Patent Application
20070038097
The present invention relates to ultrasonic imaging systems and, in particular, to an introducer for use with an ultrasonic imaging system. In a particularly preferred embodiment, the invention relates to an introducer for use with transurethral ultrasonic imaging systems.
When performing ultrasonic imaging within a tissue region or body lumen, such as a patient's urethra, it is important to ensure proper coupling of the energy generated and received by an imaging transducer to the surrounding tissues, and it is also often important to protect the surrounding tissues from abrasion or other harm.
The present invention is directed to an introducer that functions to enhance energy transfer or acoustic coupling between an imaging transducer that is placed within a body lumen, such as a patient's urethra, and surrounding tissues. In various embodiments, the present invention also relates to the configuration, storage, and packaging of such an introducer.
Exemplary embodiments of the present invention that are shown in the drawings are summarized below. These and other embodiments are more fully described in the Detailed Description section. It is to be understood, however, that there is no intention to limit the invention to the forms described in this Summary of the Invention or in the Detailed Description. One skilled in the art can recognize that there are numerous modifications, equivalents and alternative constructions that fall within the spirit and scope of the invention as expressed in the claims.
In one presently preferred embodiment, an introducer is provided which comprises a tubular member defining a lumen wherein the tubular member comprises an open proximal end that is adapted to connect to an ultrasonic imaging system to allow insertion of an ultrasonic imaging catheter into the lumen. The tubular member further comprises a closed distal end and an imaging section that is transparent to ultrasonic waves. The introducer also may contain an acoustic coupling medium to enhance acoustic coupling between the ultrasonic imaging catheter, the tubular member, and any surrounding tissues. A seal may be used to retain the acoustic coupling medium within the lumen, and in such embodiments, the seal preferably is breachable or may be penetrated by the ultrasonic imaging catheter.
In the above described embodiment, the seal may be provided, for example, by a cap structure, a releasable tubular seal, or a clamped fold of the tubular member. And, depending upon the intended application, the acoustic coupling medium may comprise water, some other type of liquid, such as saline solution, or a gel.
In still further embodiments, the introducer may include a distal tip or plug that may be used to position the distal end of the introducer within a particular region of interest, such as adjacent a patient's bladder sphincter or bladder neck.
As previously stated, the above-described embodiments and implementations are for illustration purposes only. Numerous other embodiments, implementations, and details of the invention are easily recognized by those of skill in the art from the following descriptions and claims.
For the sake of convenience, several terms used to describe various human anatomical structures and embodiments of the invention are defined below. It should be understood that these are provided merely to aid the understanding of the description, and that the definitions should in no way limit the scope of the invention, which is defined by the appended claims.
Anterior: Situated at the front or the front surface of an organ.
Apex of the prostate: The end of the prostate gland located farthest away from the urinary bladder.
Axial/Longitudinal: Along the centerline of the urethra, regardless of patient position.
Biopsy: The removal of a small sample or samples of tissue for examination under a microscope or other device.
Bladder: The hollow organ that stores and discharges urine from the body.
Bladder neck: The outlet area of the bladder. It is composed of circular muscle fibers (bladder sphincter), and helps control urine flow from the bladder into the urethra.
Catheter drive mechanism: A motion control system that can provide axial and/or rotational motion to an imaging catheter, or an ultrasonic transducer disposed within an imaging catheter.
Distal: Remote, farther from any point of reference (the opposite of proximal).
Genitourinary system: Pertaining to the genital and urinary systems.
Imaging catheter: A tubular mechanism, containing an ultrasonic transducer for organ-tissue imaging.
Inferior: Anatomically refers to a lower surface of an organ, or a location situated below a given reference point.
Intraluminal: Within a lumen, such as a vessel or other tubular passage within the body, an organ of the body, or an area of tissue within the body.
Introducer: A device that facilitates the insertion of a catheter into the urethra.
Periluminal: Around a lumen, such as a vessel or other tubular passage within the body, an organ of the body, or an area of tissue within the body.
Posterior: Situated at the back or the back surface of an organ.
Prostatic Urethra: The segment of the urethra, which is surrounded by prostatic tissue from the proximal end at the bladder neck to the distal end at the apex of the prostate gland.
Proximal: Closer to any point of reference.
Superior: Anatomically refers to an upper surface of an organ, or situated above a given reference point.
Transducer: A device, which transforms one form of energy to another form of energy (e.g. electrical to acoustical energy, or, conversely, acoustical to electrical energy).
Transurethral: A procedure performed through the urethra.
Transverse: Placed crosswise, situated at right angles to the long axis of an organ.
Various embodiments of the invention are directed to an introducer for use with a transurethral ultrasonic imaging system. Some embodiments include an acoustic coupling medium, and others include a sheath which covers the introducer, protecting it from contamination. A further embodiment includes a sheath and a lubricant to facilitate insertion of the introducer into a patient. Other embodiments include a hydrophilic coating on the introducer to enhance lubricity and elements to facilitate hydrating the hydrophilic coating. Some embodiments have a rigid plug at the tip of the introducer to facilitate proper placement of the ultrasonic transducer prior to imaging. The system elements and various embodiments of the invention are described in detail with reference to the appended drawings.
At the proximal end 106 the introducer 100 has a connector 110. At the distal end 108 there is a distal seal 112 which performs the function of closing the distal end 108 to the passage of fluid. FIG IA illustrates the distal seal as a plug. In another embodiment (not shown) the distal seal is formed from the end of the tubular member 102 without additional material.
At another point along the length of the tubular member 102 a proximal seal 114 is situated.
Within the tubular member 102 and between the distal seal 112 and the proximal seal 114 a volume is defined. This volume is filled with an acoustic coupling medium 116. The purpose of acoustic coupling medium is to allow passage of ultrasonic waves with minimal loss. Air is a very poor coupling medium for ultrasonic imaging. Examples of good ultrasonic coupling media are: pure water, water with certain additives, certain mineral oils, and certain gels.
The tip 306 of the ultrasonic imaging catheter 302 contains an ultrasonic transducer 304 whose purpose is to send out ultrasonic waves and detect the reflections of those waves from non-homogeneous regions of the organ being imaged. The ultrasonic imaging system 200 may rotate the ultrasonic transducer 304 to obtain planar or conical image slices. The ultrasonic imaging system 300 may also move the transducer 304 axially to obtain a 3-D image.
In order for the ultrasonic imaging system 300 to function properly the ultrasonic waves emanating from and returning to the transducer 304 should not be impeded. There is therefore an imaging section 118 of the introducer, corresponding to the axial travel of the transducer 304, where the tip of the catheter 306 should remain immersed in the coupling medium 116 and the tubular member 102 should be transparent to ultrasonic waves. An example of a structural material that is transparent to ultrasonic waves is polyethylene.
In accordance with an embodiment of the invention the tubular member 102 has an outside diameter of approximately 4 mm. The outside diameters of other embodiments fall in the range of 2.5 mm to 8 mm. In accordance with an embodiment of the invention the wall thickness of the tubular member 102 is approximately 0.2 mm. The wall thickness of other embodiments fall in the range of 0.1 mm to 0.5 mm
Turning now to
In accordance with an embodiment of the invention a proximal seal 114 is created by folding the tubular member 102 over on itself. Those skilled in the art will note that this construction is valid with or without the sheath 122. A restraint 120 maintains the seal until the restraint 120 is removed by the user in order to insert an imaging catheter into the catheter.
In accordance with another embodiment of the invention, a cap 124 covers the open proximal end 106 of the introducer. The cap 124 is attached to the connector 110. The cap 124 is removed prior to the insertion of an imaging catheter and prior to the connection of the introducer to an ultrasonic imaging system.
In accordance with an embodiment of the invention a lubricant 126 occupies the space between the outside of the tubular member 102 and the inside of the sheath 122. As the sheath 122 is removed a substantial amount of lubricant 126 remains with the tubular member 102. This lubricant aids in the safe insertion of the tubular member 102 into the patient's urethra.
The sheath 122 may be constructed of a flexible, impermeable material such as polyethylene.
The hydrophilic introducer system 103 also may include a proximal seal 114, a water-based acoustic coupling medium 116, a sheath 122, a distal one-way valve 130, and a distal opening 132.
In another embodiment of the invention the proximal seal 114 also acts as a one-way valve—allowing air from outside to enter as the catheter 302 is being withdrawn.
In another embodiment of the invention there is a proximal one-way valve (not shown) in addition to the proximal seal 114.
Turning now to
During a 3-D imaging session it is important to place the ultrasonic transducer 304 in a suitable position before imaging begins due to mechanical travel limitations and patient discomfort considerations. For example, if a complete scan of the prostate 404 is desired, using an ultrasonic imaging system 300 which withdraws the imaging catheter 302 while imaging, then the transducer 304 should initially be positioned (within the urethra) so the initial 2-D image is on the distal side of, yet close to, the prostate 404, the distal side of the prostate 404 being the side towards the urinary bladder 408.
In accordance with an embodiment of the invention the introducer 100 includes a relatively rigid plug 136 at the distal tip. In other embodiments this rigid structure may assume other configurations, such as a thickened or enlarged section of the tubular member 102. The purpose of the rigid plug 136 is to define the distal tip of the catheter 100 as it is being inserted into the urethra. When the rigid plug 136 reaches the bladder sphincter 406 there will be increased resistance when inserting the introducer 100. This is a signal for the person inserting the introducer 100 to stop as this point closely approximates the ideal starting point for the ultrasonic transducer 304. During imaging the introducer 100 remains stationary relative to the patient while axial movement of the imaging catheter 302 occurs relative to the introducer 100.
It will be evident to a person ordinarily skilled in the art that one or more of the embodiments mentioned above provide the following advantages during transurethral ultrasonic imaging of the genitourinary system of a patient. The introducer may significantly reduce the incidence of cross-contamination between patients since it isolates the ultrasonic imaging catheter from contact with the patient's bodily fluids, and since it is disposable due to its relatively low manufacturing cost. The introducer may serve as an anchoring device, maintaining a fixed relationship to the patient as the ultrasonic imaging catheter is moved axially, thus allowing precise control of the movement of the ultrasonic transducer relative to the patient's organ being imaged. A rigid plug at the tip of the introducer may aid in the proper initial placement of the ultrasonic transducer. The sheath helps maintain cleanliness and sterility of the introducer even after the introducer is installed on the ultrasonic imaging system and up to the point the introducer is inserted into a patient's urethra. The sheath may contain a lubricant to facilitate insertion of the introducer into a patient's urethra. The introducer may have a hydrophilic coating to provide lubricity. A sheath and associated valves may enable convenient wetting of the hydrophilic coating.
While the invention is susceptible to various modifications and alternative forms, specific examples thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the invention is not to be limited to the particular forms or systems or methods disclosed, but to the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the appended claims.
