Ultrasonic probe

Abstract

Ultrasonic Probe This description relates to an ultrasonic probe (400) extending along a longitudinal direction (Z), the ultrasonic probe comprising an acoustic attenuation structure (420) extending in the longitudinal direction, and an acoustic component (210) positioned on a first face (420A) of the acoustic attenuation structure and comprising an array of ultrasonic transducers; the acoustic attenuation structure comprising: - a stack (221) of at least one acoustic attenuation layer of a material suitable for attenuating ultrasonic waves, said stack extending along a plane comprising the longitudinal direction; and - a mechanical reinforcement structure (422) in said stack;the mechanical reinforcement structure comprising at least one first metal element (423A) associated with at least one second metal element (423B), the at least one first and at least one second metal elements extending in two different directions from the plane of the stack. Figure for the abstract: Fig. 4A;

Description

Title of the invention: Ultrasonic probe technical field

[0001] This description relates generally to ultrasonic probes comprising ultrasonic transducers.

[0002] The present description relates in particular to ultrasonic probes integrated into catheters, which can be referred to as ultrasound catheters.

[0003] An example of the application of such ultrasound probes relates to intracardiac echocardiography, or ICE, where an ultrasound probe is integrated into a catheter which is directed towards a region of a heart, or into a surrounding region, to produce images of the region. Previous technique

[0004] It has already been proposed to integrate a small ultrasound probe into a catheter, which can then be referred to as an ultrasound catheter. The ultrasound catheter can be intended to be introduced into an anatomical region of a patient, in particular to perform imaging of the anatomical region.

[0005] Ultrasound catheters have been designed for use in many anatomical regions, for example, for diagnostic, therapeutic, and / or surgical purposes. Among the known techniques are intravascular ultrasound (IVUS) and intracardiac echocardiography (ICE). In both techniques, a transducer array, or transducer array, is typically positioned at one end of a catheter to emit ultrasound waves. This is generally referred to as the distal end of the catheter, through which the catheter is guided into the region of the body to be examined. The transducers can then be used to receive ultrasound waves reflected back from specific features of the anatomical region.The reflected ultrasound waves can be transmitted to a processing device adapted to process them in order to produce an image of the area of ​​the body in which the catheter is placed.

[0006] The image produced can be an image of a surface, for example a section, or an image of a volume.

[0007] An IVUS catheter is generally used in a blood vessel (artery or vein) and is usually associated with a guidewire having a flexible tip to direct the catheter into the vessel.

[0008] An ICE catheter is generally used in a region of the heart, or even in a surrounding structure, to image that region, for example to prepare, guide, and / or facilitate medical procedures. An ICE catheter is not generally designed to be associated with a guidewire, but rather generally includes a distal end that can be articulated by a guiding mechanism located in a handle at a proximal end of the catheter. The distal end can be connected to a flexible coupler located at one end of a flexible tubular element.

[0009] An ultrasonic probe generally comprises an array of ultrasonic transducers adapted to emit and receive ultrasonic waves, via the front face of these transducers. Typically, an ultrasonic probe includes, on the rear face of the transducers, an acoustic attenuation layer, which may be known as "backing," to attenuate the ultrasonic waves. The ultrasonic probe may include an interconnect substrate to provide an electrical connection between the ultrasonic transducers and circuits, connectors, and / or components external or internal to the ultrasonic probe.

[0010] It would be desirable to have an ultrasonic probe available, at least partially mitigating some of the disadvantages of known ultrasonic probes.

[0011] In particular, there is a need for an ultrasonic probe which ensures mechanical support and flatness for the mounting and positioning of ultrasonic transducers, while maintaining a small external diameter of the probe, typically less than 3 mm. Summary of the invention

[0012] One embodiment overcomes all or part of the disadvantages of known ultrasonic probes.

[0013] One embodiment provides for an ultrasonic probe extending in a longitudinal direction, the ultrasonic probe comprising an acoustic attenuation structure extending in the longitudinal direction, and an acoustic component positioned on a first face of the acoustic attenuation structure, the acoustic component comprising an array of ultrasonic transducers; the acoustic attenuation structure comprising: - a stack of at least one acoustic attenuation layer made of a material suitable for attenuating ultrasonic waves, said stack extending along a plane including the longitudinal direction; and - a mechanical reinforcement structure in said stack, the mechanical reinforcement structure comprising at least a first metallic element associated with at least a second metallic element, the at least first and at least second metallic elements extending in two different directions from the plane of the stack.

[0014] According to one embodiment, the acoustic component has a first length and the acoustic attenuation structure has a second length greater than the first length, the acoustic component being positioned on a first portion of the acoustic attenuation structure.

[0015] According to one embodiment, the acoustic attenuation structure comprises a second portion not covered by the acoustic component, the second portion forming a support for electronic components, for example a flexible printed circuit is positioned between the second portion and the electronic components.

[0016] According to one embodiment: - the material of at least one acoustic attenuation layer comprises a polymer, a resin, an epoxy resin, a silicone, or a matrix based on a polymer, resin, epoxy resin or silicone, and may, for example, include acoustically absorbent fillers; and / or - the mechanical reinforcement structure is made of stainless steel, tungsten, titanium, or a combination of at least two of these materials.

[0017] According to one embodiment, each of the at least one first and at least one second metallic elements is a metallic wire or a metallic rod.

[0018] According to one embodiment, each of the at least one first and at least one second metallic elements has a circular, triangular, square, rectangular, polygonal, I-shaped or H-shaped cross-section.

[0019] According to one embodiment, at least one first metallic element and at least one second metallic element are wound helically around each other along an axis, for example an axis parallel to the longitudinal direction, forming a braid.

[0020] According to one embodiment, at least one first metallic element is substantially perpendicular to at least one second metallic element, forming a metallic grid or a metallic lattice.

[0021] According to one embodiment, at least one first metallic element and at least one second metallic element are interspersed.

[0022] According to one embodiment, at least one first metallic element and at least one second metallic element are intertwined.

[0023] According to one embodiment, the mechanical reinforcement structure is flush with a second face of the acoustic attenuation structure, opposite the first face, for example each of at least one first and at least one second metallic elements is housed in a groove in the at least one acoustic attenuation layer, said groove being open to said second face.

[0024] According to one embodiment, the mechanical reinforcement structure is embedded in at least one acoustic attenuation layer, for example said at least one acoustic attenuation layer is molded around said mechanical reinforcement structure.

[0025] According to one embodiment, the stack comprises a first acoustic attenuation layer assembled on a second acoustic attenuation layer, and the mechanical reinforcement structure is positioned between said first and second acoustic attenuation layers, for example is housed in at least one housing formed by a first open groove in the first acoustic attenuation layer and a second open groove in the second acoustic attenuation layer, the opening of the second groove being opposite the opening of the first groove.

[0026] According to one embodiment, the stack comprises a single layer of acoustic attenuation.

[0027] According to one embodiment, the acoustic attenuation structure is devoid of electrical connection functions.

[0028] According to one embodiment, the ultrasonic probe further comprises a sheath, preferably made of an acoustically transparent material, adapted to envelop and retain at least the acoustic component and the acoustic attenuation structure, the sheath being for example an encapsulation sheath.

[0029] According to one embodiment, the sheath forms a tubular body comprising: - a first portion around the acoustic component and the acoustic attenuation structure, said first closed portion being substantially hemispherical under the acoustic attenuation structure and flat or curved above the acoustic component; and - a second portion around the acoustic attenuation structure, said second portion having a substantially circular cross-section. Brief description of the drawings

[0030] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments, given by way of non-limiting example, in relation to the accompanying figures, among which:

[0031] [Fig.1] is a three-dimensional view representing an example of an ultrasonic probe;

[0032] Figure 2a is a three-dimensional view representing an ultrasonic probe according to one embodiment;

[0033] [Fig.2B] is a three-dimensional view representing in detail the acoustic attenuation structure of the ultrasonic probe of [Fig.2A];

[0034] [Fig.3A], [Fig.3B], [Fig.3C], [Fig.3D], [Fig.3E] and [Fig.3F] are cross-sectional views representing several variants of acoustic attenuation structure of an ultrasonic probe according to an embodiment;

[0035] Figure 4a is a three-dimensional view representing an ultrasonic probe according to another embodiment;

[0036] [Fig.4B] is a three-dimensional view representing in detail the acoustic attenuation structure of the ultrasonic probe of [Fig.4A];

[0037] [Fig.5] represents a variant of a mechanical reinforcement structure;

[0038] [Fig.6] represents another variant of the mechanical reinforcement structure;

[0039] Fig. 7 represents another variant of the mechanical reinforcement structure; and

[0040] [Fig. 8] is a three-dimensional view representing an ultrasonic probe according to a example of a project. Description of the implementation methods

[0041] The same elements have been designated by the same reference numerals in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same reference numerals and may have identical structural, dimensional and material properties.

[0042] For the sake of clarity, only the steps and elements necessary for understanding the described embodiments have been shown and are detailed. In particular, the ultrasonic transducers of the described ultrasonic probes have not been detailed, as the described embodiments are compatible with all or most known ultrasonic transducer structures. Furthermore, the other electronic components of the described ultrasonic probes have not been detailed, as the described embodiments are compatible with all or most common electronic components of ultrasonic probes.

[0043] 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 linked through one or more other elements.

[0044] In the following description, when reference is made 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", "superior", "inferior", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made, unless otherwise specified, to the orientation of the figures or to an ultrasonic probe in a normal operating position.

[0045] Unless otherwise specified, the expressions "approximately", "roughly", and "on the order of" mean to within 10% or 10°, preferably to within 5% or 5°.

[0046] In the following description, when a transducer is referred to, unless otherwise specified, it refers to an ultrasonic transducer, and when a probe is referred to, unless otherwise specified, it refers to an ultrasonic probe.

[0047] An ultrasonic transducer is a transducer adapted to convert an electrical signal into an ultrasonic wave, and conversely, to convert an ultrasonic wave into an electrical signal. Depending on the type of transducer, the electrical signal may correspond to a voltage, a current, or an electrical charge.

[0048] The transducer network may include any type of ultrasonic transducer, or even several different types of ultrasonic transducers.

[0049] In the following description, ultrasonic transducers formed in a layer of single-crystal or polycrystalline piezoelectric material, for example PZT (lead-zirconia titanium), or of a composite material such as a PZT layer including polymer-filled grooves, are shown. A layer of piezoelectric material is a layer whose thickness can vary when a voltage is applied to it.

[0050] Alternatively, and although a rear-facing attenuation layer is less necessary, ultrasonic transducers can be microelectromechanical systems, or MEMS (Micro-Electro-Mechanical System), implementing microelectronic production technologies. A MEMS-type transducer generally consists of a deformable membrane suspended above a cavity. In one embodiment, the deformable membrane is displaced or deformed by capacitive effect using an electrode attached to the membrane and an electrode separated by the cavity. This type of ultrasonic transducer is known by the acronym CMUT (Capacitive Micro-machined Ultrasonic Transducer), that is, a micro-machined capacitive ultrasonic transducer, or capacitive membrane transducer.In another embodiment, the deformable membrane is displaced or deformed by piezoelectric effect using a layer of piezoelectric material equipped with two electrodes attached to the membrane. This type of ultrasonic transducer is known by the acronym PMUT, from the English Piezoelectric Micro-machined Ultrasonic Transducer, i.e., a micro-machined piezoelectric ultrasonic transducer, or a membrane piezoelectric transducer.

[0051] In the following description, references to a catheter are made, broadly defined, to a thin, rod-shaped device, generally flexible, hollow or solid, intended to be inserted into a region of a human or animal body (e.g., a cavity, a lumen, a duct, etc.), generally for the purpose of injecting a fluid or draining its contents. An ultrasound catheter is defined as a catheter equipped with a probe ultrasound, generally intended to perform imaging in a region of a human or animal body.

[0052] In the following description, a distal end refers to an end through which an ultrasound probe, or catheter, is introduced into a medium to be analyzed, and a proximal end refers to an end opposite the distal end. The proximal end generally corresponds to an electrical connection, or wiring, end of the ultrasound probe, or catheter.

[0053] In the following description, unless otherwise specified, reference is made to an electrical collector, which corresponds to a set of conductive tracks insulated from one another within the collector and arranged on, and / or in, an insulating substrate. A collector may be designated as an interconnecting substrate, and it may be flexible.

[0054] Fig. 1 is a three-dimensional view representing an example of an ultrasonic probe 100.

[0055] The ultrasonic probe 100 extends along a longitudinal direction Z, along an axis 101 parallel to this longitudinal direction, without this axis necessarily being an axis of symmetry.

[0056] The ultrasound probe 100 can be intended to be integrated into a catheter, at the distal end of the catheter, to form an ultrasound catheter, for example an ICE catheter.

[0057] The ultrasonic probe 100 has a distal end 100A and a proximal end 100B.

[0058] The ultrasonic probe 100 includes an acoustic component 110. The acoustic component 110 is a planar component. The acoustic component 110 comprises an array of ultrasonic transducers (not shown) adapted to emit and receive ultrasonic waves, via the front face 110A of the acoustic component, corresponding to the front faces of the transducers. The acoustic component 110 is located near the distal end 100A.

[0059] The acoustic component 110 may include a linear array, comprising, for example, a strip of ultrasonic transducers aligned side by side along the axis 101, the transducers being able to extend perpendicularly to this axis (in the X direction). For example, a linear array may include between approximately 30 and 250 ultrasonic transducers, particularly for two-dimensional (2D) imaging.

[0060] Alternatively, the acoustic component 110 may comprise an array of ultrasonic transducers distributed along two directions in the plane of the acoustic component. For example, an array may comprise between approximately 200 and 2000 ultrasonic transducers, particularly for three-dimensional (3D) imaging.

[0061] The imaging component 110 comprises, on the front face 110A, a piezoelectric layer 111.

[0062] The acoustic component 110 comprises, on its rear face 110B, an acoustic attenuation layer 112 made of a material suitable for attenuating ultrasonic waves, for example, a material with low acoustic impedance. The acoustic attenuation layer may be known by the English term "backing". The low acoustic impedance material may have the advantage of attenuating, for example, absorbing or damping, the ultrasonic waves emitted by the transducers, particularly on the rear face of the transducers.

[0063] The ultrasonic transducers are formed in the piezoelectric layer 111 and in the acoustic attenuation layer 112. Other layers may be included, not detailed here.

[0064] The ultrasonic probe 100 may include an integrated circuit layer (not shown), for example under the acoustic component 110 or at a distance from the acoustic component 110 in the longitudinal direction Z. The integrated circuit layer may be configured to select some of the transducers of the transducer array to be used for the transmission / reception of ultrasonic waves, to transmit control signals to the selected transducers so that they generate and transmit ultrasonic waves, and / or to accept, or even amplify, return signals from the selected transducers when the latter receive reflected ultrasonic waves.

[0065] The ultrasonic probe 100 further comprises a mechanical support 120, which may be referred to as a stiffener. The acoustic component 110 is positioned on a distal portion 121 of the mechanical support 120. The mechanical support 120 provides mechanical support and secures / mounts the ultrasonic transducers, ensuring their flatness and correct positioning. The mechanical support 120 can also provide rigidity to the ultrasonic probe 100.

[0066] The mechanical support 120 extends along the longitudinal direction Z.

[0067] A proximal portion 122 of the mechanical support 120 is not covered by the acoustic component 110. This proximal portion can be covered by other electronic components, for example, passive electronic components, which can be selected from one or more of the following: a capacitor, a resistor, a thermistor, an inductor (not shown). A flexible printed circuit board (FPCB) (not shown) can be positioned on the proximal portion 122 of the mechanical support 120, for example, between the proximal portion 122 and the electronic components. The flexible printed circuit board can extend between the electronic components and the support. mechanical 120, and can also extend under the acoustic component 110 to form an interconnection collector.

[0068] The ultrasonic probe 100 further includes a sheath 130 made of an acoustically transparent material, adapted to enclose and retain at least the acoustic component 110 and the mechanical support 120. It may be an encapsulation sheath adapted to encapsulate the acoustic component 110 and the mechanical support 120. Since the sheath 130 is intended to be in contact with the tissues of the anatomical region into which the catheter is introduced, it is preferably biocompatible.

[0069] In the example shown, the sheath 130 forms a tubular body with a closed distal portion 131 whose cross-section is substantially a semicircle forming a flat portion above the acoustic component 110, an open proximal portion 132 of substantially circular cross-section, and an intermediate portion 133 between the distal portion 131 and the proximal portion 132.

[0070] A drawback of such an ultrasound probe with a mechanical support beneath an acoustic attenuation layer is that it results in a substantial stacking thickness. However, the ultrasound probe may be intended to be inserted, for example with a catheter, into a small anatomical space. The external diameter of the ultrasound probe is generally a few millimeters, for example, less than 5 mm, or even 3 mm. The stacking thickness cannot generally be reduced without resulting in a reduction of acoustic attenuation (if the thickness of the acoustic attenuation layer is reduced) and / or a reduction in the flatness and rigidity of the ultrasound probe (if the thickness of the mechanical support is reduced).

[0071] The inventors propose an ultrasonic probe that meets the improvement needs described above and overcomes all or part of the drawbacks of known ultrasonic probes. In particular, the inventors propose an ultrasonic probe whose diameter can be reduced without degrading its performance and rigidity.

[0072] Embodiments of ultrasonic probes will be described below. The embodiments described are not limiting, and various variations will become apparent to those skilled in the art from the indications in this description.

[0073] Figure 2A is a three-dimensional view representing an ultrasonic probe 200 according to one embodiment. Figure 2B is a three-dimensional view showing in detail the acoustic attenuation structure 220 of the ultrasonic probe 200 of Figure 2A. The acoustic attenuation structure of Figure 2B is shown rotated 180° with respect to Figure 2A.

[0074] The ultrasonic probe 200 of Figures 2A and 2B has many elements in common with the ultrasonic probe 100 of [Fig.1] and only the differences between the two ultrasonic probes 100 and 200 are detailed in the following description.

[0075] The ultrasonic probe 200 of Figures 2A and 2B differs from the ultrasonic probe 100 of [Fig. 1] primarily in that it does not comprise an acoustic attenuation layer and a mechanical support, but rather a mechanically reinforced acoustic attenuation structure 220 that also forms a mechanical support. This acoustic attenuation structure thus fulfills at least the two functions of acoustic attenuation and mechanical support.

[0076] The acoustic attenuation structure 220 extends in the longitudinal direction Z of the ultrasonic probe 200.

[0077] The acoustic component 210 is positioned on an upper face 220A (first face) of the acoustic attenuation structure 220, for example on a distal portion 220C (first portion) of the acoustic attenuation structure 220.

[0078] The acoustic attenuation structure 220 is, for example, parallelepiped in shape, for example of low thickness, typically between 50 µm and 2 mm thick. Alternatively, the acoustic attenuation structure may, for example, have a rectangular cross-section with a curvature in the longitudinal direction Z under the area covered by the acoustic component 210. The acoustic component 210 is then also curved so that the entire lower face 210B of the acoustic component 210 is in contact with the upper face 220A of the acoustic attenuation structure 220.

[0079] In the embodiment of [Fig. 2A], the acoustic attenuation structure 220 has a length L2 (second length) greater than the length L1 (first length) of the acoustic component 210. Thus, a proximal portion 220D (second portion) of the acoustic attenuation structure 220 is not covered by the acoustic component 210. The proximal portion 220D can form a support for other electronic components, for example, passive electronic components, which can be selected from one or more of the following electronic components: a capacitor, a resistor, a thermistor, an inductor (not shown). A flexible printed circuit board, or FPCB, (not shown) can be positioned on the proximal portion 220D of the mechanical support 220, for example, between the proximal portion 220D and the electronic components.The flexible printed circuit board can extend between the electronic components and the mechanical support 220, and can also extend under the acoustic component 210 to form an interconnect collector.

[0080] Alternatively, the acoustic attenuation structure may have a length substantially equal to the length of the acoustic component 210.

[0081] The acoustic attenuation structure 220 comprises: - an acoustic attenuation layer 221, made of a material suitable for attenuating ultrasonic waves (acoustic attenuator material), preferably a material with low acoustic impedance, for example a polymer, a resin, an epoxy resin, a silicone, a matrix based on a polymer, resin, epoxy resin or silicone, a combination of at least two of these materials, or any other material or combination of materials suitable for attenuating acoustic waves, which may further include acoustically absorbing or diffusing fillers, for example tungsten or carbon particles; and - a mechanical reinforcement structure 222 in the acoustic attenuation layer 221: the mechanical reinforcement structure may include one or more metallic elements, for example made of stainless steel, tungsten, titanium, a combination of at least two of these materials, or any other material or combination of materials suitable for mechanically reinforcing the acoustic attenuation layer.

[0082] The acoustic attenuation layer can be a stack of several layers of one or more acoustic attenuation materials. More generally, an acoustic attenuation layer can be a stack of one or more acoustic attenuation layers.

[0083] The acoustic attenuation layer 221 may have a thickness greater than 0.3 mm, for example between 0.3 and 1 mm.

[0084] The mechanical reinforcement structure 222 allows for the mechanical reinforcement of the acoustic attenuation layer 221, in particular increasing the mechanical rigidity of the acoustic attenuation layer 221. The mechanical reinforcement structure 222 can also have a thermal drainage function. The mechanical reinforcement structure 222 can also have an acoustic wave-breaking function.

[0085] In the embodiment of Figures 2A and 2B, the mechanical reinforcement structure 222 comprises several metallic elements 223 inserted into the acoustic attenuation layer 221.

[0086] The metallic elements 223 shown in Figures 2A and 2B are cylindrical metal rods with a circular cross-section, extending along the longitudinal direction Z of the ultrasonic probe 200, and these metal rods are flush with a lower face 220B (second face) of the acoustic attenuation structure 220. Other embodiments of the mechanical reinforcement structure can be considered by a person skilled in the art. For example, the mechanical reinforcement structure may comprise a single metallic element. Other examples of assembling one or more metallic elements in the acoustic attenuation layer are described later in connection with Figures 3A to 3F.

[0087] In the embodiment shown in Figures 2A and 2B, the mechanical reinforcement structure 222, in particular the metallic elements 223, extends along the entire length of the ultrasonic probe 200. Alternatively, the metallic elements may extend over a partial length of the ultrasonic probe, for example, at least over the portion of the ultrasonic probe that receives the acoustic component (distal portion, or first portion). More generally, the mechanical reinforcement structure may extend over all or part of the length of the ultrasonic probe, and for example, at least over the portion of the ultrasonic probe that receives the acoustic component.

[0088] In the embodiment of Figures 2A and 2B, the mechanical reinforcement structure 222, in particular the metallic elements 223, extend mainly along the longitudinal direction Z. Alternatively, the mechanical reinforcement structure and / or the metallic elements may extend in a direction of the plane of the ultrasonic probe other than the longitudinal direction Z, or along at least two directions of the plane of the acoustic attenuation layer 221. More generally, the mechanical reinforcement structure may extend along one or more directions of the plane of the acoustic attenuation layer 221, or comprise metallic elements that extend along one or more directions of the plane of the acoustic attenuation layer 221. For example, the mechanical reinforcement structure may comprise a metallic grid or a metallic mesh.

[0089] The metallic elements may have a shape other than a cylindrical rod with a circular cross-section, for example a rod with a triangular, square, rectangular or more broadly polygonal cross-section, with an I or H cross-section. Alternatively, the metallic elements may have a helical or braided shape, as in the example described in connection with Figure 4. The metallic elements may extend in several directions from the plane of the acoustic attenuation layer 221, for example to form a lattice, as in the example described in connection with Figures 5, 6 and 7.

[0090] The acoustic attenuation structure 220 is preferably devoid of electrical connection functions.

[0091] Similar to the ultrasonic probe 100 of [Fig. 1], the ultrasonic probe 200 of Figures 2A and 2B has a distal end 200A and a proximal end 200B, with the acoustic component 210 located near the distal end 200A. The acoustic component 210 is a planar or thin parallelepiped component comprising an array of ultrasonic transducers adapted to emit and receive ultrasonic waves. The front face 210A of the acoustic component 210 corresponds to the front faces of the transducers. The rear face 210B of the acoustic component 210 is positioned on the acoustic attenuation structure 220.

[0092] Similar to the ultrasonic probe 100 of [Fig. 1], the ultrasonic probe 200 of Figures 2A and 2B comprises a sheath 230, preferably made of a material acoustically transparent, suitable for enveloping and retaining at least the acoustic component 210 and the acoustic attenuation structure 220. It may be an encapsulation sleeve suitable for encapsulating the acoustic component 210 and the acoustic attenuation structure 220. Indeed, the shape of the acoustic component 210 and the acoustic attenuation structure 220 is suitable for such encapsulation.

[0093] Since the sheath 230 is intended to be in contact with tissues of an anatomical region into which the ultrasound probe assembled to a catheter is inserted, it is preferably biocompatible. For example, the sheath 230 may be made of an elastomeric material or any other suitable biocompatible material.

[0094] In the example shown, the sheath 230 forms a tubular body with a closed distal portion 231 (first portion) whose cross-section is substantially a semicircle, the flat portion of which is oriented above the acoustic component 210, an open proximal portion 232 (second portion) with a substantially circular cross-section, and an intermediate portion 233 (third portion) between the distal portion 231 and the proximal portion 232. The distal end of the sheath 230 may form a lens. For example, the sheath 230 comprises a curved lower outer wall 234 coupled to a curved proximal upper outer wall 235 at the level of the proximal portion 232, which transforms, in the intermediate portion 233, into a flat distal upper outer wall 236 at the level of the distal portion 231.

[0095] By replacing the acoustic attenuation layer and the mechanical support of [Fig. 1] with the acoustic attenuation structure of Figures 2A and 2B, and more generally with the acoustic attenuation structure of an ultrasonic probe according to one embodiment, the thickness of the stack of [Fig. 1] can be reduced, thereby reducing the diameter of the sheath, and thus of the ultrasonic probe, while ensuring good mechanical strength and flatness for the mounting and positioning of the ultrasonic transducers. For example, the mechanical reinforcement structure can prevent the acoustic attenuation layer from bending during the mounting of the ultrasonic transducers. This does not, however, prevent the ultrasonic probe from being bent after the transducers are mounted, provided that the materials of the acoustic component and the acoustic attenuation structure allow it.Preferably, the mechanical reinforcement structure is positioned at least opposite the acoustic component, or at least opposite the ultrasonic transducers.

[0096] Furthermore, such an acoustic attenuation structure can be simple to manufacture and integrate into a standard manufacturing process for an ultrasonic probe. In other words, it does not complicate the manufacture of the ultrasonic probe. Examples of integration are described below.

[0097] Furthermore, as described below, the mechanical reinforcement structure can act as an acoustic diffuser, for example when it comprises several metallic wires (or cables), in particular several metallic wires in several directions. The impedance difference at the interface between the attenuating material of the acoustic attenuation layer and the metallic wires allows an acoustic wave originating from the transducer array to be deflected. This deflected wave will therefore propagate through the attenuating material over a longer distance than a normal wave at the emitting surface of the transducers and will thus be attenuated more significantly upon its return to the transducer array.

[0098] Figures 3A, 3B, 3C, 3D, 3E, and 3F are cross-sectional views representing several variants of the acoustic attenuation structure of an ultrasonic probe according to one embodiment. The different variants of the acoustic attenuation structure can replace the acoustic attenuation structure 220 of Figures 2A and 2B.

[0099] Figures 3A to 3F show in particular several variations for integrating the reinforcement structure, in the form of one or more metal rods, into a stack of one or more acoustic attenuation layers. These different variations can be adapted to integrate any other mechanical reinforcement structure into a stack of one or more acoustic attenuation layers.

[0100] The acoustic attenuation structure 320A of [Fig. 3A] corresponds substantially to the acoustic attenuation structure 220 of [Fig. 2B] (rotated 180°), in which an adhesive 324 is further shown around each of the two metal rods 323. The adhesive 324 allows the metal rods 323 to be fixed in grooves 325 machined in the acoustic attenuation layer 321 from a lower face 321B of said acoustic attenuation layer 321. This lower face 321B is opposite an upper face 321A on which an acoustic component, such as the acoustic component 210 described in connection with [Fig. 2A], is positioned. The adhesive 324 is, for example, an epoxy adhesive. The adhesive 324 may advantageously be made of an acoustic attenuating material, for example, equivalent to the material of the acoustic attenuation layer 321.

[0101] The acoustic attenuation structure 320B of [Fig.3B] is similar to the acoustic attenuation structure 320A of [Fig.3A], except that it comprises only a metal rod 323 assembled with glue 324 in a groove 325 machined in the acoustic attenuation layer 321.

[0102] The variants in Figures 3A and 3B allow the use of acoustic attenuating materials that are not necessarily suitable for molding, for example, materials that are not necessarily polymerizable. This makes it possible to use a greater number of attenuating materials compared to a molding technique.

[0103] The acoustic attenuation structure 320C of [Fig. 3C] differs from the acoustic attenuation structure 320A of [Fig. 3A] in that the metal rods 323 are embedded in the acoustic attenuation layer 326. In other words, the metal rods 323 are not flush with one face of the acoustic attenuation layer 326. In other words, the acoustic attenuation layer 326 is all around the metal rods 323.

[0104] For example, the acoustic attenuation layer 326 can be formed by molding around the metal rods 323.

[0105] The acoustic attenuation structure 320D of [Fig.3D] is similar to the acoustic attenuation structure 320C of [Fig.3C], except that it comprises only a metal rod 323 embedded in the acoustic attenuation layer 326.

[0106] In the examples in Figures 3C and 3D, each metal rod 323 is substantially vertically centered in the acoustic attenuation layer 326. This is not limiting and each metal rod could be vertically off-center, for example be closer to the lower face 326B of the acoustic attenuation layer 326 than to its upper face 326A, or closer to the upper face 326A of the acoustic attenuation layer 326 than to its lower face 326B.

[0107] The acoustic attenuation structure 320E of [Fig. 3E] differs from the acoustic attenuation structure 320A of [Fig. 3A] in that, instead of a single acoustic attenuation layer, there is a stack 327 of two acoustic attenuation layers, an upper layer 327A (first layer) on top of a lower layer 327B (second layer). The upper and lower layers are assembled by positioning the lower face of the upper layer 327A on the upper face of the lower layer 327B. A thin layer of adhesive 328 can be positioned between the upper and lower layers 327A, 327B to fix them together.

[0108] The upper layer 327A comprises upper grooves 329A (first grooves) open to the lower face of the upper layer, and the lower layer 329B comprises lower grooves 329B (second grooves) open to the upper face of the lower layer. The lower grooves 329B are substantially the same shape and dimensions as the upper grooves 329A, the spacing between two lower grooves 329B being substantially equal to the spacing between two upper grooves 329A.

[0109] The upper and lower layers 327A, 327B are assembled, lower face of the upper layer against upper face of the lower layer, so as to enclose each metal rod 323 in an upper groove 329A positioned opposite a lower groove 329B. Thus, two upper and lower grooves 329A, 329B facing each other form a housing 329, sized to receive a metal rod 323 when the upper and lower layers 327A, 327B are assembled one on top of the other. The metal rods 323 are thus enclosed in the stack 327 of acoustic attenuation layers, between the upper and lower layers 327A, 327B. The housing 329 can be of similar dimensions to the groove 325 of figures 3A and 3B.

[0110] The metal rods 323 can be fixed in the upper and lower grooves 329A, 329B by glue 324, which may be similar to the glue of [Fig.3A].

[0111] The acoustic attenuation structure 320F of [Fig.3F] is similar to the acoustic attenuation structure 320E of [Fig.3E], except that it comprises only a metal rod 323 enclosed in a housing 329 formed by two upper and lower grooves 329A, 329B (first and second grooves) opposite each other.

[0112] In the examples in Figures 3E and 3F, each metal rod 323 is substantially vertically centered in the stack 327 of acoustic attenuation layers. In other words, the top and bottom layers 327A, 327B of the stack 327 have substantially the same thickness. This is not limiting, and each metal rod 323 could be vertically off-center. For example, the bottom layer 327B could be thinner than the top layer 327A, or conversely, the top layer 327A could be thinner than the bottom layer 327B.

[0113] Figure 4A is a three-dimensional view representing an ultrasonic probe 400 according to another embodiment. Figure 4B is a three-dimensional view showing in detail the acoustic attenuation structure of the ultrasonic probe 400 of Figure 4A.

[0114] The 400 ultrasonic probe of [Fig. 4A] has many features in common with the 200 ultrasonic probe of [Fig. 2A], and only the differences between the two 200 and 400 ultrasonic probes are detailed in the following description. The features in common with [Fig. 2A] retain the same reference numerals.

[0115] The ultrasonic probe 400 of Figures 4A and 4B differs from the ultrasonic probe 200 of [Fig. 2A] primarily in that the mechanical reinforcement structure 422 of the acoustic attenuation structure 420 comprises two metal braids 423 (metal elements), instead of straight metal rods. Each braid 423 comprises two metal wires 423A, 423B wound helically around each other along a longitudinal axis (parallel to the longitudinal direction Z). This can be described as a twisted pair. More generally, the mechanical reinforcement structure could comprise a braid of several metal wires wound helically around each other along the longitudinal axis, in the manner of a strand with more than two wires. The metal wires are, for example, made of the same material. Alternatively, the metal wires may be made of different materials.

[0116] The braids 423 of figures 4A and 4B therefore replace the metallic elements 223 of figures 2A and 2B.

[0117] One or more braids 423 of Figures 4A and 4B could replace all or part of the metallic elements 323 of Figures 3A to 3F. In other words, each of the embodiments of Figures 3A to 3F can be applied to the embodiment of [Fig. 4A].

[0118] Such a braid allows for the re-diffusion of acoustic waves. Indeed, a wave emitted by a transducer of the acoustic component 210 and directed towards a metal wire of the mechanical reinforcement structure 422 has a direction substantially parallel to the Y direction. It is then reflected, in whole or in part, by the interface between the material of the metal element 423 and the attenuating material of the acoustic attenuation layer 221. The circular shape of each metal wire acts on the incident surface like a diverging mirror; the reflected surface towards the transducer is therefore diffused divergently. Consequently, its power per unit solid angle is reduced and undergoes greater attenuation since the distance traveled by the reflected surface in the acoustic attenuation material is greater than that of a wave reflected in the same Y direction as the incident surface.

[0119] Fig. 5 represents a variant of the mechanical reinforcement structure 522. Fig. 6 represents another variant of the mechanical reinforcement structure 622. Fig. 7 represents another variant of the mechanical reinforcement structure 722.

[0120] The variants in Figures 5 to 7 show mechanical reinforcement structures, each in the form of a weave of metal wires, or wire mesh. A wire mesh is defined as a structure comprising first metal wires interspersed or interlaced with second metal wires substantially perpendicular to the first wires.

[0121] By intersecting, it is meant that the first metal wires 523A and the second metal wires 523B intersect each other at a plurality of nodes, as seen in the variant of [Fig. 5]. In this variant, the metal wires are substantially straight, that is, they are not curved. Metal wires that are not necessarily flexible can be used.

[0122] By interlaced, it is meant that the first metal wires 623A, 723A and the second metal wires 623B, 723B do not intersect at knots, but rather pass over and under each other. Each first wire passes successively under and then over (or over and then under) the second wires, and similarly each second wire passes successively under and then over (or over and then under) the first wires, in the manner of weaving, as seen in the variants of Figures 6 and 7. In these variants, the The metal wires are not straight, that is to say they are curved, and flexible enough to be able to be intertwined.

[0123] In the variant of [Fig.7], thicker metal wires are shown than in the third variant, which may be flexible metal rods.

[0124] Each truss in Figures 5 to 7 can replace the metal elements 323 and 423 in Figures 3A to 3F, or the mechanical reinforcement structure 422 in [Fig. 4A]. In other words, each embodiment of Figures 5 to 7 can be inserted into each embodiment of Figures 3A to 3F and 4A.

[0125] In the variants of figures 4 to 7, the mechanical reinforcement structure is composed of metal wires, more or less thick, and more or less flexible, which do not all extend in the same direction from the plane of the acoustic attenuation layer, or of the stack of acoustic attenuation layers.

[0126] One advantage of these variants is that they allow acoustic waves to be re-diffused in several directions, in the same way as for the metal braid in Figures 4A and 4B, as explained further.

[0127] Figure 8 is a three-dimensional view representing an 800 ultrasonic probe according to an exemplary embodiment. Figure 8 represents a non-limiting example of an embodiment of an ultrasonic probe incorporating an acoustic attenuation structure. Other embodiment examples may be considered by those skilled in the art.

[0128] The ultrasonic probe 800 has a front face 800A and a rear face 800B, and it includes an acoustic component 810 on the front face 800A, and an acoustic attenuation structure 820 on the rear face 800B. The acoustic component 810 is positioned on the acoustic attenuation structure 820.

[0129] The acoustic component 810 is a planar component comprising an array of ultrasonic transducers adapted to emit and receive ultrasonic waves, via the front face of the acoustic component, corresponding to the front face 800A of the ultrasonic probe and the front faces of the transducers. The front face 800A of the ultrasonic probe 800 is the face intended to be oriented towards the region to be analyzed.

[0130] The acoustic component 810 comprises a piezoelectric layer 811. Alternatively, there could be several piezoelectric layers stacked one on top of the other.

[0131] The upper 811A and lower 81 IB faces of the piezoelectric layer 811 are metallized, that is to say that the piezoelectric layer 811 comprises a core of piezoelectric material covered on each of its upper 811A and lower 811B faces by a metallic layer: a first metallic layer 812 on the lower face 81 IB and a second metallic layer 813 on the upper face 811A.

[0132] The first metallic layer 812 can be structured, i.e. divided over its entire thickness, to form several first electrodes isolated from each other.

[0133] The second metallic layer 813 can form a single whole second electrode or be structured, i.e. divided over its entire thickness, to form several second electrodes isolated from each other.

[0134] The acoustic component 810 further comprises, on the front face 800A of the ultrasonic probe 800, an acoustic impedance matching layer 814, or impedance matching layer. The acoustic impedance matching layer 814 may be at least partially in contact with the metallized piezoelectric layer 811, in particular with the second metallized layer 813. The impedance matching layer 814 may be a stack of impedance matching layers whose acoustic impedance decreases between the metallized piezoelectric layer 811 and the medium in which the ultrasonic probe 800 is intended to be installed. The stack of impedance matching layers may include layers of different materials, for example, impedance-matching gradient layers. The material of the 814 impedance matching layer is preferably electrically non-conductive.As an example, the 814 impedance matching layer may include a polymer, for example an epoxy resin, for example a filled polymer.

[0135] A metallic strip or foil may be provided (not shown) between the second metallic layer 813 and the impedance matching layer 814 and extend from at least one lateral face of the acoustic component 810 for mass reconnection with the rest of the ultrasonic probe.

[0136] The ultrasonic probe 800 further comprises a collector 830, which may be part of the acoustic component 810. The collector may be designated as the interconnecting substrate. The collector 830 is disposed on the lower face 81 IB of the metallized piezoelectric layer 811, beneath the first metal layer 812, for example, beneath the first electrodes when the first metal layer 812 is structured. The collector 830 comprises an insulating substrate 831, for example, a flexible substrate, for example, made of a polyimide material, and metal tracks 832 on the upper face of the insulating substrate 831. Each metal track 832 may be connected to one of the first electrodes.

[0137] In the example shown, the collector 830 extends along one side of the ultrasound probe 800, but this is not limiting. Alternatively, for example in the case of an intracardiac catheter, the collector may extend in the longitudinal direction Z of the ultrasound probe 800, for example towards the proximal end of the ultrasound probe. The collector may be a multilayer collector. The collector may include, in addition to the metallic tracks on its upper surface, other tracks metallic on its lower face or on an intermediate layer for a multilayer collector. A track located on a first layer of the multilayer collector can be connected with a track of a second layer of the multilayer collector by a vertical connection otherwise called a "via".

[0138] The acoustic attenuation structure 820 is disposed under the collector 830, for example in contact with the insulating substrate 831. A sound attenuation structure 820 corresponding to the sound attenuation structure 320E of [Fig. 3E] is shown in [Fig. 8] with a mechanical reinforcement structure in the form of a lattice instead of straight rods. Thus, the sound attenuation structure 820 of [Fig. 8] comprises a stack 827 of two sound attenuation layers, an upper layer 827A (first layer) on a lower layer 827B (second layer), which are assembled so as to enclose a metal lattice 822 forming the mechanical reinforcement structure, which may be similar to one of the mechanical reinforcement structures of Figures 5, 6 and 7. Alternatively, a mechanical reinforcement structure similar to that of [Fig. 3E] could be inserted into the stack 827.4B], that is to say in the form of a braid, or even several of these mechanical reinforcement structures.

[0139] Other acoustic attenuation structure variants may be suitable, for example the variants in Figures 3A, 3B, 3C, 3D and 3F, which may be in combination with any of the mechanical reinforcement structures in Figures 4B, 5, 6 and 7.

[0140] The ultrasound probe according to the embodiments can find applications in the field of intracardiac echocardiography (ICE), or even in the field of intravascular ultrasound imaging (IVUS), the ultrasound probe being integrated into a catheter.

[0141] Various embodiments and variations have been described. A person skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will become apparent to a person skilled in the art.

[0142] Finally, the practical implementation of the embodiments and variants described is within the reach of a person skilled in the art, based on the functional indications given above.

Claims

Demands

1. Ultrasonic probe (400; 800) extending along a longitudinal direction (Z), the ultrasonic probe comprising an acoustic attenuation structure (320A; 320B; 320C; 320D; 320E; 320F; 420; 820) extending in the longitudinal direction, and an acoustic component (210; 810) positioned on a first face (420A) of the acoustic attenuation structure, the acoustic component comprising an array of ultrasonic transducers; the acoustic attenuation structure comprising: - a stack (221; 321; 326; 327; 827) of at least one acoustic attenuation layer (221; 321; 326; 327A, 327B; 827A, 827B) of a material suitable for attenuating ultrasonic waves, said stack extending along a plane including the longitudinal direction; and - a mechanical reinforcement structure (422; 522; 622; 722; 822) in said stack; the mechanical reinforcement structure comprising at least one first metallic element (423A; 523A; 623A;723A) associated with at least one second metallic element (423B; 523B; 623B; 723B), the at least one first and at least one second metallic elements extending in two different directions from the plane of the stack.;

2. Ultrasonic probe (400) according to claim 1, wherein the acoustic component (210) has a first length (L1) and the acoustic attenuation structure (420) has a second length (L2) greater than the first length, the acoustic component being positioned on a first portion (420C) of the acoustic attenuation structure.

3. Ultrasonic probe (400) according to claim 2, wherein the acoustic attenuation structure (420) comprises a second portion (420D) not covered by the acoustic component (210), the second portion forming a support for electronic components, for example a flexible printed circuit is positioned between the second portion and the electronic components.

4. Ultrasonic probe according to any one of claims 1 to 3, wherein: - the material of at least one acoustic attenuation layer comprises a polymer, a resin, an epoxy resin, a silicone, or a matrix based on polymer, resin, epoxy resin or silicone, and may for example include acoustically absorbing fillers; and / or - the mechanical reinforcement structure is made of stainless steel, tungsten, titanium, or a combination of at least two of these materials.

5. Ultrasonic probe according to any one of claims 1 to 4, wherein each of at least one first and at least one second metallic element is a metallic wire or a metallic rod.

6. Ultrasonic probe according to any one of claims 1 to 5, wherein each of at least one first and at least one second metallic element has a circular, triangular, square, rectangular, polygonal, I-shaped or H-shaped cross-section.

7. Ultrasonic probe (400) according to any one of claims 1 to 6, wherein at least one first metallic element (423A) and at least one second metallic element (423B) are helically wound around each other along an axis, for example an axis parallel to the longitudinal direction (Z), forming a braid (423).

8. Ultrasonic probe (800) according to any one of claims 1 to 6, wherein at least one first metallic element (523A; 623A; 723A) is substantially perpendicular to at least one second metallic element (523B; 623B; 723B), forming a metallic grid or a metallic lattice.

9. Ultrasonic probe according to claim 8, wherein at least one first metallic element (523A) and at least one second metallic element (523B) are interspersed.

10. Ultrasonic probe according to claim 8, wherein at least one first metallic element (623A; 723A) and at least one second metallic element (623B; 723B) are intertwined.

11. Ultrasonic probe (400) according to any one of claims 1 to 10, wherein the mechanical reinforcement structure (422) is flush with a second face (420B) of the acoustic attenuation structure (420), opposite the first face (420A), for example, each of at least one first and at least one second metallic elements is housed in a groove (325) in the at least one acoustic attenuation layer (221), said groove being open at said second face.

12. Ultrasonic probe (800) according to any one of claims 1 to 10, wherein the mechanical reinforcement structure (822) is embedded in at least one acoustic attenuation layer (827A, 827B), for example said at least one acoustic attenuation layer is molded around said mechanical reinforcement structure.

13. Ultrasonic probe according to any one of claims 1 to 12, wherein the stack (327; 827) comprises a first acoustic attenuation layer (327A; 827A) assembled on a second acoustic attenuation layer (327B; 827B), and the mechanical reinforcement structure is positioned between said first and second acoustic attenuation layers, for example is housed in at least one housing (329) formed by a first groove (329A) open in the first acoustic attenuation layer and a second groove (329B) open in the second acoustic attenuation layer, the opening of the second groove being opposite the opening of the first groove.

14. Ultrasonic probe according to any one of claims 1 to 12, wherein the stack (221; 321; 326) comprises a single acoustic attenuation layer (221; 321; 326).

15. Ultrasonic probe according to any one of claims 1 to 14, wherein the acoustic attenuation structure is devoid of electrical connection functions.

16. Ultrasonic probe according to any one of claims 1 to 15, further comprising a sheath (230), preferably of an acoustically transparent material, adapted to enclose and retain at least the acoustic component (210) and the acoustic attenuation structure (420), the sheath being for example an encapsulation sheath.

17. Ultrasonic probe according to claim 16, wherein the sheath (230) forms a tubular body comprising: - a first portion (231) around the acoustic component (210) and the acoustic attenuation structure (420), said first enclosed portion being substantially hemispherical below the acoustic attenuation structure and planar or curved above the acoustic component; and - a second portion (232) around the acoustic attenuation structure (420), said second portion having a substantially circular cross-section.

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