Devices and methods for measuring anatomic regions

A guidewire insertion tool configured to measure a length of an anatomic region. The tool can include a housing, a light chamber, and a track at least partially extending through the light chamber. The track is adapted to guide a guidewire as it is advanced through the insertion tool. The tool can also include an optical sensor assembly in optical communication with the light chamber. The optical sensor assembly can include one or more light sources, an optical sensor, and a magnifier. The one or more light sources can be adapted to direct light toward a portion of the guidewire within the track, and the optical sensor can be adapted to receive reflected light from the portion of the guidewire within the tract. A processing unit can analyze data from the optical sensor assembly to determine the length of the anatomic region and output the measurement to a display.

BACKGROUND

Field

The present disclosure relates to the use of guidewires or catheters to measure anatomic regions. In some embodiments, techniques and devices described herein may be used to accurately position surgical devices in the body.

Description of the Related Art

During diagnostic and therapeutic procedures, a guidewire or catheter can be inserted into the vasculature and advanced to the organ of interest, usually through a sheath. The site of insertion depends on the modality of use.

A guidewire is often inserted through a hemostatic valve disposed at a proximal end of a sheath and advanced to the organ of interest. The hemostatic valve is a passive mechanical device that facilitates the introduction of the guidewire by opening when the guidewire is inserted through the valve and closing when the guidewire is removed. The hemostatic valve provides a seal around the guidewire to limit the blood loss and leakage of contrast during procedures. Angioplasty balloons, stents, ablation devices, or other devices can be introduced over the guidewire and into the organ, thus allowing the device to travel to the target region and deliver the intended therapy.

Various embodiments are depicted in the accompanying drawings for illustrative purposes, and should in no way be interpreted as limiting the scope of the embodiments. Furthermore, various features of different disclosed embodiments can be combined to form additional embodiments, which are part of this disclosure.

DETAILED DESCRIPTION

During the diagnosis and treatment of vascular lesions, measuring the length of the lesions is essential for certain medical diagnoses and treatments (e.g., to select an appropriately sized balloon or implant to use), as well as for accurate, reproducible placement of diagnostic and therapeutic devices during medical and surgical procedures. Sometimes an area needs to be treated repeatedly during a medical procedure or a device needs to be placed at an identical position at which initial therapy was delivered. During these scenarios, a method of determining or measuring the initial and subsequent position of the device in relation to an anatomic lesion will increase the accuracy of diagnosis and therapy.

To advance a guidewire to a lesion, the guidewire can be introduced through a wire insertion tool, such as the wire insertion tool1illustrated inFIG. 1. The wire insertion tool1includes an elongate tube1athat is connected to a hub1b. The hub1bis used to facilitate introduction of the guidewire into a patient's body. The elongate tube1ais connected to the hub1b, and includes a lumen through which the guidewire is inserted. The wire insertion tool1can be advanced through a guide sheath (not shown), which can include a hemostatic valve. The elongate tube1akeeps the hemostatic valve open to prevent interference with guidewire manipulation. During the insertion of other devices (e.g., to perform an angioplasty procedure, stent implantation, ablation, or otherwise), the wire insertion tool1can be removed, leaving the guidewire in place. Although wire insertion tools1have been designed to facilitate rapid insertion and reinsertion, wire insertion tools1similar to those ofFIG. 1are typically passive mechanical devices with no capabilities to measure dimensions of lesions or other anatomical regions.

Anatomic lesions in arteries or veins can be visualized using angiographic images by injecting radiographic contrast (or in the case of endoscopy or laparoscopy, direct visualization). These images can be used to estimate a length of the lesion based on a size of the catheter. Alternatively, wires and catheters with fixed radiopaque or moving members with radiopaque markers can be used define the length of a lesion. However, there are challenges with measuring anatomic lesion lengths using an imaging modality such as fluoroscopy because of the tortuous nature of vascular structures. Accordingly, there is still a need for devices and methods to accurately measure the length of a lesion to facilitate accurate and reproducible placement of a surgical device at an anatomic region of interest.

Although certain devices and methods have been described herein with respect to measuring the length of a vascular lesion using a guidewire, the devices and methods described herein can be used with other diagnostic and therapeutic procedures (e.g., other transcatheter procedures, biopsies, endoscopic procedures, laparoscopic procedures, etc.) or other devices (e.g., catheters, sheaths, surgical tools, etc.).

Guidewire Insertion Tool

The present disclosure is directed toward methods and devices to measure the length of a lesion or other anatomical feature. In one embodiment, as shown inFIG. 2, such devices and methods are adapted to determine the displacement of a guidewire6(or catheter or other device) relative to a fixed point of a guidewire insertion tool, such as, for example, the guidewire insertion tool10illustrated. The guidewire insertion tool10is compatible with different elongate devices (e.g., guidewire, catheter, or otherwise), such that, depending on the procedure, an operator can advance the elongate device through the guidewire insertion tool10. The guidewire insertion tool10can also be compatible with a guide sheath, such that the elongate device can be advanced through the guidewire insertion tool10and through the guiding sheath (as discussed in greater detail below with respect toFIGS. 6A and 6B, below).

Through fluoroscopic or other methods of visualization, a guidewire6can be advanced toward, to, and/or across a lesion. As the guidewire6traverses the lesion, the distance the guidewire6moves relative to a fixed point in the guidewire insertion tool10, such as an optical sensor assembly40, can be determined by the guidewire insertion tool10. In such manner, the guidewire insertion tool10can include a processor50to determine the length of the lesion and and/or the distance from an insertion point to the beginning or end of the lesion based on the relative movement of the guidewire6. The processor50can output the calculated measurement to the display4. Using such techniques, the operator is able to accurately measure the size of a lesion to accurate select an appropriate treatment device. In some embodiments, the operator is further able to accurately and reproducibly place the surgical device in an anatomic region of interest.

As illustrated inFIGS. 3A and 3B, the guidewire insertion tool10can include a housing3that accommodates and supports an optical sensor assembly40(seeFIG. 2B). The optical sensor assembly40is adapted to measure the distance a guidewire (e.g., the guidewire6ofFIGS. 6A and 6B) moves relative to a fixed point (e.g., a position of an optical sensor44) in the guidewire insertion tool10. During the procedure, at least the housing3of the guidewire insertion tool10(and any required power source) is positioned outside the body.

As shown inFIGS. 3A and 3B, the housing3can include a front portion12, an intermediate portion14, and a rear portion16. The front portion12and the rear portion16can form an exterior of the guidewire insertion tool10. The intermediate portion14can be positioned between the front portion12and the rear portion16and can form a lighting chamber18with the first portion12. The lighting chamber18can span across less than about 50% of a surface of the intermediate portion, less than about 30% of a surface of the intermediate portion, less than about 15% of a surface of the intermediate portion, less than about 10% of a surface of the intermediate portion, such as between about 5% and 20% or between about 10% and about 25% of a surface of the intermediate portion.

The guidewire insertion tool10can include a track20(sometimes referred to as a tract) through which a guidewire6can be advanced (seeFIG. 2B). The track20can keep the guidewire6in focus for detection by the optical sensor assembly40. The track20can extend from an aperture5on the exterior of the housing3, through the lighting chamber18, to a needle2(seeFIGS. 2A and 2B) positioned on the exterior surface of the housing3. The needle2is adapted to interface with a guide sheath (not shown). In some embodiments, the needle2is omitted.

As illustrated inFIG. 2B, a majority of the track20is fully enclosed such that only a portion of the guidewire extending through the light chamber18is visible. The track20can include a proximal section comprising a circumferentially enclosed lumen extending through a proximal portion12aof the front portion12. The track20can include an intermediate section comprising a groove formed in the front portion12and extending through the light chamber. The track can include a distal section comprising a circumferentially enclosed lumen extending through a distal portion12bof the front portion12. The circumferentially enclosed portions of the track20can reduce difficulties associated with manipulating a floppy guidewire. Alternatively, the majority of the portion of the guidewire6extending through the track20can be visible. For example, the track20can be a groove extending across the front portion12. The track20may include one or more narrow guide features to guide the guidewire through the guidewire insertion tool10.

To facilitate manipulation of the floppy guidewire, the aperture5can be funnel-shaped, and can be flush with the housing3(seeFIG. 4A) or project as appendage from the housing (not shown). Any other aperture present along the track20, such as the aperture21at the distal portion12bof the first portion12a, can also be funnel-shaped.

The track20and the needle2can be sized to eliminate frictional interference between the hemostatic valve of the guide sheath and the guidewire6during guidewire manipulation. For example, the clearance between the guidewire6and the track20and/or needle2can be less than about 1 mm or between about 1 mm and about 10 mm, such as between about 1 mm and 5 mm. In some embodiments, the clearance is less than 1 mm. It can be desirable to reduce, minimize, or eliminate guidewire friction because such friction can interfere with the operator's tactile feel and with guidewire advancement. In some embodiments, the guidewire insertion tool10can include a hemostatic one-way valve to prevent the flow of body fluids and other fluids used during surgical procedures into the lighting chamber18.

As shown inFIG. 3B, the optical sensor assembly40can be positioned between the intermediate portion14and the rear portion16. The optical sensor assembly40can include a lens42, an optical sensor44(e.g., a photodetector, photodiode, image sensor, optoelectronic sensor, or otherwise), and a light source46. The optical sensor assembly40can be adapted to detect the movement of the guidewire6as it slides within the track20. A processor (not shown) can be adapted to execute specific instructions to determine the length of the lesion based on the detected guidewire6movement.

If the optical sensor44is an image sensor, the processing unit50can be adapted to execute specific instructions to analyze pixel shifts between successive images (e.g., by following a surface pattern on the guidewire6) collected by the optical sensor44. The optical sensor44can capture a number of successive images per second (e.g., about 100 images/sec, about 500 images per/sec, about 1000 images per/sec, or more), each image having an array of monochromatic or chromatic pixels (e.g., 16×16, 18×18, or otherwise). As an example, the number of successive images can include a first image and a second image. The processing unit50can be adapted to execute specific instruction to calculate a shift in one or more pixels between the first and second images to determine the amount of guidewire movement. By analyzing pixel shifts (or changes in detected light that is emitted from the light source46, reflected off of and/or scattered by the guidewire6, and detected by the optical sensor44), the processor is able to measure the distance the guidewire has traveled as the guidewire6moves relative to the optical sensor44.

If the optical sensor44is a photodetector, the processing unit50can be adapted to execute specific instructions to analyze the changes in the light reflected from a surface of the guidewire6collected by the optical sensor44to measure the distance that the guidewire has traveled as the guidewire6moves relative to the optical sensor44.

The particular process executed by the processor can be calibrated to measure the guidewire6movement in standard measurements, for example, in imperial or metric units of length and display the measurement on the electronic display4(seeFIG. 3A). A power source (e.g., a battery, capacitor, etc.) (not shown) provides energy to one or more of the light source, processor, detector, or display.

The distance between the track20and the optical sensor44can be determined based upon the focal length of the lens42. The focal length can be between about 1 mm and about 10 mm, for example, between about 1 mm and 5 mm, such as about 3 mm. For example, the spacing between the track20and the optical sensor44can be selected so the guidewire6is positioned at or near the focal length of the lens42when inserted into the guidewire insertion tool10. By positioning the guidewire at the focal length (or focal point) of the lens42, the optical sensor44is able to detect and measure movement of the guidewire6within the track20. In some embodiments, the track20is a path or lumen in which a guidewire may be manipulated, e.g., advanced into the patient's body.

The intermediate portion14can include a window22that provides optical access to visualize the track20, such that the light source46can illuminate the light chamber18and the optical sensor44can detect and monitor a surface of the moving guidewire6. The presence of the light chamber18can concentrate the light source46for better visualization of the guidewire6. The walls surrounding the light chamber18can be at least one of opaque, dark-colored (e.g., black), non-reflective, matte-finished, patterned, and/or textured to optimize visualization of the guidewire6. For example, a striped wall pattern (e.g., white and black) or textured stripes can provide greater contrast between the guidewire6and the light chamber18and enhance visibility and imaging of the guidewire for image processing. The intermediate portion14can include a support structure26surrounding the window22to support a lens42.

One or more light sources46(e.g., light emitting diode (LED), laser diode, or infrared light source) can be used as an optical source for the optical sensor assembly40. The light sources46can include a direct light source or a diffuse light source. When measuring movement of a shiny elongate structure extending through the guidewire insertion tool10, infrared light can be particularly helpful. In some embodiments, the guidewire insertion tool10can include a dimmer to control the intensity and/or brightness of the light emitted from the light source46. The dimmer may be controlled by the processor and can be adjusted to select an optimal light exposure to visualize the guidewire6.

As shown inFIG. 3B, the light source46and the optical sensor44can be positioned on opposite sides of the lighting chamber18, e.g., the light source46and the optical sensor44can be spaced apart across a transverse plane of the guidewire insertion tool10or spaced apart across a longitudinal plane of the guidewire insertion tool10. However, the optical sensor44and the light source46need not be disposed diametrically across from each other (e.g., at opposite sides of the lighting chamber18). For example, the optical sensor44and the light source46can be offset from in multiple directions. Depending on the angle of the light emitted and the position of the optical sensor44, the guidewire insertion tool10may include a prism, mirror or other technology that can directionally divert light towards the optical sensor44.

If the guidewire insertion tool10includes more than one light source46, the light sources46can provide light from different angles. If the light source46is a dual laser source, the light source46can cause a dark field effect to eliminate the interference from the light scatter caused by any shiny surface. If the light source46provides undiffused light and the guidewire6is shiny, the details of the guidewire6can be distorted as the guidewire6moves through the guidewire insertion tool10. As described above, a striped wall pattern (e.g., white and black) or textured stripes can provide greater contrast between the guidewire6and the light chamber18and enhance visibility. An optical diffuser can eliminate the fixed pattern created by the light source to improve the performance of the optical sensor when tracking movement of the guidewire6.

The lens42or separate transparent structure can magnify the patterns on the guidewire6and can be disposed between the track20and the optical sensor44. Such magnification facilitates the monitoring of the guidewire6by enhancing mirror patterns inherent on the surface of the guidewire6.

As shown inFIG. 3A, the guidewire insertion tool10can include an alphanumeric display4that can show the distance traversed by the guidewire6. For example, the guidewire insertion tool10the display4can be visible through openings28,30in the front portion12and the intermediate portion14, respectively). The guidewire insertion tool10can include a button9(or other actuator) that can zero the counter and display4.

In some embodiments, the guidewire insertion tool10can include a disposable component and a reusable component. The disposable component can include one or more elements that contact the guidewire and/or operator during use. The reusable component can include light generation, detection, processing and power elements. For example, in one embodiment, the disposable component includes one or more of a housing, aperture, track, light chamber, and/or needle. The reusable component can include one or more of the processor, optical sensor assembly, and/or power source. The reusable component is adapted to attach to the disposable component and detect and measure the distance traversed by a guidewire through the track of the disposable component.

In some embodiments, the housing3may include more or less components than the front portion12, intermediate portion14, and the rear portion16. For example, the housing3may not include the intermediate portion14. Rather the optical sensor assembly40may include a portion of the light chamber18, the support structure26, and/or the window22. As another example, the housing3may include additional housing components. The intermediate portion14, the rear portion, the optical sensor assembly40, processor50, and/or power source can form the reusable component. The front portion12and an additional housing portion (not shown) can form a disposable component including the light chamber18and the track20.

Although the housing3of the guidewire insertion tool10is illustrated as being a rectangular prism inFIG. 2with the longer side extending in a transverse direction of the guidewire insertion tool10, the housing3can take on other general shapes as shown inFIGS. 5A-5D, e.g., a rectangular prism with the longer side extending in a longitudinal direction of the guidewire insertion tool10, a cylinder (seeFIG. 5B), a cube (seeFIG. 5C), a T-shape (FIG. 5D), a sphere, or otherwise.

Method of Use

FIGS. 6A and 6Billustrate the guidewire insertion tool10being used during an angioplasty procedure of the right coronary artery. First, a guide sheath17can be positioned in the body (e.g., through a femoral artery) with a hemostatic valve enabled sheath adapter19resting on an outer surface of the skin S. A guiding catheter15can be inserted into the sheath17through the hemostatic valve enabled sheath adapter19and advanced to the coronary artery8. The needle2of the guidewire insertion tool10can be introduced through the hemostatic valve enabled adapter23of the guiding catheter15to prevent frictional interference between the guidewire6and the hemostatic valve of the guide sheath17. Such frictional interference may impede movement of the guidewire6. The guidewire6is inserted into the guidewire insertion tool10at the aperture5. The guidewire6is advanced into the guidewire insertion tool10such that it passes through the track20(not shown) and exits the guidewire insertion tool via the needle2. Since the needle2is positioned within a hemostatic valve enable adapter23of the guiding catheter15, the guidewire6is within the patient's vasculature as it exits the needle2. The guidewire6is advanced to a proximal end of an angiographically visible lesion13(seeFIG. 6A). Once the tip of the guidewire6is positioned at a first location13a(e.g., positioned at the proximal end of the vascular lesion13), the button9can be actuated to zero the counter and display4. As the guidewire6is manually advanced and crosses the lesion13under fluoroscopic visualization, the distance traveled by the tip of the guidewire6inside the vessel8can be measured by the guidewire insertion tool10positioned outside the body. When the tip of the guidewire6reaches a second position13b(e.g., the distal end of the lesion13), the distance traversed by the guidewire6from the time of zeroing denotes the length of the lesion13(seeFIG. 6B). Thereafter, the guidewire insertion tool10can be removed over the guidewire6, and a catheter or other device can be advanced over the guidewire6and the diagnostic and/or therapeutic procedure can be performed. When the procedure is complete, the guidewire6, the guiding catheter15, and the guide sheath can be removed.

If a balloon or implantable device is being positioned in the vessel, the length of the lesion can help determine an appropriately sized device. For example, the user may select a balloon or implantable device (e.g., stent, etc.) having the same or greater length of the lesion. The lesion length provided by this method is more accurate than visual estimation (e.g., using fluoroscopic or other visualization techniques), which can be difficult in view of the curves and other myriad of anatomic variations in the vasculature.

The guidewire insertion tool10can also be used to determine a length or distance from an access point to the lesion using the method described above. After the insertion length has been determined, the tip of a different device can be advanced over the distance indicated by the electronic display4to enable the operator to reproducibly position the different device or reinsert the same guidewire6to the same location. For example, the user can reset the counter by pressing the reset button9as soon as the guidewire is inserted into the patient's body (e.g., at the hemostatic valve) or at another fixed location. As the guidewire is advanced to the lesion (or other anatomical target), the guidewire insertion tool10measures the length of guidewire passing across and through the track20. When the guidewire reaches the anatomical target, the display4displays the distance from the point at which the reset button9was pressed to the anatomical target.

As another example, if the insertion length has been determined based on previously taken images (e.g., CT scan, x-rays, etc.), the guidewire insertion tool10can be used to determine whether the guidewire6has been advanced the pre-determined length.

As mentioned above, the processing unit50can be configured with specific instructions to analyze data collected by the optical sensor assembly40to convert changes in successive data collections to a length measurement. One embodiment of such process70is illustrated in the flow chart ofFIG. 7. The process70begins when the operator zeros the counter, for example, by actuating the button9(block72). When the process70begins, the light source46and the optical sensor assembly46can be activated and the counter and display can be reset (block74). As the guidewire6is advanced through the guidewire insertion tool10, the optical sensor assembly40can collect a plurality of data collections, e.g., a first image (block76) and a next image (block78). The processing unit50can determine the amount and direction of guidewire movement by analyzing the changes between the first and next images, e.g., by analyzing pixel shifts or changes in reflected light, to calculate a length traversed by the guidewire6(block80). If the processing unit50determines the guidewire has been advanced, the counter can be increased. If the processing unit50determines the guidewire has been retracted, the counter can be decreased. The amount of movement can be output to the display4as a unit of length (block82). If the process is reset (e.g., by actuation of the button9) (block84), the counter and display can be reinitialized (block74). If the process is not reset, the optical sensor assembly40can collect the next image (block78). This process can be continuous until the insertion tool is turned off.

Terminology

Depending on the embodiment, certain acts, events, or functions of any of the processes or algorithms described herein can be performed in a different sequence, can be added, merged, or left out altogether (e.g., not all described operations or events are necessary for the practice of the algorithm). Moreover, in certain embodiments, operations or events can be performed concurrently.

The terms “approximately,” “about,” and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” and “substantially” may refer to an amount that is within less than 10% of the stated amount, as the context may dictate.

The term “generally” as used herein represents a value, amount, or characteristic that predominantly includes or tends toward a particular value, amount, or characteristic. As an example, in certain embodiments, as the context may dictate, the term “generally rectangular” can refer to a shape that departs from the 90 degree angles of the rectangle by less than or equal to 20 degrees. As another example, in certain embodiments, as the context may indicate, the term “generally perpendicular” can refer to an angle that departs from exactly perpendicular by less than or equal to 20 degrees.

Although certain embodiments and examples have been described herein, it will be understood by those skilled in the art that many aspects of the guidewire insertion tool shown and described in the present disclosure may be differently combined and/or modified to form still further embodiments or acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure. A wide variety of designs and approaches are possible. No feature, structure, or step disclosed herein is essential or indispensable.

Moreover, while illustrative embodiments have been described herein, the scope of any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations and/or alterations as would be appreciated by those in the art based on the present disclosure. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to the examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive. Further, the actions of the disclosed processes and methods may be modified in any manner, including by reordering actions and/or inserting additional actions and/or deleting actions. It is intended, therefore, that the specification and examples be considered as illustrative only, with a true scope and spirit being indicated by the claims and their full scope of equivalents.

Any methods disclosed herein need not be performed in the order recited. The methods disclosed herein include certain actions taken by a practitioner; however, they can also include any third-party instruction of those actions, either expressly or by implication. For example, actions such as “advancing a guidewire to a lesion” include “instructing advancement of a guidewire to a lesion.”