Ultrasound imaging system

Abstract

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

Description

DESCRIPTION TITLE: Ultrasound Imaging System This application is based on, and claims priority from, French patent application No. 23 / 09676 filed on September 14, 2023 and entitled "Ultrasonic imaging system" which is considered to be an integral part of this description within the limits provided by law. Technical field

[0001] This description relates generally to the field of ultrasound imaging systems. Prior art

[0002] Portable ultrasound systems, generally called POC (Point Of Care) systems, have already been proposed, designed to be brought close to a patient at a non-medical intervention site.

[0003] Such a system typically comprises a portable ultrasound probe, and a mobile terminal such as a smartphone or tablet adapted to communicate with the probe. The probe makes it possible to acquire ultrasound data from the patient's body, this data being transmitted to the mobile terminal, and processed to generate images displayed in real time on a screen of the mobile terminal to allow the user to carry out an examination of the patient.

[0004] It would be desirable to improve at least partially some aspects of known ultrasound systems. Summary of the invention

[0005] For this, one embodiment provides an ultrasound imaging system comprising a set of N probes ultrasound imaging, where N is an integer greater than or equal to 2, and a master device external to the probes, in which each ultrasound probe comprises: - a set of elementary ultrasonic transducers; an electronic transmission-reception circuit adapted to apply electrical excitation signals to the elementary transducers of the probe and to read and digitize electrical response signals from the elementary transducers of the probe; - a digital processing circuit adapted to control the electronic transmission-reception 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 in which the master device is adapted to synchronously control the emission and / or reception of ultrasonic waves by the probes, in which the master device is configured to control P probes among the N probes, with P being a strictly positive integer and strictly less than N, to synchronously emit ultrasonic waves and to control P' probes among the (NP) other probes, with P' being a strictly positive integer and less than or equal to NP, to receive the ultrasonic waves emitted by a body to be analyzed.

[0006] According to one embodiment, each ultrasonic probe comprises a device for geolocating the probe.

[0007] According to one embodiment, in each probe, the geolocation device of the probe is adapted to measure the position of the probe according to three degrees of mechanical freedom in translation and according to three degrees of mechanical freedom in rotation.

[0008] According to one embodiment, in each probe, the geolocation device comprises a satellite or closed environment geolocation chip, possibly coupled to inertial sensors.

[0009] According to one embodiment, in each probe, the geolocation device is an ultrasonic geolocation system configured to control the emission and reception of ultrasonic waves by the elementary ultrasonic transducers of the probe.

[0010] According to one embodiment, the master device is configured to spatially align the images acquired by the different probes relative to the same fixed reference point, taking into account positioning data of the probes measured by the geolocation device of each probe.

[0011] According to one embodiment, the master device is adapted to control the P probes to synchronously emit ultrasonic waves so as to exert a pushing force by acoustic radiation pressure on an area of ​​a body to be analyzed, and to implement an imaging function of said area by the remaining NP probes of the system.

[0012] According to one embodiment, the synchronization accuracy of the probes relative to each other is less than 10 ms, or less than 10 ps, ​​or less than 20 ns.

[0013] According to one embodiment, the communication circuit of each probe is a wireless communication circuit, via radio link.

[0014] According to one embodiment, the master device is adapted to control the P probes to emit ultrasonic waves in a synchronized manner and to control the other probes to receive the ultrasonic waves diffused by the body, following a variety of scattering angles, so as to characterize the microstructure of the body examined.

[0015] According to one embodiment, in each probe, the digital processing circuit of the probe is adapted to detect dazzling of the probe by another probe and emit an alert signal to the master device, the master device being adapted to modify the synchronization of the probes accordingly.

[0016] According to one embodiment: - during an initialization phase, each probe signals its presence and indicates to the master device an identification number specific to the probe, then the master device communicates to each probe a passage order and initiates with each probe a clock synchronization sequence; 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 end of operation signal indicating its passage number, which constitutes an operation trigger signal for the probe having the next passage number. Brief description of the drawings

[0017] These and other features and advantages will be set forth in detail in the following description of particular embodiments given without limitation in relation to the attached figures, among which:

[0018] Figure 1 schematically represents an example of an ultrasound imaging system according to one embodiment;

[0019] Figure 2 shows in more detail, in block form, an example of an ultrasound probe of an ultrasound imaging system according to one embodiment; and

[0020] Figure 3 shows in more detail, in block form, an example of a mobile terminal of an ultrasound imaging system according to one embodiment. Description of the embodiments

[0021] 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.

[0022] For the sake of clarity, only the steps and elements useful for understanding the embodiments described have been shown and are detailed. In particular, the production of the ultrasonic transducers and the various electronic circuits of the ultrasonic probes of the systems described have not been detailed, the production of these elements being within the scope of the person skilled in the art from the indications of the present description. Similarly, the production of an external device for controlling the ultrasonic probes of the systems described has not been detailed, the production of such a device being within the scope of the person skilled in the art from the indications of the present description.

[0023] Unless otherwise specified, when referring to two elements connected together, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") together, this means that these two elements can be connected or be connected by means of one or more other elements.

[0024] Unless otherwise specified, the expressions "about", "approximately", "substantially", and "of the order of" mean to within 10%, preferably to within 5%.

[0025] According to one aspect of the described embodiments, a system is provided comprising a plurality of ultrasound imaging probes controlled by a single master device, external to the probes, the master device being adapted to synchronously control the emission and / or reception of ultrasound waves by the probes. This makes it possible to offer a wider range of examination scenarios. The ultrasound probes are preferably portable probes, for example of the POC type. The master device may be a portable terminal, for example a smartphone or a touch tablet. The master device may be configured to communicate with one or more (for example all) of the ultrasound imaging probes of the system.

[0026] Figure 1 schematically represents an example of an ultrasound imaging system according to one embodiment.

[0027] The system of Figure 1 comprises a plurality of portable ultrasound imaging probes 100, for example POC probes. In Figure 1, three ultrasound probes 100 have been shown. The embodiments described are however not limited to this particular case, and apply, more generally, regardless of the number N of ultrasound probes 100 of 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 from 3 to 20. The system further comprises a master device 110 external to the probes, adapted to control the probes 100 in a synchronized manner. In the example of Figure 1, each probe 100 is connected to the master device 110 via a wireless link 120, for example a radio link. Thus, each probe 100 is adapted to receive data, in particular control data, from the master device 110, and to transmit data, for example ultrasound images, to the master device 110, via a wireless link 120. As a variant, the wireless links 120 can be replaced by wired links, for example of the USB type.

[0028] The ultrasonic probes 100 are for example identical, apart from manufacturing variations. Each probe 100 comprises a set of elementary ultrasonic transducers (not detailed in the figure), for example arranged in a linear array or in a matrix. Each probe further comprises an electronic transmission-reception circuit (not detailed in the figure) 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 further comprises a communication circuit adapted to transmit and receive data via the communication link 120 connecting the probe to the master device 110. Each probe 100 may further comprise a battery providing electrical power to the various electronic components of the probe.

[0029] An advantage of the proposed system is that it comprises a plurality of handheld ultrasound probes that can be controlled in a synchronized manner to scan the same patient. This makes it possible in particular to speed up the examination of the patient. This also allows an enlargement of the field of vision compared to that of a single probe. It is thus possible to reconstruct a larger investigation volume than that obtained with a single probe. This also makes it possible to obtain functionalities that are not usually accessible using a single handheld probe, such as for example the implementation of wave elastography analyses. decoupled thrust shear and imaging, or multiple scattering angle imaging functions.

[0030] For this, according to one aspect of the embodiments described, each ultrasound probe 100 comprises a clock signal generator. The master device 110 is adapted to carry out joint and synchronized programming of the transmission-reception sequences of the multiple probes 100. The master device 110 is further adapted to pool the ultrasound imaging data acquired by all of the different probes 100.

[0031] During a phase of acquisition of an ultrasound image of a body to be analyzed by a probe 100 of the system, an ultrasound wave is first sent towards the body to be analyzed during a transmission phase, then a return ultrasound wave, retrodiffused by the anatomical structures of the body to be analyzed, is measured during a reception phase.

[0032] During the emission phase, also called ultrasonic firing, the elementary transducers of the probe are for example controlled in parallel to emit an ultrasonic excitation pulse, for example in the form of a convergent wave or a plane wave, in the direction of the body to be analyzed, or in the form of a divergent wave.

[0033] During the reception phase, an acoustic signal reflected by the superficial or internal structure of the body to be analyzed is measured by means of each elementary transducer of the probe during a time window of acquisition of determined duration. An image of the superficial or internal structure of the body can thus be reconstructed. In practice, to obtain a good quality image, several successive emission-reception cycles can be repeated. Hereinafter, M denotes the number of successive emission-reception cycles carried out to acquire an image, with M being an integer, for example included in the range going from 1 to 300. In addition, the acquisition sequences can be repeated to obtain a video stream, for example from 1 to 100 images per second. Thus, for example, in the case of an acquisition implementing M=100 successive emission-reception cycles per image, the acquisition of a video stream of 25 images per second implements an ultrasonic firing frequency of the order of M*25 Hz = 2.5 kHz.

[0034] As a non-limiting example of application, the N portable probes 100 can be manipulated respectively by N different users independently on different areas of a polytrauma patient, so as to speed up the patient examination time.

[0035] In this case, the master device can advantageously be configured to synchronize the N probes of the device so that a single ultrasound probe 100 emits or receives ultrasound waves at each instant of the examination phase. This makes it possible in particular to prevent several probes from firing at the same time. This also makes it possible to prevent a probe from firing an ultrasound shot during a reception phase of another probe. This can also make it possible to prevent the return wave measured by an ultrasound probe from being polluted by an ultrasound shot carried out by another probe.

[0036] For example, if we denote by 100i, . . . 100 respectively Nthe N ultrasound probes of the system, the master device 110 can be configured to successively control the acquisition of an ultrasound image by each probe 100i, with i being an integer ranging from 1 to N. At each acquisition of an image by a probe 100i, the M transmission-reception cycles necessary for the reconstruction of the image are implemented successively, before starting the acquisition of another image by another probe. The sequence of the N successive acquisitions can then be repeated, for example periodically, for example at a rate allowing a video stream to be obtained, for example from 1 to 100 images per second, by ultrasound probe.

[0037] Alternatively, the N probes are controlled successively to each implement a single transmission-reception cycle. For each probe, the transmission phase (ultrasonic firing) is implemented after the end of the reception phase of another ultrasonic wave by the previous probe. The sequence is repeated M times so that each probe performs the M transmission-reception cycles necessary for the reconstruction of an image. The entire sequence can be repeated, for example periodically, for example at a rate making it possible to obtain a video stream, for example from 1 to 100 images per second, per ultrasonic probe.

[0038] Alternatively, in the case where M is greater than or equal to 3, the N probes are controlled successively to each implement L successive emission-reception cycles, with L being an integer greater than 1 and less than M. When the N probes have each carried out L emission-reception cycles, the sequence is repeated, until the M emission-reception cycles necessary for the reconstruction of an image have been carried out for each probe. The entire sequence can be repeated, for example periodically, for example at a rate making it possible to obtain a video stream, for example from 1 to 100 images per second, per ultrasonic probe.

[0039] Alternatively, N ultrasonic shots are carried out successively by the N probes, then, after the last shot, N corresponding reception phases are implemented successively by the N probes so that each probe measures an echo of the wave it emitted. The sequence is then repeated M times so as to allow the reconstruction of one image per probe. The entire sequence can be repeated, for example periodically, for example at a rate allowing a video stream to be obtained, for example from 1 to 100 images per second, by ultrasound probe.

[0040] The synchronization accuracy of the various ultrasonic probes is for example less than 50 ms, preferably less than 10 ms, for example less than 1 ms. Alternatively, the synchronization accuracy is of the order of 1 ms, or of the order of 1 ps, or of the order of 10 ns.

[0041] In this operating mode, each ultrasound probe can be connected to a specific portable terminal, for example a smartphone or a tablet, to allow each operator to view in real time, i.e. during the examination, the images acquired by the probe that he is handling. The master device can be one of the N portable terminals, or an additional device, for example a computer or a remote server, not necessarily portable. The master device can then be configured to communicate with one or more portable terminals among the N portable terminals associated with the probes, rather than directly with the corresponding probe(s).

[0042] The system can further be adapted to detect collisions, i.e. the dazzling of an active probe in reception by another probe in transmission. This detection can be carried out in the processing circuit 205 (figure 2) internal to each probe. The dazzling detection is for example based on a comparison of the echo signal read by the probe with a dazzling threshold. When a probe detects dazzling, the transmission-reception cycle affected by the dazzling is eliminated and is not taken into account for the reconstruction of the image.

[0043] If the collision is repeated and degrades the image quality, the clock signal of the probe may be modified, either by a phase jump, or by 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.

[0044] For example, collisions detected by the probe are communicated to the master device, which can decide to modify the firing order of the probes.

[0045] Alternatively or in a complementary manner, the N image streams acquired respectively by the N probes can be transmitted to the master device, for example to create the patient's file and / or to allow simultaneous viewing of all the images acquired by a caregiver.

[0046] Advantageously, by considering the patient and the organs to be imaged as sufficiently static, the images acquired respectively by the multiple probes 100 can be spatially aligned with respect to each other to reconstruct an investigation volume of larger dimensions.

[0047] For this purpose, preferably, each ultrasound probe 100 comprises a geolocation device capable of measuring the position according to the six mechanical degrees of freedom (three degrees of translation and three degrees of rotation) of the probe, and of storing the evolution, as a function of time, of said position. The temporal evolution of the position of each probe can be transmitted to the master device 110 via the associated communication link 120. The master device 110 can thus spatially align the images acquired by the different probes with respect to a fixed reference point and reconstruct a three-dimensional volume from these images.

[0048] The geolocation device may, for example, include a satellite geolocation chip (e.g. example a GPS chip), or a local geolocation system in a closed environment, possibly associated with inertial sensors, for example of the MEMS type (from the English “MicroElectroMechanical System” - microelectromechanical system).

[0049] Advantageously, the system of Figure 1 can be used to implement more complex imaging functionalities, implementing synchronized programming of the emission and reception sequences of the different ultrasound probes in the same ultrasound event, taking into account in particular the position of each probe.

[0050] For example, the system of Figure 1 can be used to implement a shear wave elastography analysis. For this, a tissue pushing function by radiation force is performed by the synchronized firings of P among the N ultrasound probes of the system, with P a strictly positive integer and strictly less than N, while an imaging function of the shear displacement wave, by emission and then reception of ultrasound waves, is implemented by the remaining NP probe(s) of the system.

[0051] For this purpose, the synchronization accuracy of the various ultrasonic probes is, for example, less than 10 ps, ​​preferably less than 1 ps.

[0052] The duration to create the thrust radiation force is for example between 10 ps and 1 ms, for example of the order of 100 ps. The period of the shear wave is for example between 1 ms and 100 ms, for example of the order of 10 ms. The propagation time of the shear wave is for example between 1 ms and 100 ms, for example of the order of 10 ms.

[0053] An advantage of the system in Figure 1 is that it allows the pushing phase to be decoupled from the imaging phase, which in particular avoids a latency time between pushing and imaging.

[0054] This also makes it possible to share the power consumption associated with the thrust between several probes, and to distribute the heat dissipation associated with the thrust between several probes. This makes it possible, for example, to increase the repetition rate of the thrust phases during an examination.

[0055] In addition, having several synchronized probes, located at different positions and at different angles relative to the area targeted by the thrust, makes it possible to make the estimation of the movement more robust and to improve the quality of the elastograms, or to evaluate the anisotropy of the propagation speed of the shear wave, in relation to anatomical structures such as, for example, the direction of the muscle fibers.

[0056] More generally, fine synchronization, for example less than 10 ps, ​​preferably less than 1 ps, of the ultrasound probes 100, makes it possible to implement various processing and / or imaging functionalities requiring relatively high acoustic power. For example, it may be possible to distribute on the N ultrasound probes 100 of the system a sequence of focused therapeutic ultrasound shots, alternating with imaging for the guidance and monitoring of the shots, or even a sequence of ultrasound shots making it possible to facilitate the local administration of a drug and its guidance.

[0057] Alternatively, the ultrasonic probes 100 may be synchronized to allow the simultaneous emission of ultrasound by P probes among the N probes 100, with P being a strictly positive integer and less than or equal to N, and the reception of the resulting echoes by the N probes in a single ultrasonic emission-reception event.

[0058] This allows to increase the emission and reception surface, and thus to allow an improved reconstruction in terms of signal to noise ratio and lateral resolution.

[0059] When the probes 100 are mechanically free relative to each other, their relative positioning can be adapted according to the examination to be carried out, for example so as to bypass an obstacle such as the ribs of a patient.

[0060] This also makes it possible to increase the diversity of scattering angles of ultrasound shots. Scattering at different angles and its quantification makes it possible, for example, to characterize microstructural properties of tissues, properties that cannot be measured in standard single-probe ultrasound where the ultrasound wave received by the probe results solely from backscattering.

[0061] For this purpose, the synchronization precision of the different ultrasonic probes is, for example, less than 1 ms, for example less than 20 ns, preferably less than 10 ns.

[0062] Such synchronization precision also advantageously makes it possible to implement ultrasonic triangulation shots to determine the position and orientation, according to the six degrees of mechanical freedom, of each ultrasonic probe 100 of the system. Such an ultrasonic geolocation mechanism can advantageously replace a device for geolocating probes by satellite or closed environment and / or by means of inertial sensors.

[0063] For this, the probes are for example programmed by the master device 110 to implement a sequence specific geometric calibration. The calibration sequence may for example include a set of shots, aimed at the patient. For example, if we consider a pair of ultrasound probes 100 each in contact with the patient, a first probe may transmit successively with each of its ultrasound transduction elements (for example one at a time, one after the other). The second probe may receive simultaneously with all its ultrasound transduction elements. We can then generate a set of ultrasound data making it possible to evaluate the time of flight of each transduction element of the first probe to each transduction element of the second probe, then reconstruct from transducer geometry data and a sound speed hypothesis, the relative positions of distance and angle between the N probes.

[0064] According to one embodiment, the master device 110 is configured to control P probes from among the N probes 100, with P being a strictly positive integer and strictly less than N, to emit ultrasonic waves in a synchronized manner, for example simultaneously, and to control P' probes from among the (NP) other probes, with P' being a strictly positive integer and less than or equal to NP, to receive the ultrasonic waves diffused by a body to be analyzed.

[0065] This allows, for example, the implementation of cooperative multi-probe 3D reconstruction operations. An advantage of this mode of operation (compared to the use of successive emission / reception sequences by each probe) is that it allows the acquisition of a volume image of a rapidly moving body or organ.

[0066] For example P is an integer strictly greater than 1 and / or P' is an integer strictly greater than 1.

[0067] The P probes used for transmission can also be used for reception, in addition to the P' other probes used for reception only. It should be noted that the use of the P transmitting probes for reception does not require any additional synchronization since these P probes have already been synchronized for transmission.

[0068] The waves emitted by the P probes are for example plane or divergent waves, which allows the cooperative use of the probes to implement unconventional imaging scenarios, for example ultrafast imaging scenarios.

[0069]

[0068] For example, the system of Figure 1 can be used to implement an analysis by so-called ultrafast imaging. For this, an emission in the form of a plane or divergent wave is executed by the synchronized shots of P among the N ultrasonic probes of the system, with P a strictly positive integer, for example strictly greater than 1, and strictly less than N. The direction of the shot of each of the P ultrasonic probes can form an angle relative to the normal to the emission surface of the probe so that the combined shots of the P ultrasonic probes form a plane or divergent wave whose characteristics (direction, radius of curvature) are previously communicated to each probe 100 by the master device 110. The orientation of each of the probes is for example determined by their geolocation device.The reception of ultrasonic waves scattered or reflected by the medium is implemented by P' probes among the remaining NP probes, with P' a strictly positive integer, for example strictly greater than 1, and less than or equal to N, and by the P emitting probes. The signals received by the P+P' ultrasonic probes are transmitted to the master device to reconstruct a. volume image. For example, with P = 2 the two probes are synchronized to emit a diverging wave each according to a given angular sector. In reception the two P probes already synchronized for emission to which is added a third probe synchronized for reception only (therefore P' = 1 in this example) detect the ultrasound signal diffused or reflected by the entire insonified medium and transmit it to the master system with their geolocation information for reconstruction of a volume image

[0070] Figure 2 shows in more detail, in block form, an example of an ultrasound probe 100 of the ultrasound imaging system of Figure 1.

[0071] In the example shown, the probe 100 comprises a set 201 of elementary transducers (not detailed in the figure), for example arranged in a 2D matrix or in a linear array. The transducers of the set 101 are for example transducers of the CMUT type (capacitive membrane ultrasonic transducers), piezoelectric transducers, for example of the PMUT type (piezoelectric micromachined ultrasonic transducer), crystal transducers, or any other type of ultrasonic transducers.

[0072] The probe 100 of Figure 2 further comprises a transceiver circuit 203 adapted to apply electrical excitation signals to the elementary transducers of the probe and to read and digitize electrical response signals from the elementary transducers of the probe.

[0073] The probe 100 of Figure 2 further comprises a digital processing circuit 205 adapted to control the electronic transmission-reception circuit 203 in transmission, and to process digital response signals provided by analog-digital converters of the transmission-reception circuit 203. The digital processing circuit 205 comprises for example a microprocessor or microcontroller, and a memory circuit (not detailed in the figure). The memory circuit is for example adapted to store the digital data of one or more ultrasound images acquired by the probe before their transfer to a device external to the probe. The digital processing circuit 205 is further adapted to memorize one or more sequences of instructions for transmitting and receiving ultrasonic waves by the transducers of the probe, and to control the transmitting and receiving circuit 203 to execute said sequences.

[0074] The probe 100 of Figure 2 further comprises a circuit 207 for generating a clock signal. The circuit 207 provides a clock signal applied to an input node of the digital processing circuit 205. The clock signal provided by the circuit 207 allows precise timestamping of the events in each probe, at the desired synchronization precision between the probes. The synchronization of the different probes with respect to each other can be implemented by a network time protocol or NTP (from the English "Network Time Protocol"). For this, the clocks of the probes can be synchronized to a clock of the master device. Alternatively, in the case where the probes are equipped with GPS chips, the GPS chip can be configured to receive a clock signal from the GPS system which can serve as a reference clock for all the probes.

[0075] The probe 100 of Figure 2 further comprises a geolocation device 209 capable of measuring the position according to the six mechanical degrees of freedom (three degrees of translation and three degrees of rotation) of the probe. 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 secured to a housing of the probe. The device 209 is for example adapted to provide geolocation signals to the digital processing device 205. The digital processing device 205 is adapted to store the temporal evolution of the location signals of the probe provided by the device 209.

[0076] Alternatively, the device 209 is an ultrasonic geolocation device. It then comprises a memory circuit storing instructions for transmission-reception sequences of ultrasonic signals making it possible to determine, by time-of-flight measurements, the respective positions and orientations of the different probes of the system. The geolocation sequences are for example executed by the digital processing circuit 205 on instructions from the master device 110.

[0077] The probe 100 of FIG. 2 further comprises a communication circuit 211, for example a wireless communication circuit by radio link, adapted to transmit data bidirectionally between the digital processing circuit 205 and an external device, for example a corresponding communication circuit of the master device 110 or another device.

[0078] All of the elements 201, 203, 205, 207, 209 and 211 described above are for example integrated into a protective housing 213 of the probe, for example a plastic or metal housing, for example a hermetic housing. The dimensions of the housing 213 are for example of the order of a few centimeters to a few tens of centimeters. For example, the largest dimension of the housing is between 10 and 30 cm.

[0079] Figure 3 shows in more detail, in block form, an example of the master device 110 of the system of Figure 1.

[0080] In this example, the device 110 is a mobile terminal, for example of the smartphone or digital tablet type. It comprises a digital processing circuit 301, comprising for example a microprocessor and one or more memory circuits (not detailed in the figures).

[0081] The device 110 of Figure 2 further comprises a communication circuit 303, for example a wireless communication circuit by radio link, adapted to transmit data bidirectionally between the digital processing circuit 301 and one or more external devices, for example a corresponding communication circuit of a probe 100 of the system.

[0082] The device 110 comprises for example a display screen, not shown, controlled by the digital processing circuit 301 to display ultrasound images transmitted by the probes 100.

[0083] 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, the described embodiments are not limited to the example described above in which the probes 100 are in respective housings that are entirely mechanically free from one another. Alternatively, all or some of the N probes 100 of the system may be attached to a deformable support, for example a medical mattress.

[0084] Furthermore, the described embodiments are not limited to the medical application examples mentioned above. More generally, the described systems can be used in any other application field, medical or non-medical, which can benefit from the use of a plurality of synchronized ultrasonic probes, for example in the field of non-destructive ultrasonic testing.

[0085] Furthermore, in the embodiments described above, the synchronization of the ultrasonic probes is ensured directly by the external master device. Alternatively, the probes can synchronize with each other autonomously after an initialization sequence implemented by the master device.

[0086] Upon initialization, each probe (or each portable terminal associated with a probe) signals its presence and indicates its identification number to the master device. The master device communicates to each probe its passage order and initiates a clock synchronization sequence with each probe. The allocation of passage orders can be random, or take into account the location of the probes if this information is known.

[0087] This initialization is performed before the exam starts.

[0088] During the examination phase, each time a probe has completed a predefined operation (an ultrasonic shot, or one or more transmission-reception cycles), it signals this to the other probes by indicating its passage number. This constitutes an operation trigger instruction signal for the probe with the next passage number, which then starts the predefined operation that it must carry out.

[0089] To improve system robustness, each probe can calculate a timeout value based on its order of operation. If no operation trigger instruction arrives at the probe within a time period corresponding to the calculated timeout value, the probe executes the operation for which it is programmed.

[0090] Finally, the practical implementation of the embodiments and variants described is within the reach of those skilled in the art from the functional indications given above.

Claims

CLAIMS 1. Ultrasound imaging system comprising a set of N ultrasound imaging probes (100), where N is an integer greater than or equal to 2, and a master device (110) external to the probes, in which each ultrasound probe (100) comprises: a set (201) of elementary ultrasound transducers; - an electronic transmission-reception circuit (203) adapted to apply electrical excitation signals to the elementary transducers of the probe and to read and digitize electrical response signals from the elementary transducers of the probe; a digital processing circuit (205) adapted to control the electronic transmission-reception circuit (203) of the probe; - a clock signal generator (207); and - a communication circuit (211) adapted to transmit data between the digital processing circuit (205) of the probe and the master device (110), and in which the master device (110) is adapted to synchronously control the emission and / or reception of ultrasonic waves by the probes (100), in which the master device (110) is configured to control P probes among the N probes (100), with P being a strictly positive integer and strictly less than N, to synchronizedly emit ultrasonic waves and to control P' probes among the (NP) other probes, with P' being a strictly positive integer and less than or equal to NP, to receive the ultrasonic waves diffused by a body to be analyzed.

2. System according to claim 1, in which each ultrasonic probe (100) comprises a device (209) for geolocating the probe.

3. System according to claim 2, in which, in each probe (100), the device (209) for geolocating the probe is adapted to measure the position of the probe according to three degrees of mechanical freedom in translation and according to three degrees of mechanical freedom in rotation.

4. System according to claim 2 or 3, in which, in each probe (100), the geolocation device (209) comprises a satellite or closed environment geolocation chip, possibly coupled to inertial sensors.

5. System according to claim 2 or 3, in which, in each probe (100), the geolocation device (209) is an ultrasonic geolocation system configured to control the emission and reception of ultrasonic waves by the elementary ultrasonic transducers of the probe.

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

7. System according to any one of claims 1 to 6, in which the master device (110) is adapted to control the P probes to synchronously emit ultrasonic waves so as to exert a pushing force by acoustic radiation pressure on an area of a body to be analyzed, and to implement an imaging function of said area by the remaining NP probes of the system.

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

9. System according to any one of claims 1 to 8, in which the communication circuit (211) of each probe (100) is a wireless communication circuit, by radio link.

10. System according to any one of claims 1 to 10. 9, wherein the master device (110) is adapted to control the P probes to synchronously emit ultrasonic waves and to control the (NP) other probes to receive the ultrasonic waves scattered by the body, according to a variety of scattering angles, so as to characterize the microstructure of the body examined.

11. System according to any one of claims 1 to 12. 10, in which, in each probe (100), the digital processing circuit (205) of the probe is adapted to detect a dazzling of the probe by another probe and to emit an alert signal to the attention of the master device, the master device being adapted to modify the synchronization of the probes accordingly.

12. System according to any one of claims 1 to 12. 11, in which: - during an initialization phase, each probe signals its presence and indicates to the master device an identification number specific to the probe, then the master device communicates to each probe a passage order and initiates with each probe a clock synchronization sequence; 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 end of operation signal indicating its passage number, which constitutes an operation trigger signal for the probe having the next passage number.

13. System according to any one of claims 1 to 12, used to implement an analysis of a medium by ultrafast imaging, in which an ultrasonic emission in the form of a plane or divergent wave is executed by the synchronized shots of said P probes (100), and the reception of the ultrasonic waves diffused or reflected by the medium is implemented by said P probes and said P' probes (100).

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