The present disclosure concerns devices and methods for ultrasound use within the human body.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 62/203,983 filed Aug. 12, 2015, which is herein incorporated by reference in its entirety.

BACKGROUND

Ultrasound technology has been used for therapeutic and diagnostic medical procedures, which can include providing imaging of internal portions of a body. For example, devices have been proposed for ultrasound imaging within blood vessels to view the condition of the vessel and/or placement or condition of a device placed in the vessel, as well as to help to determine plaque volume and the degree of stenosis within an artery lumen. That information is often difficult to obtain through angiographic imaging and exterior ultrasound imaging, particularly in regions having multiple overlapping arterial segments.

In some examples of intraluminal ultrasound procedures, a catheter is fitted with a transducer. A wire guide is positioned within a body conduit through use of angiography or ultrasound and is used to safely direct the catheter through the anatomy. The catheter is slid over the wire guide and positioned near the farthest end of the wire guide. The transducer transmits and/or receives ultrasound waves. When a transducer is placed within the body, commonly it is inside a protective envelope, such as a tube, catheter, or similar housing or enclosure. The material of such an envelope may be selected for its similarity in acoustic impedance to that of bodily fluids, so that there is little or no attenuation as ultrasound waves travel from that material to the fluids or tissues of the body. The inner pocket or volume of the body within which the transducer is placed needs a coupling medium having an acoustic impedance similar to that of the envelope material and the body's fluids to allow maximum transmission. Without such medium, transmission of the ultrasound waves may be significantly impeded. Suitable coupling media include biocompatible fluids such as saline, certain oils, alcohols, and other fluids.

Of course, some coupling media (e.g. saline) can be corrosive over time, particularly of metallic materials. If a corrosive coupling medium is to be used, a drawback is that degradation of part(s) of the transducer or other aspects of the device (e.g. structure used to turn or move the transducer) may occur. An unacceptably short shelf life for the product may thus result with such medium. Thus, the relatively low-cost medium of saline has significant downside to a practical internal transducer product.

Embodiments of internal transducer products using piezoelectric motors to turn or otherwise move a transducer have also been suggested. Applicable piezoelectric motors generally need dry conditions to operate, as they require a high friction contact area between a stator and a clutch. If fluid touches that contact area or interface, the friction will be substantially reduced, thereby also reducing the torque output of the motor. Accordingly, in such embodiments to prevent fluid from contacting the motor, a seal is included between the motor and the transducer to prevent leakage of the coupling medium from the volume around the transducer toward the motor. Such seals can fail over time, which is one potential factor in shelf life for such products.

Further difficulties arise in constructing adequate catheters having transducers in very small sizes in order to safely reach particular body conduits, such as for example with intravascular applications. Problems with existing two dimensional designs include wire guide channels which block a portion of the acoustic window. Additionally, wire guide channels take up valuable space in the catheter that could otherwise be used by ultrasound hardware.

Other problems exist in current catheter configurations. For example, in many cases in order to visualize the entirety of a significant length within the body (e.g. surfaces or portions of tissue, or of devices), the device must be moved along that length, with respective images of cross sections taken at particular locations. Such movement may be inexact, slow, result in distorted images, and the images are not provided in real time. Additionally, existing devices do not provide imaging information to aid in insertion of the catheter and can thus include risks associated with blind insertion.

Three-dimensional information provides the added value that it can be used to help in navigation and confirmation of position of devices within body conduits. In an intravascular example, catheters can be pulled back within vessels at a controlled speed and the image data obtained via ultrasound can be processed in order to create three-dimensional information. However, the catheter tip motion and angle must be known in order to produce accurate and usable data. Three-dimensional images may be acquired by one-dimensional arrays connected to a mechanical actuator which moves the arrays within the catheter or other device. Such designs are often expensive.

There remains a need for a catheter positionable over a wire guide which can provide accurate and efficient preparation and application of ultrasound, including efficient fluid injection means. There also remains a need for such a device that can view a medical device and one or more tissues or tissue parts simultaneously, particularly in cases in which the device and tissue(s) could not have been imaged reliably in any two-dimensional plane.

SUMMARY

Among other things, there are disclosed embodiments of devices for medical ultrasound application within a patient, and methods for making and using them. For example, a device for medical ultrasound in particular embodiments includes a housing having a longitudinal axis, a transducer configured for transmitting and/or receiving ultrasound signals and operatively coupled with a drive shaft extending substantially along the longitudinal axis wherein the transducer and the drive shaft positioned within the housing and the transducer rotates about the longitudinal axis in response to rotation of the drive shaft. Also included in this embodiment is a non-rotating wire guide positioned along the longitudinal axis within the housing and a torque cable offset a distance from the longitudinal axis, the torque cable operably connected to the drive shaft and a motor so that the drive shaft rotates in response to the torque cable. Optionally, a first gear is operably connected to the torque cable and a second gear is operably connected to the drive shaft, wherein the second gear is configured to interact with the first gear such that the second gear is configured to rotate when the first gear rotates. Optionally, in this particular embodiment, the first gear has a rotational axis offset from the longitudinal axis and the first gear is configured to rotate about the rotational axis and the second gear is configured to rotate about the longitudinal axis when the first gear rotates. In any embodiment, the device includes a mounting piece positioned within the housing, the mounting piece is configured to receive the transducer and the drive shaft, wherein the mounting piece defines a lumen that aligns with the longitudinal axis and is sized to receive the wire guide such that the wire guide is non-rotatable, and the mounting piece is configured to rotate about the longitudinal axis. Optionally in this embodiment, the device includes a slip ring assembly operably connected to the mounting piece and the torque cable. In some embodiments, the mounting piece defines a bore that extends along the longitudinal axis, and the slip ring assembly includes a stationary mount piece configured to retain the drive shaft sized to operatively mate with the bore. In any embodiment, the device includes a pusher piece operably connected to the housing, the pusher piece defining a plurality of lumens that span the length of the pusher piece wherein one of the plurality of lumens is sized to receive the wire guide and another of the plurality of lumens is sized to receive the torque cable. In this embodiment, optionally, another of the plurality of lumens of the pusher piece is sized to receive one or more transducer electrical wires operably connected to the transducer. In any embodiment, the housing is a catheter.

As another example a medical ultrasound device includes a housing having a longitudinal axis, a transducer positioned within the housing wherein the transducer is configured for transmitting and/or receiving ultrasound signals, and a mounting piece positioned within the housing and operatively coupled with a torque cable that is configured to rotate the mounting piece about the longitudinal axis. The mounting piece is also configured to receive the transducer, wherein the mounting piece defines a lumen that aligns with the longitudinal. Also included is a torque cable operably connected to the mounting piece to transmit torque to the mounting piece.

Optionally the device can include a non-rotating wire guide positioned within the housing along the longitudinal axis and a gear assembly positioned within the housing, the gear assembly having a first gear interactively coupled to a second gear, wherein the first gear is rotatably mounted to a stationary mount piece within the housing and the first gear is operatively connected to the torque cable, and the second gear is rotatably mounted to the stationary mount piece about the longitudinal axis. In some embodiments, the mounting piece defines a lumen sized to receive the wire guide. Other embodiments the device includes a second torque cable operably connected to the transducer, the first torque cable and the second torque cable configured to pivot and to rotate the transducer. In other embodiments the device includes a pusher piece operably connected to the housing, the pusher piece defining a plurality of lumens that span the length of the pusher piece wherein one of the plurality of lumens is sized to receive the wire guide and a second of the plurality of lumens is sized to receive the torque cable. Further in this embodiment, the lumen sized to receive the wire guide can include an ultrasound-transmissive fluid. In any embodiment, the device includes a motor positioned exteriorly to the housing, wherein the motor is operably connected to the torque cable.

Optionally the device includes a motor positioned exteriorly to the housing and a gear assembly mounted on the motor, wherein the torque cable is operably connected to the gear assembly and the torque cable is further configured to receive the wire guide therein. In some embodiments, the torque cable is offset a distance from the longitudinal axis. In any embodiment of the device, the transducer can be operatively coupled with a drive shaft extending substantially along the longitudinal axis such that the transducer and the drive shaft are positioned within the housing and the transducer rotates about the longitudinal axis in response to rotation of the drive shaft.

In yet another embodiment of a medical ultrasound device, the device includes a housing having a longitudinal axis, a non-rotating wire guide positioned within the housing along the longitudinal axis, a transducer positioned within the housing wherein the transducer is configured for transmitting and/or receiving ultrasound signals. The device also includes a mounting piece positioned within the housing and operatively coupled with a torque cable that is configured to rotate the mounting piece about the longitudinal axis, the mounting piece also configured to receive the transducer, wherein the mounting piece defines a lumen that is sized to receive the wire guide. The device further includes a torque cable operably connected to the mounting piece to transmit torque to the mounting piece, the torque cable further configured to receive the wire guide therein and a gear assembly mounted on a motor exterior to the housing, wherein the torque cable is also operably connected to the gear assembly.

Further forms, objects, features, aspects, benefits, advantages, and embodiments of the present invention will become apparent from a detailed description and drawings provided herewith.

