated communication link 120. Thus, the master device 110 can spatially align the images acquired by the various probes with respect to a fixed reference point and reconstruct a three-dimensional volume based on these images.

[0049] For example, the geolocation device can comprise a satellite geolocation chip (for example a GPS chip) or a local indoor geolocation system, possibly associated with inertial sensors, for example of the MEMS (MicroElectroMechanical System) type.

[0050] Advantageously, Figure 1 The system of the application can be used to implement more complex imaging functions, in particular considering the position of each probe, the synchronized programming of the transmission and reception sequences of the different ultrasound probes in the same ultrasound event.

[0051] For example, Figure 1 The system of the application can be used to implement a shear wave elastography analysis. For this purpose, the tissue push function using the radiation force is performed by the synchronized emission of P probes out of the N ultrasound probes of the system, where P is a positive integer smaller than N, while the shear wave displacement imaging function by ultrasound transmission and reception is implemented by the remaining N-P probes of the system.

[0052] For this purpose, the synchronization accuracy of the various ultrasound probes is for example less than , preferably less than .

[0053] For example, the time needed to generate the push radiation force is in the range of 1 ms, for example in the order of 100 . The period of the shear wave is for example in the range of 1 ms to 100 ms, for example in the order of 10 ms. The shear wave propagation time is for example in the range of 1 ms to 100 ms, for example in the order of 10 ms.

[0054] Figure 1 The advantage of the system of

[0055] This further enables sharing of the electrical power consumption associated with the pushing between the multiple probes, and distributing the heat dissipation associated with the pushing between the multiple probes. For example, this enables increasing the repetition rate of the pushing phase during the examination.

[0056] Moreover, the fact of having multiple synchronized probes, which are located at different positions and have different angles with respect to the region targeted by the pushing, enables a more robust estimation of the motion and improves the quality of the elastogram, or also enables evaluating the anisotropy of the shear wave propagation velocity in relation to the anatomical structure, for example the direction of the muscle fibers.

[0057] More generally, the fine synchronization of the ultrasound probes 100, for example less than 10 , preferably less than 1 , allows enabling various processing and / or imaging functions that need to implement a relatively high acoustic power. For example, it is possible to provide a sequence of therapeutic ultrasound emissions distributed in focus on the N ultrasound probes 100 of the system, alternating with imaging for guiding and monitoring the emissions, or also to provide a sequence of ultrasound emissions enabling facilitating the local administration of a drug and its guidance.

[0058] As a variant, the ultrasound probes 100 can be synchronized to allow P probes among the N probes 100 to transmit ultrasound waves simultaneously, with P being a positive integer less than or equal to N, and to allow receiving the echoes generated by the N probes in the same ultrasound transmission-reception event.

[0059] This enables increasing the transmission and reception surface area, allowing an improved reconstruction in terms of signal-to-noise ratio and lateral resolution.

[0060] When the probes 100 are mechanically free with respect to each other, their relative position can be adjusted according to the examination to be performed, for example in order to bypass obstacles such as the patient's ribs.

[0061] This further enables an increased diversity of ultrasound beam scattering angles. For example, scattering at different angles and quantification thereof enables characterizing microscopic structural properties of the tissue, which cannot be measured in standard ultrasound with a single probe, where the outcome of the ultrasound received by the probe only comes from backscattering.

[0062] For this purpose, the synchronization accuracy of the different ultrasound probes is for example less than 1 ms, for example less than 20 ns, preferably less than 10 ns.

[0063] This synchronization accuracy further advantageously enables ultrasound triangulation emission to determine the position and orientation of each ultrasound probe 100 in the system according to its six mechanical degrees of freedom. This ultrasound geolocation mechanism can advantageously replace satellite or indoor and / or inertial sensor geolocation devices for the probes.

[0064] For this purpose, for example, the master device 110 programs the probes to implement a specific geometric calibration sequence. For example, the calibration sequence can comprise a set of emissions against the patient. For example, considering a pair of ultrasound probes 100, each in contact with the patient, the first probe can successively send (for example, one at a time, one after the other) with each of its ultrasound transducer elements. The second probe can simultaneously receive with all of its ultrasound transducer elements. A set of ultrasound data can then be generated, which enables evaluating the time of flight from each transducer element of the first probe to each transducer element of the second probe, then reconstructing the relative distances and angular positions between the N probes based on the transducer geometry data and the assumption of the speed of sound.

[0065] According to an embodiment, the master device 110 is configured to control P probes among the N probes 100, with P being a positive integer smaller than N, to emit ultrasound waves in a synchronized manner, for example simultaneously, and to control P' probes among the (N-P) other probes, with P' being a positive integer smaller than or equal to N-P, to receive ultrasound waves scattered by the body to be analyzed.

[0066] This enables, for example, performing a coordinated multi-sensor 3D reconstruction operation. The advantage of this mode of operation (compared to using a successive transmission / reception sequence for each probe) is that it enables acquiring volumetric images of a body or organ moving quickly.

[0067] For example, P is an integer greater than 1 and / or P' is an integer greater than 1.

[0068] The P probes used for transmission can also be used in reception mode, in addition to the P' other probes used only in reception mode. It should be noted that using the P transmission probes in reception mode does not require additional synchronization, since these P probes are already synchronized for transmission.

[0069] For example, the waves sent by the P probes are plane waves or divergent waves, which allow the collaborative use of the probes to implement unconventional imaging scenarios, such as ultrafast imaging scenarios.

[0070] For example, Figure 1 The system of Figure 1 can be used to implement so-called ultrafast imaging analysis. For this purpose, the transmission in the form of plane waves or divergent waves is performed by the simultaneous emission of P out of N ultrasound probes in the system, where P is a positive integer, for example greater than 1 and less than N. The emission direction of each of the P ultrasound probes can form an angle with respect to the normal to the emission surface of the probe, so that the combined emission of the P ultrasound probes forms a plane wave or a divergent wave, characterized (direction, radius of curvature) by the master device 110 previously communicated to each probe 100. For example, the orientation of each probe is determined by its geopositioning device. The reception of the ultrasound waves scattered or reflected by the medium is implemented by P' probes out of the remaining N-P probes (where P' is a positive integer, for example greater than 1 and less than or equal to N) and the P transmitting probes. The signals received by the P+P' ultrasound probes are sent to the master device to reconstruct the volumetric image. For example, when P=2, two probes are synchronized to respectively transmit divergent waves according to a given angular sector. At reception, the P probes that have been synchronized for transmission, plus a third probe that is synchronized only for reception (thus P'=1 in this example), detect the ultrasound signals scattered or reflected by the entire acoustic transmission medium and send them to the master system, together with their geopositioning information, to reconstruct the volumetric image.

[0071] Figure 2 An example of an ultrasound probe 100 of the ultrasound imaging system of Figure 1 is shown in more detail in the form of a block. Figure 1

[0072] In the example shown, the probe 100 comprises a component 201 of elementary transducers (not shown in detail in the figures), for example arranged in a 2D matrix or linear array. The transducers of the component 101 are, for example, transducers of the CMUT (Capacitive Micromachined Ultrasonic Transducer) type, piezoelectric transducers (for example of the PMUT (Piezoelectric Micromachined Ultrasonic Transducer) type), crystal transducers or any other type of ultrasound transducer.

[0073] Figure 2 The probe 100 of Figure 1 also comprises a transceiver circuit 203 adapted to apply an electrical excitation signal to the elementary transducers of the probe and to read and digitize the electrical response signals coming from the elementary transducers of the probe.

[0074] Figure 2 ​The probe 100 also comprises a digital processing circuit 205, which is adapted to control the electronic transceiver circuit 203 in transmit mode, and to process the digital response signal provided by the analog-to-digital converter of the transceiver circuit 203. The digital processing circuit 205 comprises, for example, a microprocessor or microcontroller and a memory circuit (not shown in detail). The memory circuit is adapted, for example, to store the digital data of one or more ultrasound images acquired by the probe, before transmitting them to a device external to the probe. The digital processing circuit 205 is also adapted to store one or more sequences of instructions for the transmission and reception of ultrasound waves by the transducers of the probe, and to control the execution of said sequences by the transceiver circuit 203.

[0075] Figure 2 The probe 100 also comprises a clock signal generation circuit 207. The circuit 207 delivers a clock signal applied to an input node of the digital processing circuit 205. The clock signal delivered by the circuit 207 allows precise time stamping of events in each probe, and reaches the required synchronization accuracy between the probes. The synchronization of the different probes with respect to each other can be achieved by the Network Time Protocol or NTP. For this purpose, the clock of the probe can be synchronized with the clock of the master device. As a variant, in the case where the probe is equipped with a GPS chip, the GPS chip can be configured to receive a clock signal from the GPS system, which can be used as a reference clock for all the probes.

[0076] Figure 2 The probe 100 also comprises a geolocation device 209, which is able to measure the position according to the six mechanical degrees of freedom of the probe (three degrees of translation and three degrees of rotation). The device 209 comprises, for example, a satellite geolocation chip, possibly associated with inertial sensors, for example of the MEMS type. The device 209 is, for example, mechanically integral with the housing of the probe. The device 209 is adapted, for example, to provide a geolocation signal to the digital processing device 205. The digital processing device 205 is adapted to store the temporal variations of the probe position signal provided by the device 209.

[0077] As a variant, the device 209 is an ultrasonic geolocation device. It then comprises a memory circuit which stores instructions for a sequence of transmission and reception of ultrasound signals, making it possible to determine the respective positions and orientations of the various probes in the system by time-of-flight measurements. The geolocation sequence is executed, for example, by the digital processing circuit 205 on the instructions of the master device 110.

[0078] Figure 2 The probe 100 also comprises a communication circuit 211, for example a radio communication circuit, adapted to transmit data bi-directionally between the digital processing circuit 205 and an external device, for example a corresponding communication circuit of the master device 110 or of another device.

[0079] For example, all the above elements 201, 203, 205, 207, 209 and 211 are integrated in a protective casing 213 of the probe, for example a plastic or metal casing, for example a hermetic casing. The dimensions of the casing 213 are for example of the order of a few centimetres to a few tens of centimetres. For example, the largest dimension of the casing is in the range 10 to 30 cm.

[0080] Figure 3 The elements of the probe 100 are shown in more detail in the form of blocks Figure 1 An example of a master device 110 of the system.

[0081] In this example, the device 110 is a mobile terminal, for example of the smartphone or digital tablet type. It comprises digital processing circuitry 301, for example comprising a microprocessor and one or more memory circuits (not shown in the drawing).

[0082] Figure 2 The device 110 also comprises communication circuitry 303, for example radio communication circuitry, adapted to bi-directionally transmit data between the digital processing circuitry 301 and one or more external devices, for example the corresponding communication circuitry of the probes 100 of the system.

[0083] The device 110 comprises a display screen (not shown), for example controlled by the digital processing circuitry 301, to display the ultrasound images transmitted by the probes 100.

[0084] Various embodiments and variants have been described. The person skilled in the art will understand that certain features of these various embodiments and variants can be combined and that other variants will become apparent to the person skilled in the art. In particular, the described embodiments are not limited to the above example in which the probes 100 are completely mechanically free with respect to each other in respective casings. As a variant, all or part of the N probes 100 of the system can be attached to a deformable support, for example a medical mattress.

[0085] Furthermore, the described embodiments are not limited to the above example of medical application. More generally, the described system can be used in any other medical or non-medical field of application that can benefit from the use of multiple synchronized ultrasound probes, for example in the field of non-destructive ultrasonic testing.

[0086] Furthermore, in the above embodiments, the synchronization of the ultrasound probes is directly ensured by the external master device. As a variant, the probes can synchronize with each other autonomously after implementation of an initialization sequence by the master device.

[0087] After initialization, each probe (or each portable terminal associated with a probe) signals its presence to the master device and indicates its identification number. The master device transmits to each probe its channel order and initiates a clock synchronization sequence with each probe. The allocation of the channel order can be random or, if this information is known, the positions of the probes can be taken into account.

[0088] This initialization is performed before the start of the examination.

[0089] During the examination phase, each time a probe has completed a predefined operation (ultrasound emission or one or more transmit-receive cycles), it signals the other probes by indicating its sequence number. This forms an instruction signal for triggering the operation of the probe with the next sequence number, which then starts the predefined operation it needs to perform.

[0090] To improve the robustness of the system, each probe can calculate a timeout value based on its channel order. If no operation trigger instruction arrives at the probe within the time period corresponding to the calculated timeout value, the probe performs its programmed operation.

[0091] Finally, the practical implementation of the described embodiments and variants is within the capabilities of a person skilled in the art, based on the functional indications given above.

Claims

1. An ultrasound imaging system comprising an assembly of N ultrasound imaging probes (100), wherein N is an integer greater than or equal to 2; and a main device (110) external to the probes, wherein each ultrasound probe (100) comprises: - Components of a basic ultrasonic transducer (201). - Electronic transceiver circuit (203), adapted to apply an electrical excitation signal to the basic transducer of the probe, and to read and digitize the electrical response signal from the basic transducer of the probe; - Digital processing circuit (205), which is adapted to control the electronic transceiver circuit (203) of the probe; - Clock signal generator (207); and - A communication circuit (211) adapted to transmit data between the digital processing circuit (205) of the probe and the main device (110), Furthermore, the main device (110) is adapted to synchronously control the probe (100) to transmit and / or receive ultrasonic waves. The main device (110) is configured to control P of the N probes (100) to transmit ultrasonic waves synchronously, where P is a positive integer less than N, and to control P' of the other (NP) probes to receive ultrasonic waves scattered by the body to be analyzed, where P' is a positive integer less than or equal to NP.

2. The system of claim 1, wherein each ultrasonic probe (100) includes a device (209) for geolocating the probe.

3. The system according to claim 2, wherein, In each probe (100), the device (209) for geolocating the probe is adapted to measure the position of the probe according to three translational mechanical degrees of freedom and three rotational mechanical degrees of freedom.

4. The system according to claim 2 or 3, wherein, In each probe (100), the geolocation device (209) includes a satellite or indoor geolocation chip optionally coupled to an inertial sensor.

5. The system according to claim 2 or 3, wherein, In each probe (100), the geolocation device (209) is an ultrasonic geolocation system configured to control the transmission and reception of ultrasonic waves by the basic ultrasonic transducer of the probe.

6. The system according to any one of claims 2 to 5, wherein, The master device (110) is configured to take into account probe positioning data measured by the geolocation device (209) of each probe and spatially align images acquired by different probes (100) relative to the same fixed reference point.

7. The system according to any one of claims 1 to 6, wherein, The main device (110) is adapted to control the P probes to transmit ultrasonic waves in a synchronous manner so as to apply a pushing force on the body area to be analyzed by acoustic radiation pressure and to realize the function of imaging the area by the remaining NP probes in the system.

8. The system according to any one of claims 1 to 7, wherein, The synchronization accuracy of the probes (100) relative to each other is less than 10 ms, or less than , or less than 20 ns.

9. The system according to any one of claims 1 to 8, wherein, The communication circuit (211) of each probe (100) is a radio communication circuit.

10. The system according to any one of claims 1 to 9, wherein, The main device (110) is adapted to control the P probes to transmit ultrasonic waves synchronously according to various scattering angles, and to control (NP) other probes to receive the ultrasonic waves scattered by the body in order to characterize the microstructure of the body being examined.

11. The system according to any one of claims 1 to 10, wherein, In each probe (100), the digital processing circuit (205) of the probe is adapted to detect glare of the probe caused by another probe and send an alarm signal to the master device, which is adapted to change the synchronization of the probe accordingly.

12. The system according to any one of claims 1 to 11, wherein: - During the initialization phase, each probe signals its presence and indicates its unique identifier to the master device. The master device then transmits the channel sequence to each probe and initiates a clock synchronization sequence with each probe; then... - After the initialization phase, during the inspection phase, each time a probe has completed a predefined operation, it sends an operation end signal to other probes, indicating its channel number, which forms the operation trigger signal for the probe with the next channel number.

13. The system according to any one of claims 1 to 12, used for analyzing a medium by ultrafast imaging, wherein, Ultrasonic transmission in the form of plane waves or divergent waves is performed by the synchronous transmission of the P probes (100), and the reception of ultrasonic waves scattered or reflected by the medium is achieved by the P probes and the P' probes (100).

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