Method and device for locating veins in a limb

Abstract

A method for locating and preferably visualizing a vein in a limb, preferably a leg, of a patient using an imaging device, the method comprising the steps of: completely or partially collapsing at least a segment of the vein to be located at a collapsed site during a collapsing step; inducing blood flow in the vein at the collapsed site while completely or partially collapsing the segment of the vein during a pumping step; and visualizing the collapsed site using the imaging device in an imaging step at least during the pumping step.

Description

Technical Field

[0001] The present invention relates to a method and a device for locating and visualizing veins in a limb of a patient, preferably in the leg, a method for compressing veins in a limb of a patient, preferably in the leg, and a degassed liquid for swelling a vein of a patient according to the claims. Background Art

[0002] Heat treatment is used for the obstruction of veins, for example to treat varicose veins.

[0003] US 8,214,052 discloses an invasive method for treating a vein using a catheter which can be heated and thereby transfers heat to the vein wall. The catheter is placed in the vein segment to be treated, heated and withdrawn from the vein.

[0004] The main disadvantage of this method is that the catheter must be inserted invasively into the vein segment to be treated, which carries the risk of perforation and is a complicated procedure for tortuous veins.

[0005] In contrast, HIFU devices allow non-invasive treatment of targets within a patient's body. In order to focus the HIFU device within the target area, the area surrounding the target area is imaged, for example, by MRI or ultrasound. In particular, a HIFU device with an integrated B-mode ultrasound imaging device is used as exemplarily described in WO2006 / 129045A.

[0006] Vein occlusion due to coagulation of the vein wall relies on a thermal effect, so blood flow during treatment is not desired, since it cools the treated vein wall. Therefore, the vein segment to be treated must be collapsed to stop or at least substantially reduce blood flow. The vein can be collapsed by compression devices, either by elevating the patient's limb with the leg in the so-called Trendelenburg position and / or by tumescent anesthesia. Since imaging of the target area must be performed while the vein is collapsed in order to focus the HIFU device, the problem of clearly visualizing the vein segment to be treated arises.

[0007] If B-mode imaging is used, the collapsed vein is barely visible. Also with color Doppler, once blood flow stops, the vein becomes invisible. If blood flow is only reduced, color Doppler may help at the beginning of thermal treatment, but as the coagulation of the vein wall causes constriction of the lumen, blood flow will be further reduced or stopped, rendering the vein invisible. Summary of the invention

[0008] It is therefore an object of the present invention to provide a method for aligning and visualizing veins within a limb which allows reliable visualization of at least partially collapsed veins and thus enables focusing of a non-invasive thermal treatment device such as a HIFU device on a target area when the vein is collapsed.

[0009] This problem is solved by a method of locating and preferably visualizing veins in a limb, preferably in a leg, of a patient using an imaging device according to the independent claim.

[0010] According to a first alternative of the method, the method comprises the following steps:

[0011] During the collapsing step, at least a section of the vein to be located is fully or partially collapsed at the collapse site.

[0012] In the sense of the present invention, a collapse of a vein is understood to mean a reduction in the cross section of a vein segment and / or a change in the shape of a vein segment.

[0013] Preferably, collapse of the vein is performed by at least one of elevating at least the patient's limb above a horizontal position, compressing the vein segment (eg, with an inflatable balloon), and swelling.

[0014] A limb, such as a leg, can be elevated in the so-called "Trendelenburg position". Alternatively, the patient can lie on their side or prone on the table with the limb elevated. In the case where the patient is lying on their back, side, or prone on the table, the table supporting the patient can also be tilted to elevate the position of the limb.

[0015] In the pumping step performed while the vein segment is fully or partially collapsed, blood flow is directed into the collapsed vein segment at the site of the collapse.

[0016] Additionally, vacuum mattresses may be used to immobilize the limb and / or the patient.

[0017] Preferably, during the pumping step, the vein is compressed and released at a compression site located near the collapsed site, preferably upstream of the collapsed site. Alternatively, other techniques may be used, for example for directing blood flow into the collapsed vein segment, such as the Vasalva maneuver, or moving / asking the patient to move a toe or finger.

[0018] Within the meaning of the present invention, near the collapsed site is understood to mean that the compression and release points are selected such that blood flow can be forced through the collapsed vein. In particular, the compression and release points are located at most 50 cm from the collapsed segment of the vein. Preferably, the compression and release points are located in the same segment of the limb where the collapsed vein segment is located (e.g., thigh or calf).

[0019] In the imaging step, at least during the pumping step, the collapsed site is imaged using an imaging device.

[0020] Preferably, the collapse site is visualized on a display connected to the imaging device.

[0021] Since the collapsed section of the vein becomes difficult to see when using known imaging devices, the blood is forced to flow through the collapsed section of the vein during the pumping step, thereby making the vein visible with the aid of the imaging device.

[0022] Therefore, the correct position of the collapsed vein segment can be located and used in subsequent steps.

[0023] Preferably, the imaging step is performed during the collapsing step and the pumping step.

[0024] By doing so, the vein segment can be localized during collapse, thus defining a region of interest where the collapsed segment of the vein should be located and will become visible during the pumping step.

[0025] Preferably, compression and release of the vein during the pumping step is performed manually by the operator.

[0026] Alternatively, compressing and releasing the vein during the pumping step is performed using a compression device.

[0027] The compression device may be integrated into a device including the imaging device, or may be a separate device, such as a tourniquet.

[0028] Preferably, the vein is compressed and released repeatedly while the vein segment is completely or partially collapsed. This is done in order to correctly and reliably locate the collapsed vein segment.

[0029] Preferably, the imaging is performed by at least one of color Doppler imaging, pulsed wave Doppler imaging, and B-mode ultrasound imaging.

[0030] In the case of using color Doppler imaging, the field of view of the color Doppler device (acquisition box) is placed over the area where the collapsed vein segment is expected to be located. Thus, during the pumping step, the blood forced to flow through the collapsed vein segment becomes visible and the collapsed segment can be located.

[0031] In the case of B-mode ultrasound imaging, the field of view of the color Doppler device is placed over the area where the collapsed venous segment is expected to be located. During the pumping step, the blood forced to flow through the collapsed venous segment changes the cross-section of the collapsed venous segment and a hypoechoic spot corresponding to the open venous segment is visualized.

[0032] In the case of using pulsed wave Doppler imaging, a measurement point is placed where the collapsed vein segment is expected to be located, and the movement of blood within the collapsed vein segment is detected.

[0033] Preferably, particularly when performing pulse wave Doppler imaging, the field of view or focus of the imaging device is shifted during the imaging step for locating the vein. While repeating the pumping step, the imaging device is shifted until the collapsed vein segment moved by the forced blood flow is imaged by the imaging device.

[0034] According to a second alternative of the method, in which a B-mode ultrasound imaging device having a main ultrasound propagation axis is used, the method comprises the following steps:

[0035] During the collapsing step, at least a section of the vein to be located is completely or partially collapsed at the collapse site.

[0036] In the sense of the present invention, a collapse of a vein is understood to mean a reduction in the cross section of a vein segment and / or a change in the shape of a vein segment.

[0037] Preferably, collapse of the vein is performed as described above by at least one of elevating at least the patient's limb above a horizontal position, compressing the vein segment (eg, with an inflatable balloon), and swelling.

[0038] During the imaging step, the collapse site is visualized using an imaging device.

[0039] As mentioned above, the collapsed segment of the vein may be poorly visible or not visible.

[0040] In order to locate the collapsed segment of the vein, in a detection step performed while the vein segment is fully or partially collapsed, at least one of the position and orientation of the imaging device is changed until a portion of the collapsed vein segment corresponding to the collapsed vein wall becomes hyperechoic, preferably visualized on a display connected to the imaging device.

[0041] A hyperechoic spot is generated when the main ultrasound propagation axis is orthogonal to the vein wall.Therefore, the position and / or orientation of the imaging device is changed until the main propagation axis of the imaging device is orthogonal to the vein wall of the collapsed vein segment.

[0042] Therefore, the collapsed vein segment can be reliably located.

[0043] Preferably, imaging of the collapsed site is performed during the collapsing step and the imaging step in order to determine a region of interest where the collapsed vein segment is expected to be located.

[0044] Preferably, changing at least one of the position and orientation of the imaging device is performed manually by an operator.

[0045] Alternatively, changing at least one of the position and the orientation of the imaging device is performed by a shifting device connected to the imaging device.

[0046] Preferably, during the imaging step, at least one of the position and orientation of the imaging device is changed by moving the imaging device in at least one direction selected from: rotation around the main ultrasound propagation axis, rotation around an axis orthogonal to the main ultrasound propagation axis, displacement in a direction orthogonal to the main ultrasound propagation axis, preferably orthogonal to an imaging plane of the imaging device, and displacement in a direction parallel to the main ultrasound propagation axis.

[0047] This is done to enable the operator or image processing unit to differentiate between spots and veins and other structures of interest.

[0048] The movement range is preferably between 0.5 mm and 10 mm, in particular between 0.2 mm and 5 mm. The imaging device is preferably displaced at a maximum speed of 5 mm / s.

[0049] In case the imaging device is displaced in a direction orthogonal to the main ultrasound propagation axis, preferably orthogonal to the imaging plane of the imaging device, the direction is preferably selected so that it is parallel to the extension direction of the vein or to the projection of the vein on the skin if the vein is not parallel to the skin, wherein the imaging plane is preferably oriented orthogonal to the extension of the vein or to the projection of the vein on the skin if the vein is not parallel to the skin. The imaging device is then displaced in an oscillating manner and scans sectors of the collapsed vein.

[0050] Preferably, the method further comprises the following steps:

[0051] The HIFU device is focused within the located collapse site during the aligning step, and at least one pulse of HIFU waves is transmitted to the aligned collapse site using the HIFU device during the treating step.

[0052] Preferably, the imaging device and the HIFU device are combined. In particular, if B-mode ultrasound imaging is used, the focus of the HIFU device is located in the imaging plane of the imaging device.

[0053] Preferably, during the detecting step, the imaging device is rotated about an axis including the focal point of the HIFU device.

[0054] This is done because the optimal position of the HIFU device may be different from the optimal position of the imaging device in order to correctly locate the collapsed vein segment. As previously described, the imaging device is displaced to orthogonal the main ultrasound propagation axis to the vein wall, thereby making the vein wall visible as a hyperechoic point. However, the optimal position of the HIFU device is when the skin is orthogonal to the main propagation axis of the HIFU waves. Therefore, the imaging device, especially when integrated into the HIFU device, is moved around an axis including the focal point of the HIFU device to keep the HIFU device focused on the target. Of course, if it is determined that the focal point of the HIFU device is not located within the collapsed vein segment, the focal point of the HIFU device can be moved to the optimal position.

[0055] Obviously, after the HIFU device is correctly aligned, it can be moved to a position that is most suitable for HIFU wave emission, thereby maintaining the focus on the located collapsed vein segment.

[0056] Preferably, in a measuring step performed before the collapsing step, at least one of a diameter and a shape of the vein at the collapsed site is determined, preferably with the patient in a standing position, and wherein a dose of thermal energy to be delivered during the treatment step is preferably determined based on at least one of the diameter and the shape of the vein.

[0057] Preferably, the flux value (energy delivered to the surface of the cylinder) is determined based on the shape and / or diameter of the vein.

[0058] The invention further relates to a method for swelling a vein in a limb of a patient, preferably in a leg. The method is preferably performed according to the method described above.

[0059] Fluid is injected near a segment of the vein at the site of collapse so that the vein is not completely surrounded by fluid, whereby the segment of the vein is closed.

[0060] For example, if the vein is superficial, it can be pushed toward the deep fascial tissue. Since the border between the fluid-filled fascia and the underlying tissue is easily visible with known imaging devices, especially B-mode imaging, the operator has a good estimate of the location of the collapsed vein segment. Moreover, most of the advantages of the classic swelling are retained: the distance to the skin is increased, adjacent sensitive structures can be protected, and the patient's pain is reduced. The side of the vein where the fluid is injected is determined based on the presence of adjacent sensitive structures to be protected and the depth of the vein compared to the ideal treatment depth of the HIFU device.

[0061] The liquid preferably contains an anesthetic active substance.

[0062] The liquid preferably comprises a physiological saline solution.

[0063] Preferably, a degassed liquid is used with a dissolved oxygen concentration below 4 mg / L, preferably below 1 mg / L, to allow for proper propagation of the HIFU waves.

[0064] The invention also relates to a tumescent degassed liquid for use in a patient's vein, having a dissolved oxygen concentration below 4 mg / L, preferably below 1 mg / L.

[0065] The preferred embodiments described above with respect to the method also apply correspondingly to the degassed liquid.

[0066] The invention further relates to a device for locating and preferably visualizing veins in a limb, preferably a leg, of a patient.

[0067] The device is preferably suitable for performing the positioning method described above. Therefore, the description of the method is also applicable to such a device accordingly.

[0068] The device includes an imaging device and a compression device for compressing and releasing the vein at a compression site located near the collapse site, preferably distal to the collapse site.

[0069] The device further comprises a control unit for controlling the imaging device and the compression device, wherein the control unit is adapted to synchronize the imaging device to perform imaging of the compression site while the compression device compresses and releases the vein near the collapsed site.

[0070] The synchronization of the imaging device and the compression device may be triggered by an operator or performed autonomously by the devices, in particular based on predetermined parameters or parameters input by the operator.

[0071] The control unit is preferably also adapted to control other systems of the device and synchronize them with the imaging means and the compression means.

[0072] In particular, in the case where the imaging device is a color Doppler or pulse wave Doppler device, in order to improve the image quality of the imaging device, the cooling system of the device that may interfere with the imaging, such as the balloon of the HIFU device, is temporarily stopped.

[0073] The invention further relates to a device for locating and preferably visualizing veins in a limb, preferably a leg, of a patient.

[0074] The device is preferably suitable for performing the positioning method described above. Therefore, the description of the method is also applicable to such a device accordingly.

[0075] The device comprises an imaging device and a displacement device for displacing the imaging device relative to a patient.

[0076] Preferably, the displacement device is connected to the imaging device and allows the imaging device to be displaced relative to the patient. Alternatively, the imaging device can be kept in a fixed position and the patient displaced by the displacement device.

[0077] In the following, therefore, displacing the imaging device by the displacement device means displacing the imaging device relative to the patient and vice versa.

[0078] The device further comprises a control unit adapted to synchronize the imaging device to perform imaging of the collapsed site of the vein segment while the imaging device is displaced by the displacement device.

[0079] The device according to the present invention preferably also comprises a HIFU device.

[0080] In this case, the control unit is further adapted to control the HIFU device, in particular to focus the HIFU device on the located collapsed vein segment and to trigger the emission of at least one pulse of HIFU waves.

[0081] In the case of using color Doppler imaging, the field of view of the color Doppler device (acquisition box) is placed over the area where the collapsed vein segment is expected to be located. Thus, during the pumping step, the blood forced to flow through the collapsed vein segment becomes visible and the collapsed segment can be located.

[0082] In the case of B-mode ultrasound imaging, the field of view is placed over the area where the collapsed venous segment is expected to be located. During the pumping step, the blood forced to flow through the collapsed venous segment changes the cross-section of the collapsed venous segment and a hypoechoic spot corresponding to the open venous segment is visualized.

[0083] In the case of using pulsed wave Doppler imaging, a measurement point is placed where the collapsed vein segment is expected to be located, and the movement of blood within the collapsed vein segment is detected.

[0084] Preferably, particularly when performing pulse wave Doppler imaging, the field of view or focus of the imaging device is shifted during the imaging step for locating the vein. While repeating the pumping step, the imaging device is shifted until the collapsed vein segment moved by the forced blood flow is imaged by the imaging device.

[0085] The control unit is preferentially adapted to automatically locate the collapsed vein segment by means of an image processing algorithm.Alternatively, the location of the collapsed vein segment may be defined by a user by means of a graphical user interface.

[0086] The control unit is also preferably adapted to maintain the focus of the HIFU device on the located collapsed vein segment when the imaging device is displaced.

[0087] Likewise, the control unit is also preferably adapted to control the displacement unit to change at least one of the position and orientation of the imaging device until a portion of the collapsed venous segment corresponding to the wall of the collapsed vein becomes hyperechoic. This is preferably visualized on a display connected to the imaging device. The detection of the hyperechoic points can be performed automatically by an image processing algorithm. Alternatively, the positioning of the hyperechoic points can be performed by a user by means of a graphical user interface.

[0088] Preferably, the displacement device is suitable for changing at least one of the position and orientation of the imaging device while performing imaging by moving the imaging device in at least one direction selected from: rotation around the main ultrasound propagation axis, rotation around an axis orthogonal to the main ultrasound propagation axis, displacement in a direction orthogonal to the main ultrasound propagation axis, preferably orthogonal to the imaging plane of the imaging device, and displacement in a direction parallel to the main ultrasound propagation axis.

[0089] In case the imaging device is displaced in a direction orthogonal to the main ultrasound propagation axis, preferably orthogonal to the imaging plane of the imaging device, the direction is preferably selected so that it is parallel to the extension direction of the vein or to the projection of the vein on the skin if the vein is not parallel to the skin, wherein the imaging plane is preferably oriented orthogonal to the extension of the vein or to the projection of the vein on the skin if the vein is not parallel to the skin. The imaging device is then displaced in an oscillating manner and scans sectors of the collapsed vein.

[0090] This is done to enable the operator or image processing unit to differentiate between spots and veins and other structures of interest.

[0091] The movement range is preferably between 0.5 mm and 10 mm, in particular between 0.2 mm and 5 mm. The imaging device is preferably displaced at a maximum speed of 5 mm / s.

[0092] Alternatively, the displacement device may be adapted to limit the movement only to a maximum range and / or to limit the direction of movement / rotation as described above, whereby the imaging device is then displaced manually by an operator.

[0093] Preferably, during the detecting step, the imaging device is rotated about an axis including the focal point of the HIFU device.

[0094] Obviously, after the HIFU device is correctly aligned, it can be moved to a position that is most suitable for HIFU wave emission, thereby maintaining the focus on the located collapsed vein segment.

[0095] The control unit is preferably adapted to control the displacement unit and the HIFU device according to a predetermined treatment plan, wherein, after having emitted at least one pulse of HIFU waves focused on a first target position within the collapsed vein segment, the imaging device and the HIFU device are automatically displaced to a second target position within the collapsed vein segment and the emission of HIFU waves is triggered. Of course, before treating the second target position, the positioning of the collapsed vein segment may be performed as described above in order to confirm the correct positioning of the collapsed vein segment performed in the previous step.

[0096] The present invention also relates to a method of occluding a vein in a limb of a patient, preferably in the leg, using a HIFU device.

[0097] As described above, HIFU waves can be used to treat veins in a non-invasive manner and induce occlusion of the vein through thermal and / or cavitation effects on the vein wall.

[0098] In the collapsing step, at least a section of the vein to be located is completely or partially collapsed at the collapse site.

[0099] This step is performed as described above with respect to other methods / apparatus of the present invention.

[0100] In the imaging step, the collapse site is located using an imaging device.

[0101] The imaging step is performed as described above with respect to the other methods / apparatus of the invention.

[0102] In some cases, depending on circumstances such as the size of the vein, the shape of the vein, or the imaging method used, the collapsed vein segment can be located without performing the pumping step or the detecting step described above.

[0103] Thus, collapsed vein segments can be localized.

[0104] In the alignment step, the focus of the HIFU device is aligned into the located collapse site during the alignment step.

[0105] In the treatment step, at least one pulse of HIFU waves is emitted to the targeted collapse site using the HIFU device.

[0106] It is clear from the above that the detailed description of the method / device of the present invention described previously also applies accordingly to the method of occluding a vein and the device for occluding a vein.

[0107] In particular, these steps may be repeated along the collapsed vein segment in order to treat the vein over a given length.

[0108] The imaging device may also be moved as previously described in order to scan the collapsed vein segment and, in particular, to improve the imaging of the collapsed vein segment by distinguishing between image artifacts such as speckle and the collapsed vein segment. BRIEF DESCRIPTION OF THE DRAWINGS

[0109] The invention will now be described in more detail by means of non-limiting exemplary embodiments and in conjunction with the accompanying drawings, which show:

[0110] Figure 1 is a flow chart of a first alternative of the method according to the invention;

[0111] Figure 2 is a flow chart of a second alternative of the method according to the invention; and

[0112] Figure 3 is a schematic arrangement of a device according to the invention. DETAILED DESCRIPTION

[0113] Figure 1 A first alternative of the method according to the invention is shown. In a first collapsing step 101, at least a section of the target vein is collapsed. As mentioned above, the vein may be collapsed by tilting the patient's limb or by swelling.

[0114] In order to reliably locate the collapsed segment of the vein using the imaging device, blood flow is forced into the collapsed segment of the vein in a pumping step 102. If the pumping step 102 is performed by compressing / releasing the vein, the compression is preferably performed upstream of the collapsed segment, either manually by an operator or using a compression device. Thus, temporary blood flow is forced through the collapsed segment of the vein, thereby making the collapsed segment visible with the aid of the imaging device during the imaging step 103.

[0115] In the case of using color Doppler as an imaging method, the blood flow becomes clearly visible. If B-mode ultrasound imaging is used, the blood flow causes the opening and closing of the collapsed venous segment. Therefore, the venous lumen appears as a hypoechoic point (corresponding to the opening and closing of the venous lumen). As an alternative, pulsed wave Doppler can also be used as an imaging step. The measurement position of the pulsed wave Doppler device is placed in the area of ​​the expected collapsed segment, and a pumping step 102 is performed. If a signal is detected by means of pulsed wave Doppler during the imaging step 103, the pulsed wave Doppler device has been correctly focused on the collapsed segment of the vein. Otherwise, the measurement position is moved and the pumping step 102 is repeated until the position of the collapsed venous segment is correctly determined in the imaging step 103.

[0116] After the correct location of the collapsed vein segment is determined, a treatment step 104 may be performed. The HIFU device is focused on the collapsed vein segment and emits one or a series of pulses of HIFU waves to treat the collapsed vein segment and occlude it.

[0117] from Figure 2 It can be seen that in the case in which an alternative of the method according to the invention is shown, first a collapsing step 101 is performed.

[0118] Instead of the pumping step 102, a detection step 202 is then performed. During the detection step 202, imaging of the region of interest around the collapsed vein segment is performed by means of B-mode ultrasound imaging.

[0119] The B-mode ultrasound imaging device has a main ultrasound propagation axis.During the detection step 202, the imaging device is moved until a hyperechoic point corresponding to the venous wall of the collapsed venous segment is detected and the position of the collapsed venous segment has been correctly determined.

[0120] In this case as well, the following may be performed after the detection step 202: Figure 1 The treatment step 104.

[0121] The HIFU device and the B-mode imaging device are preferably a combined device, wherein the focus of the HIFU device is located in the imaging plane of the imaging device.

[0122] In this case, the displacement of the B-mode imaging device implicitly also causes the displacement of the HIFU device. If the vein does not extend parallel to the skin, the HIFU device will not be in the optimal position for transmitting the HIFU waves (where the HIFU beam is orthogonal to the skin surface to enhance the transmission of the HIFU waves through the skin). In this case, after the detection step 202 has been performed and the correct position of the area to be treated has been determined, the combined B-mode imaging device and HIFU device are shifted to the optimal position for transmitting the HIFU waves, with the focus of the HIFU device being on the area to be treated. Thus, there are two different positions / angles, one optimal for visualization (e.g., the main ultrasound propagation axis is orthogonal to the wall of the collapsed vein segment) and the other optimal for delivering the HIFU energy (e.g., the main propagation axis of the HIFU waves is orthogonal to the skin).

[0123] In case the combined B-mode imaging device and HIFU device are displaced by means such as a robotic arm, the device may comprise a control unit designed to correctly move the combined B-mode imaging device and HIFU device. In this case, the correct position of the area to be treated may be defined by the user or automatically detected by an image processing algorithm of an image processing unit connected to the control unit.

[0124] Figure 3A device 1 according to the invention is shown. The device 1 comprises a treatment head comprising a HIFU device 2 and an imaging device 3. The treatment head is mounted on a robotic arm 4. A compression device 5 is placed adjacent to the treatment head. The device 1 further comprises a control unit 6, which is connected (schematically indicated by dashed lines) to the HIFU device 2, the imaging device 3, the robotic arm 4, the compression device 5 and a user interface 7.

[0125] The user interface 7 comprises a display 8 and a plurality of switches 9 for manually controlling the device 1 .

[0126] The patient P lies on a tilted table 10 so that the vein to be targeted is already collapsed.

[0127] The control unit 6 is adapted to control the movement of the HIFU device 2, the imaging device 3, the robotic arm 4 and the compression device 5 in order to perform the above method. Furthermore, the user can control the operation of the device 1 via a user interface 7. The display 8 displays, among other information, the image generated by the imaging device 3. The switch 9 is used to trigger different functions of the device 1, in particular to switch to different operating modes, to trigger the HIFU device 2 to emit HIFU waves (if the device 1 does not do this automatically), to move the treatment head via the robotic arm 4, etc.

[0128] As an example, the device 1 is adapted to perform a reference Figure 1 In the case of the described method, the control unit 1 controls the synchronization of the imaging device 2 and the compression device 5 while performing the pumping step 102 and the imaging step 103. Therefore, the collapsed vein segment can be correctly located. After the collapsed vein segment is located, the control unit 1 controls the correct focusing of the HIFU device 2 on the collapsed vein segment and the triggering of the emission of the HIFU waves.

[0129] In the implementation of the reference Figure 2 In the case of the method described, the control unit 1 synchronizes the movement of the treatment head and therefore the imaging device 3, so as to orient the imaging device 3 until the hyperechoic point corresponding to the collapsed vein segment wall has been correctly positioned. In addition, the control unit 1 then controls the correct positioning of the focused HIFU device 2 to optimally emit the HIFU waves. Preferably, when performing a vein scan as described above, the control unit 1 also controls the movement of the treatment head by means of the robot arm 4.

Claims

1. A method for locating a vein in a patient's limb using an imaging device selected from a color Doppler imaging device, a pulsed wave Doppler imaging device, and a B-mode ultrasound imaging device, the method comprising the following steps: a. collapsing at least a segment of the vein to be positioned at the collapse site to stop blood flow during the collapsing step, so that the segment of the vein is not visible by B-mode ultrasound imaging and / or Doppler imaging, wherein the collapse of the vein is performed by raising at least a limb of the patient above a horizontal position or compressing the vein segment; b. during the pumping step, causing blood flow within the vein at the site of the collapse while causing the segment of the vein to collapse; and c. At least during the pumping step, in an imaging step, visualizing the collapsed site using the imaging device, and detecting the collapsed segment by one of: i) detection of induced blood flow by color Doppler imaging; ii) detecting a signal of the pulse wave Doppler imaging device; and iii) Detection of hypoechoic spots by B-mode ultrasound imaging.

2. The method according to claim 1, wherein: The imaging step is performed during the collapsing step and the pumping step.

3. The method according to claim 1, wherein: Compression and release of the vein during the pumping step is performed manually.

4. The method according to claim 1, wherein: Compression and release of the vein during the pumping step is performed using a compression device.

5. The method according to one of claims 1 to 2, wherein: As the segment of the vein collapses, the vein is repeatedly compressed and released.

6. The method according to claim 1, wherein: The field of view or focus of the pulsed wave Doppler imaging device is moved during the imaging step for locating the collapsed vein segment.

7. The method according to one of claims 1 to 2, further comprising the steps of: d. During the alignment step, the focus of the HIFU device is aligned within the located collapse site.

8. A method for locating a vein in a patient's limb using a B-mode ultrasound imaging device having a primary ultrasound propagation axis, the method comprising the steps of: a. collapsing at least a segment of the vein to be aligned at the collapse site to stop blood flow during the collapsing step, thereby making the segment of the vein invisible by B-mode ultrasound imaging, wherein the collapse of the vein is performed by raising at least a limb of the patient above a horizontal position or compressing the vein segment; b. imaging the collapsed portion using the imaging device during the imaging step; c. In the detection step, while the segment of the vein collapses, change at least one of the position and orientation of the imaging device until a hyperechoic point corresponding to the venous wall of the collapsed venous segment is detected, wherein the hyperechoic point is formed when the main ultrasound propagation axis is orthogonal to the venous wall.

9. The method according to claim 8, wherein: Imaging of the collapsed site is also performed during the collapsing step.

10. The method according to one of claims 8 to 9, wherein: Changing at least one of the position and orientation of the imaging device is performed manually.

11. The method according to one of claims 8 to 9, wherein: Changing at least one of the position and orientation of the imaging device is performed by a shifting device connected to the imaging device.

12. The method according to one of claims 8 to 9, wherein: During the detection step, at least one of the position and orientation of the imaging device is changed by moving the imaging device in at least one direction selected from: rotation around the main ultrasound propagation axis, rotation around an axis orthogonal to the main ultrasound propagation axis, displacement in a direction orthogonal to the main ultrasound propagation axis, and displacement in a direction parallel to the main ultrasound propagation axis.

13. The method according to one of claims 8 to 9, further comprising the steps of: d. During the alignment step, the focus of the HIFU device is aligned within the located collapse site.

14. The method according to claim 13, wherein: The imaging device is rotated during the detecting step about an axis including a focal point of the HIFU device.

15. The method according to one of claims 8 to 9, wherein: In the measuring step performed before the collapsing step, at least one of a diameter and a shape of the vein at the collapsed site is determined.

16. A device for locating and visualizing a vein in a limb of a patient for performing the method according to one of claims 1 to 15, the device comprising an imaging device and a compression device for compressing and releasing the vein at a compression site located near the collapse site, and further comprising a control unit for controlling the imaging device and the compression device, wherein The control unit is adapted to synchronize the imaging device to perform imaging of the compression site while the compression device compresses and releases the vein near the collapsed site.

17. The device of claim 16, further comprising a HIFU device.

Images