Patent Application
20140031677
The invention relates generally to an apparatus and method for aiding needle biopsies, and more particularly, to an optical coherence tomography (“OCT”) imaging and tissue sampling system and method.
Early diagnosis and a proper stage determination are key factors that contribute to cancer cure success. A cancer's stage is based on the primary tumor's size and whether it has spread to other areas of the body. If cancer cells are present only in the layer of cells where they developed and have not spread, the stage is in situ. If cancer cells have penetrated the original layer of tissue, the cancer is invasive. When a cancer-suspect mass is identified with radiological imaging, a percutaneous biopsy (e.g., inserting a needle into the patient to collect a tissue sample) is usually performed to further investigate that mass, determine the stage, and determine the most effective therapy option.
Percutaneous biopsy has become established as a safe, effective procedure for cancer diagnosis. Successful percutaneous needle biopsy has been applied in most organ systems with excellent results and few complications. The key to these procedures has been the use of imaging guidance, which allows for the safe passage of a needle into an organ or mass, to obtain tissue for cytologic or histologic examinations. Image-guided biopsy is less invasive than open exploration to obtain these same tissues. Because of the lower morbidity and mortality of the minimally-invasive procedures, image-guided biopsy can be applied to patients who are too ill to undergo surgery or who wish to avoid convalescence from large diagnostic laparotomy procedures. In most settings percutaneous or transcutaneous biopsy is the first approach to diagnosis.
Biopsy is the best current method for confirming the presence of cancer. Core biopsy is the preferred method of tissue acquisition for obtaining adequate material cancer biomarkers analysis. Unfortunately, the difficulty in sampling enough biological material and heterogeneity of tissue, especially in patients that had surgery of radiotherapy, can cause biopsy sensitivity/specificity to vary within a large range (e.g., about 70% to about 95%). If biopsy results are negative, the clinician is put in a difficult situation because the clinician has to decide how to manage the patient when contradictory results from investigations are obtained. Therefore, any measure to improve biopsy success adequate for biomarker analysis would be considered highly significant.
What is needed is instrumentation and an approach for aiding transcutaneous and endoscopic biopsies with the goal of increasing the success rate of biopsies. The approach is based on the use of optical coherence tomography (“OCT”), which is a high-resolution imaging technique that can be used to assess tissue cellularity at the tip of a biopsy needle. OCT has proven its capability to image tissue morphology at the micron scale, and thus has enabled the diagnosis of cancer disease in the early stage, at the epithelial level. However, the use of OCT for imaging interstitial tissue is somewhat limited due to the lack of minimally invasive probes that can be deployed alone, or by means of biopsy needles, to image tissue morphology in various organs, for example, lungs, breast, pancreas, liver or kidney, where a natural lumen does not exist or cannot be used to image deeper within the organ. OCT applicability and translation to clinical use, especially for imaging interstitial tissue, has been limited by the lack of adequate probes that can be deployed safely without significantly disrupting tissue morphology and inducing severe bleeding, while providing high-quality images.
Embodiments of the invention relate to apparatuses and methods for differentiating tissue types using OCT imaging. The apparatuses and methods can aid biopsies performed through a long needle, usually computed tomography scan (“CT Scan”) or ultrasound guided to the biopsy site, or biopsies through a regular short biopsy needle. A hand-held OCT probe and scanning engine can be used to perform tissue sampling through a biopsy needle. For longer biopsy needles, the OCT probe can be controlled by a scanning engine placed close to the proximal end of the needle. A tissue differentiation algorithm can be implemented via software on a processor to differentiate between different types of tissue. This tissue differentiation algorithm can differentiate between various tissue types: adipose (e.g, body fat), fibrous (e.g., connective tissue), cancer, scar, or necrotic tissue, etc.
In one aspect, the invention features a method of imaging and sampling a tissue. The method includes inserting a catheter probe into a biopsy needle attachable to a hand-held scanning and sampling device and maneuvering the biopsy needle to an investigation site. In some embodiments, the biopsy needle is attachable to a tabletop scanning and sampling device. The method also includes capturing a three-dimensional image of the tissue at the investigation site.
In another aspect, the invention features a hand-held optical coherence tomography imaging and tissue sampling system. The system includes a hand-held unit including a handle and an elongated member. The system also includes a biopsy needle coupled to a distal end of the elongated member. An electromechanical device is coupled to a proximal end of the elongated member. The electromechanical device is configured to rotate and pull an optical coherence tomography probe within the biopsy needle so that a three-dimensional helical or axial scan of tissue is captured processing unit.
In another aspect, the invention features n optical coherence tomography probe The probe includes a single-mode optical fiber. A spacer (e.g., a coreless fiber) is coupled (e.g., fused) to the single-mode fiber and an optical element (e.g., a 45 deg polished ball lens) is coupled to the spacer. The optical element includes a gold coating on a surface of the optical element. In some embodiments the gold coating is reflective. The gold coating can be on a polished surface of the optical element.
The method can also include removing the catheter probe from the biopsy needle. An aspirate can be performed at the investigation site. The aspirate can be performed in situ.
In some embodiments, capturing the three-dimensional image is performed in situ. The three-dimensional image can be captured at a tip region of the biopsy needle. The three-dimensional image can include micron scale images of tissue morphology at the investigation site. In some embodiments capturing the three-dimensional image includes rotating and pulling the catheter probe within the biopsy needle to generate a three-dimensional helical or axial scan of the tissue at the investigation site.
A reflectivity profile or texture of the three-dimensional image, or both can be analyzed to determine a nature of the tissue and the investigation site. In some embodiments identifying, in real time, the nature of the tissue at the investigation site can be identified in real time. The nature of the tissue at the investigation site can be displayed to a user while maneuvering the biopsy needle. In some embodiments a sample of the tissue at the investigation site can be obtained.
In some embodiments, the catheter probe can be an optical coherence tomography probe. The optical coherence tomography probe can include an optical fiber and a protective transparent tube. The optical fiber can be disposed within the protective transparent tube. The protective transparent tube can include a nitinol tube with a polytetrafluoroethylene distal end. In some embodiments the protective transparent tube includes polytetrafluoroethylene. In some embodiments, the protective transparent tube is made solely from polytetrafluoroethylene.
The biopsy needle can be retracted to expose the catheter probe. The biopsy needle can be passed through an instrument channel of an endoscope. The biopsy needle can be about 5 feet in length. In some embodiments the biopsy needle can be about 6 feet in length. The biopsy needle can be a 19 gauge or a 22 gauge needle. Those of skill in the art recognize that other lengths can gauges of biopsy needles can be used based the specific application of the method and system.
In some embodiments, the processing unit is configured to capture and analyze the three-dimensional helical or axial scan of tissue. The processing unit can be configured to differentiate between normal tissue, scar tissue, necrotic tissue and tumor tissue.
In some embodiments, the probe also includes a protective transparent tube surrounding a segment of the optical coherence tomography probe.
A proximal end of the spacer (e.g. a coreless fiber) can be fused to an end of the single-mode fiber. The optical element can include one of a ball lens or a gradient-index fiber. The optical element can be fused to a distal end of the spacer. In some embodiments the ball lens is a 45 degree polished ball lens. The gold coating can be on a polished surface of the 45 degree polished ball lens.
Other aspects and advantages of the invention will become apparent from the following drawings and description, all of which illustrate principles of the invention, by way of example only.
The advantages of the invention described above, together with further advantages, may be better understood by referring to the following description taken in conjunction with the accompanying drawings, in which like reference characters refer to the same elements throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.
It should be understood that when an element is referred to as being “on” or “connected” or “coupled” to another element, it can be directly on or above, or connected or coupled to, the other element or intervening elements can be present. In contrast, when an element is referred to as being “directly on” or “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). When an element is referred to herein as being “over” another element, it can be over or under the other element, and either directly coupled to the other element, or intervening elements may be present, or the elements may be spaced apart by a void or gap.
Embodiments of the present invention relate to the development of a high-resolution optical imaging probe that can be deployed within organs of the body through a minimally-invasive biopsy needle or directly through the instrument channel of an endoscope and which can be used to differentiate between normal, scar, necrotic, and tumor tissue. It is well known, that tissue differentiation is a very challenging problem, especially for deeply located organs, for example, lungs, liver, pancreas, etc. While traditional radiological imaging modalities allow for high depth imaging, their resolution is limited to hundreds of microns, which is not sufficient for tissue differentiation. Recently, optical imaging techniques, such as OCT, have proven that imaging of tissue morphology at the micron scale is possible, which enables differentiation between normal and abnormal tissue. Unfortunately, OCT penetration depth is limited to several millimeters. To image tissue located at higher depths (e.g., deeper in the body), minimally invasive OCT probes have been developed. However, their relatively large size (over 1 mm in diameter), contamination by body fluids, and limited imaging performance have been the main obstacles in expanding OCT use for imaging interstitial tissue. The development of a sub-millimeter fiber optic OCT probe that can reach any organ within the body and provide micron scale OCT images is needed. It can be encapsulated within a hypodermic tube so that the imaging optics does not get contaminated by body fluids.
OCT has proven its capability to image tissue morphology at the micron scale, and thus has enabled the diagnosis of cancer diseases in their early stage, at the epithelial level, as well as various cardio diseases. However, the use of OCT for imaging of interstitial tissue is somewhat limited due to the lack of minimally invasive probes that can be deployed alone, or by means of biopsy needles to image tissue morphology in various organs, where a natural lumen does not exist or cannot be used to image deeper within the organ. OCT applicability and translation to clinical use, especially for imaging interstitial tissue, has been limited by the lack of adequate probes that can be deployed safely without significantly disrupting tissue morphology, inducing bleeding, while providing high-quality images. Currently, there are no reports of high-resolution imaging OCT probes that can be deployed through fine gauge biopsy needles (e.g., 22 gauge, 19 gauge, or smaller), with a length of several inches to several feet. Thus, imaging of less accessible organs, such as pancreas, liver, or kidney has not yet been performed with such probes. A benefit of the proposed probe and imaging approach is that it can be used in correlation with the actual biopsy procedures, without adding any complications. For example, the imaging probe can be sent through the biopsy needle and used to examine tissue composition before an aspirate will be made. The biopsy needle, with the imaging probe inside it, can be moved into the organ until adequate representation of the investigated site can be obtained. Then the imaging probe can be removed and an aspirate, or biopsy suction, can be performed from the imaging location. Thus, this new biopsy-guidance approach has the potential to significantly improve the outcome of the biopsy procedures.
An approach for increasing biopsy success rate includes the use of a hand-held system composed of a three-dimensional (“3D”) scanning engine and a fiber optic-based catheter (e.g., an OCT probe) that can be inserted in regular biopsy needles and produce 3D images of tissue morphology at the needle tip. A biopsy needle, transcutaneously inserted in the body with an imaging probe inside, can be moved into an organ, for example, lungs, breast, pancreas, liver or kidney, until adequate representation of the investigated site is obtained. The imaging probe can be removed and an aspirate or biopsy suction can be performed from the imaging location. This biopsy-guidance approach has the potential to significantly improve the outcome of biopsy procedures.
Embodiments of the invention include a minimally invasive OCT probe that can be deployed through a long (e.g., about 5 to 6 feet) biopsy needle, 22 gauge or smaller, which is usually deployed into the body through the instrument channel of an endoscope and then inserted through the organ wall (eg. stomach, colon, vagina) into a close by organ of interest. The probe can provide micron-scale images of tissue morphology, is sterilizable, and the imaging optics do not require any additional protection to avoid contamination with blood or body fluids.
Embodiments also include a method, probe and system that allows for imaging tissue morphology, at the micron scale, through a biopsy needle. Applications of the OCT probe include imaging the morphology of the organs that are only accessible through a biopsy needle, transcutaneously, or combined endoscopic and trans-organ sapling. Thus, the probe can be used to assist and guide the biopsy process by providing high resolution images of the tissue at the biopsy site. This can benefit the investigation of the highly heterogeneous tissues, for which high rates of non-diagnostic biopsies occur. This is the case for breast, pancreas, liver, kidney or lung biopsies, and especially in patients with cancer recurrence, where surgical and/or radiation therapy scars and necrosis are present. Embodiments described herein can employ OCT and/or optical coherence microscopy (“OCM”) techniques.
Other embodiments include an optical design and configuration for a combined GRIN and microlens-based probe or a microlens alone with diffraction-limited imaging performance at different adjustable imaging depths. In addition, fusion of the optical elements of the OCT probe can ensure stability, ease of manufacturing, and mechanical robustness. Encapsulation of the OCT probe within a flexible tube can allow for imaging through long biopsy needles, accurate transmission of the scanning motion (axial or rotary), and chemical sterilization. The OCT probe can be placed at the biopsy site through the long biopsy needle (e.g., a 19 Gauge, Model M00550040, Boston Scientific biopsy needle, or similar).
The hand-held OCT scanning engine 100 can image and sample tissue within the human body or an animal. The hand-held unit includes a handle 112 and an elongated member 116 having a proximal end 117 and a distal end 118. A biopsy needle (not shown) can be coupled to the holder assembly 103. The holder assembly 103, at the distal end 118 of the elongated member 116, can be used to couple a protective sheath 102, or directly to a biopsy needle. The catheter probe 101 can be passed through the holder assembly 103. The biopsy needle can contain the catheter probe 101 inside. An electromechanical device 119 that spins and translates the OCT catheter probe 101 can be coupled to the proximal end 117 of the elongated member 116. The electromechanical device 119 can include, for example, the belt 104, the FORJ 105, the FORJ body holder 106, the motor 107, the electrical connector 108, the fiber connector 109, and the motorized stage 110. The electromechanical device 119 can be configured to rotate, push and pull the catheter probe 101, e.g., an OCT or OCM probe, within the biopsy needle (not shown) so that a 3D helical or axial scan of the tissue can be captured at a processing unit (not shown).
As described above, the catheter probe 101 can be encapsulated or surrounded by a protective sheath 102. In this embodiment, the catheter probe 101 is disposed within an optically transparent protective sheath 102, which can be coupled to the holder assembly 103. The catheter probe 101, 1 can be coupled to the FORJ 105 by a fiber connector 2.
As described above, the hand-held OCT scanning engine can be configured with push and pull-back capabilities as well as rotational capabilities. That is, the hand-held OCT scanning engine can be configured to push, pull and/or rotate the probe 101. To provide the push and pull-back capabilities, the FORJ body 106 is coupled to the motorized stage 110. To provide the rotational capabilities, a motor 107 transmits the rotary motion through the FORJ 105 to the fiber connector 2 via a shaft 4 and pulley 6. The fiber connector 2 is disposed within a body 3 and rests on ball bearings 5. A pair of fiber pigtailed collimator 8 can be used for coupling a radiation beam from a stationary fiber optic 113 attached to the connector 109 to catheter probe 101, which is attached to the mobile part of the FORJ 105, specifically to connector 2.
The push, pull-back and rotational capabilities allow the hand-held OCT scanning engine 100 to generate helical tissue scans. In this manner, the scanning engine can scan a larger volume of tissue and increase the probability of detecting areas of vital tumor tissue. For example, considering an average imaging depth of 1.5 mm and a pull-back of 5 mm to 10 mm distance, a cylindrical volume of about 3 mm×5 mm to 20 mm can be investigated. This surpasses the capabilities of any existing biopsy approach. For example, in one embodiment the hand-held OCT scanning engine is configured to with an axial imaging resolution of 6 μm, a lateral imaging resolution of 10 μm, an imaging speed of 50 fps, an imaging depth of up to 2 mm, and a pull-back scanning range of 20 mm.
The fiberoptic part of the OCT catheter 101 can be encapsulated within a nitinol (i.e., nickel titanium) tube 102, with the distal end 115 open to expose the curved surface of a ball lens (not shown), or within a torque coil. In either case, the proximal end is attached to a fiber optic connector.
The protective sheath 102 can be a nitinol (i.e., nickel titanium) tube with an optically transparent distal end 115 made of polytetrafluorethylene (“PTFE”) (e.g., Teflon®). The protective sheath 102 can be made entirely of PTFE or other optically transparent material and can be dimensioned to fit within the inner diameter of a biopsy needle. The protective sheath 102 (e.g., a protective transparent tube) can be made from a combination of optically transparent materials, which are known to those of skill in the art. In some embodiments, the protective sheath 102 is flexible to allow for imaging through long biopsy needles, accurate transmission of the scanning motion, and chemical sterilization.
The protective sheath 102 can be coupled to a holder assembly 103, which is in turn coupled to the handle 112 for easy manipulation and control by a user. Referring to
The FORJ 105, coupled to an FORJ body holder 106, can include a pair of two collimators, e.g., fiber pigtailed collimator 8, to narrow a propagation of waves traveling through the device. The collimators can be, for example, a curved mirror or lens. A micro-motor 107 can be provided to rotate the catheter probe 101, so a rotary scan can be obtained. The FORJ 105 has a stator 7 with a pigtailed collimator 8. This part of the FORJ 105 is attached to the hand-held probe case 106. The FORJ rotor includes a pulley 6 attached to a sleeve 4 that holds a short segment of fiber 9 terminated with a micro connector 2 at one end and a collimator 8 at the other end. This assembly rotates inside of a holder 3 attached to the probe body 106. Ball bearings are used to hold the sleeve 4 inside of the holder 3 while allowing for rotational motion. The entire assembly 106 can be attached to a translation stage 110 to provide a translational motion of the catheter 101, which together with the rotary motion generate a 3D helical scan. The speed of the micro-motor 107 can be adjusted by a controller while an optocoupler can be used to read the position of the FORJ 105 shaft and initialize a scanning engine to always start at the same angle and sync the rotary scan with a computer data display rate. The same approach can be taken with the translational stage 110, such that a user can position the catheter probe 101 at any desired location within the tissue and search for specific features of a sample at an investigation site. The motorized stage 110 can be used to pull back the catheter probe 101 while the micro-motor 107, facilitated by belt 104 and FORJ 105, rotates the catheter probe 101 to generate a 3D helical scan. The speed of the motorized stage 110 can also be adjusted by the controller, which allows a user to modify the density of the helical scan. An electrical switch 111 can be used to start/stop the rotation of the motor 107. Electrical wires, 114 connect the switch 111 and the motor 107 to a controller. A fiber optic connector 109 can be used to optically connect the hand-held probe to the OCT engine through a single-mode fiber optic patchcord.
The hand-held OCT scanning engine 100 can be used to image and sample a tissue. The method includes inserting the catheter probe 101 into a biopsy needle. The biopsy needle can be attached to the hand-held scanning and sampling device, for example, the hand-held OCT scanning engine 100. A user can maneuver the biopsy needle to an investigation site. The investigation site can be any tissue or organ in an animal or human, for example, the lungs, liver, or kidneys. The catheter probe 101, for example an OCT or OCM probe, can capture a 3D helical or axial image of the tissue at the investigation site. The 3D image capture can be performed in situ. Instead of, or in addition to, capturing a 3D image of the tissue, a sample of the tissue can be obtained at the investigation site. Obtaining a sample of the tissue can allow the user to perform further tests on the tissue.
To capture the 3D image, the catheter probe 101, which is within the biopsy needle, can be rotated, pushed and/or pulled to generate a 3D helical or axial scan of the tissue at the investigation site. The electromechanical device 119 can rotate and pull the catheter probe from the distal end 118 to the proximal end 117 of the elongated member 116. The 3D image can include micron scale images of tissue morphology at the investigation site. The micron scale resolution images (e.g., 6 to 10 microns obtained over a 3D volume with a 3 mm diameter and a length of 5 to 20 mm allow for tissue differentiation, unlike the traditional radiological imaging modalities which do not have sufficient resolution (e.g., hundreds of microns) for tissue differentiation.
A nitinol tube 210 can be used to encapsulate or surround the catheter probe 215 and a fiber optic connector 220 can be attached to the proximal end 225 of the tube 210. A distal end 230 of the catheter probe 215 (e.g., the catheter probe 101 of
The tube 210 can be a supereleastic hypodermic tube of medical grade. The fiber optic connector 220 can be a Diamond E 2000 fiber optic connector which can be used to connect the catheter probe 215 to an OCT system, such as the OCT system of
In some embodiments, the biopsy needle 305 can be passed through an instrument channel of an endoscope (not shown). An endoscope can be used to examine the interior of a hollow organ or cavity and can be inserted directly into an organ. Therefore, when the biopsy needle 305 is used in combination with an endoscope, a 3D image of the inside of an organ or cavity can be obtained.
The biopsy needle 305 can be long, for example, the biopsy needle 305 can be about 5 feet in length. The biopsy needle 305 can be any length suitable for the site to be investigated in the patient, for example, the biopsy needle 305 can be about 3 feet, 4 feet, 6 feet, 7 feet, or any increment in between. In some embodiments, the biopsy needle can be short, for example about 6 inches in length. The biopsy needle 305 can be a 19 or 22 gauge needle or any other size that is sufficient to house the catheter probe 340.
As discussed above with respect to
As shown in
The ZEMAX optical design 400 models the propagation of rays (e.g., beam) 420 through the spacer 410, ball lens 415 and protective transparent tube 425. The protective transparent tube 425 (orthogonal views) can surround the OCT probe to protect it from being contaminated by body fluids. However, this tube inserts some aberrations of the outgoing beam (cylindrical lens effect), which causes the rays 420 to diverge into a focal point at a certain depth in the tissue 430. In some embodiments, the propagation of rays 420 through an optical element (e.g., corrective lens) can be implemented to correct this effect.
The main focusing power in this case comes from the GRIN fiber 520, which has its length calculated to focus the beam 515 into a very small spot, for example at about 750 microns depth in tissue. However, since the beam 515 needs to be scanned to create an image, it has to be deflected laterally. Therefore, a 45 deg polished ball lens 525 is attached to the GRIN fiber to deflect the beam laterally. Alternatively, a coreless fiber segment 530 can be polished at 90 degrees; however, it may become more susceptible to breakage due to sharp edges. Although the lens has a high optical power in air, when in contact with tissue or index matching fluid its power is dramatically reduced. Therefore, in some embodiments, the design is to create most of the focusing power by the GRIN fiber 520. The ball lens 525 can be made of coreless fiber to avoid inducing of astigmatism. In the case of a GRIN fiber used in place of the ball lens 525, the astigmatism can be sever and degrade image quality. The focusing parameters can be adjusted by modifying the length of the GRIN fiber 520. Table 2 shows the lengths of the GRIN fiber 520, the coreless segment 530, and the focal depth 535. The polished surface of the lens or coreless segment can be gold covered to deflect the beam laterally. Without reflective coating, the beam will refract through this surface and go forward within the tissue.
Alternatively, if the probe can be inserted in a protective sheath without immersion fluid, the GRIN segment can be removed and the ball lens can be designed to create the optical power of the catheter. In this case, the polished surface can be coated with an anti-reflection coating to reduce back reflections, while the polished surface can be gold coating protected. If not gold covered, it instead can be polished at exactly 45 deg to meet the total internal reflection condition and thus to have the beam deflected laterally.
As shown in
The subserosa (SS) is a layer of tissue between the muscularis and serosa, which sometimes is admixed with some fat (F). The submucosal (SM) layer was measured to be very thin in histology and not very well resolved in some of the OCT images. However, most of tissue boundaries remained clear and distinct at all depths, rotations, and time points. A highly scattered layer is observed on the top of the OCT image (
A catheter scanning engine 1010, for example, the hand-held OCT scanning engine 100 of
The light coming back from the sample and from the optical delay line 1050 is combined together in a fiberoptic beam splitting/combining element to create interference fringes, which are sent to a detection scheme 1047 (balanced detector) through the second and third ports 1008, 1009 of the circulator 1006. To take benefit of the balanced detector scheme, which helps to reduce the influence of the light source intensity noise, a small fraction of the light coming from the optical delay line 1050 is combined with that coming from third port 1009 of the circulator 1006 by a 50/50 coupler 1051 and then sent to the inputs of the balanced detector 1047. After converting the optical signal into an electric signal a digtizer 1045 is used to convert the analog signal into a digital one. This signal can be sent to a real-time FPGA processing board 1043, and then to a frame grabber residing in the computer 1040, or directly to the frame grabber and perform the real-time processing of the signal into a General Purpose-Graphic Processing Unit (GP-GPU) residing in the computer 1040.
The OCT or OCM system 1000 also includes a power supply 1030 that provides power to the system 1000 and controllers 1035, which can control, for example, the micro-motor 107 of
In some embodiments, algorithms for tissue differentiation can be implemented on a parallel processing architecture, such as a General Purpose-Graphic Processing Unit (GP-GPU) that will also reside in the computer 1040. The GP-GPU can enable real-time tissue differentiation and provide clinician feedback to aid diagnosis. Thus, the GP-GPU can be used to indentify, in real time, the nature of the tissue at the investigation site and display to the user the nature of the tissue at the investigation site while maneuvering the biopsy needle. The GP-GPU can either analyze a reflectivity profile or texture of the 3D image, or both, to determine the nature of the tissue at the investigation site. Advanced algorithms can be implemented into the GP-GPU to differentiate between normal tissue, scar tissue, necrotic tissue, tumor tissue, or any other type of tissue relevant to a user.
For example, the algorithms can create images that assign a color to specific tissue types (see,
where ni is the number of elements in each tissue class within the training set, and the superscript T indicates matrix transpose. The mean values for each parameter used in the algorithm, correspond to the five tissue types in the training set: adipose, fibrous, scar, tumor, and necrotic.
To determine the nature of a tissue that will be investigated, the mean values of the same parameters can be used to calculate covariant matrices and use them for calculating a quadratic discrimination score (see EQN 2),
d
i
Q=−½ ln |Si|−½(x−
where |.| stands for determinant, T is transpose, Si and Si−1 are the direct and inverse covariance matrices, xij and x are the column vector of the test and validation set parameters corresponding to the investigated tissue classes. The maximum quadratic score can be used to assign each investigated sample to a correct tissue type.
Although various aspects of the disclosed methods, devices and systems have been shown and described, modifications may occur to those skilled in the art upon reading the specification. The present application includes such modifications and is limited only by the scope of the claims.
This application claims the benefit of and priority to U.S. Provisional Application No. 61/589,082, filed Jan. 20, 2012, which is owned by the assignee of the instant application and the disclosure of which is hereby incorporated herein by reference in its entirety.
The subject matter described herein was developed in connection with funding provided by the National Institute of Health under Grant Nos. 2R44CA117218 and 5R42CA114896. The Federal government may have rights in the technology.
| Number | Date | Country | |
|---|---|---|---|
| 61589082 | Jan 2012 | US |
