Ocular ultrasound imaging probe

Abstract

An ocular ultrasound imaging probe, comprising: - a transducer (2) configured to emit an ultrasound beam from an emitting surface in a first direction (Z'); - a first support (6) carrying the transducer (2), the first support (6) being rotatable about a second direction by a first pivot (8); - a second support (12) carrying the first pivot (8), the second support (12) being rotatable about a third direction by a second pivot (14); - a frame (20) carrying the second pivot (14); wherein the first support (6) comprises a first magnet (10), and the second support (12) comprises a second magnet, the probe (1) comprising a first winding (30) configured to control the movement of the first magnet (10) and a second winding (40) configured to control the movement of the second magnet. Figure for the abbreviation: FIG. 1

Description

Title of the invention: Ocular ultrasound imaging probe technical field

[0001] The present invention belongs to the field of ocular imaging, and more specifically relates to three-dimensional ocular ultrasound imaging using an ultrasound probe. State of the art

[0002] Ocular ultrasound is a method of examining the eye that uses the physical properties of ultrasound to allow an operator to visualize a representation of the eye. Ocular ultrasound is a non-invasive imaging technique that can quickly provide useful and easily obtainable information on certain typical eye lesions using general-purpose equipment. It is particularly useful when the cornea or certain intraocular media are opaque.

[0003] While two-dimensional representations have often been used, these can only account for a small portion of the eye and are therefore less effective than three-dimensional representations of the eye. Ultrasonic probes enabling three-dimensional acquisition, notably using arrays of transducer elements, have been developed for other applications, but these probes are not suitable for ocular imaging, being too bulky and having resolutions too low for ocular imaging.

[0004] Indeed, ocular imaging has its own specific characteristics. In particular, the three-dimensional representation must be acquired with high resolution and rapidly, within a few seconds, due to the frequent movements of the eye. Furthermore, since the probe must be brought into contact with the eye, typically via an intermediate coupling medium such as a balanced saline solution (BSS) and / or an ophthalmic gel, the probe must be compact and lightweight. Presentation of the invention

[0005] The invention aims to provide an ocular ultrasound imaging probe that allows for the rapid acquisition of a three-dimensional representation of a part of an eye, while remaining compact.

[0006] For this purpose, an ocular ultrasound imaging probe is proposed, comprising: - an ultrasound transducer configured to emit from an emission surface an ultrasound beam in a first direction and to receive ultrasound; - a first support carrying the transducer, the first support being mobile in rotation around a second direction by a first pivot; - a second support carrying the first pivot, the second support being carried mobile in rotation around a third direction by a second pivot; - a chassis supporting the second pivot; in which the first support includes a first magnet, and the second support includes a second magnet, the probe including a first winding configured to control the movement of the first magnet of the first support and a second winding configured to control the movement of the second magnet of the second support.

[0007] The invention is advantageously complemented by the following features, taken alone or in any technically possible combination thereof: - the second support has a second two-element magnet located on either side of the second pivot; - the first magnet is located at a second end of the first support opposite a first end carrying the ultrasonic transducer; - the first magnet comprises two magnet elements arranged at the second end; - the probe further includes at least one position sensor configured to acquire measurements representative of an evolution of the position of the transducer caused by the first magnet and / or the second magnet; - at least one position sensor is a magnetic field sensor configured to measure a change in magnetic field caused by the first magnet and / or by the second magnet.

[0008] The invention also relates to an ocular ultrasound imaging system comprising: - an ultrasound imaging probe such as has been presented previously; - a device for supplying electrical power to the windings; - a processor configured to control an electrical flow in the windings that causes a displacement of the first support and the second support.

[0009] Preferably, the processor is configured to cause a center of the emission surface to follow, by means of the displacements of the first and second supports, a two-dimensional trajectory inscribed within a portion of an ellipsoid defining a displacement surface. Preferably, the trajectory does not intersect itself as it traverses the displacement surface. Measurement points along the trajectory where the probe is configured to emit an ultrasound beam are preferably uniformly distributed over the displacement surface. Presentation of the figures

[0010] The invention will be better understood from the following description, which relates to embodiments and variants of the present invention, given by way of non-limiting examples and explained with reference to the accompanying schematic drawings, in which:

[0011] - Fig. 1 is a cross-sectional view of an example of a probe according to an embodiment possible of the invention;

[0012] - [Fig. 2] shows a first support and a second support of an example probe according to a possible embodiment of the invention;

[0013] - [Fig. 3] shows the second support and pivots of an example of a probe according to a possible embodiment of the invention;

[0014] - [Fig. 4a] shows an example of a trajectory formed by lines distributed according an angular step;

[0015] - Figure 4b shows an example of a spiral trajectory; and

[0016] - [Fig.4c] shows an example of a trajectory with triangular movements. Detailed description

[0017] With reference to Figures 1, 2, and 3, the ocular ultrasound imaging probe 1 extends along a longitudinal direction Z. Hereafter, radial denotes a direction perpendicular to this longitudinal direction Z. The ocular ultrasound imaging probe 1 comprises an ultrasonic transducer 2 configured to emit an ultrasound beam from an emitting surface in an emitting direction constituting a first direction Z' and to receive ultrasound. The ultrasonic transducer 2 may be a single element, or may comprise several elements, typically fewer than 10 elements and preferably 5 elements or fewer, for example, arranged in a circular geometry exhibiting rotational symmetry on the emitting surface 4. For example, concentric rings may be used as transducer elements.Ultrasonic transducer 2 is, for example, of the 15 MHz (single element) or 20 MHz (5 rings) type, and is, for example, a piezoelectric transducer.

[0018] By way of example, the emitting surface of the ultrasonic transducer 2 extends over a diameter of 2 to 20 mm, and preferably from 4 to 12 mm. The ultrasonic transducer 2 is configured to emit ultrasound in a frequency range from 5 to 100 MHz, and preferably from 12 to 50 MHz.

[0019] The probe 1 also includes a first support 6 carrying the transducer 2. The first support 6 is rotatable about a second direction Y by a first pivot 8. The first support 6 includes a first magnet 10. The first support 6 extends in the first direction Z' between a first end and a second end. The first magnet 10 is preferably located at one end of the The first support 6, while the transducer 2 is located at the other end, the first pivot 8 extends between the transducer 2 and the first magnet 10 in the direction of the second Y direction, transverse to the first Z' direction. The first pivot 8 extends on both sides of the first support 6.

[0020] The first magnet 10 is configured to follow a two-dimensional trajectory inscribed within a portion of a sphere. Ideally, the first magnet 10 can therefore have a shape conforming to a portion of a sphere. However, obtaining such a first magnet 10 can be difficult and expensive. It is then possible, as in the illustrated example, for the first magnet 10 to consist of one or more magnet elements 10a, 10b, the whole forming a single magnet. The faces of the magnet elements 10a, 10b should preferably have reversed or opposite poles. In the illustrated example, for a first magnet element 10a, the south pole is closer to the pivot 8 than its north pole, while for the other magnet element 10b, the north pole is closer to the pivot 8 than its south pole.

[0021] In the illustrated example, the first magnet 10 consists of two magnet elements 10a, 10b, which are cylindrical in shape, but could be of another shape, for example rectangular or partially spherical. These two magnet elements 10a, 10b each extend along a respective extension direction, which is perpendicular to the second direction Y and intersects the first pivot 8. Preferably, these two different extension directions lie in the same plane perpendicular to the first direction Y. The two extension directions have the same angular separation from the first direction Z', which is, for example, between 1 and 50°, and preferably between 15 and 30°. When several magnet elements 10a, 10b are present, they are angularly distributed around the first direction Z', and their respective extension directions are preferably the same with respect to the first direction Z'.Thus, during the rotation of the first support 6 around the second direction Y, the magnet elements 10a, 10b travel a greater amplitude over the portion of the sphere.

[0022] The first pivot 8 is supported by a second support 12, which is made mobile in rotation about a third direction X by a second pivot 14. The second support 12 surrounds the first support 6 which passes through the second support 12 at the level of a central opening 16 provided in the second support 12. The first pivot 8 passes through this central opening 16, typically in the middle of this central opening, in the second direction Y.

[0023] The second support 12 comprises a second magnet 18, preferably located on an outer periphery opposite the central opening 16 in the second direction Y. Preferably, the second magnet 18 extends over at least 50% of a perimeter of a plane of the second support 12 passing through the third direction X, and preferably over atminus 70%. The second magnet 18 may consist of two elements 18a, 18b located on either side of the second pivot 14. This arrangement maximizes the resulting torque.

[0024] The second magnet 18 thus preferably comprises a first element 18a of the second magnet 18 and a second element 18b of the second magnet 18, arranged on the outer periphery of the second support 12 in opposite positions on either side of the central opening 16. Each element 18a, 18b of the second magnet 18 may consist of a complete magnet, with a south pole and a north pole. In this case, the poles of one element of magnet 18a, 18b are opposite to the poles of the other element of magnet 18a, 18b of the second magnet 18.Thus, by traversing the periphery of the second support 12, one successively finds a north pole of a first element 18a of the second magnet 18, a south pole of the first element 18a of the second magnet 18, a north pole of a second element 18b of the second magnet 18, a south pole of the second element 18b of the second magnet 18. Alternatively, the second magnet 18 can be of a single piece, whose poles are located on either side of the second axis 14, on the periphery of the second support 12. For example, such a monobloc second magnet 18 can pass through the first pivot 8.

[0025] The second pivot 14 is supported by a frame 20 defining an interior space 22 in which the first support 6 and the second support 12 are housed at least in part.

[0026] As illustrated in [Fig. 1], the probe also includes a first winding 30 configured to control the movement of the first magnet of the first support 6. The first winding 30 is supplied with a power supply, and the current flowing in the first winding 30, interacting with the magnet 10, generates a force acting on the magnet. Since the first support 6 is mounted to rotate freely about the second direction Y, the force acting on the first magnet 10 results in a rotation of the first support 6 about the first pivot 8, and therefore a similar rotation of the transducer 2 about the second direction Y. The emitting surface of the transducer 2 is thus displaced, and the first direction Z', constituting the direction of emission of the ultrasound beam, is therefore angularly displaced with the same angular amplitude as the rotation of the first support 6 about the first pivot 8.Thus, depending on the current flowing in the first winding 30, it is possible to adjust the angular position of the ultrasound beam around the second direction Y.

[0027] The first winding 30 is wound around the longitudinal direction Z, outside the frame 20, so that at least one plane perpendicular to the longitudinal direction Z intersects the first winding 30 and the first magnet 10. Preferably, the frame 20 includes cavities 24 accommodating the first winding 30, in order to limit the obstacles between the first winding 30 and the first magnet 10.

[0028] The probe 1 also includes a second winding 40 configured to control the movement of the second magnet 18 of the second support 12. Preferably, the second A winding 40 extends around the longitudinal direction Z and is parallel to the first winding 30. The second winding 40 is equipped with a power supply, and the current flowing through the second winding 40, interacting with the magnet 18, generates a force acting on the magnet. Since the second support 12 is mounted to rotate about the third direction X, the force acting on the second magnet 18 results in a rotation of the second support 18 about the second pivot 14, relative to the frame 20 carrying the second pivot 14. This results in a rotation of the first support 6 of the same angular amplitude about the third direction X, and therefore a similar rotation of the transducer 2 about the third direction X. The emitting surface of the transducer 2 is thus displaced, and the first direction Z', constituting the direction of emission of the ultrasound beam, is therefore angularly displaced with the same angular amplitude.Thus, depending on the current flowing in the second winding 40, it is possible to adjust the angular position of the ultrasound beam around the third direction X.

[0029] It should be noted that since the first pivot 8 is supported by the second support 12, the second direction Y is itself modified by the rotation of the second support 12 around the third direction X. The rotation of the second direction Y is however perpendicular to the third direction X.

[0030] The second winding 40 is wound around the longitudinal direction Z, outside the frame 20, so that at least one plane perpendicular to the longitudinal direction Z intersects the second winding 40 and the second magnet 18. Preferably, the frame 20 includes cavities 26 accommodating the second winding 40, in order to limit the obstacles between the second winding 40 and the second magnet 18.

[0031] To allow regulation of the angular positions of the ultrasound beam around the second Y direction and the third X direction, the probe 1 includes at least one position sensor 50, 52 configured to acquire measurements representative of a change in the position of the transducer caused by the first magnet and / or the second magnet. Preferably, a first position sensor 50 is configured to acquire measurements representative of a change in the position of the first magnet carried by the first support 6, and a second position sensor 52 is configured to acquire measurements representative of a change in the position of the second magnet carried by the second support 8. The measurements taken by the position sensor 50, 52 allow the position of the transducer 2 to be determined.

[0032] Preferably, the first position sensor 50 is carried by the chassis 20 and is located outside said chassis 20, i.e., outside the internal space 22. Preferably, the first position sensor 50 extends radially outside the first winding 30. Preferably, the probe 1 comprises at least three first sensors 50, and preferably at least four first sensors 50. Preferably, at least two first sensors 50 are angularly spaced at least 70° around the longitudinal direction Z, and preferably at least three first sensors 50 are angularly spaced at least 70°. The first position sensor 50 is, for example, implemented by one or more magnetic Hall effect position sensors, preferably four in number.

[0033] Preferably, the second position sensor 52 is carried by the chassis 20 and is located outside said chassis 20, i.e., outside the internal space 22. Preferably, the second sensor 52 extends radially outside the second winding 40. The second sensor 52 is, for example, implemented by one or more magnetic Hall effect position sensors, preferably three in number. Preferably, at least two second magnetic sensors 50 are angularly spaced at least 70° apart about the longitudinal direction Z, and preferably at least three second magnetic sensors 50 are angularly spaced at least 70° apart.

[0034] All of these sensors can be replaced by a magnetometer type sensor 51, at least biaxial, which then constitutes the position sensor configured to acquire measurements representative of an evolution of the position of the transducer caused by the first magnet and / or the second magnet.

[0035] The probe 1 is part of an ocular ultrasound imaging system further comprising a winding power supply device and a processor configured to control an electrical current in the windings 30, 40 such as to cause a displacement of the first support 6 and the second support 12. Typically, the processor receives a measurement position command corresponding to the location where the ultrasound beam is to be emitted, and the measurements from the magnetic sensors 50, 52. From this data, the processor determines the current to be circulated in the windings 30, 40 to modify the position of the magnets 10, 18, and therefore the rotation of the first support 6 and the second support 12. Preferably, the processor is also configured to control the transducer 2 to emit the ultrasound, typically as soon as the measurement position is reached.The ultrasound received by the transducer 2 is converted by it into a measurement signal corresponding to the measurement position, which accounts for a measurement along the axis of the first direction Z' for that measurement position.

[0036] As mentioned above, the proposed probe 1 allows the direction of the emitted ultrasound beam to be modified along two axes of rotation, thus enabling the emitting surface to scan an entire two-dimensional area. This results in the possibility of scanning an observation space of an eye, making it possible to obtain a three-dimensional representation of an eye. Since the movement is achieved by means of coils 30, 40 interacting with magnets 10, 18, it is possible to obtain very rapid, smooth, and highly precise movements. Preferably, the measurement ultrasound for the three-dimensional representation of an eye includes measurement signals for at least 5000 different measurement positions, and preferably for at least 30,000 different measurement positions, obtained in less than 10 seconds, preferably 5 seconds or less.

[0037] The processor is thus configured to cause a center of the emission surface, defining a measurement position, to traverse, by means of the displacements of the first support 6 and the second support 12, a two-dimensional trajectory inscribed in a portion of a sphere, designated as the displacement surface. The imaged space extends in the form of a truncated cone from this displacement surface.

[0038] In order for the ultrasound beams to efficiently cover the measurement space, different strategies for traversing the measurement positions can be adopted. For example, as illustrated in [Fig. 4a], it is possible to traverse measurement positions aligned along a line before traversing another line of measurement positions that is angularly offset from the first. However, this approach is not optimal, as it leads to an over-representation of measurement positions where the lines meet, typically at the center of the surface traversed by the measurement positions. To avoid this bias, a possible decrease in the density of measurement positions along the trajectory as the path intersects can be considered, although this would involve longer travel times and a reduction in the number of measurement positions reachable within a given time.

[0039] It is preferable to adopt a displacement strategy in which the displacement path between the measurement points does not intersect itself, and preferably in which the measurement points are uniformly distributed over the displacement surface. In the example of [Fig. 4b], a spiral path, preferably with regular spacing between the spirals, maximizes the efficiency of the displacements and thus the number of measurement points in a given time. Other approaches can be used, as in the example of [Fig. 4c], in which the path is formed by a series of broken lines.

[0040] As can be seen in [Fig. 1], a cover 60 attached to the chassis 20 can close the interior space 22 and cover the transducer 2 in order to protect it and make it watertight. In addition, an external enclosure can be provided, comprising, for example, a housing 62 extending around the probe 1.

[0041] The invention is not limited to the embodiment described and shown in the accompanying figures. Modifications remain possible, particularly with regard to the composition of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Demands

1. Ocular ultrasound imaging probe (1), comprising: - an ultrasonic transducer (2) configured to emit an ultrasound beam from an emitting surface in a first direction (Z') and to receive ultrasound; - a first support (6) carrying the transducer (2), the first support (6) being movable in rotation about a second direction (Y) by a first pivot (8); - a second support (12) carrying the first pivot (8), the second support (12) being movable in rotation about a third direction (X) by a second pivot (14); - a frame (20) carrying the second pivot (14);in which the first support (6) includes a first magnet (10), and the second support (12) includes a second magnet (18), the probe (1) includes a first winding (30) configured to control the movement of the first magnet (10) of the first support (6) and a second winding (40) configured to control the movement of the second magnet (18) of the second support (12).

2. Imaging probe according to claim 1, wherein the second support (12) has a second magnet (18) with two elements (18a, 18b) located on either side of the second pivot (14).

3. Imaging probe according to any one of claims 1 and 2, wherein the first magnet (10) is located at a second end of the first support (6) opposite a first end carrying the ultrasonic transducer (2).

4. Imaging probe according to any one of claims 1 to 3, wherein the first magnet comprises two magnet elements (10a, 10b) arranged at the second end.

5. Imaging probe according to any one of claims 1 to 4, further comprising at least one position sensor (50, 51, 52) configured to acquire measurements representative of an evolution of the position of the transducer (2) caused by the first magnet and / or the second magnet.

6. Imaging probe according to claim 5, wherein at least one position sensor (50, 51, 52) is a magnetic field sensor configured to measure a variation in magnetic field caused by the first magnet and / or by the second magnet.

7. Ocular ultrasound imaging system comprising: - an ultrasound imaging probe (1) according to any one of claims 1 to 6; - a winding power supply device; - a processor configured to control an electrical flow in the windings suitable for causing a displacement of the first support and the second support.

8. Imaging system according to claim 7, wherein the processor is configured to cause a center of the emission surface to travel, by means of the displacements of the first support (6) and the second support (12), a two-dimensional trajectory inscribed in a portion of an ellipsoid defining a displacement surface.

9. Imaging system according to claim 8, wherein the trajectory does not exhibit any overlap when traversing the displacement surface.

10. Imaging system according to any one of claims 8 and 9, wherein measurement points along the trajectory where the probe is configured to emit an ultrasound beam are uniformly distributed over the displacement surface.

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