WO2013119662A1

WO2013119662A1 - Catheter based system and method for thrombus removal using time reversal acoustics

Info

Publication number: WO2013119662A1
Application number: PCT/US2013/024929
Authority: WO
Inventors: William C. Hamilton; James J. Mitchell; Daniel K. Recinella; JR. George K. LEWIS
Original assignee: Cornell University; Angiodynamics
Priority date: 2012-02-06
Filing date: 2013-02-06
Publication date: 2013-08-15

Abstract

There is set forth in one embodiment an apparatus comprising an ultrasound translating element capable of translating ultrasound energy into electrical energy and an ultrasound wave emission unit, wherein the apparatus is operative for processing a signal from the ultrasound translating element, wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site. There is set forth in one embodiment a treatment method comprising inserting an ultrasound translating element into a patient's body, transmitting ultrasound energy, receiving the ultrasound energy with the ultrasound translating element, the ultrasound translating element generating an electrical signal responsively to the ultrasound energy, processing the electrical signal, and emitting converging ultrasound waves on a target site responsively to the processing

Description

TITLE

CATHETER BASED SYSTEM AND METHOD FOR THROMBUS REMOVAL USING

TIME REVERSAL ACOUSTICS.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U. S. Provisional Application No. 61/595,445 filed February 6, 2012 entitled, "Catheter Based System and Method for Thrombus Removal Using Time Reversal Acoustics." The above application is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The present invention relates generally to devices for disrupting thrombus within a patient's body. More specifically, the invention relates to an elongated device that causes cavitation within the thrombus to disrupt and remove the thrombus from within a lumen of a blood vessel or another cavity or lumen within a patient's body.

BACKGROUND

[0003] Devices for treating issues such as thrombosis or varicose veins at a target site within a human lumen are generally known. For example, it is known to use a catheter for infusing fluid to a target site within a blood vessel for treating issues such as thrombosis or varicose veins. It is also known to use mechanical disruption to disrupt the thrombus or placement of a filter to capture emboli originating from a thrombus. This device solves many problems currently faced by these known treatments. First, the present device is able to reliably deliver more therapeutic energy to a target area than current intravascular devices enabling it to treat thrombosis in a short amount of time. Second, the present device is designed to be small and maneuverable enough - such as the size of a standard guidewire - to be used in complex vasculature that currently known products cannot reach due to size or flexibility. Third, some embodiments of this device are designed to treat thrombosis without the use of lytic or other drugs, thereby eliminating the need to have the patient remain hospitalized overnight.

Finally, this device is designed to treat thrombosis with little or no damage to the vessel wall.

SUMMARY

[0004] The device relates to a system and method that combines the use of Time Reversal Acoustics ("TRA") with a catheter or guidewire based intravascular device 10. The intravascular catheter device 10 may be positioned at a treatment site within a vessel or other anatomical lumen 12. The intravascular device 10 may comprise at least one piezoelectric element 20 designed to receive the reflected / echoed ultrasound waves 17a from a surface transducer 13 and convert those waves into an electrical signal. The electrical signal may be created when the piezoelectric element 20 is mechanically strained, such as a vibration or other mechanical disruption, by the acoustical wave. The electrical signal created by the piezoelectric element 20 may be transmitted through the catheter 10 to a TRA device 14. The TRA device 14 receives the return electrical signals and targets the exact location of the piezoelectric element 20 using a process called time reversal acoustics (as described by Fink in U.S. Patent number 5,092,336 which is incorporated herein by reference). These altered electrical signals created by the TRA device may then transmitted to the ultrasound transducer where they are converted from the time-reversed electrical signals into ultrasound waves which converge on the site of (or offset from) the piezoelectric element 20 of the intravascular catheter 10. These converging ultrasound waves 17b may be used to mechanically disrupt a thrombus or other blockage, for example via cavitation. Additionally, these converging ultrasound waves may also be used to drive and control the flow of a fluid, such as a lytic, sclerosant, tumescent anesthesia or any other fluid, into the target tissue.

[0005] One embodiment of the current invention includes a TRA unit 14, an ultrasound transducer 13, a connector 16, an intravascular device 10 comprising a piezoelectric element 20 and conductive elements. In this embodiment the intravascular device 10 has the same diameter, strength and flexibility of a guidewire. Further, the piezoelectric element 20 may be comprised of either single or multiple piezoelectric crystals.

[0006] In yet another embodiment the intravascular device 10 is the core of a common guidewire so that the entire intravascular device 10 is coaxially surrounded by the outer surface of the guidewire. In this embodiment, the piezoelectric element 20 may be comprised of either a single or multiple piezoelectric crystals.

[0007] In yet another embodiment the intravascular device 10 is housed within a catheter body so that the intravascular device 10 now comprises a lumen or fluid channel. In this embodiment, the piezoelectric element 20 may be comprised of either a single or multiple piezoelectric crystals.

[0008] In yet another embodiment the intravascular device 10 additionally comprises an expandable tip spacer 35. The expandable tip spacer 35 element helps ensure that the piezoelectric element 20 is centrally located within the lumen of the vessel during use. [0009] In yet another embodiment the invention includes a TRA device, ultrasound transducer 13, a connector 16, an intravascular device 10 comprising a piezoelectric element 20 and conductive elements. In this embodiment the invention is intended to be used to treat varicose veins by delivering a sclerosant which is directed into the vessel wall using ultrasound waves which minimizes sclerosant dilution by blood flow.

[0010] In yet another embodiment the intravascular device 10 additionally comprises occlusion balloons located either proximally, distally, or both, from the piezoelectric element 20. The balloons allow the target area to be isolated from the general blood circulation during treatment. An advantage of this embodiment is to contain embolic particles and / or prevent the wash out of lytic, sclerosant, or other fluid being delivered.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1A - IB represents a perspective view of one embodiment of the intravascular device and TRA components.

[0012] Figure 1C represents a piezoelectric element at the distal end of an

ANGIODYNAMICS® infusion catheter.

[0013] Figure ID represents the power supply.

[0014] Figure 2 represents a partial cross-sectional side view of another embodiment of the intravascular device.

[0015] Figure 3 represents a partial cross-sectional side view of yet another embodiment of the intravascular device.

[0016] Figure 4 represents a side view and cross section of yet another embodiment of the intravascular device having pressure responsive slits.

[0017] Figure 5 represents a partial cross-sectional view of yet another embodiment of the intravascular device having distal occlusion and centering elements.

[0018] Figure 6 represents the method of use.

[0019] Figure 7 represents yet another embodiment of the method of use.

[0020] Figure 8 represents the experimental setup that was conducted to treat a clot using

TRA.

[0021] Figure 9 represents results for the experimental setup depicted in Fig. 10.

[0022] Figure 10 represents additional data results for the experimental setup depicted in Fig. 10.

[0023] Figure 11 represents additional data results comparing percentage of mass reduction between a control and TRA thrombolysis of experiment setup depicted in Fig. 10. [0024] Figures 12-20 represent an intravascular device in various embodiments.

DESCRIPTION

[0025] As seen in Fig. 1A - IB, the ultrasound clot removing device 1 includes a time reversal acoustics unit 14, a transducer 13, a connector 16, an intravascular device 10 comprising of a piezoelectric element 20 and conductive elements. An advantage of this device is that the converging ultrasound energy / waves 17b may mechanically disrupt a clot, via cavitation, in combination with additionally enhancing lytic uptake, or other clot removing drugs, within the clot. Also, the energy created may be less than what is required to create cavitation and such energy levels can "stretch" the fibrin of the thrombus which may lead to facilitating the lytic uptake and thrombus dissolution. By enhancing lytic uptake using converging ultrasound energy / waves 17b the clot is dissolved much more rapidly than with traditional techniques such as slow infusion thrombolysis procedures, which often require an overnight hospital stay. Also, by enhancing lytic distribution and absorption using converging ultrasound energy less lytic should be required for each treatment, which will make the treatment faster and safer by decreasing the chances of serious internal or external bleeding, such as an intracranial bleed which may lead to a very serious complication with lytic delivery. Alternatively, the device 1 may be used with no lytic and mechanically disrupt the clot via cavitation.

[0026] Another advantage of this embodiment is that only a surface ultrasound transducer 13 may be required. The piezoelectric element 20 acts as a beacon to receive the ultrasound waves but does not transmit ultrasound waves back to the surface transducer 30. For example, the piezoelectric elements 20 may be made using any piezo electric material such as polymer films, piezo -crystals and others. Because the intravascular catheter may not require transition of ultrasound energy, the overall size of the device is much smaller than common intravascular devices known in the art, such as IVUS, which requires a transmitting transducer in or on the catheter shaft. As such, this device may be capable of reaching more distant and tortuous vasculature with less trauma to the patient. However, in alternative embodiments the time -reversal focusing system discussed herein may also be combined with IVUS guidance to monitor the thrombolysis treatment, and or locate the thrombus real time.

[0027] Additionally, the use of external ultrasound transducer(s) allows for more intense (lower frequencies and high powers) energy to be delivered to the target location than is feasible with intravascular transducers. Additionally, the use of multiple external ultrasound transducers utilizing TRA focusing allows for more intense (lower frequencies and high powers) energy to be delivered to the target location than is feasible with a single external transducer (HIFU) because energy is spread over multiple sites which reduces the potential for unwanted heating such as skin burns. Additionally, eliminating the need to transmit ultrasound energy intravascularly also makes the intravascular device 10 less expensive to manufacture. Although as described herein, the ultrasound transducer is a surface transducer positioned on the skin of a patient, the system may also utilized an internally placed ultrasound transducer positioned a distance from the intravascular device. Also, it is conceivable that an alternate embodiment of this device would include a transducer in or on the catheter shaft.

[0028] Yet another advantage of this device is efficiency and effectiveness of the treatment due to the precise and converging ultrasound energy delivery using the TRA device. For example, the device can deliver a precise and converging energy that is capable of creating cavitation to mechanically dissolve a thrombus without causing clinically significant damage to the vessel wall or creating thermal heat damage. Moreover, it is intended that optimization of operating conditions may result in the production of micro bubble cavitation that will aid in efficiency of thrombolytic treatment. For example, as the micro bubbles are bombarded with the sinusoid ultrasound waves they oscillate and expand and contract up to a point where the stability of the micro bubble reaches a point where its structural integrity degrades causing the micro bubble to burst. The burst provides a mechanical stimulation of the surrounding tissue. Furthermore, by using a TRA based device it will incorporate and compensate for anatomical differences in each patient, whereas current technology known in the art, such as HIFU, lacks this feature and does not compensate for anatomical differences in a similar manner.

[0029] The components of the device 1 are shown in Figure 1 A - ID. The device is comprised of a TRA device 14 capable of performing time reversal acoustics algorithms.

Connected to the TRA device 14 is a surface ultrasound transducers with cabling 13 and the proximal connector 16 of the intravascular device 10. The number of surface ultrasound transducers may vary from one or two transducers to several transducers all around the treatment site.

[0030] Intravascular device 10 is comprised of an elongated shaft with at least one piezoelectric element 20 positioned near the distal end of the shaft. The piezoelectric element 20 is comprised of at least one piezoelectric crystal capable of receiving or reflecting ultrasound waves and translating, transmitting, or conducting these waves or ultrasound energy into electrical signals. [0031] The device may comprise of at least one or several ultrasound transducer 13 that emits therapeutic energy ultrasound transmissions 17a, 17b. The waves are then reflected and eventually arrive at the piezoelectric element 20. The ultrasound transducers 13 may be relatively simple transducers with high-Q and resonances of choice fabricated from PZT 4 and 8 piezo material. Various mechanical configurations of the transducers 13 may be employed including discs, cylinders, tubes, rings plates and etc. Various design approaches are possible. In one embodiment ring-piezos seem to work the best since they have low- frequency resonances in relatively low-profile configurations.

[0032] As seen in Figure ID, to power the ultrasound transducers 13 a 10-channel ultra-low output impedance power amplifier system 201 may be used. The power system 201 includes various duty-cycles, pulse parameters, and drive voltages up to 500V peak to peak. Each channel may provide more than 50 Watts of energy allowing for the delivery of large acoustic pressures for thrombolysis. Additionally the amplifier is functional over DC-5 MHz covering the range of therapeutic ultrasound levels. Finally, the amplifier can run multi frequency excitations in parallel allowing for both low and high frequency ultrasound focusing simultaneously.

[0033] The intravascular device 10 and piezoelectric element 20 are capable of translating, transmitting, or conducting electrical signals to the TRA device 14 through at least one elongated conducting element which is positioned along the elongated shaft of the

intravascular device 10. Once electrical signals are transmitted to the TRA device 14 the electrical signals are processed through the time reversal acoustics algorithm. An example of an intravascular device 10 comprising at least one piezoelectric element 20 is shown in Fig. 1C, which represents a 150 um coaxial cable used to wire and connect the piezoelectric element 20 to the tip of an Angiodynamics® infusion catheter.

[0034] Time reversal acoustics is based on the use of echoes. The TRA device 14 sends initial or targeting ultrasound waves 17a which are then echoed by the piezoelectric element 20. The time it takes for each initial or targeting ultrasound wave 17a to reach the

piezoelectric element 20 is recorded and the TRA device 14 performs time reversal acoustic algorithms. The transmission of initial or targeting ultrasound waves 17a may be triggered as a result of a timer or if the reduction in peak volume waves reaches a certain decibel. It only takes milliseconds for the initial or targeting ultrasound waves 17a to be sent, recorded, and processed with the time reversal acoustics algorithm of the TRA device 14. After the time reversal acoustics algorithm has been completed, inverse ultrasound waves are sent through the transducers 13 and results in multiple echoes of energy 17b simultaneously converging at the specific target site. Each echo that converges onto the target site has an additive or cumulative effect and intensifies the ultrasound energy 17b at the target site. This additive or cumulative effect of energy 17b creates a "converged" ultrasound and energy zone at the target site. The "converged" ultrasound and energy zone can mechanically distrust a thrombus via cavitation, create thermal energy for ablation or thrombus disruption, or drive fluids.

[0035] The intensity of these converged ultrasound waves can be adjusted to achieve a wide range of therapies, including creating cavitation and mechanically disrupting the clot, directing and focusing the flow of fluid, or can be high intensities capable of thermal ablation or creating thermal heat. Because the device is able to create controlled and converging ultrasound waves, the desired treatment area can be precisely targeted (as shown in Figure IB), providing a safer treatment without significantly damaging non-targeted tissue, such as the vessel wall or nerves surrounding a thrombus.

[0036] As seen in Fig. 2, the piezoelectric element 20 may comprise of either a single piezoelectric crystal or a series of multiple piezoelectric crystals. The placement of the piezoelectric element 20 along the intravascular device 10 may vary depending on the treatment site. In one embodiment the piezoelectric element 20 is placed near or at the distal tip of the intravascular device 10, however it is conceivable that the piezoelectric element 20 is placed at any point along the intravascular device 10. It is conceivable that the one or multiple piezoelectric elements 20 may be wired or otherwise connected to the elongated shaft using coaxial cable, braided wire, and or other electrical conductivity means. The placement of the piezoelectric elements 20 allows for focusing to multiple points along the device 10 as well as interpolation algorithms to focus in between the elements 20 of the device 10 creating a treatment region along a desired length of the device 10. An advantage to using multiple piezoelectric crystals along the piezoelectric element 20 is that a longer or larger treatment zone can be targeted as each piezoelectric crystal acts as a receiving beacon for the ultrasound waves. One advantage to targeting a larger treatment zone is it allows the user to treat a larger segment of the vasculature at one time. Another advantage of using multiple piezoelectric crystals is that the device may be capable of a faster procedure time because more ultrasound waves may converge on the piezoelectric element and can be received at once. A single piezoelectric crystal used for the piezoelectric element 20 may range in the size of .010 - .030 inches; however the range is not limited and can vary in either direction. Other materials used to create the piezoelectric element 20 would be any similar materials capable of translating ultrasound waves into electric energy. [0037] In one embodiment, the intravascular device 10 may be a coaxial shaft comprised of multiple conductive elements. An inner conductive element 15, or ground wire 15, may be comprised of a conductive material. Conductive materials may be any electrically conductive material that is flexible, strong, and conducts an electric current, such as but not limited to copper, stainless steel, nitinol, or any other electrically conductive material. Coaxially surrounding the first conductive element 15 is an insulated layer 50 used to electrically insulate the inner conductive element from the outer conductive elements 25. Because the device uses a very low electrical current, the insulated layer 50 may be very thin. For example, the insulated layer 50 can range from .0001 - .001 inches thick. The materials for the insulator may be nylon, PET, Teflon, polyimide, silicone or anything that is flexible, strong, and act as an electrical insulator.

[0038] Depending on the desired sensitivity, the piezoelectric element 20 may be cut or formed to resonate at a specific frequency, i.e., in its longitudinal, radial, axial and other conceivable modes. In one embodiment the piezoelectric element 20 may be cut or formed to resonate in its longitudinal mode at the range of sub 300 - 700kHz, specifically near 500kHz. This may allow the piezoelectric elements 20 to be thin and slender along the length of the elongated shaft, but highly sensitive to the low-frequency ultrasound. In other embodiments the piezoelectric elements 20 may be mounted around the elongated shaft, on and in the elongated shaft, or in a guide -wire itself as described below. Regardless the arrangement of the piezoelectric elements 20 with respect to the intravascular device, in all cases the piezoelectric elements 20 may be electrically isolated from the external environment using a variety of different types of coating techniques, including dipping, painting, or other known coating techniques.

[0039] A second outer conductive element or return conductor 25 may transmit electrical signals from the piezoelectric element 20 to the TRA device. The inner and outer conductive elements form a closed electrical pathway for transmission of the electrical signals from the piezoelectric crystals to the TRA generator. Optionally, the outer conductive elements may be coaxially surrounded by a second insulated material 26 to ensure the elements 25 remain electrically isolated from each other and the inner conductive element. As shown in Figure 2, the inner conductive element 15 includes connection paths to each of the plurality of piezoelectric elements 20. The second conductive element 25 may comprise a plurality of individual conductive elements which are braided within the outer wall of the shaft of the intravascular device 10. Each of the plurality of outer conductive elements 25 are attached at their distal ends directly to the piezoelectric crystal 20. The annular lumen 30 formed between the inner insulative conductive element 15/50 and the elongated shaft containing the outer conductive elements 25 may be filled with a material to prevent possible wave distortion due to the presence of air within the device. Any air pockets inside the

intravascular device 10, specifically near the piezoelectric element, may disrupt or attenuate the ultrasound waves and have a negative impact on the accuracy of the time reversal acoustics. For example, the annular 30 may be either an ultrasound gel, ballistic gel, epoxy, or other material with a law attenuation ultrasound coefficient.

[0040] In another embodiment the electrical pathway of the intravascular device 10 consists of independent leads or wires. In this design the first conductive wire or ground conductor 15 runs from the TRA device 14 to the piezoelectric element 20. The piezoelectric element 20 translates the echoed or reflected ultrasound waves 17a received from the ultrasound transducer 13 to an electric signal. This electric signal created by the translation of ultrasound waves into electricity by the piezoelectric element 20 is then carried back to the TRA device 14 via an independent conductor or return wire 25. If multiple piezoelectric crystals are used for the piezoelectric element 20 then each crystal can have its own independent return conductor 25 but all the crystals can share a same common ground conductor 15.

[0041] In one embodiment, depicted in Figure 3, the intravascular device 10 resembles a guide wire. Using a guidewire design allows for reduction in overall size of the device. The outer diameter of the intravascular guidewire device 10 may range from .005 - .038 inches; however the range may vary in either direction.

[0042] Another advantage of a guidewire configuration is that the device 10 is more easily advanced through tortuous vasculature and is capable of reaching small more distant and occluded targets. In one design this embodiment the intravascular device 10 replaces the core wire of a common guidewire. As shown in Figure 3, the device may be comprised of a pre- wound or coiled tubular body 110 with conductors 15 / 25 and at least one piezoelectric element 20 being positioned within the lumen 112 of the pre -wound or coiled guidewire 110. The guidewire device 10 may include a leading floppy tip 60 to provide an atraumatic leading tip to aid in advancement of the device to its target location. As will be described in more detail below, the leading floppy tip may include an occluding ball element 55. In this embodiment a procedure sheath may not be required so the device may be considered "sheathless".

[0043] The guidewire device may be manufactured by inserting the piezoelectric element 20 and conductors into a shell or casting element and encasing the elements in a filler 30 that hardens with time, such as an epoxy or a ballistic gel that hardens yet remains flexible. Once the filler 30 has hardened around the conductors 15 / 25 and piezoelectric element 20, the assembly is then inserted into the lumen 112 of the pre-shaped or pre-coiled guidewire 110. Alternatively, conductors 15 / 25 and piezoelectric element 20 may be inserted into the guidewire lumen and then the filler is injected. The filler 30 prevents unwanted air pockets within the device while simultaneously giving the finished device additional strength and torque-ability characteristics. Alternatively, the piezoelectric assembly may be inserted into the pre-coiled guidewire 110 and a casting element is injected into the guidewire lumen to encase the elements and eliminate air pockets.

[0044] As seen in Fig. 4, the guidewire like device may include an occluding ball element 55 as shown in Fig. 3 and described fully in U.S. Patent number 5,267,979, entitled

"PRESSURE RESPONSIVE VALVE CATHETER", and is incorporated herein by reference. The occluding ball 55 design may be used in combination with a catheter 118 for the uniform delivery of lytic or other fluids along a targeted treatment length. For example referring to Figure 4, catheter 118 is comprised of an elongated shaft including a fluid delivery lumen 65 through which the guidewire is positioned. The shaft also includes conductors 15, 25 and filler 30 as previously described. A plurality of pressure responsive slits 130 are located along a segment of the catheter shaft and are designed to open simultaneously at a pre-determined uniform pressure. As the slits 130 open, a series of fluid communication ports are created through which the lytic or other drug may be delivered. The fluid is prevented from exiting from the distal end of the catheter 118 by the occluding ball 55 of Figure 3 which blocks the catheter end hole when the guidewire is inserted into the lumen 65 of catheter 118. In yet another embodiment, the intravascular catheter device 10 may be dimensioned and designed to treat larger vessels or other large anatomical structures. The device may include an outer catheter or sheath comprising multiple lumens so as to accommodate fluid delivery and aspiration clot aspiration channels. The device may also include lumens for distal protection and/or centering elements. For example, the

intravascular device 10 may be placed in one lumen of the outer catheter while other lumens may be used as fluid channels for injecting fluid or open delivery channels.

[0045] As seen in Fig. 5, an expandable occluding element 35 or protection filter may be positioned either distally beyond the clot or proximal the clot to ensure that no lose clot debris travels to places within the vasculature that would pose risks to the patient, such as to the lungs, heart or brain. The expandable distal occluding element 35 or protection filter may be used to assist in removing clot fragments or debris remaining after the initial treatment. Additionally, an external vacuum syringe or pump may be attached to the device; wherein the external vacuum syringe or pump provides the clot removal system with the ability to aspirate the clot material through the lumen of the intravascular device 10. The device and the external vacuum syringe or pump may work together or independently to remove nearly liquefied thrombus particles from the treatment zone. The size of the device may range up to 12 - 20F; however other sizes are possible and conceived.

[0046] In one embodiment the expandable distal occluding element 35 or protection filter may be coaxially disposed within lumen of the intravascular device 10 and the expandable distal occluding element or protection filter is freely moveable relative to the intravascular device 10. The expandable distal occluding element 35 or protection filter may be advanced or retracted without moving the intravascular device 10. Alternatively, the expandable distal occluding element 35 or protection filter may be fixed to the intravascular device 10 so that when shaft is either advanced or retracted the expandable distal occluding element or protection filter will move in unison with the device.

[0047] In yet another embodiment the intravascular device 10 may include a tip spacer embodiment. A similar coaxial expanding tip spacer embodiment was previously disclosed in U.S. Patent number 7,559,329, filed June 12, 2007, entitled "METHOD OF TREATING A BLOOD VESSEL WITH AN OPTICAL FIBER HAVING A SPACER", and is incorporated herein by reference. A tip spacer ensures that the distal section of the catheter containing the piezoelectric element 20 is centered within the lumen of the vessel and within the clot mass. Due to centering within the vessel, converging ultrasound energy is more precisely positioned at the center of the vessel on the clot so as to better protect the vessel wall from being damaged by the converging ultrasound energy. Two examples of spacer designs are shown in Figure 5. In one embodiment, the expanding tip spacer 35 may be pre-curved to form a cage like structure preferably made of nitinol or other shape memory type material such as stainless steel or a polymer material. The expanding tip spacer element may be secured directly to the intravascular device 10. Alternatively, the expanding tip spacer may be coaxially movable along the intravascular device 10 so that the intravascular device 10 and the expandable tip spacer 35 move independently of one another. The expandable tip spacer 35 may form a series of different shapes including, but not limited to, a number of legs or ribs extended in a bow shape; a basket or funnel shape comprised of a series of wires meshed or woven together; or a series of individual wires woven together to form a helical shape. The expanding tip spacer 35 may also comprise of an inflatable balloon. The balloon may be positioned on the catheter shaft near the distal end of the device. The balloon element may be inflated to position the piezoelectric element 20 within the center of the vessel and/or clot mass. The inflatable balloon and intravascular device 10 may be coaxially arranged so as to allow independent movement or they may be fixed and secured to one another at some point along the longitudinal axis.

[0048] The devices described herein may be used to treat other venous disease such as venous reflux which causing varicose veins. The device may be used to enhance delivery of sclerosant agents to damage the vessel wall, causing the vein to collapse. One example of such an agent is Sotradecol® sclerosant. When treating a vein with sclerosant, it is critical to deliver the drug directly to vessel wall itself rather than directing the fluid in the vessel lumen and blood. Sclerosant diluted by blood will be washed away and ineffective in damaging the vein wall. The devices of the current invention may be used to deliver sclerosant agents in a more precise and effective manner by directing converging ultrasound energy into the target region while delivering sclerosant into the region. The catheter based intravascular device 10 with either an open distal end or pressure responsive slits along the elongated catheter body used in combination with an occluding ball 55 guidewire may be used for delivery.

Sclerosant delivered through the device will exit from either the pressure responsive slits located on the intravascular device 10 or through the open distal end. Converging ultrasound energy is used to drive the sclerotherapy into vessel walls provides for a higher concentration of the drug to come in contact with the vessel wall, resulting in less dilution of the drug by the blood and accordingly less drug being required to obtain a positive clinical outcome.

[0049] One method of use will now be described with reference to the flow chart shown in is in Figure 6. The first step is to gain access to the vessel or other anatomical lumen using common techniques known in the art. The intravascular device 10 is inserted and advanced until the piezoelectric element 20 is located at the treatment zone (101). Once the intravascular device 10 is in place, the user may activate the TRA electronics to establish the electrical pathways with the intravascular device (102). The user then delivers ultrasound waves from the surface transducers to the patient's body (103). The piezoelectric element 20 vibrates when the reflected ultrasound waves impact the piezoelectric element 20 and translates these waves into electrical signals. The signals are transmitted from the piezoelectric elements to the TRA unit via the return conductors 25 (104). The TRA unit calculates the TRA focusing signals (105) using time reversal acoustics algorithms. The TRA device 14 creates ultrasound waves 17b in a specific sequence that results in multiple echoes simultaneously converging at the specific target site (106). If necessary, the user may deliver lytic (107A) or a sclerosing agent (107B), which are both optional. Each echo that converges onto the target site has an additive or cumulative effect and intensifies the ultrasound energy 17b at the target site (108), therefore creating a "converging" ultrasound effect at the target site which can mechanically distrust a thrombus or drive a fluid (109).

[0050] If the device is being used to remove a deep vein thrombus or other clot material in a vessel then the user may optionally deliver a fluid or drug, such as lytic, to the treatment site to aid in destruction and removal of the thrombus. The user may deliver a lytic agent through the open fluid channel in the catheter 108 A. The converging ultrasound energy may aid in driving or delivering the lytic, or other selected fluid, into the selected tissue, such as the thrombus or fibrin tissue itself. If the user is using the device to treating varicose veins then the user may select to deliver a sclerosing agent through the open fluid channel in the catheter 108B. The converging ultrasound waves may increase uptake of the sclerosing agent into the selected tissue, such as the vein walls. The user may repeat steps as necessary to treat other segments of the vessel and/or to enhance treatment outcome. Additionally, it is conceived that the TRA converging ultrasound energy may be in a range that is capable to ablate a vein using thermal energy.

[0051] Another method of use is shown in Fig. 7. The first step is to place the elongated shaft 301, may be either a catheter or guidewire, at the target 305. Next, the TRA transducers 310 may be placed around the vicinity of the target 305 area. Computer 315 may then send electrical signals to the TRA electronics 320 to fire a short burst which is recorded and detected by the elongated shaft 301. The recorded signals are then cross-correlated with the excitation signal, thereby time reversing it, and retransmitted via the TRA electronics 320. This last step may be done consecutively on one or more channels. Once all channels of TRA focusing are established, the channels may be activated in parallel to provide highly accurate ultrasound focusing. During the highly accurate ultrasound focusing, the elongated shaft 301 may continuously monitor the ultrasound energy being delivered in real time.

Focusing ultrasound in this way may be applied to one or more piezoelectric elements 20 located along the elongated shaft 301, applied at one or more frequencies and various pulse sequences, pressures or other exposure parameters.

[0052] As seen in Figure 8, an experimental setup has been conducted using phantom leg model with fluid flow. The experiment was setup with a clot being inserted into a phantom leg model, a fluid pump using saline to push the clot up into the gel-leg phantom. Once the clot is in the restriction an elongated shaft, in this experiment the shaft was a catheter however it is conceivable a guidewire could also be used, is equipped with piezoelectric elements and inserted into the clot. The external transducers are positioned in the region around the thrombus and treatment area. Once setup, the system is powered up and the time- reversal focusing algorithm focus energy to the catheter.

[0053] The clots for the experiment consisted of freshly harvested bovine blood. Two types of blood clots were used: first, a clot that naturally occurred, and second, a clot that had its formation assisted with prothrombin addition. Clots were placed within the phantom model and sonicated via TRA focused ultrasound.

[0054] Ultrasound assisted thrombolysis based on TRA was performed using the following parameters. Operating frequency of ultrasound transducers was set to be 342KHz, peak-peak pressure amplitude was restricted to be in between 30Kpa-48Kpa for a duty cycle of 92%. The treatment duration was limited to 5 hours. The weight of porcine blood clots was measured before and after the treatment to determine the loss of mass.

[0055] The average clot mass loss for control groups over a six hour period are as shown in Figure 9. The column labeled "phantom" refers to clot mass loss observed in the phantom model, while the columns labeled "Saline and Water" refer to clot mass loss in the these solutions while placed in a beaker. The non-thrombin controls have considerably increased variability versus the thrombin clots which the data shows had less variability in the control data. However, both thrombin and no-thrombin control clots exhibit similar weight loss in the control data sets. Average clot mass loss for blood clots which were thrombolysed using TRA based ultrasound focusing are shown in Fig. 10. Clots with thrombin were lysed by 53% and those without thrombin 67%, showing the effect of TRA based ultrasound focusing had an approximate 2x increase in percentage mass loss over respective control data.

[0056] The control data shows that in the absence of any ultrasound energy there is no significant loss of clot mass. For thrombin controls we observe p-values of 0.29 between phantom controls and saline controls and 0.09 between saline controls and water bath controls respectively indicating that the data sets are not significantly different. A similar analysis for thrombin controls shows that phantom control data set and the saline control data set has a p-value of 0.901 and the saline control data and water bath control datasets have a p- value of 0.752. Thus we can observe that percentage loss of mass amongst control clots in different environments is not statistically different.

[0057] Application of TRA focused ultrasound energy shows an enhancement of

thrombolysis with thrombin clots showing an average reduction of 58.848%) (p-values:

phantom controls 5.633e-6, saline controls 0.0979, water bath controls 3.52e-6) and the non- thrombin ones showing a reduction of 66.748%. (p-values: phantom controls 0.00144, saline controls 7.07e-5, water bath controls 0.0025). The percentage mass loss and variance in thrombin and non thrombin clots is significantly higher compared to the control clots. We observe a greater variance in non-thrombin clots owing to less robust clots compared to the thrombin stabilized clots.

[0058] Figure 11 represents the TRA thrombolysis data results versus the control data results within the phantom model for 5 hours of 342KHz, peak-peak pressure between 30Kpa-

48Kpa, and a TRA duty cycle of 92%. These results indicate that TRA focusing of 342kHz ultrasound can significantly reduce the clot mass over controls within a 5 hour treatment window.

[0059] Additionally, another experiment was carried out using ex vivo treatment of cadaver parts. In this experiment, ex vivo beef liver and porcine limb experiments to asses focusing capability of the TRA-DVT system as well as look for potential histological damage due to ultrasound exposure for 5 hours at the 40kPa treatment pressure. The TRA-DVT system was successfully able to focus in the cadaver model at 1 MHz and 342 kHz. After 3 hours of 342kHz 40kPa exposure at a 92% TRA duty cycle the porcine iliac maintained structural integrity with no thermal damage. The experiment was successful in proving that the TRA system can work externally focusing through objects such as fat and muscle while producing a strong signal without attenuation.

[0060] There is set forth herein a device for treating a thrombus, comprising: time reversal acoustic ultrasound generator; an ultrasound transducer; an intravascular device comprising a distal end; a piezoelectric element positioned near the distal end of the intravascular device; said intravascular device 10 further comprising a first conductive and second conductive element; and a connector.

[0061] There is also set forth herein a method for treating a thrombus comprising: inserting a device capable of receiving ultrasound waves, said device comprising a distal end and a piezoelectric element positioned near the distal end of the device; transmitting ultrasound waves using an ultrasound transducer; receiving the ultrasound waves with said piezoelectric element; transmitting the electric signals generated by the piezoelectric element to a time reversal acoustic unit; calculating the electrical signals using a time reversal acoustic algorithm; and sending converging ultrasound waves to the piezoelectric element; and disrupting a clot.

[0062] There is set forth hereinabove an elongated device comprising: an ultrasound translating element capable of translating ultrasound energy; wherein the ultrasound translating element generates electrical signals for processing for determination of converging ultrasound waves converging on a target site. [0063] There is also set forth hereinabove an apparatus comprising: an ultrasound translating element capable of translating ultrasound energy into electrical energy; an ultrasound wave emission unit; wherein the apparatus is operative for processing a signal from the ultrasound translating element; wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site.

[0064] There is also set forth hereinabove a treatment method comprising: inserting an ultrasound translating element into a patient's body; transmitting ultrasound energy; receiving the ultrasound energy with the ultrasound translating element, the ultrasound translating element generating an electrical signal responsively to the ultrasound energy; processing the electrical signal; emitting converging ultrasound waves on a target site responsively to the processing.

[0065] There is also set forth hereinabove an apparatus comprising: first and second ultrasound translating elements capable of translating ultrasound energy into electrical energy; an ultrasound wave emission unit; wherein the apparatus is operative for processing a signal from the first and second ultrasound translating elements; wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site.

[0066] There is also set forth hereinabove a treatment method comprising: inserting an ultrasound translating element into a patient's body; transmitting ultrasound energy; receiving the ultrasound energy with the ultrasound translating element, the ultrasound translating element generating an electrical signal responsively to the ultrasound energy; processing the electrical signal; delivering a drug or fluid; emitting converging ultrasound waves on a target site responsively to the processing, wherein the emitting aiding in the delivering a drug or fluid.

[0067] There is also set forth hereinabove an apparatus comprising: an elongated device having a ultrasound translating element capable of translating ultrasound energy into electrical energy; an ultrasound wave emission unit; wherein the apparatus is operative for processing a signal from the ultrasound translating element; wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site, wherein the elongated device is characterized by one or more of (a) the elongated device includes a coaxial cable having an inner conductor and an outer conductor for transmission of the signal for the processing, (b) the elongated device includes a prewound or coiled tubular body, wherein the ultrasound translating element is positioned within the tubular body; (c) the elongated device includes a guidewire and a floppy tip for guiding the guidewire.

[0068] There is also set forth hereinabove an apparatus comprising: an elongated device having a ultrasound translating element capable of translating ultrasound energy into electrical energy; an ultrasound wave emission unit; wherein the apparatus is operative for processing a signal from the ultrasound translating element; wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site, wherein the elongated device is characterized by one or more of (a) the elongated device is adapted for fluid delivery; (b) the elongated device is adapted for fluid delivery and includes a lumen for fluid delivery, (c) the elongated device is adapted for fluid delivery and includes a slit for fluid delivery, (d) the elongated device is adapted for fluid delivery and includes an occluding ball for retention of fluid.

[0069] There is also set forth hereinabove an apparatus comprising: an elongated device having a ultrasound translating element capable of translating ultrasound energy into electrical energy; an ultrasound wave emission unit; wherein the apparatus is operative for processing a signal from the ultrasound translating element; wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site, wherein the elongated device is characterized by one or more of (a) the elongated device includes an expandable element adapted for aiding removal of fragment or debris, and (b) the elongated device includes spacer for centrally locating the ultrasound translating element within the elongated device.

[0070] There is also set forth hereinabove an elongated device comprising: an ultrasound translating element capable of translating ultrasound energy; a coaxial cable having an inner conductor and an outer conductor; wherein the inner conductor and the outer conductor are connected to the ultrasound translating element; wherein the outer conductor transmits electrical signals for processing for determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element.

[0071] There is also set forth hereinabove an elongated device comprising: a prewound or coiled tubular body; an ultrasound translating element capable of translating ultrasound energy, the ultrasound translating element being positioned within the tubular body; wherein the ultrasound translating element generates electrical signals for processing for

determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element. [0072] There is also set forth hereinabove an elongated device comprising: a prewound or coiled tubular body; an ultrasound translating element capable of translating ultrasound energy, the ultrasound translating element being positioned within a lumen of the tubular body; wherein the ultrasound translating element generates electrical signals for processing for determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element.

[0073] There is also set forth hereinabove an elongated device comprising: an ultrasound translating element capable of translating ultrasound energy, the ultrasound translating element; an expandable occluding element; wherein the ultrasound translating element generates electrical signals for processing for determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element; wherein the expandable occluding element is adapted to aid in the removal of remaining fragments or debris resulting from the converging ultrasound waves.

[0074] There is also set forth hereinabove an elongated device comprising: an ultrasound translating element capable of translating ultrasound energy; a tip spacer; wherein the ultrasound translating element generates electrical signals for processing for determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element; wherein the tip spacer is adapted to center the ultrasound translating element within the intravascular device.

[0075] There is also set forth hereinabove an elongated device comprising: an ultrasound translating element capable of translating ultrasound energy; filler material surrounding the ultrasound translating element; wherein the ultrasound translating element generates electrical signals for processing for determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element; wherein the filler material is adapted to prevent air pockets about the ultrasound translating element.

[0076] Excepts from the incorporated by reference documents US Patent No.

5,092,336, US Pat. No. 5,267,979 (formatted to avoid reference number and figure number duplication) and US Pat No. 7,559,329 (formatted to avoid reference number and figure number duplication) are set forth herein.

[0077] [The following is an excerpt from US Pat. No. 5,092, 336]

[0078] It is an object of the invention is to provide a process and device for accurately focusing an ultrasonic beam on a target of high reflectivity, such as a calculus, and to provide self-adaptation of the wave front to the shape and position of the target itself, possibly for the purpose of destroying it, whatever the shape of an interface or of interfaces between the array of transducers providing the ultrasonic beam and the target.

[0079] For that, the invention uses a technique which may be termed "phase conjugation sound amplification" due to some analogy with phase conjugation mirrors used in optics. With this technique, starting from an incident ultrasonic wave which diverges from a target (a calculus reflecting a beam which it receives, for example) a convergent wave may be formed which follows exactly the opposite path, possible distortions being compensated for. For that, the divergent wave is received on an array of detectors, the signals received are reversed in time as regards both their shape and their time distribution (i.e. their laws of variation in time are reversed and their orders of occurrence are reversed) and the signals thus reversed are applied to the array.

[0080] In most cases, the target will constitute a secondary source, which reflects or scatters a wave beam applied to it. The target may for instance consist of:

[0081] a stone reflecting a beam received from an array of illumination transducers, a small size tumor impregnated with a contrast agent (which renders it possible to carry out ultrasonic hyperthermia), a fault in a solid object,

[0082] a small size cavity within the ground, close to the surface.

[0083] An initial illumination of the zone where the target is expected to be found will provide an indication on the boundaries of the latter, which has an acoustic impedance very different from that of the surrounding and which will appear as a secondary source.

[0084] Consequently, there is provided a process according to the invention, including the steps of:

[0085] (a) illuminating a zone including a target to be detected with an unfocused beam;

[0086] (b) individually storing the shapes and positions of echo signals delivered by the transducers of an array; and

[0087] (c) reversing the distribution in time and the shapes of the signals for obtaining reversed signals and applying said reversed signal to the respective transducers.

[0088] Echoes which are originally quite low may be progressively amplified, by applying an amplification coefficient at each reversal.

[0089] Possibly some or all transducers of the array are used, rather than separate means, for illuminating the zone during step (a).

[0090] The process may use iteration, by repeating a sequence consisting of steps (b) and (c), after a first illumination of the zone concerned in which a target is sought, which has a reflectivity higher than the average reflectivity of the environment. Each time reversal of the echo enhances the ratio between the energy reflected by the target of high reflectivity and the energy reflected or scattered by local irregularities.

[0091] The final step of the process may consist of recording and/or displaying the final sound wave front. However, when the process of the invention is used for destructing stones in tissues, such destruction may be made by focusing ultrasound energy with the same array or with another array which is better adapted to delivery of a high amount of energy. In both cases, the wave front of the destruction beam will reproduce the recorded and/or displayed wave front. Once the final wave front has been recorded, it will often be sufficient to use only the time distribution of the first maxima received in return by each of the transducers of the array after several iterations and to energize the destruction transducer array by simply respecting such time distribution, while disregarding the secondary lobes of the signal received and stored in digital form. Identification of the maximum of each signal and of its location in time raises no problem for well-known digital techniques exist for that purpose, using analog or digital correlators now commercially available. In some cases, it may however be advantageous to determine the time delay function to be respected, by evaluating the cross-correlations between a pair of signals.

[0092] Another solution consists in using, for destruction purpose, electronics which are distinct from the localization electronics but receive the information stored during

localization, the same transducer array being used for localization and destruction.

[0093] During step (c) of the last sequence, an amplification gain is adopted such that destruction of the calculus is caused if such a purpose is to be obtained while the energy transmitted during localization may possibly be low.

[0094] It is important to note that the process which has just been described achieves a progressive self adaptation of the wave form to the shape of the target; the distribution in time of the signals applied to the transducers and the shapes of the signals finally reflect exactly the shape of the calculus.

[0095] The process as hereinbefore described makes it possible to focus an ultrasound beam on the target which has a maximum reflectivity in an environment (or on a plurality of strongly reflecting targets if they are mutually spaced). Such focusing, when used for display purpose, "erases" the targets which have a lesser reflectivity and are masked by the target (or the targets) of maximum reflectivity. After a strongly reflecting target has been detected and localized, it may be useful to detect and localize targets which have a lesser reflectivity and which were masked by a main target during the initial focusing process. For that purpose, there is provided a process which includes, after a first focusing sequence as defined hereinabove, an additional sequence including the steps of: [0096] (al) illuminating the zone including the previously localized target with a non- focused wave beam;

[0097] (bl) collecting and storing echo signals received by the transducers of the array and individually storing the shapes and positions in time of said echo signals;

[0098] (b2) individually subtracting the echo signals received by each transducer of the array and stored during the last step (b) as defined above from the stored echo signals obtained during step (bl);

[0099] (cl) reversing the distribution time and the shapes of the results of the subtraction for obtaining further reversed signals and applying said further reversed signals to the respective transducers.

[0100] By repeating steps (bl) and (cl), the target whose reflectivity level is immediately lower than that of the target localized during the first sequence of operation may be detected and its position may be determined.

[0101] The above-defined process for detecting less reflective targets is simple but has a limitation: the final localization of the most reflecting target during the first sequence results from n transmission-reception sequences (n being an integer typically greater than 1) and the transfer function of the transducers modifies the echo signal upon each sequence. For removing the perturbating effect due to the accumulated distortions, step (bl) may include the additional phase consisting in subjecting the echo signals received by the transducers to n convolution operations, each corresponding to a transmission-reception sequence, before the echo signals representing the wave front on the most reflective object are subtracted.

[0102] Rather than carrying n convolution operations on the first reflected wave front, it is possible to carry out n deconvolution operations on the stored wave front.

[0103] The invention also provides a device for implementing the above-defined process, comprising: a transducer array; and, associated with each transducer of the array, a processing channel comprising an A/D converter, memory means, a programmable power transmitter controlled by the memory means, and means for energizing the transmitters in accordance with a time distribution which is reverse of the distribution stored in said memory means.

[0104] The device may be complemented with echography means for displaying the echo producing targets in the observation zone; targets on which the energy will subsequently be focused may be selected, for example by selecting some only of the transducers for later use.

[0105] Due to this arrangement, the energy applied to the transducers is used under much better conditions than in the past. In particular, if calculus is small of size, the focal spot may be reduced to the minimum allowed by diffraction and which, for an ultrasonic frequency of 1 MHz, is a few mm. sup.2. It is not necessary that the transducers be accurately positioned in the array, for the time reversal accommodates possible positioning errors.

[0106] [End of excerpt from US Pat. No. 5,092, 336]

[0107] [The following is an excerpt from US Pat. No. 5,267,979]

[0108] Catheter A10 has an elongated catheter body A12 with an annular side wall A14 defining a catheter lumen A16. The catheter body A12 has a proximal portion A18 with an opening (not shown) through which fluid is introduced into the catheter lumen. Catheter body A12 has a distal portion A22. The distal portion A22 includes an infusion length A24 with a plurality of slits A26 which serve as pressure responsive valves. In at least the areas of the infusion length A24, the catheter side wall is a single wall.

[0109] As best shown in FIGS. 13 and 14, the distal portion A22 of catheter sidewall A14 includes a tapered zone AA13. This taper AA13 creates a seat A40 for an occluding ball A38 associated with an occluding wire A41. The inner diameter of the two portions of the catheter sidewall A14, proximal and distal of the taper AA13, can vary dependent upon the intended use of catheter A10. In one embodiment of the invention, the catheter A10 has an inner diameter of about 0.047 inches and the end distal of the taper AA13 is a straight portion AA23 having a length of about 0.20 inches and an inner diameter of about 0.037 inches. The taper zone AA13 has an angle of approximately 20 degrees and a length of about 0.02 inches.

[0110] Occluding wire A41 includes a distal coil spring A36 having an outer diameter of about 0.035 inches. Distal coil spring A36 protects the arterial wall from the catheter tip. Occluding ball A38 has a diameter of about 0.044 inches. When advanced in catheter A10, the occluding ball A38 seats in the taper AA13 to seal the distal end hole A22c of catheter A10. By sealing end hole A22c fluid flow from the distal end hole A22c is prevented.

Occluding wire A41 may be retracted to open end hole A22c. When the occluding ball A38 is seated and end hole A22c is sealed, all fluid flow is from the slits A26. When the occluding ball is not seated in the taper AA13, both fluid and an associated guide wire (not shown) may exit from the end hole A22c.

[0111] Alternately, a shallow taper can extend along an end area of the catheter to reduce the catheter diameter to less than the diameter of the wire A41 so that a wire can be used to effect the sealing and unsealing of the end hole A22c.

[0112] [End of excerpt from US Pat. No. 5,267,979]

[0113] [The following is an excerpt from US Pat. No. 7,559,329] [0114] A preferred embodiment of the present invention is shown in FIGS. 15-16. The endovascular laser treatment device Al shown in FIG. 15 and FIG. 16 includes an optical fiber A3 which is comprised of clad-coated fiber A13 and jacket A15. The device also includes an outer sleeve A17, fitting assembly A7, which also acts as a deployment mechanism, compression gasket A45 and a compression cap A47. The optical fiber A3 transmits the laser energy from a laser generator (not shown) into a vessel. The fitting assembly A7 acts as a deployment mechanism for a spacer element to be discussed in detail later herein. The compression gasket A45 and compression cap A47 provide a sealing function and when compressed, generate friction sufficient to maintain the position of the optical fiber A3.

[0115] As is well known in the art, the optical fiber A3 is typically comprised of a 600- micron laser fiber A13 encased in a thick polymer jacket A15 for the entire length of the fiber A3 except for approximately 4 mm at the distal end. The jacket A15 prevents the fragile fiber from breaking during use. A thin intermediate cladding (not shown) creates a barrier through which the laser energy cannot penetrate, thus causing the energy to move

longitudinally through the fiber A3 to the distal end where the laser energy is emitted. At the distal end, the bare fiber A13 extends unprotected from the polymer jacket A15. The proximal end of the optical fiber A3 is connected to a SMA or similar-type connector A9, which can be attached to the laser generator (not shown). At the distal end, the optical fiber tip is ground and polished to form a flat face Al 1. Thus, the flat face Al 1 of the optical fiber A3 tip directs the laser energy from the fiber in a longitudinal direction.

[0116] The outer sleeve A17 is a tubular structure preferably comprised of a flexible, low- friction material such as nylon. The outer sleeve A17 is arranged coaxially around the optical fiber A3. For accommodation of the 600 micron optical fiber core, the outer sleeve A17 inner diameter is preferably about 0.045", although other diameters can be used for different optical fiber sizes. The outer diameter of the sleeve A17 is sized to fit within a standard 5F sheath. Typically, a sleeve A17 dimensioned with a 0.066" outer diameter should slidably fit within the lumen of a 5F sheath, which has an approximate inner diameter of 0.070".

[0117] The outer sleeve A17 is coaxially arranged around the optical fiber A3 and

permanently attached to the fiber A3 at the distal end of the sleeve A17 at point A23 which defines a bonding zone between the fiber A3 and the distal end of the sleeve A17. The outer sleeve A17 can be moved longitudinally relative to the optical fiber A3 except at the point A23. The sleeve A17 includes a plurality of longitudinal slits A21 in the tubing at the distal end to define a plurality of ribs A19 each arranged between two adjacent slits. Preferably, there are three to six slits while the embodiment shown has five slits to define five ribs A19. The ribs A19 disposed near the distal tip Al 1 of the optical fiber A3 define a spacer element that positions the distal tip Al 1 away from the inner wall of the vessel. When the sleeve A17 is moved longitudinally toward the fiber tip Al 1 relative to the optical fiber A3, the slits A21 expand radially outward to deploy the spacer element A19, as will be explained in more detail below. At the proximal end, the sleeve A17 is permanently bonded to the distal fitting component A33 at the sleeve/fitting assembly bond point A25, as more clearly shown in FIG. 16.

[0118] A fitting assembly A7 positioned at the proximal end of the outer sleeve A17 provides the mechanism by which the spacer element A19 is moved from an undeployed to deployed position. The fitting assembly A7 is comprised of a distal fitting component A33, a proximal fitting component A35 and a compression cap A47 threadably connected to the proximal fitting component A35. In the preferred embodiment, the two fitting components A33 and A35 are permanently attached together at bond point A41.

[0119] The distal fitting component A33 includes a male luer connector A27 or other similar type connection element which functions to connect the endovascular laser treatment device Al to other commonly used medical devices such as a hemostasis sheath. The outer sleeve shaft A17 is bonded to the male luer connector A27 of the distal fitting component A33 at point A25. The distal fitting component A33 has a longitudinal channel A39 through which the optical fiber A3 is positioned.

[0120] The proximal fitting component A35 also includes a longitudinal channel A39, as shown in FIG. 16, through which the optical fiber A3 is positioned. The proximal end of the fitting component A35 includes a cavity into which a gasket A45 is positioned. The gasket A45 is made of silicone or other compressible material with a central opening through which the optical fiber A3 passes. The gasket A45 provides the dual functions of sealing the channel A39 and providing friction sufficient to maintain the longitudinal position of the optical fiber A3 within the channel A39. The gasket compression threads A43 at the proximal end of fitting component A35 provide an axially moveable connection between the fitting A35 and the compression cap A47. When the compression cap A47 is threaded into the fitting A35, the gasket A45 is compressed, thus tightening the seal and increasing the friction between the fiber 3 and the gasket A45. When the compression cap A47 is loosened relative to the compression threads 43, the gasket seal is relaxed and the friction against the optical fiber decreased.

[0121] When assembled together, the proximal fitting component A35 and the distal fitting component A33 form a hollow positioning chamber A31 as shown in FIG. 16. Within the positioning chamber A31 is a positioning element A29 that is permanently attached to the optical fiber jacket A15 at bond point A37. During deployment of the spacer element A19, the positioning element A29 provides the function of limiting the longitudinal movement of the combined fitting assembly A7/outer sleeve A17 relative to the optical fiber A3. In the undeployed position, the positioning element A29 is in contact with the distal chamber face A65. Longitudinal movement of fitting assembly causes the positioning element A29 to be repositioned within the chamber A31. Forward longitudinal movement of the fitting

A7/outer sleeve A17 is stopped when the positioning element A29 comes in contact with proximal chamber face A67.

[0122] When the positioning element A29 is against the proximal chamber face A67, the spacer element A19 is fully deployed as illustrated in FIG. 17. In this position, the spacer ribs A19 are expanded radially outward, forming a space barrier between the fiber tip Al 1 and the inner vein wall. The mechanism for expansion is based on the forward longitudinal movement of the outer sleeve A17 proximal to the fiber/sleeve distal bond point A23. Since the optical fiber A3 is held stationary during deployment, and the fiber is permanently bonded to the sleeve A17 at point A23, the portion of the sleeve A17 within the slit zone expands as the sleeve is pushed forward. The device Al is designed to allow expansion of the slit zone to a maximum predetermined diameter. Alternatively, an intermediate expansion diameter can be achieved by controlling the amount of longitudinal movement within the chamber A31.

[0123] According to the invention, the spacer element A19 provides several important advantages among others. In an undeployed position, as shown in FIGS. 12 and 13, the outer diameter and profile of the spacer element A19 is equal to the outer sleeve A17, allowing for easy insertion and positioning within the vein. The fitting assembly A7 provides the user with an easy, simple means for deploying the spacer element A19 while maintaining the position of the fiber tip Al 1 stationary within the vein. When deployed, the spacer element A19 creates a barrier between the fiber tip Al 1 and the inner vein wall, thereby minimizing unequal laser energy distribution.

[0124] The preferred embodiment of this invention as illustrated in FIGS. 15-17 may be used with a standard hemostasis introducer sheath. Endovenous laser sheaths are typically 45 centimeters in length, although 60 and 65 centimeter sheaths are also well known in the art. The length of the endo vascular laser treatment device Al is determined based on the length of the sheath being used for the procedure. According to the invention, the endovascular laser treatment device Al can be sized to fit standard-length sheaths or custom-length sheaths. Further, the assembly Al can be provided by itself or in a package that includes either the standard length sheath or custom-length sheath.

[0125] FIGS. 18-20 show the endovascular laser treatment device Al with a hemostasis introducer sheath A49. As is known in the art, the hemostasis introducer sheath assembly A49 is comprised of a sheath shaft A53, a sheath distal tip A51, a sidearm port A57 with connecting tubing, a stopcock assembly A61, and a hemostasis valve gasket A59 housed within proximal opening of the sheath fitting A55. A connector element A63 provides a means to connect the hemostasis sheath assembly A49 to the endovascular laser treatment device Al .

[0126] To assemble the endovascular laser treatment device Al to the hemostasis introducer sheath A49, the fiber tip Al 1/outer sleeve A17 tip is first inserted into and advanced through the sheath connector element A63 and sheath shaft A53 lumen until the sheath tip A51 and fiber tip Al 1 are in substantial alignment as shown in FIG. 15. At this point, with the fiber tip Al 1 protected within the sheath tip A51 , the user may adjust the position of the combined laser treatment device Al and sheath A49. Maintaining the fiber tip Al 1 position relative to the sheath tip A51 position during any user adjustments may be facilitated by the use of a temporary stop (not shown) slidably connected to the fiber A3. The temporary stop mechanism was previously disclosed in U.S. patent application Ser. No. 10/316,545, filed Dec. 11, 2002 and entitled "Endovascular Laser Treatment Device", which is incorporated herein by reference. The temporary stop maintains the fiber tip Al 1/sheath tip A51 alignment in a protective position until removed by the user.

[0127] To expose the fiber tip Al 1 and spacer element A19 beyond the sheath tip A51, the sheath fitting A55 is retracted while holding the fiber A3 stationary. Retracting the sheath fitting A55 rather than advancing the fiber A3 ensures that the correct pre -operative fiber tip Al 1 /spacer element A19 position is maintained. The sheath fitting A55 is retracted until the sheath connector element A63 comes into contact with the male luer connector A27.

Threading the two connectors A27 and A63 together securely connects the endovascular laser treatment device Al to the hemostasis introducer sheath assembly A49. Once connected, the fiber tip Al 1 and spacer element A19 are automatically exposed in the proper operable position. A dual-thread arrangement, commonly used in medical devices, is shown in FIG. 19, but other methods of connection may be used to connect the two fittings together.

[0128] FIG. 19 shows the endovascular laser treatment device Al/hemostasis introducer sheath A49 connected with the spacer element A19 in the exposed and undeployed position. In the undeployed position, the distal segment of the outer sleeve shaft A17 extends beyond the sheath tip A51 enough to completely expose the length of the slits A21. To deploy the spacer element A19, the optical fiber is held stationary while the connected sheath fitting A55/fitting assembly A7 is advanced forward. Longitudinal movement of connected fittings A55 and A7 cause the positioning element A29 to be repositioned within the chamber A31. Forward longitudinal movement of the fitting A7/outer sleeve A17 is stopped when the positioning element A29 comes in contact with proximal chamber face A67. When the positioning element A29 is against the proximal chamber face A67, the spacer element A19 is fully deployed as illustrated in FIG. 20. In this position, the spacer ribs A19 are expanded radially outward, forming a space barrier between the fiber tip Al 1 and the inner vein wall.

[0129] [End of excerpt from US Pat. No. 7,559,329]

[0130] A small sample of systems methods and apparatus that are disclosed hereinabove in paragraphs [0001] through [0023] and [0025] through [0061] with reference to Figs. lA-11 is as follows:

[0131] Al . An elongated device comprising: an ultrasound translating element capable of translating ultrasound energy; wherein the ultrasound translating element generates electrical signals for processing for determination of converging ultrasound waves converging on a target site.

[0132] Bl . An apparatus comprising: an ultrasound translating element capable of translating ultrasound energy into electrical energy; an ultrasound wave emission unit;

wherein the apparatus is operative for processing a signal from the ultrasound translating element; wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site. B2. The apparatus of Bl, wherein the apparatus includes a second ultrasound wave emission unit.

B3. The apparatus of Bl, wherein the ultrasound wave emission unit is an ultrasound transducer. B4. The apparatus of Bl, wherein the processing includes performing a time reversal acoustic algorithm. B5. The apparatus of Bl, wherein the apparatus comprises an elongated device including the ultrasound translating element. B6. The apparatus of Bl, wherein the apparatus is operative so that the target site is at the ultrasound translating element. B7. The apparatus of Bl, wherein the apparatus comprises an elongated device which includes the ultrasound translating element, the elongated device having a coaxial cable comprising an inner conductor and an outer conductor for transmission of the signal for the processing. B8. The apparatus of Bl, wherein the apparatus comprises an elongated device which includes the ultrasound translating element, the elongated device being characterized by one or more of (a) the elongated device includes a prewound or coiled tubular body, wherein the ultrasound translating element is positioned within the tubular body; (b) the elongated device includes a guidewire and a floppy tip for guiding the guidewire. B9. The apparatus of Bl, wherein the apparatus comprises an elongated device which includes the ultrasound translating element, the elongated device being characterized by one or more of (a) the elongated device is adapted for fluid delivery; (b) the elongated device is adapted for fluid delivery and includes a lumen for fluid delivery, (c) the elongated device is adapted for fluid delivery and includes a slit for fluid delivery, (d) the elongated device is adapted for fluid delivery and includes an occluding ball for retention of fluid. BIO. The apparatus of Bl, wherein the apparatus comprises an elongated device which includes the second ultrasound translating element, the elongated device being characterized by one or more of (a) the elongated device includes an expandable element adapted for aiding removal of fragment or debris, and (b) the elongated device includes spacer for centrally locating the ultrasound translating element within the elongated device.

[0133] C 1. A treatment method comprising: inserting an ultrasound translating element into a patient's body; transmitting ultrasound energy; receiving the ultrasound energy with the ultrasound translating element, the ultrasound translating element generating an electrical signal responsively to the ultrasound energy; processing the electrical signal; emitting converging ultrasound waves on a target site responsively to the processing. C2. The treatment method of C 1 , wherein the emitting aids in the destruction of a thrombus. C3. The treatment method of CI, wherein the emitting aids in the delivery of a drug or fluid. C3. The treatment method of C 1 , wherein the emitting aids in the destruction of a thrombus and aids in the delivery of a drug or fluid. C4. The treatment method of CI, wherein the processing includes performing a time reversal acoustic algorithm. C4. The treatment method of CI, wherein the method includes using a elongated device which includes the ultrasound translating element.

[0134] Dl . An apparatus comprising: first and second ultrasound translating elements capable of translating ultrasound energy into electrical energy; an ultrasound wave emission unit; wherein the apparatus is operative for processing a signal from the first and second ultrasound translating elements; wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site. D2. The apparatus of Dl, wherein the ultrasound wave emission unit is an ultrasound transducer. D3. The apparatus of Dl, wherein the processing includes performing a time reversal acoustic algorithm. D4. The apparatus of Dl, wherein the apparatus includes an elongated device on which the ultrasound translating element is disposed. D5. The apparatus of Dl, wherein the apparatus is operative so that the target site is at the first ultrasound translating element. D6. The apparatus of Dl, wherein the apparatus is operative so that the target site is at the second ultrasound translating element. D7. The apparatus of Dl, wherein the apparatus is operative so that the target site is offset from each of the first ultrasound translating element and the second ultrasound translating element. D8. The apparatus of Dl, wherein the apparatus comprises an elongated device which includes the first ultrasound translating element and the second ultrasound translating element, the elongated device having a coaxial cable comprising an inner conductor and an outer conductor for

transmission of the signal for the processing. D9. The apparatus of Dl, wherein the apparatus comprises an elongated device which includes the first ultrasound translating element and the second ultrasound translating element, the elongated device being characterized by one or more of (a) the elongated device includes a prewound or coiled tubular body, wherein the ultrasound translating element is positioned within the tubular body; (b) the elongated device includes a guidewire and a floppy tip for guiding the guidewire. D10. The apparatus of Dl, wherein the apparatus comprises an elongated device which includes the first ultrasound translating element and the second ultrasound translating element, the elongated device being characterized by one or more of (a) the elongated device is adapted for fluid delivery; (b) the elongated device is adapted for fluid delivery and includes a lumen for fluid delivery, (c) the elongated device is adapted for fluid delivery and includes a slit for fluid delivery, (d) the elongated device is adapted for fluid delivery and includes an occluding ball for retention of fluid. Dl 1. The apparatus of Dl, wherein the apparatus comprises an elongated device which includes the first ultrasound translating element and the second ultrasound translating element, the elongated device being characterized by one or more of (a) the elongated device includes an expandable element adapted for aiding removal of fragment or debris, and (b) the elongated device includes spacer for centrally locating the ultrasound translating element within the elongated device.

[0135] El . A treatment method comprising: inserting an ultrasound translating element into a patient's body; transmitting ultrasound energy; receiving the ultrasound energy with the ultrasound translating element, the ultrasound translating element generating an electrical signal responsively to the ultrasound energy; processing the electrical signal; delivering a drug or fluid; emitting converging ultrasound waves on a target site responsively to the processing, wherein the emitting aiding in the delivering a drug or fluid. E2. The treatment method of El, wherein the emitting aids in the destruction of a thrombus. E3. The treatment method of El, wherein the treatment method includes using an elongated device having a fluid delivery lumen, wherein the ultrasound translating element is disposed in the elongated device. E4. The treatment method of El, wherein the treatment method includes using an elongated device having a pressure sensitive slit, wherein the drug or fluid is delivered through the pressure sensitive slit. E5. The treatment method of El, wherein the delivering includes delivering a sclerosant agent to a vein to cause the vein to collapse. E6. The treatment method of El, wherein the delivering includes delivering a lytic to aid in a destruction of a thrombus. E7. The treatment method of El, wherein the method includes removing remaining fragments or debris resulting from the emitting using an elongated device including the ultrasound translating element. E8. The treatment method of El, wherein the processing includes performing a time reversal acoustic algorithm.

[0136] Fl . An apparatus comprising: an elongated device having a ultrasound translating element capable of translating ultrasound energy into electrical energy;

an ultrasound wave emission unit; wherein the apparatus is operative for processing a signal from the ultrasound translating element; wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site, wherein the elongated device is characterized by one or more of (a) the elongated device includes a coaxial cable having an inner conductor and an outer conductor for transmission of the signal for the processing, (b) the elongated device includes a prewound or coiled tubular body, wherein the ultrasound translating element is positioned within the tubular body; (c) the elongated device includes a guidewire and a floppy tip for guiding the guide wire.

[0137] Gl . An apparatus comprising: an elongated device having a ultrasound translating element capable of translating ultrasound energy into electrical energy;

an ultrasound wave emission unit; wherein the apparatus is operative for processing a signal from the ultrasound translating element; wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site, wherein the elongated device is characterized by one or more of (a) the elongated device is adapted for fluid delivery; (b) the elongated device is adapted for fluid delivery and includes a lumen for fluid delivery, (c) the elongated device is adapted for fluid delivery and includes a slit for fluid delivery, (d) the elongated device is adapted for fluid delivery and includes an occluding ball for retention of fluid.

[0138] HI . An apparatus comprising: an elongated device having a ultrasound translating element capable of translating ultrasound energy into electrical energy; an ultrasound wave emission unit; wherein the apparatus is operative for processing a signal from the ultrasound translating element; wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site, wherein the elongated device is characterized by one or more of (a) the elongated device includes an expandable element adapted for aiding removal of fragment or debris, and (b) the elongated device includes spacer for centrally locating the ultrasound translating element within the elongated device.

[0139] II . An elongated device comprising: an ultrasound translating element capable of translating ultrasound energy; a coaxial cable having an inner conductor and an outer conductor; wherein the inner conductor and the outer conductor are connected to the ultrasound translating element; wherein the outer conductor transmits electrical signals for processing for determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element.

[0140] Jl . An elongated device comprising: a prewound or coiled tubular body; an ultrasound translating element capable of translating ultrasound energy, the ultrasound translating element being positioned within the tubular body; wherein the ultrasound translating element generates electrical signals for processing for determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element. J2. The elongated device of Jl, wherein the elongated device includes a floppy tip. J3. The elongated device of J2, wherein the elongated device includes an occluding ball.

[0141] Kl . An elongated device comprising: a prewound or coiled tubular body; an ultrasound translating element capable of translating ultrasound energy, the ultrasound translating element being positioned within a lumen of the tubular body; wherein the ultrasound translating element generates electrical signals for processing for determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element. K2. The elongated device of Kl, wherein the elongated device includes an elongated shaft having a fluid delivery lumen defined therein. K3. The elongated device of Kl, wherein the elongated device includes a fluid delivery slit. K4. The elongated device of Kl , wherein the elongated device includes a flexible filler encasing the ultrasound translating element and conductors connected to the ultrasound translating element.

[0142] LI . An elongated device comprising: an ultrasound translating element capable of translating ultrasound energy, the ultrasound translating element; an expandable occluding element; wherein the ultrasound translating element generates electrical signals for processing for determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element; wherein the expandable occluding element is adapted to aid in the removal of remaining fragments or debris resulting from the converging ultrasound waves.

[0143] Ml . An elongated device comprising: an ultrasound translating element capable of translating ultrasound energy; a tip spacer; wherein the ultrasound translating element generates electrical signals for processing for determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element; wherein the tip spacer is adapted to center the ultrasound translating element within the intravascular device. M2. The elongated device of Ml, wherein the tip spacer is expandable.

[0144] Nl . An elongated device comprising: an ultrasound translating element capable of translating ultrasound energy; filler material surrounding the ultrasound translating element; wherein the ultrasound translating element generates electrical signals for processing for determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element; wherein the filler material is adapted to prevent air pockets about the ultrasound translating element. N2. The elongated device of Nl, wherein the filler material is adapted to harden but remain flexible.

[0145] 01. A device for treating a thrombus, comprising: time reversal acoustic ultrasound generator; an ultrasound transducer; an intravascular device comprising a distal end; a piezoelectric element positioned near the distal end of the intravascular device; said intravascular device 10 further comprising a first conductive and second conductive element; and a connector.

[0146] PI . A method for treating a thrombus comprising: inserting a device capable of receiving ultrasound waves, said device comprising a distal end and a piezoelectric element positioned near the distal end of the device; transmitting ultrasound waves using an ultrasound transducer; receiving the ultrasound waves with said piezoelectric element;

transmitting the electric signals generated by the piezoelectric element to a time reversal acoustic unit; calculating the electrical signals using a time reversal acoustic algorithm; sending converging ultrasound waves to the piezoelectric element; and disrupting a clot.

[0147] While the present invention has been described with reference to a number of specific embodiments, it will be understood that the true spirit and scope of the invention should be determined only with respect to claims that can be supported by the present specification. Further, while in numerous cases herein wherein systems and apparatuses and methods are described as having a certain number of elements it will be understood that such systems, apparatuses and methods can be practiced with fewer than or greater than the mentioned certain number of elements. Also, while a number of particular embodiments have been described, it will be understood that features and aspects that have been described with reference to each particular embodiment can be used with each remaining particularly described embodiment.

Claims

What is claimed:

1. An apparatus comprising:

first and second ultrasound translating elements capable of translating ultrasound energy into electrical energy;

an ultrasound wave emission unit;

wherein the apparatus is operative for processing a signal from the first and second ultrasound translating elements;

wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site.

2. The apparatus of claim 1, wherein the ultrasound wave emission unit is an ultrasound transducer.

3. The apparatus of claim 1, wherein the processing includes performing a time reversal acoustic algorithm.

4. The apparatus of claim 1, wherein the apparatus includes an elongated device on which the ultrasound translating element is disposed.

5. The apparatus of claim 1, wherein the apparatus is operative so that the target site is at the first ultrasound translating element.

6. The apparatus of claim 1, wherein the apparatus is operative so that the target site is at the second ultrasound translating element.

7. The apparatus of claim 1, wherein the apparatus is operative so that the target site is offset from each of the first ultrasound translating element and the second ultrasound translating element.

8. The apparatus of claim 1, wherein the apparatus comprises an elongated device which includes the first ultrasound translating element and the second ultrasound translating element, the elongated device having a coaxial cable comprising an inner conductor and an outer conductor for transmission of the signal for the processing.

9. The apparatus of claim 1, wherein the apparatus comprises an elongated device which includes the first ultrasound translating element and the second ultrasound translating element, the elongated device being characterized by one or more of (a) the elongated device includes a prewound or coiled tubular body, wherein the ultrasound translating element is positioned within the tubular body; (b) the elongated device includes a guidewire and a floppy tip for guiding the guidewire.

10. The apparatus of claim 1, wherein the apparatus comprises an elongated device which includes the first ultrasound translating element and the second ultrasound translating element, the elongated device being characterized by one or more of (a) the elongated device is adapted for fluid delivery; (b) the elongated device is adapted for fluid delivery and includes a lumen for fluid delivery, (c) the elongated device is adapted for fluid delivery and includes a slit for fluid delivery, (d) the elongated device is adapted for fluid delivery and includes an occluding ball for retention of fluid.

11. The apparatus of claim 1 , wherein the apparatus comprises an elongated device which includes the first ultrasound translating element and the second ultrasound translating element, the elongated device being characterized by one or more of (a) the elongated device includes an expandable element adapted for aiding removal of fragment or debris, and (b) the elongated device includes spacer for centrally locating the ultrasound translating element within the elongated device.

12. A treatment method comprising :

inserting an ultrasound translating element into a patient's body;

transmitting ultrasound energy;

receiving the ultrasound energy with the ultrasound translating element, the ultrasound translating element generating an electrical signal responsively to the ultrasound energy;

processing the electrical signal;

delivering a drug or fluid;

emitting converging ultrasound waves on a target site responsively to the processing, wherein the emitting aiding in the delivering a drug or fluid.

13. The treatment method of claim 12, wherein the emitting aids in the destruction of a thrombus.

14. The treatment method of claim 12, wherein the treatment method includes using an elongated device having a fluid delivery lumen, wherein the ultrasound translating element is disposed in the elongated device.

15. The treatment method of claim 12, wherein the treatment method includes using an elongated device having a pressure sensitive slit, wherein the drug or fluid is delivered through the pressure sensitive slit.

16. The treatment method of claim 12, wherein the delivering includes delivering a sclerosant agent to a vein to cause the vein to collapse.

17. The treatment method of claim 12, wherein the delivering includes delivering a lytic to aid in a destruction of a thrombus.

18. The treatment method of claim 12, wherein the method includes removing remaining fragments or debris resulting from the emitting using an elongated device including the ultrasound translating element.

19. The treatment method of claim 12, wherein the processing includes performing a time reversal acoustic algorithm.

20. An apparatus comprising:

an elongated device having a ultrasound translating element capable of translating ultrasound energy into electrical energy;

an ultrasound wave emission unit;

wherein the apparatus is operative for processing a signal from the ultrasound translating element;

wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site, wherein the elongated device is characterized by one or more of (a) the elongated device includes a coaxial cable having an inner conductor and an outer conductor for transmission of the signal for the processing, (b) the elongated device includes a prewound or coiled tubular body, wherein the ultrasound translating element is positioned within the tubular body; (c) the elongated device includes a guide wire and a floppy tip for guiding the guidewire.

21. An apparatus comprising:

an ultrasound wave emission unit;

wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site, wherein the elongated device is characterized by one or more of (a) the elongated device is adapted for fluid delivery; (b) the elongated device is adapted for fluid delivery and includes a lumen for fluid delivery, (c) the elongated device is adapted for fluid delivery and includes a slit for fluid delivery, (d) the elongated device is adapted for fluid delivery and includes an occluding ball for retention of fluid.

22. An apparatus comprising:

an ultrasound wave emission unit;

wherein responsively to the processing the apparatus controls the ultrasound wave emission unit to converge ultrasound waves on a target site, wherein the elongated device is characterized by one or more of (a) the elongated device includes an expandable element adapted for aiding removal of fragment or debris, and (b) the elongated device includes spacer for centrally locating the ultrasound translating element within the elongated device.

23. An elongated device comprising:

an ultrasound translating element capable of translating ultrasound energy;

a coaxial cable having an inner conductor and an outer conductor; wherein the inner conductor and the outer conductor are connected to the ultrasound translating element;

wherein the outer conductor transmits electrical signals for processing for

determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element.

24. An elongated device comprising:

a prewound or coiled tubular body;

an ultrasound translating element capable of translating ultrasound energy, the ultrasound translating element being positioned within the tubular body;

wherein the ultrasound translating element generates electrical signals for processing for determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element.

25. The elongated device of claim 24, wherein the elongated device includes a floppy tip.

26. The elongated device of claim 25, wherein the elongated device includes an occluding ball.

27. An elongated device comprising:

a prewound or coiled tubular body;

an ultrasound translating element capable of translating ultrasound energy, the ultrasound translating element being positioned within a lumen of the tubular body;

28. The elongated device of claim 27, wherein the elongated device includes an elongated shaft having a fluid delivery lumen defined therein.

29. The elongated device of claim 27, wherein the elongated device includes a fluid delivery slit.

30. The elongated device of claim 27, wherein the elongated device includes a flexible filler encasing the ultrasound translating element and conductors connected to the ultrasound translating element.

31. An elongated device comprising:

an ultrasound translating element capable of translating ultrasound energy, the ultrasound translating element;

an expandable occluding element;

wherein the ultrasound translating element generates electrical signals for processing for determination of converging ultrasound waves converging on a target site based on a location of the ultrasound translating element;

wherein the expandable occluding element is adapted to aid in the removal of remaining fragments or debris resulting from the converging ultrasound waves.

32. An elongated device comprising:

an ultrasound translating element capable of translating ultrasound energy;

a tip spacer;

wherein the tip spacer is adapted to center the ultrasound translating element within the intravascular device.

33. The elongated device of claim 32, wherein the tip spacer is expandable.

34. An elongated device comprising:

an ultrasound translating element capable of translating ultrasound energy;

filler material surrounding the ultrasound translating element;

wherein the filler material is adapted to prevent air pockets about the ultrasound translating element.

35. The elongated device of claim 34, wherein the filler material is adapted to harden but remain flexible.