阅读说明：本技术 具有集成到超声换能器的密封膜的瞬时弹性成像探头 (Transient elastography probe with sealing membrane integrated to ultrasound transducer ) 是由 洛朗·桑德兰 于 2019-09-16 设计创作，主要内容包括：本发明的一个方面涉及一种瞬时弹性成像探头(100),包括：-探头本体(101)；-超声换能器(103),被配置为沿着轴线产生超声波束,超声波束从超声换能器(103)的面(107)产生；-振动器(102),位于探头本体(101)内部并且被布置成引起超声换能器(103)沿着预定轴线的移动；超声波换能器(103)安装在振动器(102)上,使得预定轴线和超声波束的轴线彼此重合,其特征在于,瞬时弹性成像探头包括环绕超声波换能器(103)的外轮廓的密封膜(104)。(One aspect of the invention relates to a transient elastography probe (100) comprising: -a probe body (101); -an ultrasound transducer (103) configured to generate an ultrasound beam along an axis, the ultrasound beam being generated from a face (107) of the ultrasound transducer (103); -a vibrator (102) located inside the probe body (101) and arranged to cause movement of the ultrasound transducer (103) along a predetermined axis; an ultrasonic transducer (103) is mounted on a vibrator (102) such that a predetermined axis and an axis of an ultrasonic beam coincide with each other, characterized in that the instantaneous elastography probe comprises a sealing film (104) surrounding an outer contour of the ultrasonic transducer (103).)

1. A transient elastography probe (100), comprising:

a probe body (101);

an ultrasound transducer (103) configured to generate an ultrasound beam along an axis, the ultrasound beam being generated from a face (107) of the ultrasound transducer (103) intended to be in contact with a body of a patient;

a vibrator (102) located inside the probe body (101) and arranged to cause movement of the ultrasound transducer (103) along a predetermined axis;

-the ultrasonic transducer (103) is mounted on the vibrator (102) such that the predetermined axis and the axis of the ultrasonic beam coincide with each other, characterized in that the ultrasonic transducer comprises a sealing film (104) surrounding the outer contour of the ultrasonic transducer (103) and covering the face (107) of the ultrasonic transducer (103).

2. The probe (100) according to claim 1, wherein the ultrasound transducer (103) and membrane (104) assembly constitutes a detachable end piece (106).

3. The probe (100) according to any one of the preceding claims, wherein the ultrasound transducer (103) has an axis of symmetry corresponding to the axis of the ultrasound beam.

4. The probe (100) according to any one of the preceding claims, wherein the ultrasound transducer (103) is connected to the probe body (101) through the membrane (104).

5. The probe (100) according to any one of the preceding claims, wherein the membrane (104) is made of an elastomer.

6. The probe (100) according to claim 5, wherein the membrane (104) is made of a silicone-type elastomer.

7. The probe (100) according to any one of the preceding claims, wherein a portion (105) of the membrane (104) in contact with the face (107) of the ultrasound transducer (103) forms an acoustic lens configured to focus the ultrasound beam.

8. The probe (100) according to claim 7, wherein the portion (105) of the membrane (104) in contact with the face (107) of the ultrasound transducer (103) is convex.

9. The probe (100) according to claim 7, wherein the portion (105) of the membrane (104) in contact with the face (107) of the ultrasound transducer (103) is concave.

10. The probe (100) according to any one of the preceding claims, wherein the membrane (104) is made of an electrically insulating material.

11. The probe (100) according to any one of the preceding claims, wherein the membrane (104) is bonded to the ultrasound transducer (103).

12. The probe (100) according to any one of the preceding claims, wherein a portion of the membrane (104) between the ultrasound transducer (103) and the probe body (101) is deformable.

13. The probe (100) according to any of claims 7 to 9, wherein the outer diameter of the portion (105) of the membrane (104) in contact with the face (107) of the ultrasound transducer (103) is between 3mm and 25 mm.

14. The probe (100) according to any of claims 7 to 9, wherein the thickness of the membrane of the portion (105) of the membrane (104) in contact with the face (107) of the ultrasound transducer (103) is between 50 μ ι η and 5 mm.

15. The probe (100) according to any of the preceding claims, wherein all or part of the ultrasound transducer (103) has a frustoconical shape, the face (107) of the ultrasound transducer (103) corresponding to the base of the frustoconical shape of minimum area.

Technical Field

The technical field of the invention is transient elastography probes, in particular transient elastography probes comprising an ultrasound transducer integrated with a sealing membrane.

The present invention relates to a transient elastography probe usable for measuring viscoelasticity of human or animal tissue, and in particular to a transient elastography probe comprising an ultrasound transducer provided with a sealing membrane.

Background

Several liver diseases can be diagnosed by assessing the viscoelastic properties of liver tissue. Chronic viral hepatitis, alcoholic and non-alcoholic steatohepatitis, autoimmune hepatitis, viral hepatitis, primary biliary cirrhosis are all responsible for the progressive changes in cirrhosis. In some cases, this increase in stiffness, also known as fibrosis, can lead to cirrhosis and liver insufficiency with serious consequences for the patient.

One of the most reliable and effective techniques for measuring liver stiffness is transient elastography (see, for example, "WFUMB guidelines and clinical applications of Ultrasound elastography part 3: liver", published in "Ultrasound in Med. and biol.", 41, 5, 2015 by G.Ferraiol et al).

The applicant has developed and sold a product calledFor example see patent documents EP1169636 and EP1531733, which use an elastography technique called "vibration controlled transient elastography" (VCTE) developed by the applicant for measuring liver stiffness.

In VCTE applications, the measurement of liver stiffness is based on a measurement of the propagation velocity of the instantaneous shear wave within the examined tissue. To make such measurements, a specific probe has been developed. The probe includes at least one vibrator and at least one ultrasonic transducer.

For example, inIn the probe, a vibrator displaces and pushes an ultrasound transducer towards the body of a patient. This pulse motion generates a transient shear wave that propagates within the liver. Then theDisplacements caused by the propagation of shear waves are detected by transmitting high-frequency, short-lived ultrasonic pulses into the medium under investigation.

During the examination, the ultrasound transducer is then in direct contact with the body of the patient or with a water-based gel that facilitates ultrasound transmission. Therefore, the ultrasound transducer must be waterproof to prevent its deterioration while enabling an effective and painless examination of the patient.

Disclosure of Invention

The present invention provides a solution to the above-mentioned problems by making it possible to perform a transient elastography examination that is painless to the patient and without the risk of deterioration of the probe used.

One aspect of the invention relates to a transient elastography probe, comprising:

-a probe body;

-an ultrasound transducer configured to generate an ultrasound beam along an axis, the ultrasound beam being generated from a face of the ultrasound transducer;

-a vibrator located inside the probe body and arranged to cause movement of the ultrasound transducer along a predetermined axis;

the ultrasonic transducer is mounted on the vibrator so that the predetermined axis and the axis of the ultrasonic beam coincide with each other, characterized in that the instantaneous elastography probe comprises a sealing film surrounding the outer contour of the ultrasonic transducer.

Thanks to the invention, the ultrasound transducer is surrounded by a membrane that makes the probe waterproof, avoiding damage to it during inspection. The membrane also makes it possible to cover corner points on the face of the ultrasound transducer in order to make the examination painless to the patient. Finally, the membrane simplifies obtaining sufficient dielectric insulation to ensure that the probe meets the requirements relating to current regulations.

In addition to the features already mentioned in the preceding paragraphs, a probe according to an aspect of the invention may have one or more of the following features, considered alone or according to all technically possible combinations thereof.

Advantageously, the ultrasonic transducer and the membrane assembly constitute a detachable end piece (end piece).

Therefore, the ultrasonic transducer used can be adapted to the patient, and the diameter of the probe portion in contact with the patient differs depending on the form of the patient.

Advantageously, the ultrasound transducer has an axis of symmetry corresponding to the axis of the ultrasound beam.

Advantageously, the ultrasound transducer is connected to the probe body by a membrane.

Advantageously, the membrane is made of an elastomer.

Thus, the membrane is flexible and deforms when the ultrasound transducer moves.

Advantageously, the membrane is made of silicone-type elastomer.

Advantageously, the portion of the membrane in contact with the face of the ultrasound transducer forms an acoustic lens configured to focus the ultrasound beam.

Thus, the ultrasound beam is better focused, which makes it possible to obtain more accurate measurements. In this case, the portion of the membrane located in front of the face of the ultrasound transducer will be convex or concave depending on whether the propagation velocity of ultrasound in the lens is smaller or larger than the propagation velocity of ultrasound in water.

Advantageously, the portion of the membrane in contact with the face of the ultrasound transducer is convex.

Advantageously, the portion of the membrane in contact with the face of the ultrasound transducer is concave.

Advantageously, the membrane is made of an electrically insulating material.

Thus, the membrane enables better dielectric insulation of the probe. In fact, in the existing configurations, it is more difficult to achieve dielectric insulation, since the ultrasound transducer is provided with a film covering only the face of the ultrasound transducer. Also, dielectric leakage may occur on the periphery of the film.

Advantageously, the membrane is bonded to the ultrasound transducer.

Advantageously, the portion of the membrane between the ultrasound transducer and the probe body is deformable.

Therefore, when the ultrasonic transducer is displaced by the vibrator located in the probe body, the membrane is deformed.

Advantageously, the portion of the membrane in contact with the face of the ultrasound transducer has an outer diameter of between 3mm and 25 mm.

Advantageously, the thickness of the portion of the membrane in contact with the face of the ultrasound transducer is between 50 μm and 5 mm.

Advantageously, all or part of the ultrasonic transducer has a frustoconical shape, the face of the ultrasonic transducer corresponding to the base of the frustoconical shape of minimum area.

Thus, the surface in contact with the patient is not too wide, which makes it easier to accommodate the face of the ultrasound transducer in the intercostal space of the patient, while at the same time arranging space at the level of the wider back face to accommodate electronic components.

The invention and its various applications will be best understood by reference to the following specification and drawings which are appended hereto.

Drawings

The drawings are presented for purposes of illustration and not limitation.

Figure 1A shows a schematic view of a transient elastography probe according to a first aspect of the present invention.

Fig. 1B shows a schematic view of a transient elastography probe according to a first aspect of the invention, from which an end piece consisting of an ultrasound transducer covered with a sealing membrane is detached.

Fig. 2A shows a schematic view of a conical ultrasound transducer and a circular membrane.

Fig. 2B shows a schematic view of the ultrasound transducer shown in fig. 2A covered with the membrane shown in fig. 2A constituting a detachable end piece.

Fig. 3A shows a schematic view of an ultrasonic wave emitted by an ultrasonic transducer without a membrane, and more specifically of an ultrasonic wave reflected at a point F located at a distance d from the ultrasonic transducer.

Fig. 3B shows a schematic view of an ultrasonic wave emitted by an ultrasonic transducer covered with a membrane constituting an acoustic lens, and more specifically shows a schematic view of an ultrasonic wave reflected on a point F located at a distance d from the ultrasonic transducer and constituting a focal point of the acoustic lens.

Fig. 3C shows the diffraction impulse response at point F of fig. 3A and 3B when the ultrasound transducer is not provided with a membrane and when the ultrasound transducer is provided with a membrane.

Detailed Description

Unless otherwise indicated, identical elements appearing in different figures have a single reference numeral.

A first aspect of the invention relates to a transient elastography probe.

"transient elastography probe" refers to a probe capable of implementing VCTE (vibration controlled transient elastography) technology, i.e., a probe that can estimate the propagation velocity of a low frequency shear wave in a medium under study by using ultra-high frequency ultrasound to measure the local displacement of the medium during the passage of the shear wave. The propagation velocity makes it possible to estimate the viscoelastic parameters of the medium.

In the remainder of the description, the terms "probe" and "transient elastography probe" will be used indiscriminately.

In fig. 1A, a probe 100 according to a first aspect of the invention is shown.

The probe 100 includes:

-a probe body 101;

-a vibrator 102;

-an ultrasound transducer 103; and

a membrane 104.

The ultrasound transducer 103 is configured to generate an ultrasound beam. An ultrasound beam is generated at the level of the face 107 of the ultrasound transducer 103.

For example, the ultrasonic transducer 103 has an axis of symmetry a. The propagation axis of the ultrasound beam is parallel to the symmetry axis a.

For example, the ultrasonic transducer 103 has a truncated cone shape or a cylindrical shape as shown in fig. 2A, and the axis of the cone or the axis of the cylinder is the symmetry axis a.

The ultrasonic transducer has a length of, for example, more than 10 mm.

In fig. 2A, the face 107 corresponds to the small base or minimum area base of the conical ultrasonic transducer 103. In practice, a truncated cone has two bases lying in parallel planes, called the small base and the large base, the area of the small base being smaller than the area of the large base.

In fig. 1A, the face 107 corresponds to the base of the cylindrical ultrasonic transducer 103 which is not in contact with the vibrator 102.

The probe body 101 has a shape that enables the probe 100 to be held in an operator's hand during a transient elastography examination. For example, the probe body 101 has the shape of a solid of revolution having the same axis as the axis of symmetry a of the ultrasonic transducer 103, in particular, the probe body 101 has a cylindrical shape, the axis of symmetry a of the ultrasonic transducer 103 being the axis of the cylinder. The probe body 101 includes a rounded outer end 108.

The dimensions of the probe body 101 are selected to enable an operator to hold the probe 100 in his hand. For example, where the probe body 101 is cylindrical, the outer diameter of the probe body 101 is between 20mm and 80 mm.

The vibrator 102 is located inside the probe body 101, and the ultrasonic transducer 103 is mounted on the vibrator 102.

The vibrator 102 is configured to cause movement of the ultrasonic transducer 103 along a predetermined axis coinciding with the symmetry axis a of the ultrasonic transducer 103. This movement makes it possible to push the ultrasound transducer 103 against the patient body during the transient elastography examination and thus to generate low frequency shear waves.

The ultrasound transducer 103 is in contact with the body of the patient at its face 107.

As shown in fig. 2A, the conical ultrasound transducer 103 being in contact with the patient at the small base of the frustum cone means that the face 107 has a smaller surface than the back face corresponding to the large base of the frustum cone, which facilitates positioning the probe 100 in the intercostal space of the patient while leaving sufficient space to accommodate electronic components at the back face.

The ultrasound transducer 103 is covered with a membrane 104, which membrane 104 surrounds the outer contour of the ultrasound transducer 103 and ensures a sealing of the ultrasound transducer 103. For example, the membrane 104 is bonded to the ultrasonic transducer 103. The membrane 104 may also be overmolded onto the ultrasound transducer 103.

The film 104 covers the entire ultrasonic transducer 103 so that dielectric leakage that occurs when the film 104 covers only the face 107 of the ultrasonic transducer 103 can be avoided.

A portion 105 of the membrane 104 covers a face 107 of the ultrasound transducer 103.

The membrane 104 makes it possible to cover corner points on the face 107 of the ultrasound transducer 103 to make the examination painless for the patient.

For example, the portion of the membrane 104 between the probe body 101 and the ultrasound transducer 103, and in particular the portion of the membrane 104 intended to be in contact with the patient, is deformable. Therefore, when the ultrasonic transducer 103 is displaced by the vibrator 102 located in the probe body 101, the membrane 104 is deformed.

For example, the membrane 104 is made of an elastic material, thereby imparting elastic properties to the membrane 104. Specifically, the film 104 is made of silicone.

For example, the membrane 104 is made of an insulating material to ensure better dielectric insulation of the probe 100.

According to the embodiment shown in fig. 1A, the ultrasound transducer 103 is connected to the probe body 101 by means of a membrane 104.

For example, the membrane 104 has a circular shape, and the contour of the membrane 104 is arranged on the periphery of the end 108 of the probe body 101. The end 108 of the probe body 101 comprises, for example, a groove so that the contour of the membrane 104 can be inserted. The membrane 104 may, for example, be further bonded or clamped to the probe body 101.

Thus, the ultrasonic transducer 103 and membrane 104 assembly can be easily replaced and constitute a detachable end piece 106 as shown in fig. 1B or fig. 2B.

Different sized end pieces 106 may then be used to tailor the characteristics of the emitted ultrasound waves to the patient's morphology. For example, the end piece 106 may include an ultrasound transducer 103 selected from the following ultrasound transducers:

an ultrasonic transducer 103 having a center frequency of 8MHz and a diameter of 3 mm;

an ultrasound transducer 103 with a central frequency of 5MHz and a diameter of 5mm, an end piece 106 equipped with an ultrasound transducer of this type being suitable for measuring the elasticity of the liver of a child or small adult;

an ultrasound transducer 103 with a central frequency of 3.5MHz and a diameter of 7mm, an end piece 106 equipped with an ultrasound transducer of this type being suitable for measuring the elasticity of the adult liver;

an ultrasound transducer 103 with a 2.5MHz center frequency and a diameter of 10mm, an end piece 106 equipped with an ultrasound transducer of this type being suitable for measuring the elasticity of the liver of obese adults;

an ultrasonic transducer 103 having a center frequency of 1.5MHz and a diameter of 12 mm.

In fact, the smaller the diameter of the ultrasound transducer 103, the smaller the distance traveled in the medium by the ultrasound waves emitted by the ultrasound transducer 103. Thus, in the case of obese patients, the layer of adipose tissue between the skin and the liver is larger than in non-obese patients, and therefore the diameter of the ultrasound transducer 103 must be larger in order to make measurements in the liver rather than in adipose tissue.

The end piece 106 may be screwed or clipped to the probe body 101, for example.

For example, the end-piece 106 may include an LED type diode.

The outer diameter of the portion 105 of the membrane 104 in contact with the face 107 of the ultrasonic transducer 103 is for example between 3mm and 25 mm.

The portion 105 of the membrane 104 in contact with the face 107 of the ultrasonic transducer 103 has a thickness of between 50 μm and 5mm, for example.

As shown in fig. 3B, the portion 105 of the membrane 104 may constitute an acoustic lens capable of focusing an ultrasound beam.

For clarity, in fig. 3B, the portion 105 of the membrane 104 is shown as being separate from the ultrasound transducer 103, but in practice, the portion 105 of the membrane 104 is in contact with the face 107 of the ultrasound transducer 103.

In fig. 3A and 3B, the ultrasound transducer 103 emits an ultrasound beam with a propagation direction parallel to the symmetry axis a of the ultrasound transducer 103.

In fig. 3B, the ultrasound beam is focused by the acoustic lens at a point F located at a distance d from the portion 105 of the membrane 104, the point F constituting the focal point of the acoustic lens. All rays reach the focal spot F at the same time, which is advantageous in terms of the duration of the diffraction impulse response of the system.

In fig. 3A, without the portion 105 of the membrane 104, the path of the ultrasound beam does not deviate. The focal point F is defined by the "natural" focusing of the piston-type ultrasound transducer 103, with the disadvantage that the duration of the diffractive impulse response is greater than with acoustic lens focusing.

The diffraction impulse response at point F is shown in fig. 3C in the case where the ultrasonic beam is not focused and in the case where the ultrasonic beam is focused at point F by the portion 105 of the membrane 104 constituting the acoustic lens. V is the propagation velocity of the ultrasound in the medium under consideration.

It can be noted that in the case of focusing with a lens, the diffraction impulse response at a time approximately equal to the d/V time is shorter, which is more advantageous for obtaining good axial and lateral resolution of the probe 100.

In the presence of an acoustic lens, the intensity of the signal reflected by point F is also greater than without the acoustic lens, since the rays add coherently at the focal point F.

The diffraction impulse response at point F is more dispersed in time without the acoustic lens than if it were present, because the ultrasonic rays do not add perfectly coherently because they reach the focal point F after traveling a greater or lesser distance.

The acoustic lens may be concave or convex depending on whether the speed of propagation of ultrasound in the lens is less than or greater than the speed of propagation of ultrasound in water.