Systems and methods for detecting or distinguishing an organization or an artifact

Abstract

The surgical system includes at least one light emitting element and an array of light sensors disposed at a working end of a surgical instrument, wherein each light sensor in the array of light sensors is adapted to generate a signal including a non-pulsatile component. The system also includes a controller coupled to the array of light sensors, the controller including an analyzer configured to determine a curve of the non-pulsatile component of the signal of each of the individual light sensors in the array of light sensors, smooth the curve, calculate a derivative of the smoothed curve, invert the smoothed curve, calculate a derivative of the inverse-smoothed curve, take a difference of the derivatives, smooth the resulting curve, estimate zero crossings of the smoothed resulting curve, apply a sign function to points adjacent each zero crossing, if present, and identify a region of interest, if present, based on the result.

Description

Technical Field

[0001] This patent relates to systems and methods for detecting or differentiating tissues or artifacts such as blood vessels, and more particularly to systems and methods for detecting or differentiating tissues or artifacts that include a system having at least one light emitting element and at least one light sensor disposed at a working end of a shaft.

[0002] In the surgical field, systems and methods for identifying artifacts, particularly blood vessels, during a surgical procedure provide valuable information to the surgeon or surgical team. U.S. hospitals lose billions of dollars annually in irrecoverable costs due to inadvertent vascular injuries during surgery. Furthermore, the patients involved face a mortality rate of up to 32% and are likely to require corrective treatment and an additional nine-day hospital stay, resulting in additional treatment costs in the tens of thousands of dollars if not hundreds of thousands of dollars. As a result, there is significant value in methods and systems that enable accurate determination of the presence of blood vessels and other vessels in the surgical field to reduce or avoid these costs.

[0003] Systems and methods for providing information regarding the presence of blood vessels in the surgical field are particularly important during minimally invasive surgical procedures. Conventionally, surgeons have relied on touch to identify blood vessels and avoid inadvertent injury to these vessels during surgery. With the shift to minimally invasive surgeries such as laparoscopic and robotic surgeries, surgeons have lost the ability to use direct visualization and touch to determine the presence of blood vessels within the surgical field. As a result, surgeons must primarily rely on habit and experience to determine whether blood vessels are present in the surgical field. Unfortunately, anatomical irregularities occur frequently due to congenital anomalies, scarring from past surgeries, and body habitus (e.g., obesity). In such situations, systems and methods that enable surgeons to determine the presence and / or characteristics of vessels within the surgical field (in some cases in real-time or near real-time) during surgery would be of great advantage.

[0004] On the one hand, it is considered advantageous to provide a system and method for providing information regarding the presence of blood vessels within the surgical field. However, if these systems and methods make the surgical procedure more complex, the adoption of such systems and methods will be hindered. Accordingly, it is advantageous for the system and method not to involve a surgeon or surgical team having to significantly consider or significantly prepare the surgical field or patient in order to use a system or method for detecting or differentiating tissues or artifacts such as blood vessels.

[0005] As will be described in more detail below, the present invention provides an improved identification for avoiding or separating tissues or artifacts such as vasculature without unduly complicating surgical instruments or surgical procedures, embodying an advantageous alternative to existing systems and methods. A user interface is described. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] According to one aspect of the present disclosure, a surgical system includes a surgical instrument, at least one light emitting element disposed at a working end of the surgical instrument, and an array of optical sensors disposed at the working end of the surgical instrument, wherein individual optical sensors within the array of optical sensors are adapted to generate a signal containing a non-pulsatile component, an array of optical sensors, and a controller coupled to the array of optical sensors. The controller includes an analyzer that determines a curve of the non-pulsatile component of each signal of the individual optical sensors in the array of optical sensors, smooths the curve to generate a smoothed curve, calculates the derivative of the smoothed curve, inverts the smoothed curve to generate an inverse-smoothed curve, calculates the derivative of the inverse-smoothed curve, takes the difference between the derivative of the inverse-smoothed curve and the derivative of the smoothed curve, generates a resulting curve, smooths the resulting curve to generate a smoothed resulting curve, estimates the zero-crossings of the smoothed resulting curve, and if present, applies a sign function to the points adjacent to each zero-crossing to generate a result, and if present, is configured to identify a region of interest based on the results of the points adjacent to each zero-crossing, if present.

Brief Description of the Drawings

[0007] The present invention will be more fully understood from the following description in connection with the accompanying drawings. Some of the figures may be simplified by omitting selected components to more clearly show other components. The omission of components in some of the figures does not necessarily indicate the presence or absence of a particular component in any of the exemplary embodiments, except as explicitly defined in the corresponding written description. None of the drawings are necessarily to scale.

[0008]

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[0009] The embodiments described herein provide systems and methods for detecting or distinguishing regions of interest within a curve, which systems and methods also include the detection or distinction of tissue or artifacts such as blood vessels, and which systems and methods can be used with or in a surgical system or surgical instrument. Such a system can include at least one light emitting element disposed at a working end of a surgical instrument and an array of optical sensors disposed at the working end of the surgical instrument, where individual optical sensors within the array of optical sensors are adapted to generate a signal that includes a non-pulsatile component. The system can include a controller coupled to the array of optical sensors, and the controller includes an analyzer. The analyzer determines a curve of the non-pulsatile component of each respective signal of the individual optical sensors within the array of optical sensors, smooths the curve to generate a smoothed curve, calculates a derivative of the smoothed curve, inverts the smoothed curve to generate an inverted smoothed curve, calculates a derivative of the inverted smoothed curve, takes a difference between the derivative of the inverted smoothed curve and the derivative of the smoothed curve to generate a resulting curve, smooths the resulting curve to generate a smoothed resulting curve, estimates zero crossings of the smoothed resulting curve, and if present, applies a sign function to points adjacent to each zero crossing to generate a result, and if present, is configured to identify a region of interest based on the results of the points adjacent to each zero crossing if present.

[0010] Turning first to FIGS. 1 - 6, an embodiment of such a surgical system 100 is illustrated. Using this system 100, for example, the characteristics (e.g., presence, diameter, etc.) of a blood vessel V within a region 102 of tissue T proximate to the working end 104 of a surgical instrument 106 can be determined. The blood vessel V may be connected to other blood vessels along with the region 102 of tissue T, and further, it will be appreciated that the blood vessel V may extend beyond the region 102 to be in fluid communication with other organs (e.g., the heart) found within the patient's body. Further, the tissue T appears in FIGS. 1 - 4 to completely surround the blood vessel V (both peripherally and in length), although this need not be the case in all examples using the system 100. For example, the tissue T may only partially surround the blood vessel V, and / or may only surround a portion of the length of the blood vessel V, or the tissue T may be a very thin layer covering the blood vessel V. As a further example, the blood vessel V may be a blood vessel, and the tissue T may be connective tissue, adipose tissue, and / or liver tissue, although it is not limited thereto.

[0011] According to the illustrated embodiment, the working end 104 of the surgical instrument 106 is also the distal end of the shaft 108. Thus, the working end and the distal end are referred to as the working end 104 or the distal end 104. Further, the shaft 108 also has a proximal end 110, and a grip or handle 112 (referred to herein as the grip 112 without distinction) is disposed at the proximal end 110 of the shaft 108. The grip 112 is designed according to the nature of the instrument 106; for the thermal ligation device illustrated in FIG. 1, the grip 112 may be a pistol grip including a trigger 114. As one option, a finger ring disposed on a substantially scissor - type grip may also be used.

[0012] The working end or distal end 104 and the proximal end 110 having the grip 112 are shown as being disposed at opposite extreme ends of the shaft 108, but it will be appreciated that certain surgical instruments have a working end (e.g., where the tool tip is attached) disposed at an opposite extreme end of the shaft and a grip region disposed intermediate the opposing working ends. In accordance with the terms "distal" and "proximal" as used herein, the working end of such an instrument is referred to herein as the distal end and the grip region as the proximal end. However, with respect to the illustrated embodiment, the distal end and the proximal end are disposed at opposite extreme (or simply opposite) ends of the shaft 108.

[0013] As described above, according to the illustrated preferred embodiment, the surgical system 100 comprises a sensor having at least one light emitting element 120 (or simply the light emitting element 120) and one or more light sensors or detectors 122 (or simply the light sensor 122). See FIGS. 2-4. According to the illustrated embodiment, a controller 124 is coupled to the light emitting element 120 and the light sensor 122, and the controller 124 can comprise a splitter 126 and an analyzer 128, as will be described below. See FIG. 1.

[0014] The light emitting element 120 is disposed at the working end 104 of the surgical instrument 106. Also, the optical sensor 122 is also disposed at the working end 104 of the surgical instrument 106. In either case, the phrase "disposed" may refer to the physical placement of the light emitting element 120 or the optical sensor 122 at the working end 104, or the placement of an optical fiber or other light guide at the working end 104. The light guide is coupled to the light emitting element 120 or the optical sensor 122, and thus the light emitting element 120 or the optical sensor 122 may be disposed elsewhere. The system 100 can operate according to a transmittance-based approach, and as a result, the optical sensor 122 is disposed facing the light emitting element 120 on the opposite side of the light emitting element 120, such as on the joe on the opposite side of the surgical instrument 106 as shown in, for example, FIG. 2. Note that the system 100 may include a reflectance-based system (for detecting vessels and / or tissue facing forward), and as a result, the light emitting element 120 and the optical sensor 122 may face in a common direction, and the distance between them may be fixed, such as on a single joe of a two-joe device (see FIG. 3). Alternatively, the light emitting element 120 and the optical sensor 122 of the reflectance-based system may be configured such that the distance between the light emitting element 120 and the optical sensor 122 can be adjusted, for example, by disposing the light emitting element 120 at the end or tip of one joe of a two-joe device and disposing the optical sensor 122 at the end or tip of the other joe of the two-joe device (see FIG. 4). Regarding the operation of such a reflectance-based system, PCT application number PCT / US17 / 17436 filed on February 10, 2017 is hereby incorporated by reference in its entirety.

[0015] The light-emitting element 120 may be configured to emit light having at least one wavelength. For example, the light-emitting element 120 may emit light having a wavelength of 660 nm. This can be achieved with a single element, or a plurality of elements (these elements may be arranged or configured in an aligned manner, for example, as will be described in detail below). In a similar manner, the light sensor 122 is configured to detect light having at least one wavelength (e.g., 660 nm). According to the embodiment described herein, the light sensor 122 includes a plurality of elements, and these elements are arranged or configured in an aligned manner.

[0016] According to a particular embodiment, the light-emitting element 120 can be configured to emit light having at least two different wavelengths, and the light sensor 122 can be configured to detect light having at least two different wavelengths. As an example, the light-emitting element 120 can be configured to emit light in the visible region, and the light sensor 122 can be configured to detect light in the near-infrared region or the infrared region. Specifically, the light-emitting element 120 emits light, and the light sensor 122 can detect light at 660 nm and 910 nm. Such an embodiment can be used, for example, to ensure optimal transmission of the blood vessel V and the surrounding tissue T under in-vivo conditions.

[0017] Depending on the influence of changes in blood flow, light of a third wavelength may be emitted and detected. That is, if it is found that the detection method is susceptible to changes in the blood flow velocity within the blood vessel of interest, light at 810 nm (i.e., the isosbestic point) can be emitted and detected to normalize the results in order to limit or eliminate the influence of changes in the blood flow velocity. Light of additional wavelengths may be used.

[0018] According to some embodiments, an individual optical sensor 122 is configured to generate a signal that includes a first pulsatile component and a second non-pulsatile component. It will be appreciated that the first pulsatile component can be the alternating current (AC) component of the signal, and the second non-pulsatile component can be the direct current (DC) component. When the optical sensor 122 is in the form of an array, the pulsatile information and the non-pulsatile information can be generated for each component of the array, or at least for each component of the array that defines at least one column of the array.

[0019] With respect to the pulsatile component, it will be appreciated that blood vessels can be described as having a characteristic pulsation of about 60 pulses (or heartbeats) per minute. Although this may vary depending on the patient's age and condition, the range of pulsations is typically from about 60 to about 100 pulses (or heartbeats) per minute. The optical sensor 122 generates a signal having a specific AC waveform corresponding to the movement of blood through the blood vessel, which is passed to the controller 124. In particular, the AC waveform corresponds to light absorbed or reflected by the pulsatile blood flow within the blood vessel. On the other hand, since the DC component corresponds mainly to light absorbed, reflected, and / or scattered by the tissue, the blood vessel may appear as a "shadow" or "depression" in the curve formed by the DC signals from each of the sensors within the sensor array.

[0020] According to such an embodiment, the controller 124 can be coupled to the optical sensor 122 and include a splitter 126 for separating the first pulsatile component and the second non-pulsatile component for each component of the optical sensor array 122. Further, the controller 124 can include an analyzer 128 for determining the presence and / or characteristics of the blood vessel V in the region 102 proximate to the working end 104 of the surgical instrument 106 based on the pulsatile component (at least in part). According to the embodiments described herein, the analyzer can make its determination by first detecting or differentiating the region of interest in the DC signal from the optical sensor 120 of the system 100.

[0021] Before discussing the details of the determination of the region of interest, further details of the system can be discussed with reference to, for example, the transmittance-based embodiments of FIGS. 1 and 2. The light-emitting element 120 can include one or more elements as described above. According to the embodiment schematically shown in FIG. 2, the optical sensor 122 can include a first light-emitting element 120-1, a second light-emitting element 120-2, and a third light-emitting element 120-3. All of the light-emitting elements may be configured to emit light at a specific wavelength (e.g., 660 nm), or a specific light-emitting element may emit light at a wavelength different from that of other light-emitting elements. Each light-emitting element can be, for example, a light-emitting diode.

[0022] As shown in FIG. 2, with respect to an embodiment in which the light-emitting element 120 is in the form of an array including one or more light-emitting diodes, the diodes can be arranged in the form of a one-dimensional array, a two-dimensional array, or a three-dimensional array. An example of a one-dimensional array includes arranging the diodes along a line in a single plane, and an example of a two-dimensional array can include arranging the diodes in a plurality of rows and columns in a single plane. Further examples of two-dimensional arrays can include arranging the diodes along a line on or within a curved surface. Further examples of three-dimensional arrays can include diodes arranged in a plurality of planes on or within a curved surface, for example, in a plurality of rows and columns.

[0023] Also, the optical sensor 122 can also include one or more elements. Also, according to the embodiment shown in FIG. 2, the optical sensor 122 can include a first optical sensor 122-1, a second optical sensor 122-2, an nth optical sensor 122-n, and the like. Similar to the case of the light-emitting elements 120-1, 120-2, 120-3, the optical sensors 122-1, 122-2, 122-3, 122-n may be arranged in an array, and the description regarding the above array also applies here.

[0024] In practice, when the array of optical sensors 122 includes a row of optical sensors (such as in FIG. 2), the array 122 can alternatively be referred to as a linear array. The individual optical sensors 122 of the array 122 can be arranged adjacent to each other, or the optical sensors can be spaced apart from each other. The individual optical sensors that define a row of optical sensors may be separated from each other by optical sensors that define a row or column of a different array. However, according to a particular embodiment, the array can comprise a charge-coupled device (CCD), in particular a linear CCD imaging device comprising a plurality of pixels. As another option, a CMOS sensor array can be used.

[0025] In addition to the light-emitting element 120, the sensor 122, and the controller 124, the system 100 can comprise hardware and software. For example, when using one or more light-emitting elements 120, a drive controller can be provided to control the switching of the individual light-emitting elements. Similarly, when comprising one or more sensors 122, a multiplexer can be provided, which can be coupled to the sensor 122 and an amplifier. Further, the controller 124 can include a filter and analog-to-digital conversion as required.

[0026] According to a particular embodiment, the splitter 126 and the analyzer 128 can be defined by one or more electrical circuit components. According to other embodiments, one or more processors (or simply a processor) can be programmed to perform the operations of the splitter 126 and the analyzer 128. According to further embodiments, the splitter 126 and the analyzer 128 may be defined partly by electrical circuit components and partly by a processor programmed to perform the operations of the splitter 126 and the analyzer 128.

[0027] For example, splitter 126 may include, or may be defined by, a processor programmed to separate a first pulsatile component from a second non-pulsatile component. Further, analyzer 128 may include, or may be defined by, a processor programmed to determine (or, for example, quantify the size of) the presence of vessel V within region 102 proximate to working end 104 of surgical instrument 106 based on the first pulsatile component. The instructions by which the processor is programmed may be stored on a memory associated with the processor, the memory being capable of comprising one or more tangible, non-transitory computer-readable memories storing computer-executable instructions that, when executed by the processor, can cause one or more processors to perform one or more operations.

[0028] Regarding the operation of such a transmittance-based system for determining characteristics of tissue and / or artifacts (such as vessels, e.g., blood vessels or ureters), where the characteristics can include position and dimensions (e.g., length, width, diameter), by way of example and not limitation, U.S. Patent Publication Nos. 2015 / 0066000, 2017 / 0181701, 2018 / 0042522, and 2018 / 0098705 are hereby incorporated by reference in their entireties. Regarding related structures and operations that can address issues related to the operation of such a system, PCT Application Nos. PCT / US16 / 55910, filed Oct. 7, 2016, and PCT / US17 / 48651, filed Aug. 25, 2017, are hereby incorporated by reference in their entireties.

[0029] FIGS. 5 and 6 illustrate an embodiment of surgical system 100 in combination with an embodiment of video system 200, such as may be used during conventional minimally invasive surgery or laparoscopic surgery. Video system 200 includes a video camera or other image capture device 202, a video or other associated processor 204, and a display 206 having a display screen 208.

[0030] As shown, video camera 202 is directed at region 102 proximate to the working ends 104 of two surgical instruments 106. As shown, both surgical instruments 106 are part of an embodiment of surgical system 100 as illustrated in FIG. 2 and discussed above. In this case, instruments 106 each include visual indicator 130. However, it will be appreciated that according to other embodiments, only one of instruments 106 may include visual indicator 130. Although other components of surgical system 100 are omitted for ease of illustration, components of system 100 such as splitter 126 and analyzer 128 may be housed within the same physical housing as video processor 204.

[0031] Signals from video camera 202 are passed through video processor 204 to display 206, whereby a surgeon or other member of the surgical team can typically view region 102, which is typically inside the patient, as well as the working ends 104 of surgical instruments 106. Since visual indicator 130 is proximate to working end 104 and thus region 102, visual indicator 130 is also visible on display screen 108. As described above, this advantageously enables a surgeon to receive visual cues or warnings via visual indicator 130 through the same display 206 and the same display screen 208 as region 102 and working end 104. This then limits the need for the surgeon to look elsewhere for information transmitted via visual indicator 130.

[0032] FIG. 6 shows another embodiment of the video system 200 that can be used in connection with one embodiment of the surgical system 100. According to this embodiment, the video processor 204 is not disposed in a housing separate from the video camera 202', but rather is disposed within the same housing as the video camera 202'. According to a further embodiment, instead, the video processor 204 can be disposed within the same housing as the remaining portion of the display 206' as the display screen 208'. Otherwise, the above description related to the embodiment of the video system 200 shown in FIG. 5 is equally applicable to the embodiment of the video system 200 shown in FIG. 6.

[0033] The user interface 130 advantageously enables a surgeon or surgical team to view the output from the controller 124, while also allowing other output devices to be included in the user interface 130, as shown in FIGS. 1 and 2. For example, an alert may be displayed on the video monitor 300 used in the surgery (e.g., the displays 206, 206' of FIGS. 5 and 6), or the color, blink, size, or otherwise appearance of the image on the monitor may be changed by the alert. Also, the auxiliary output may be in the form of, or include, a speaker 302 that provides an audible alarm. Further, the auxiliary output may be in the form of, or incorporate, a safety lockout associated with the surgical instrument 106 that interrupts the use of the surgical instrument 106. For example, the lockout may prevent ligation or cauterization if the surgical instrument 106 is a thermal ligation device. As a further example, the auxiliary output may be in the form of a tactile feedback system such as a vibrator 304, which may be attached to or integrally formed with the handle or handpiece of the surgical instrument 106 to provide a tactile indication or alarm. In addition to the light-emitting element disposed at the working end 104 of the surgical instrument 108, one or more light-emitting elements may be disposed at the proximal end 110 of the shaft 108, such as being disposed or attached on, for example, the grip or handle 112, to provide a visual display or alarm. Various combinations of these specific forms of auxiliary output may be used.

[0034] As described above, the surgical system 100 may also include a surgical instrument 106 having a working end 104 to which a user interface 130 and sensors (and in a preferred embodiment, a light emitting element 120 and a light sensor 122) are (alternatively, removably / reversibly, or permanently / irreversibly) attached. Instead, the user interface 130 and sensors may be integrally (i.e., as one unit) formed with the surgical instrument 106. Also as described, the user interface 130 and sensors can be attached to a separate instrument or tool that is used in combination with the surgical instrument or tool 106.

[0035] As described above, in one embodiment, the surgical instrument 106 can be a thermal ligation device. In another embodiment, the surgical instrument 106 can simply be a grasper or grasping forceps having opposing jaws. According to further additional embodiments, the surgical instrument can be other surgical instruments such as, for example, an irrigator, a surgical stapler, a clip applier, a robotic surgical system, etc. According to still further embodiments, the surgical instrument may hold the user interface and sensors and have no other function other than to position them within the surgical area. The illustration of a single embodiment does not preclude the use of the system 100 in combination with other surgical instruments or tools 106.

[0036] In the context of one or more of the systems described above, it will be appreciated that the identification of the region of interest is important as a prelude to the characterization of artifacts (e.g., determination of the diameter of a vasculature) from data received from an array of light sensors. Further, it is advantageous for the identification of the region of interest to be relatively robust compared to environmental factors that may affect the identification of the region of interest. Also, it is advantageous for the identification of the region of interest to minimize the computational burden for performing the identification. In conjunction with the former, an identification system and method that minimizes the computational burden can also facilitate the use of the system and method in a real-time or near real-time implementation.

[0037] As described above, the system 100 described includes a light emitting element 120 and a light sensor 122, and the signal from the light sensor may include a pulsating (or AC) component and a non-pulsating (or DC) component. The systems and methods for identifying regions of interest described herein utilize the non-pulsating or DC component. This DC data can be described with respect to a DC curve that includes DC data from a plurality of light sensors arranged in an array (e.g., a linear array, etc.) according to at least one embodiment described herein.

[0038] Generally, the method shown in FIG. 7 can be used to determine a region of interest where a "dip" occurs in the DC curve (i.e., a region along the DC curve where the profile decreases and then increases). According to certain embodiments, all dips can be identified as regions of interest. According to other embodiments, the region of interest can then be further processed to determine which of the regions of interest are more likely (or highly likely) to be associated with a particular artifact, such as a blood vessel, especially a blood vessel. For example, regions of interest that are more likely (or highly likely) to be associated with a blood vessel can be separated from regions of interest associated with heterogeneous or highly absorbent tissue. In this way, this method can be used to locate and track blood vessels along the sensor array in real time.

[0039] As described with reference to FIG. 7, a method 300 for identifying a region of interest is described, which can be used in the embodiments of the above-described system 100. An embodiment of the method 300 shown in FIG. 7 starts at block 302, where the system 100 controls the light-emitting element 120 to emit light of one or more wavelengths. The method 300 continues at block 304, where the optical sensor 122 receives the light and generates a signal according to the detected light. Perhaps, a significant portion of the light received by the optical sensor 122 is from the light-emitting element 120, but it will be recognized that ambient light (i.e., light from other light sources) can also contribute to the light received by the optical sensor 122. Further, consistent with the above discussion, the light received by the optical sensor 122 can include a pulsatile component and a non-pulsatile component, particularly when the light is received after passing through tissue containing vasculature such as blood vessels.

[0040] At block 306, the system 100 separates the signal received from the optical sensor 122 into a pulsatile component and a non-pulsatile component. For example, a splitter 126 can be used to separate different components of the signal. Further, it will be recognized that the method 300 utilizes the non-pulsatile (or DC) component, but the pulsatile (or AC) component can also be utilized by the system 100 in a separate manner or in combination with the output of the method 300.

[0041] According to one embodiment of the method 300, the system 100 smooths the DC curve (this curve can include DC signals corresponding to each of the optical sensors 122 along the array). In this regard, smoothing can include filtering, and the filtering can also include averaging. Smoothing of the DC curve helps to focus on the sensor that generates the signal with the clearest DC signal compared to other sensors.

[0042] At block 310, system 100 determines the derivative of the smoothed DC curve (smoothed DC curve) generated at block 308. In particular, system 100 determines the derivative using three-point numerical differentiation, although other n-point numerical differentiations can be used instead. System 100 determines the derivative using numerical differentiation, reducing the computational load caused by method 300.

[0043] At block 312, system 100 inverts the smoothed signal determined at block 308. At block 314, system 100 determines the derivative of the inverted smoothed DC curve (inverted smoothed DC curve). As in the case of block 310, the system can determine the derivative, for example, by using three-point numerical differentiation. Again, using numerical differentiation can reduce the computational load of method 300.

[0044] At block 316, system 100 subtracts the derivative determined at block 314 from the derivative determined at block 310. Next, system 100 smooths the result of this subtraction at block 316 (referred to as the result curve) to generate a smoothed result curve (smoothed result curve) at block 318. Next, system 100 interpolates the smoothed result curve at block 320 for use in the remainder of method 300. Optionally, the smoothed result curve can be used in the remainder of method 300.

[0045] At block 322, system 100 estimates the zero crossings of the smoothed (and optionally interpolated) result curve. Next, at block 324, system 100 applies a sign function to the points adjacent to the estimated zero crossings of the result curve, and at block 326, determines whether the result of applying the sign function to the adjacent points exhibits a particular pattern. In particular, system 100 can analyze the results for patterns of [1, -1, 1], [1, -1], [-1, 1] for the points adjacent to the zero crossings. This pattern suggests that a depression has occurred in the original signal curve. Next, system 100 identifies this region as a region of interest at block 328.

[0046] As reflected in FIG. 7, the system can identify multiple regions of interest at block 328. That is, based on the number of zero crossings and the patterns established for the points adjacent to those zero crossings, the system can identify whether there are no regions of interest, one region of interest, or multiple regions of interest. When identifying multiple regions of interest, the determination at block 328 may be repeated or performed multiple times.

[0047] As further reflected in method 300 of FIG. 7, in a situation where multiple regions of interest are determined at block 328, system 100 can perform additional actions at block 330 to select one or more regions of interest from the multiple regions determined at block 328. For example, in some embodiments, a particular region of interest can be selected compared to other regions based on the likelihood that a vasculature is associated with that region. In other embodiments, for example, when attempting to identify different tissues, all of the regions of interest can be considered. Next, system 100 performs further analysis for one or more regions of interest at block 332, such as determining the size (e.g., diameter or effective diameter) of the vasculature associated with these regions of interest, according to methods disclosed, for example, in references incorporated herein by reference in their entirety.

[0048] As an example of an action that can be performed to select one or more regions of interest from a plurality of identified regions of interest, method 350 is shown in FIG. 8. This method can be used to determine which of the regions of interest among the plurality of regions of interest are more or less likely to have associated vasculature (e.g., blood vessels such as arteries or veins). Generally, method 350 first determines which regions of interest may overlap and resolves whether overlapping regions of interest should be treated as a single region of interest or as separate regions of interest. After resolving the overlap issue, method 350 then attempts to determine whether each of the remaining regions of interest is likely to be associated with vasculature. As described above, after executing method 350, it is possible for a plurality of regions to be identified as regions of interest that may be subject to further processing.

[0049] Method 350 begins at block 352 where a determination is made as to whether any of the regions of interest overlap. This determination can be made based on whether the starting point of a region of interest is between the starting and ending points of another region of interest and / or whether the ending point or region of interest is between the starting and ending points of another region of interest. As described above, the starting and ending points of a region of interest can be determined by comparing the results of the sign function. If there are overlapping regions of interest, method 350 proceeds to block 354; if there are no overlapping regions of interest, method 350 proceeds to block 362.

[0050] Assuming that it is determined in block 352 that at least two regions of interest overlap, an analysis of the proximity of the regions of interest is performed in block 354. Generally, if the regions of interest are close enough such that it is not likely that any two blood vessels are actually that close, system 100 can treat those regions of interest as a single region of interest; otherwise, those regions can be treated as separate regions. According to one embodiment, the determination of proximity can include 1) determining the proximity between the ending points of adjacent regions, 2) determining the proximity between the starting point of a region and the ending point of the previous region, and 3) determining the proximity between the starting points of adjacent regions. That is, D is,

Number

Number

[0051] After solving the problem of overlapping regions, method 350 continues to determine which of the remaining regions are more or less likely to be related to artifacts such as vasculature. This determination can answer either or both of these questions (i.e., more or less likely), but the goal is to identify more likely regions of interest for further processing. Method 350 of FIG. 8 includes one embodiment for making this determination, but other embodiments are also possible for making this determination.

[0052] According to method 350, at block 362 a plurality of parameters are analyzed to determine whether each of the regions of interest is likely (or unlikely) to be related to vasculature. Each of the parameters can be analyzed at block 364 to determine whether the parameter is satisfied, such as by comparing the parameter to a threshold associated with the parameter. After each parameter is compared to its respective threshold, the results of all the comparisons are analyzed at block 366 to determine, for example, by comparing the analysis performed at block 364 to further criteria, whether there is a high likelihood of vasculature. Next, the determination made at block 366 is provided as an output at block 368 for the purpose of identifying regions of interest for further processing, such as as part of method 300 of FIG. 7. It will be appreciated that the operations of blocks 362, 364, 366, 368 may be repeated as necessary to handle all of the identified regions of interest.

[0053] In the embodiment of FIG. 8, the following five parameters are considered: 1) width, 2) standard deviation of the derivative of the region of interest, 3) average value of the derivatives of the individual values of the sensors associated with the region of interest / standard deviation of the derivatives of the individual values of the sensors associated with the region of interest, 4) minimum value among the individual values of the sensors associated with the region of interest, and 5) standard deviation of the individual values of the sensors associated with the region of interest / average value of the individual values. According to other embodiments, other parameters can be considered, and the total number of parameters may be more or less than five. These parameters may be determined in a specific order at block 362, or may be determined simultaneously or substantially simultaneously. Method 350 may determine each parameter separately and proceed directly to the analysis of the parameters at block 364, or may determine all the parameters at block 362 (sequentially or simultaneously / substantially simultaneously) and then proceed to block 364.

[0054] At block 364, the parameters determined at block 362 are analyzed to determine whether the parameters indicate that it is likely or unlikely that a blood vessel is associated with the region of interest. For example, the width parameter can be compared to a minimum width. The minimum width represents an actual limit regarding the size of the expected or vessel of interest. As described above, the use of threshold comparison is not the only analysis method that can be used to determine whether the parameters suggest, more or less, the presence of a blood vessel in the region of interest.

[0055] In block 366, based on the analysis of each of the parameters determined in block 362 at block 364, it is determined whether the vasculature is likely or unlikely to be associated with the region of interest. For example, according to this embodiment, determining whether there is a high likelihood of the presence of vasculature requires satisfying all the parameters. According to other embodiments, for example, it may be sufficient if a simple majority of the parameters exceeds a relevant threshold. Still other embodiments may use a weighted average of the results of the parameter comparisons. In any case, after the determination is made at block 366, the result is provided at block 368.

[0056] After the system 100 determines the region of interest to be evaluated, such as by using the method as shown in FIG. 8, the system 100 can characterize the artifact at block 332 of FIG. 7. For example, the characterization that occurs at block 332 may include determining whether the artifact is a vasculature, and if it is a vasculature, whether the vasculature is a particular type of vasculature (e.g., an artery). Alternatively, the characterization that occurs at block 332 may be between different types of tissues. As a further alternative, the characterization may include determining the dimensions of the artifact: for example, if the artifact is a vasculature, the dimensions may be the diameter (if the vasculature is considered or assumed to be circular in cross-section) or the effective diameter (if the vasculature is considered or assumed to be non-circular in cross-section and the maximum dimension of the entire vasculature may be used instead of the actual diameter).

[0057] In this regard, one or more actions performed by system 100 at block 332 to determine characteristics of tissue and / or artifacts (such as vessels like blood vessels or ureters) (the characteristics may include location and dimensions (such as length, width, diameter, etc.)) may, by way of example and not limitation, for a transmittance-based system, include those described in U.S. Patent Publication Nos. 2015 / 0066000, 2017 / 0181701, 2018 / 0042522, and 2018 / 0098705. Each of these is hereby incorporated by reference in its entirety.

[0058] In conclusion, the foregoing description shows details of different embodiments of the present invention, but the legal scope of the present invention should be understood to be defined by the language of the claims appended hereto. The detailed description should be construed as merely exemplary and not as an exhaustive description of all possible embodiments of the present invention. It is impractical, if not impossible, to describe all possible embodiments of the present invention. Using current technology or technologies developed after the filing date of this application, numerous other embodiments can be implemented, but these will still fall within the scope of the claims that define the present invention.

[0059] Also, in the present invention, unless a term is explicitly defined using the phrase "as used herein, the term '...' shall mean..." or similar language, there is no intention to explicitly or implicitly limit the meaning of such term beyond its plain or ordinary meaning, and it should also be understood that such term should not be construed as being limited in scope based on any description made in any section of the present invention (other than the language of the claims). Within the scope in which the present invention refers to the terms mentioned in the claims appended to this application in a manner consistent with a single meaning solely for the purpose of clarity and without confusing the reader, it is not intended to limit the terms of such claims to that single meaning by implication or otherwise. Finally, unless a claim element is defined by reciting the term "means" and a function without reciting any structure, it is not intended that the scope of any claim element be construed based on the application of 35 U.S.C. § 112(f).

Claims

1. A surgical system including a surgical instrument, at least one light emitting element disposed at a working end of the surgical instrument, an array of optical sensors disposed at the working end of the surgical instrument, wherein individual optical sensors within the array of optical sensors are adapted to generate a signal including a non-pulsatile component, the array of optical sensors, a controller coupled to the array of optical sensors comprising, the controller includes an analyzer, the analyzer, determine a curve of the magnitude of the non-pulsatile component of each signal of the individual optical sensors along the array of optical sensors, smooth the curve to generate a smoothed curve, calculate a derivative of the smoothed curve, invert the smoothed curve to generate an inverse-smoothed curve, calculate a derivative of the inverse-smoothed curve, take the difference between the derivative of the inverse-smoothed curve and the derivative of the smoothed curve to generate a result curve, smooth the result curve to generate a smoothed result curve, estimate a zero crossing of the smoothed result curve, if a zero crossing exists, apply a sign function to points adjacent to each zero crossing to generate a result, if a zero crossing exists, identify a region of interest based on the result of points adjacent to each zero crossing configured to surgical system.

2. The analyzer is configured to calculate a three-point derivative of the smoothed curve to calculate the derivative of the smoothed curve, The surgical system according to claim 1.

3. The analyzer is configured to calculate a three-point derivative of the inverse-smoothed curve to calculate the derivative of the inverse-smoothed curve, The surgical system according to claim 1.

4. The analyzer is configured to interpolate the smoothed result curve before estimating a zero crossing of the smoothed result curve, The surgical system according to claim 1.

5. The analyzer is configured to identify a plurality of regions of interest based on the result of points adjacent to each zero crossing, identify a region from the plurality of regions of interest, and characterize an artifact associated with the region, The surgical system according to claim 1.

6. The controller includes a processor and a memory, The analyzer determines a curve of the non-pulsatile component of the respective signals of the individual light sensors in the array of the light sensors, smooths the curve to generate a smoothed curve, calculates a derivative of the smoothed curve, inverts the smoothed curve to generate an inverse-smoothed curve, calculates a derivative of the inverse-smoothed curve, takes a difference between the derivative of the inverse-smoothed curve and the derivative of the smoothed curve to generate a result curve, smooths the result curve to generate a smoothed result curve, estimates zero-crossings of the smoothed result curve, and if present, applies a sign function to points adjacent to each zero-crossing to generate a result, and if present, identifies a region of interest based on the result of points adjacent to each zero-crossing if present. comprising the processor programmed as described above, The surgical system according to claim 1. **Claim 7** The analyzer is configured to characterize an artifact based on the identified region of interest. The surgical system according to claim 1. **Claim 8** The analyzer is configured to determine a diameter or an effective diameter of a blood vessel based on the identified region of interest. The surgical system according to claim 7.

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