Patent Publication Number: US-2020297442-A1

Title: Systems and methods for monitoring patient motion during a medical procedure

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and benefit of the filing date of U.S. Provisional Patent Application No. 62/546,366, entitled “SYSTEMS AND METHODS FOR MONITORING PATIENT MOTION DURING A MEDICAL PROCEDURE,” filed Aug. 16, 2017, which is hereby incorporated by reference in its entirety. 
    
    
     FIELD 
     The present disclosure is directed to systems and methods for monitoring the motion of a patient or of a medical system relative to the patient during a medical procedure. 
     BACKGROUND 
     Minimally invasive medical techniques are intended to reduce the amount of tissue that is damaged during medical procedures, thereby reducing patient recovery time, discomfort, and harmful side effects. Such minimally invasive techniques may be performed through natural orifices in a patient anatomy or through one or more surgical incisions. Through these natural orifices or incisions physician may insert minimally invasive medical instruments (including surgical, diagnostic, therapeutic, or biopsy instruments) to reach a target tissue location. One such minimally invasive technique is to use a flexible and/or steerable elongate device, such as a flexible catheter, that can be inserted into anatomic passageways and navigated toward a region of interest within the patient anatomy. Other minimally invasive techniques may include the user of relatively rigid devices manipulated within the patient anatomy. Control of such an elongate device by medical personnel involves the management of several degrees of freedom including at least the management of insertion and retraction of the elongate device as well as steering of the device. In addition, different modes of operation may also be supported. 
     During a medical procedure, the patient may move. In some instances, this may depend on the type of anesthesia the patient is placed under. For example, an involuntary bodily movement may occur, or the patient may be bumped or otherwise moved by a physician or another person present in the surgical environment. Additionally, the minimally invasive system may be moved relative to the patient. Such movements can cause complications during the minimally-invasive procedures, including image-guided medical procedures. 
     Accordingly, it would be advantageous to provide improved methods and systems for monitoring patient motion during a medical procedure. 
     SUMMARY 
     The embodiments of the invention are best summarized by the claims that follow the description. 
     Consistent with some embodiments, an exemplary method of controlling an elongate instrument during a medical procedure involving motion of the elongate instrument relative to a patient is provided. The method includes generating, by a control system, a first model of the elongate instrument, and generating, by the control system, a second model of the elongate instrument based on a reference pose of the elongate instrument. The method further includes comparing, by the control system, the first model with the second model and determining, by the control system, a state of a system configuration based on the comparison. 
     Consistent with some other embodiments, an exemplary medical system is provided. The medical system includes an elongate instrument having a sensor system, and a control system in communication with the sensor system to measure a pose of the elongate instrument. The control system is adapted to perform operations. Such operations may include generating a first model of the elongate instrument, and generating a second model of the elongate instrument based on a reference pose of the elongate instrument. The operations may further include comparing the first model with the second model, and determining a state of a system configuration based on the comparison. 
     Consistent with some other embodiments, an exemplary method is provided. The method includes generating, by a control system, a first model of an elongate instrument based on a measured state of the elongate instrument, and generating, by the control system, a second model of the elongate instrument based on a reference state of the elongate instrument and a user command. The method further includes comparing, by the control system, the first model with the second model, and determining, by the control system, a state of a system configuration based on the comparison. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory in nature and are intended to provide an understanding of the present disclosure without limiting the scope of the present disclosure. In that regard, additional aspects, features, and advantages of the present disclosure will be apparent to one skilled in the art from the following detailed description. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         FIG. 1  is a simplified diagram of a teleoperated medical system according to some embodiments. 
         FIG. 2A  is a simplified diagram of a medical instrument system according to some embodiments. 
         FIG. 2B  is a simplified diagram of a medical instrument system with an extended medical tool according to some embodiments. 
         FIG. 2C  is a diagram of a medical instrument system with a kinematic chain according to some embodiments. 
         FIGS. 3A and 3B  are simplified diagrams of side views of a patient in patient coordinate space including a medical instrument mounted on an insertion assembly according to some embodiments. 
         FIG. 4  is a flowchart of a method for monitoring patient movement during a medical procedure according to some embodiments. 
         FIGS. 5A, 5B, and 5C  illustrate the distal end of the medical instrument systems of  FIGS. 2A-C ,  3 A, and  3 B, during use within a human lung according to some embodiments. 
         FIGS. 6A and 6B  illustrate images that may be used in identifying patient motion patient according to some embodiments. 
         FIG. 7  depicts simplified diagram of a side view of a patient having an endotracheal tube inserted to facilitate use to the medical instrument system according to some embodiments. 
         FIG. 8  depicts a user interface according to some embodiments. 
         FIG. 9  is a flowchart of another method for monitoring patient movement during a medical procedure according to some embodiments. 
         FIG. 10A  depicts a system configuration of a medical instrument associated with a measured model according to some embodiments. 
         FIG. 10B  depicts another system configuration of the medical instrument of  FIG. 10A  associated with a reference model according to some embodiments. 
         FIG. 10C  shows a portion of the measured model of  FIG. 10A  and a corresponding portion of a predicted model of the medical instrument, according to some embodiments. 
         FIG. 10D  depicts another system configuration of a medical instrument associated with a measured model according to some embodiments. 
         FIG. 10E  depicts another system configuration of the medical instrument of  FIG. 10A  associated with a reference model according to some embodiments. 
         FIG. 10F  shows a portion of the measured model of  FIG. 10D  and a corresponding portion of a predicted model of the medical instrument, according to some embodiments. 
         FIGS. 11A and 11B  show representations of measured and predicted models that may be compared to determine patient motion according to some embodiments. 
     
    
    
     Embodiments of the present disclosure and their advantages are best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures, wherein showings therein are for purposes of illustrating embodiments of the present disclosure and not for purposes of limiting the same. 
     DETAILED DESCRIPTION 
     In the following description, specific details are set forth describing some embodiments consistent with the present disclosure. Numerous specific details are set forth in order to provide a thorough understanding of the embodiments. It will be apparent, however, to one skilled in the art that some embodiments may be practiced without some or all of these specific details. The specific embodiments disclosed herein are meant to be illustrative but not limiting. One skilled in the art may realize other elements that, although not specifically described here, are within the scope and the spirit of this disclosure. In addition, to avoid unnecessary repetition, one or more features shown and described in association with one embodiment may be incorporated into other embodiments unless specifically described otherwise or if the one or more features would make an embodiment non-functional. 
     In some instances well known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the embodiments. 
     This disclosure describes various instruments and portions of instruments in terms of their position, orientation, and/or pose in three-dimensional space. As used herein, the term “position” refers to the location of an object or a portion of an object in a three-dimensional space (e.g., three degrees of translational freedom along Cartesian X, Y, and Z coordinates). As used herein, the term “orientation” refers to the rotational placement of an object or a portion of an object (three degrees of rotational freedom—e.g., roll, pitch, and yaw). As used herein, the term “pose” refers to the position of an object or a portion of an object in at least one degree of translational freedom and to the orientation of that object or portion of the object in at least one degree of rotational freedom (up to six total degrees of freedom). As used herein, the term “shape” refers to a set of poses, positions, or orientations measured along an object. 
     The disclosure is generally directed to methods and systems for monitoring the motion of a patient undergoing a medical procedure. In some approaches a dedicated device may be used to monitor a patient P. Embodiments of the present disclosure utilize information from assemblies and instruments that have a primary purpose other than monitoring patient motion. Accordingly, embodiments of the present disclosure may obviate the need of a dedicated patient motion monitoring device by enabling other systems and devices to secondarily provide patient motion monitoring means. The principles of the present disclosure may also be applied to dedicated devices to improve their accuracy and performance in monitoring patient motion. While some embodiments provided herein are discussed primarily with respect to medical procedures, any reference to medical or surgical instruments and medical or surgical methods is non-limiting. The systems, instruments, and methods described herein may be used for animals, human cadavers, animal cadavers, human or animal tissue removed from human or animal anatomy and not to be returned to such human or animal anatomy, non-surgical treatment, diagnosis, or cosmetic improvements. The systems, instruments, and methods described herein may also be used for industrial systems and general robotic or teleoperational systems, including those for manipulating or otherwise interacting with work pieces not comprising human or animal tissue. 
       FIG. 1  is a simplified diagram of a teleoperated medical system  100  according to some embodiments. In some embodiments, teleoperated medical system  100  may be suitable for use in, for example, surgical, diagnostic, therapeutic, or biopsy procedures. As shown in  FIG. 1 , medical system  100  generally includes a teleoperational manipulator assembly  102  for operating a medical instrument  104  in performing various procedures on a patient P. Teleoperational manipulator assembly  102  is mounted to or near an operating table T. An input control device or master assembly  106  allows an operator O (e.g., a surgeon, a clinician, or a physician as illustrated in  FIG. 1 ) to control teleoperational manipulator assembly  102  and, in some embodiments, to view the interventional site. 
     Teleoperational manipulator assembly  102  supports medical instrument  104  and may include a kinematic structure of one or more non-servo controlled links (e.g., one or more links that may be manually positioned and locked in place, generally referred to as a set-up structure) and a teleoperational manipulator. Teleoperational manipulator assembly  102  may optionally include a plurality of actuators or motors that drive inputs on medical instrument  104  in response to commands from the control system (e.g., a control system  112 ). The actuators may optionally include drive systems that, when coupled to medical instrument  104 , advance the medical instrument  104  into a naturally or surgically created anatomic orifice. Other drive systems may move the distal end of medical instrument  104  in multiple degrees of freedom, which may include three degrees of linear motion (e.g., linear motion along the X, Y, Z Cartesian axes) and in three degrees of rotational motion (e.g., rotation about the X, Y, Z Cartesian axes). Additionally, the actuators can be used to actuate an articulable end effector of medical instrument  104  for grasping tissue in the jaws of a biopsy device and/or the like. Actuator position sensors such as resolvers, encoders, potentiometers, and other mechanisms may provide sensor data to the medical system  100  describing the rotation and orientation of the motor shafts. This position sensor data may be used to determine motion of the objects manipulated by the actuators. 
     Teleoperated medical system  100  may include a sensor system  108  with one or more sub-systems for receiving information about the instruments of teleoperational manipulator assembly  102 . Such sub-systems may include a position/location sensor system (e.g., an electromagnetic (EM) sensor system); a shape sensor system for determining the position, orientation, speed, velocity, pose, and/or shape of a distal end and/or of one or more segments along a flexible body that may make up medical instrument  104 ; and/or a visualization system for capturing images from the distal end of medical instrument  104 . The sensor system  108  may include a plurality of sensors disposed along a kinematic chain of the manipulator assembly  102 , in some embodiments. 
     Teleoperated medical system  110  may also include a control system  112 . Control system  112  includes at least one memory and at least one computer processor (not shown) for effecting control between medical instrument  104 , master assembly  106 , sensor system  108 , and display system  110 , and/or other components of the medical system  100 . Control system  112  also includes programmed instructions (e.g., a non-transitory machine-readable medium storing the instructions) to implement some or all of the methods described in accordance with aspects disclosed herein, including instructions for providing information to display system  110 . While control system  112  is shown as a single block in the simplified schematic of  FIG. 1 , the system may include two or more data processing circuits with one portion of the processing optionally being performed on or adjacent to teleoperational manipulator assembly  102 , another portion of the processing being performed at master assembly  106 , and/or the like. The processors of control system  112  may execute instructions comprising instruction corresponding to processes disclosed herein and described in more detail below. Any of a wide variety of centralized or distributed data processing architectures may be employed. Similarly, the programmed instructions may be implemented as a number of separate programs or subroutines, or they may be integrated into a number of other aspects of the teleoperational systems described herein. In one embodiment, control system  112  supports wireless communication protocols such as Bluetooth, IrDA, HomeRF, IEEE 802.11, DECT, and Wireless Telemetry. 
     In some examples, control system  112  may transmit signals instructing one or more actuators of teleoperational manipulator assembly  102  to move medical instrument  104 . Medical instrument  104  may extend into an internal surgical site within the body of patient P via openings in the body of patient P. Any suitable conventional and/or specialized actuators may be used. 
     During a virtual navigation procedure, sensor system  108  may be used to compute an approximate location of medical instrument  104  with respect to the anatomy of patient P. The location can be used to produce both macro-level (external) tracking images of the anatomy of patient P and virtual internal images of the anatomy of patient P. The system may implement one or more electromagnetic (EM) sensors, fiber optic sensors, and/or other sensors to register and display a medical implement together with preoperatively recorded surgical images, such as those from a virtual visualization system, are known. For example U.S. patent application Ser. No. 13/107,562 (filed May 13, 2011) (disclosing “Medical System Providing Dynamic Registration of a Model of an Anatomic Structure for Image-Guided Surgery”) which is incorporated by reference herein in its entirety, discloses one such system. 
       FIG. 2A  is a simplified diagram of a medical instrument system  200  according to some embodiments, in some embodiments, medical instrument system  200  may be used as medical instrument  104  in an image-guided medical procedure performed with teleoperated medical system  100 . In some examples, medical instrument system  200  may be used for non-teleoperational exploratory procedures or in procedures involving traditional manually operated medical instruments, such as endoscopy. Optionally, medical instrument system  200  may be used to gather (i.e., measure) a set of data points corresponding to locations within anatomic passageways of a patient, such as patient P. 
     The medical instrument system  200  of  FIGS. 2A and 2B  includes elongate device  202  (also referred to as elongate instrument  202 ), such as a flexible catheter, coupled to a drive unit  204 . The drive unit  204  may include a plurality of actuators that can be controlled to steer a distal portion of the elongate device. In some embodiments, the drive unit  204  may include capstans or rotating elements that can be rotated to steer at least a distal portion of the elongate device  202 . Elongate device  202  includes a flexible body  216  having proximal end  217  and distal end  218 . 
     Medical instrument system  200  further includes a tracking system  230  for determining the position, orientation, speed, velocity, pose, and/or shape of distal end  218  and/or of one or more segments  224  along flexible body  216  using one or more sensors and/or imaging devices as described in further detail below. The entire length of flexible body  216 , between distal end  218  and proximal end  217 , may be effectively divided into segments  224 . If medical instrument system  200  is consistent with medical instrument  104  of a teleoperated medical system  100 , tracking system  230  may be included as a subsystem of the control system  112 . Thus, tracking system  230  may optionally be implemented as hardware, firmware, software or a combination thereof, which interact with or are otherwise executed by one or more computer processors, which may include the processors of control system  112  in  FIG. 1 . 
     Tracking system  230  may optionally track distal end  218  and/or one or more of the segments  224  using a shape sensor  222 . Shape sensor  222  may optionally include an optical fiber aligned with flexible body  216  (e.g., provided within an interior channel (not shown) or mounted externally). The optical fiber of shape sensor  222  forms a fiber optic bend sensor for determining the shape of flexible body  216 . In one alternative, multiple optical fiber cores including Fiber Bragg Gratings (FBGs) are used to provide strain measurements in structures in one or more dimensions. Various systems and methods for monitoring the shape and relative position of an optical fiber in three dimensions are described in U.S. patent application Ser. No. 11/180,389 (filed Jul. 13, 2005) (disclosing “Fiber optic position and shape sensing device and method relating thereto”); U.S. patent application Ser. No. 12/047,056 (filed on Jul. 16, 2004) (disclosing “Fiber-optic shape and relative position sensing”); and U.S. Pat. No. 6,389,187 (filed on Jun. 17, 1998) (disclosing “Optical Fibre Bend Sensor”), which are all incorporated by, reference herein in their entireties. Sensors in some embodiments may employ other suitable strain sensing techniques, such as Rayleigh scattering, Raman scattering, Brillouin scattering, and Fluorescence scattering. In some embodiments, the shape of the elongate device may be determined using other techniques. For example, a history of the distal end pose of flexible body  216  can be used to reconstruct the shape of flexible body  216  over the interval of time. In some embodiments, tracking system  230  may optionally and/or additionally track distal end  218  using a position sensor system  220 . Position sensor system  220  may be a component of an EM sensor system with positional sensor system  220  including one or more conductive coils that may be subjected to an externally generated electromagnetic field. Each coil of EM sensor system  220  then produces an induced electrical signal having characteristics that depend on the position and orientation of the coil relative to the externally generated electromagnetic field. In some embodiments, position sensor system  220  may be configured and positioned to measure six degrees of freedom, e.g., three position coordinates X, Y, Z and three orientation angles indicating pitch, yaw, and roll of a base point or five degrees of freedom, three position coordinates X, Y, Z and two orientation angles indicating pitch and yaw of a base point. Further description of a position sensor system is provided in U.S. Pat. No. 6,380,732 (filed Aug. 11, 1999) (disclosing “Six-Degree of Freedom Tracking System Having a Passive Transponder on the Object Being Tracked”), which is incorporated by reference herein in its entirety. 
     In some embodiments, tracking system  230  may alternately and/or additionally rely on historical pose, position, or orientation data stored for a known point of an instrument system along a cycle of alternating physiological motion, such as breathing. This stored data may be used to develop shape information about flexible body  216 . In some examples, a series of positional sensors (not shown), such as electromagnetic (EM) sensors similar to the sensors in position sensor  220  may be positioned along flexible body  216  and then used for shape sensing. In some examples, a history of data from one or more of these sensors taken during a procedure may be used to represent the shape of elongate device  202 , particularly if an anatomic passageway is generally static. 
     Flexible body  216  may also house cables, linkages, or other steering controls (not shown) that extend between drive unit  204  and distal end  218  to controllably bend distal end  218  as shown, for example, by broken dashed line depictions  219  of distal end  218 . In some examples, at least four cables are used to provide independent “up-down” steering to control a pitch of distal end  218  and “left-right” steering to control a yaw of distal end  281 . Steerable elongate devices are described in detail in U.S. patent application Ser. No. 13/274,208 (filed Oct. 14, 2011) (disclosing “Catheter with Removable Vision Probe”), which is incorporated by reference herein in its entirety. The drive unit  204  may include sensors or encoders that produce linear or rotational position data, force data characterizing a force applied by the drive unit  204  on a particular cable, and/or tension data characterizing a tension on a particular cable. Additionally, some embodiments of the drive unit  204  may include a sled or carriage that can be controlled to move the proximal end  217  of the flexible body  216 , and thereby the distal end  218 , along an insertion axis. The position of the carriage along the insertion axis may be monitored by a sensor or encoders. As noted herein, the sensors or encoders that provide position data may also provide velocity data and acceleration data that characterize movement of a medical instrument system like the medical instrument system  200 , for example. 
     Elongate device  202  may be steerable or, alternatively, the system may be non-steerable with no integrated mechanism for operator control of the bending of distal end  218 . In some examples, one or more lumens, through which medical instruments can be deployed and used at a target surgical location, are defined in the walls of flexible body  216 . 
     In some embodiments, medical instrument system  200  may include a flexible bronchial instrument, such as a bronchoscope or bronchial catheter, for use in examination, diagnosis, biopsy, or treatment of a lung. Medical instrument system  200  is also suited for navigation and treatment of other tissues, via natural or surgically created connected passageways, in any of a variety of anatomic systems, including the colon, the intestines, the kidneys and kidney calices, the brain, the heart, the circulatory system including vasculature, and/or the like. 
     The information from tracking system  230  may be sent to a navigation system  232  where it is combined with information from visualization system  231  and/or the preoperatively obtained models to provide the physician or other operator with real-time position information. In some examples, the real-time position information may be displayed on display system  110  of  FIG. 1  for use by the physician O in the control of medical instrument system  200 . In some examples, control system  112  of  FIG. 1  may utilize the position information as feedback for positioning medical instrument system  200 . Various systems for using fiber optic sensors to register and display a surgical instrument with surgical images are provided in U.S. patent application Ser. No. 13/107,562, filed May 13, 2011, disclosing, “Medical System Providing Dynamic Registration of a Model of an Anatomic Structure for Image-Guided Surgery,” which is incorporated by reference herein in its entirety. 
       FIG. 2C  illustrates a medical instrument system  250 , which may be used as the medical instrument system  104  in a medical procedure performed with teleoperated medical system  100 .  FIG. 2C  is a perspective view of a manipulator  252  of a control arm that may be mounted to or incorporated into the manipulator assembly  102  of  FIG. 1 . The medical instrument system  250  includes a kinematic chain made up of a plurality of joints. At least some of the joints in the kinematic chain include joint sensors or encoders that can communicate with the control system  112  of  FIG. 1  to provide joint sensor data to facilitate monitoring and control of the medical instrument system  250 . The joint sensor data may include position data such that the control system  112  can generate a model of the medical instrument system  250 , such that when a back end position and orientation of the manipulator  252  is known, a distal end position and orientation of each component along the kinematic chain of the medical instrument system  250 . 
     The manipulator  252  includes a yaw servo joint  254 , a pitch servo joint  256 , and an insertion and withdrawal (“I/O”) actuator  258 . A surgical instrument  259  is shown mounted at an instrument spar  260  including a mounting carriage  261 . Yaw servo joint  254  provides yaw motion  270 , pitch joint  256  provides pitch motion  272 , and I/O actuator  258  provides insertion and withdrawal motion  274  through the remote center. The manipulator  252  may include an encoder to track position, velocity, and/or acceleration associated with servo positions along the insertion axis of the I/O actuator  258  and other encoders to track position and velocity of yaw servo joint  254  and pitch servo joint  256 . 
     In some examples, medical instrument system  200  or the medical instrument system  250  may be teleoperated within the context of the medical system  100  of  FIG. 1  as the manipulator assembly  102  or a component thereof. In some embodiments, teleoperational manipulator assembly  102  of  FIG. 1  may be replaced by direct operator control. In some examples, the direct operator control may include various handles and operator interfaces for hand-held operation of the instrument. 
       FIGS. 3A and 3B  are simplified diagrams of side views of a patient coordinate space including a medical instrument mounted on an insertion assembly according to some embodiments. As shown in  FIGS. 3A and 3B , a surgical environment  300  includes the patient P is positioned on the operating table T. Within surgical environment  300 , a medical instrument  304  is coupled to an instrument carriage  306 . The medical instrument  304  may be provided by the medical instrument system  200  of  FIGS. 2A and 2B . In some embodiments, medical instrument  304  may use EM sensors, shape-sensors, and/or other sensor modalities. Instrument carriage  306  is mounted to an insertion stage  308  fixed within surgical environment  300 . Alternatively, insertion stage  308  may be movable but have a known location (e.g., via a tracking sensor or other tracking device) within surgical environment  300 . Instrument carriage  306  may be a component of a teleoperational manipulator assembly (e.g., teleoperational manipulator assembly  102 ) that couples to medical instrument  304  to control insertion motion (i.e., motion along the A axis) and, optionally, motion of a distal end  318  of an elongate device  310  in multiple directions including yaw, pitch, and roll. The elongate device  310  may be a flexible, steerable catheter. Instrument carriage  306  or insertion stage  308  may include actuators, such as servomotors, (not shown) that control motion of instrument carriage  306  along insertion stage  308 . 
     Elongate device  310  is coupled to an instrument body  312 . Instrument body  312  is coupled and fixed relative to instrument carriage  306 . In some embodiments, an optical fiber shape sensor  314  is fixed at a proximal point  316  on instrument body  312 . In some embodiments, proximal point  316  of optical fiber shape sensor  314  may be movable along with instrument body  312  but the location of proximal point  316  may be known (e.g., via a tracking sensor or other tracking device). Shape sensor  314  measures a shape from proximal point  316  to another point such as distal end  318  of elongate device  310 . Medical instrument  304  may be substantially similar to medical instrument system  200 . 
     A position measuring device  320  provides information about the position of instrument body  312  as it moves on insertion stage  308  along an insertion axis A. Position measuring device  320  may include resolvers, encoders, potentiometers, and/or other sensors that determine the rotation and/or orientation of the actuators controlling the motion of instrument carriage  306  and consequently the motion of instrument body  312 . In some embodiments, insertion stage  308  is linear. In some embodiments, insertion stage  308  may be curved or have a combination of curved and linear sections. 
       FIG. 3A  shows instrument body  312  and instrument carriage  306  in a retracted position along insertion stage  308 . In this retracted position, proximal point  316  is at a position L 0  on axis A. In  FIG. 3B , instrument body  312  and instrument carriage  306  have advanced along the linear track of insertion stage  308  and distal end  318  of elongate device  310  has advanced into patient P. In this advanced position, the proximal point  316  is at a position L 1  on the axis A. In some examples, encoder and/or other position data from one or more actuators controlling movement of instrument carriage  306  along insertion stage  308  and/or one or more position sensors associated with instrument carriage  306  and/or insertion stage  308  is used to determine the position L x  of proximal point  316  relative to position L 0 . In some examples, position L x  may further be used as an indicator of the distance or insertion depth to which distal end  318  of elongate device  310  is inserted into the passageways of the anatomy of patient P. 
       FIGS. 3A and 3B  also depict an anti-buckling guide  322 , which is an extendible mechanism, such as a lattice or other deployable structure, that supports the proximal end of the elongate device  310  during insertion and retraction. Additional details of exemplary extendible mechanisms are included in the disclosure of PCT/US17/41160 filed Jul. 7, 2017 titled “Guide Apparatus for Delivery of an Elongate Device and Methods of Use,” which is incorporated herein in its entirety. 
       FIG. 4  is a flowchart of a method  400  of monitoring patient motion during a medical procedure to detect motion of the patient undergoing the procedure. The method  400  may utilize a medical instrument having a primary purpose other than patient motion monitoring. As illustrated in  FIG. 4 , the method  400  includes several enumerated steps or operations, which may be performed in the illustrated sequence. Embodiments of the method  400  may include additional or alternative operations before, after, in between, or as part of the enumerated operations. Some embodiments of the method  400  may omit one or more of the enumerated operations. Furthermore, embodiments of the method  400  may include executable instructions stored on a computer-readable medium and executed by a processor, such as a processor of the control system  112  of  FIG. 1 , to perform the operations of method  400 . 
     Accordingly, an embodiment of the method  400  may begin at operation  402  in which state information may be received from a control system in communication with the medical instrument. At operation  404 , the control system may detect motion of at least a portion of the medical instrument. The control system may compare the motion of the portion of the medical instrument with a threshold motion value that is based on the state information received from the control system, at operation  406  to determine a state of the medical instrument or the patient. This may include determining patient motion. At operation  408 , the control system may generate a communication for rendering in a display system based on the comparison of the motion with the threshold motion value and determination of patient motion. And at operation  410 , the control system may alter control of the medical instrument based on the comparison. For example, the control system may alter control of the medical instrument by putting the medical instrument in a safe state or safe mode. This safe state may include removing power from a drive unit, like the drive unit  204  of  FIG. 2A , so that the medical instrument becomes compliant or limp. In some embodiments, the safe state may alter control of additional medical instrument or of instrument introduce via the medical instrument, such as an ablation probe or other energized instrument. In the safe state, the control system may disconnect or power down an energy supply provided to the energized instrument. 
     To better explain embodiments of the method  400 , reference is made herein to additional  FIGS. 5A-C  and  6 A-B, which relate to the positioning of the elongate device  310  of  FIGS. 3A and 3B  through anatomic passageways  502  of the lungs  500  of the patient P of  FIGS. 1 and 3 . These passageways  502  include the trachea and the bronchial airways. As shown in  FIGS. 3A and 3B , as the carriage  306  moves along the insertion stage  308 , the elongate device  310  is advanced within the anatomic passageways  502  of the lungs  500 . To navigate the elongate device  310  within the lungs  500 , the physician O may steer the distal end  318  of the elongate device  310  while directing the movement of the carriage  306  along the insertion axis A. In navigating through the anatomic passageways  502  (i.e., in a drive state or drive mode), the elongate device  310  assumes a shape that may be measured by the shape sensor  314  extending within the elongate device  310 . The control system  112  may also interrogate the shape sensor  314  and/or additional sensors that may provide shape and/or positional information (such as electromagnetic systems and/or joint sensors) when the elongate device  310  is in a parked state or parked mode in which no movement commands are received via the master assembly  106  from the physician O. At operation  402 , the state of the medical system  100  may be received by, the control system  112  from state information indicating which of several possible states is currently implemented. In addition to the parked state and the drive state, the medical system  100  may have a treatment state in which a medical treatment is being applied to the patient anatomy proximate the distal end  318  of the elongate device  310 . For example, the medical treatment may be the insertion of a biopsy needle, an ablation process, a cauterization process, an imaging process, an injection or drug delivery process, or any other medical treatment. 
     As described herein, in order to navigate to a desired location, the teleoperated medical system  100  may provide real-time imaging to the physician O. The real-time images may be captured images. In some embodiments, an image capture device is positioned at the distal end  318  of the elongate device  310 . The real-time images may be simulated or virtual images rendered based on a computer model derived from preoperative images or intraoperative images. The virtual images may depict the elongate device  310  in images that show an external perspective of the patient P. Additionally, the virtual images may depict a representation of the interior surfaces of the passageways  502  of the lung  500  from a perspective determined by the position and orientation of the distal and  318  of the elongate device  310 . Such imaging is discussed in more detail in connection with  FIGS. 6A and 6B , described further below. 
     At operation  404 , the control system  112  may detect motion of at least a portion of the elongate device  310 . Motion may be detected by monitoring for a change in the position of the elongate device  310  over time. For example, the position of the elongate device  310  may be sampled 10 times per second, 100 times per second, or at another suitable frequency. As shown in  FIG. 5B , the distal tip  318  of the elongate device  310  has moved from a first position  504 A to a second position  504 B. This motion may be quantified using information from the fiber optic shape sensor  314 , an electromagnetic position sensor, or by comparison of optical images obtained within the anatomical passageways  502 . The control system  112  may compare the movement between the first and second positions  504  with a threshold movement value. The threshold movement value may be implemented by the control system  112  to prevent false identification of movement of the distal end  318  as patient movement. For example, due to temperature fluctuations or other minor changes, a change in the indicated position of the distal tip  318 , or another portion of the elongate device  310 , may be registered without any significant positional change or movement taking place. 
     As illustrated in  FIG. 5B , the threshold movement value may be determined relative to the direction of movement. As shown, lateral movement of the distal tip  318  may have a threshold movement value  506 A, while the insertion/withdrawal (I/O) movement may have a threshold movement value  506 B. As illustrated, the lateral threshold movement value  506 A may be less than the I/O threshold movement value  506 B, in some embodiments. Additionally, the magnitude of the threshold movement values  506  may be dependent upon the state of the medical system  100 . For example, when the state information received at operation  402  indicates that the medical system  100  (or the manipulator assembly  102  thereof) is in a parked state, the magnitude of the threshold movement values  506  may be smaller than when the state information indicates a drive state. Furthermore, the threshold movement value may be realized as a shape in three-dimensions around the distal tip  318 , in some embodiments. Thus, a given movement of the distal tip  318  in Cartesian X, Y, and Z coordinates that moves beyond that three-dimensional threshold may be regarded by the control system  112  as indicative of patient motion. The shape may be circular, ovoid, rectangular, symmetric, asymmetric, or otherwise shaped. The three-dimensional threshold shape may be defined in part by the threshold movement values  506  and be a function thereof. In some embodiments, the frequency of detected movement and threshold movement may be quantified and compared alternatively or in addition to magnitude of detected and threshold movements to determine patient motion. 
     In general, actual movement of the elongate device  310  may occur when the medical system  100  is in the parked state due to cyclical physiological motion, such as respiratory motion in the lung  500 . In other embodiments, cardiac motions may be detected from shape/position information obtained from the elongate device  310 . Such expected natural motions may be considered by the control system  112  when identifying patient motion. In order to avoid incorrectly triggering the control system  112  to identify motion of the patient P due to expected physiological motion, the threshold movement values  506  associated with the parked state may be sufficient to account for such physiological motion. The shape/position information obtained from the elongate device  310  during the parked state may be used to identify and quantify, physiological motion such as from heartbeat or respiration. For example, shape/position information may be collected over a period of time and when identified as cyclical or periodic, can be considered physiological motion. The magnitude of the periodic motion can be used to help determine a value for threshold movement values used to establish patient motion. In additional embodiments, because the effect of physiological motion may depend upon the position of the elongate device  310 , the magnitude of the threshold movement values  506  may be based on an insertion depth or a three-dimensional position of the distal tip  318 . For example, because the main bronchii of the lungs  500  may move less than the bottom lobe of the lungs  500  during normal respiration, the threshold movement values may be lower when the portion of the elongate device  310  being monitored is positioned within the main bronchii than when it is positioned more deeply in the lungs  500 . In alternative embodiments, physiological motion can be detected using separate sensors or equipment such as a respiratory monitor, monitoring an artificial respirator, monitoring an electro-cardiogram of the patient, monitoring thoracic movement of the patient using a movement pad, and/or the like. 
     As shown in  FIG. 5B , the distal tip  318  has moved a distance greater than the lateral threshold movement value  506 A. Consequently, when the control system  112  compares the movement of the distal tip  318  with the lateral threshold movement value  506 A at operation  406 , the control system  112  may detect the movement as indicative of significant movement of the patient P. 
     Referring now to  FIG. 5C , patient motion may be detected during a drive state as well. As noted above, the threshold movement values  506  may be different when the medical system  100  is in a drive state than when the medical system  100  is in a parked state. Additionally, when the medical system  100  is in a parked state as indicated by state information received at operation  402 , the control system  112  may receive and analyze movement commands from the physician O as provided via the master assembly  106 . For example, prior to receipt of a movement command, the distal tip  318  of the elongate device  310  may be in a first position  508 A. A received movement command may be represented by the commanded motion vector  510 . In other words, the movement command received from the physician O is intended to and should direct the distal tip  318  (and the trailing portions of the elongate device  310 ) to move as indicated by the vector  510 , e.g. toward the wall alt the first branch point in the bronchus. 
     Instead, the distal tip  318  moves to a second position  508 B, as shown in  FIG. 5C . This movement may be calculated by the control system  112  as the actual motion vector  512 , which is different than the commanded motion vector  510 . Because the state information indicates that the medical system  100  is in a drive state, the control system  112  may compare the commanded motion vector  510  with the actual motion vector  512  and determine a difference therebetween. When the difference between the commanded motion vector  510  and the actual motion vector  512  exceeds a threshold motion value, the control system  112  may determine that some motion of patient P has occurred. In some embodiments, actuator current or torque may be measured and compared to the actual motion vector  512 . The comparison can be evaluated against a threshold actuator value to determine patient motion. For example, actuators may apply an amount of torque to hold or move the elongate device  310  at or to a desired position. If the elongate device  310  made contact with tissue during patient motion, the amount of torque required for the desired motion would be increased above the threshold actuator value indicating patient movement. 
     Referring now to  FIGS. 6A and 6B , shown therein are images that may be used by the control system  112  to determine a motion of the distal tip  318  of the elongate device  310 .  FIG. 6A  includes an image  600 A that represents a virtual view from the distal tip  318 . This virtual view is an interior view of a model of the lungs  500 , such as a surface model derived from preoperative or intraoperative medical images, such as a CT scan.  FIG. 6B  includes an image  600 B that represents an actual view obtained by an image capture device positioned at the distal tip  318  of the elongate device  310  positioned within lungs  500 . The control system  112  may select to the virtual view of image  600 A based on the state indicated by the received state information, in some embodiments. For example, when the medical system  100  is in a parked state, a position and orientation of the distal tip  318  of the elongate device  310  may be used to generate a virtual view of the three-dimensional surface model of the lungs from the perspective indicated by the position and orientation. When the medical system  100  is in a drive state, the control system  112  may generate and use a predicted perspective of the distal tip  318 , so that the actual image  600 B may be compared with the portion of the surface model that should be in view at a given time based on the commanded motion of the distal tip  318 . The control system  112  may utilize image processing techniques to compare the virtual view of the image  600 A with the actual view of the image  600 B. Depending on the relationship between the images  600 , the control system  112  may be able to estimate a difference in the perspectives therebetween. 
     In some embodiments, the control system  112  may search the model to find an image best corresponding to the actual image  600 B and then calculate a difference in position and orientation therebetween. The position of the expected image  600 A and the position of the searched-for image identified in the model corresponding best to the actual image  600 B may be calculated by the control system  112 . Additionally, the control system  112  may compare the actual image  600 B with the virtual image  600 A to determine a difference in position and/or orientation therebetween. The difference in position may be by used the control system  112  to determine a motion of the distal tip  318 . This motion may then be compared with a threshold motion value to determine whether the patient P has moved significantly. 
     In some embodiments, both the images  600 A and  600 B may be actual images. For example, the image  600 A may be an image obtained before a degree of motion is detected while the image  600 B may be an image obtained after that degree of motion is detected. The control system  112  may compare the images  600  with virtual views obtained from the model of the lungs  500 . For example, the control system  112  may utilize the images  600  to search for matching images provided by virtual views in an area close to the distal tip  318 . When matches of both the images  600  are identified, a vector between positions associated with the matched images in the model of lungs  500  may be used to identify motion of the distal tip  318 . This identified motion vector may be compared with a threshold motion value in an embodiment of the operation  406  of method  400 . 
     In some additional embodiments, more than one motion sensing modality may be used in detecting patient motion in order to improve accuracy. For example, information from both the shape sensor  314  (a first motion detecting modality) and image processing (a second motion detecting modality) may be used to determine that a patient motion has occurred. In some embodiments, thresholds may be set such that if either of two sensing modalities indicates motion, then the control system  112  takes steps to mitigate the motion. Additionally, other embodiments may include thresholds that are lower and are required to be exceeded for multiple modalities before the control system  112  identifies patient motion. 
     As described herein, reference is frequently made to motion of the patient P. Some embodiments of the present disclosure provide for the detection of motion of the patient P relative to the patient coordinate frame, the detection of motion of a portion of the patient P with respect to another portion (e.g., motion of the lungs relative to the trachea), and/or the detection of motion of the patient P relative to the medical system  100  itself. Some other embodiments of the present disclosure provide for the detection of motion of the patient P by detecting motion of the medical system  100  relative to the patient P. Thus, motion of the patient P as used herein may refer to relative motion between the body of the patient P and the medical instrument  104  and/or the manipulator assembly  102 , regardless of whether it is the body of the patient P that moves or whether it is the medical instrument  104  or manipulator  102  that moves. 
     In some instances, the physician O or another person present in the vicinity of the medical instrument  104  and/or the manipulator assembly  102  may cause motion of the medical instrument  104  and/or the manipulator assembly  102 . For example, the physician O may accidentally bump the instrument  104 , causing motion of the distal tip of the elongate device  310 . This accidental bumping of the instrument  104  may thus be interpreted by the control system  112  as patient motion. The control system  112  may automatically perform one or more operations to prevent harm from resulting from this patient motion. For example, the physician O may bump the medical instrument system  250  of  FIG. 2C . The encoders at the servo joints  254  and  256  may report motion or a change in position to the control system  112 . That motion would be compared with expected motion, whether in a parked state or a drive state, to determine whether or not the patient has moved. Thus, motion of components of the medical system  100  relative to patient P may be detected and responded to by the control system  112  as motion of the patient P. 
     Referring now to  FIG. 7 , an exemplary endotracheal (ET) tube  700  is illustrated as positioned within the patient P to facilitate insertion of the elongate device  310  into the lungs  500  of the patient P. A cross-sectioned portion  702  shows a portion of the elongate device  310  extending within the ET tube  700 . The geometry of the ET tube  700  may be provided to the control system  112  so that a bend  704  of the ET tube  700  may be known to the control system  112 . Even if a bend  704  in the tube is not precisely known, the curvature may be sufficiently distinctive to be identified in shape data as corresponding to the upper respiratory track and trachea because the portion of the elongate device  310  at the proximal end of the ET tube  700  forms a known angle (nearly 90°) with respect to the portion of the elongate device  310  at the distal end of the ET tube  700 . The pose of the proximal end of the elongate device  310  may be known due to sensors extending therein, like the optical fiber shape sensor  314  in the illustrated embodiment. Based on this shape information and known curvature of the ET tube  700 , the trachea of the patient P may be identified. During a medical procedure within the lungs, the trachea of the patient may be unlikely to move due to the presence of the elongate device  310 . Accordingly, the portion of the elongate device  310  positioned within the ET tube  700  at any given time may be monitored in order to identify any motion of the patient P. When motion of this portion of the elongate device  310  is detected by the control system  112 , the motion is likely, to be interpreted by the control system  112  as indicative of patient motion. In other words, a threshold motion value associated with the endotracheal tube  700  may be smaller than a threshold motion values used to detect patient motion at the distal tip  318  of the elongate device  310 . 
     Some embodiments of the ET tube  700  may include a known shape feature, such as the perturbation  706  shown near the distal end of the ET tube  700 . The perturbation  706  may be a small undulation or other feature that may be readily detected by the control system  112  from the shape information received from the elongate device  310 . In such embodiments, the portion of the elongate device  310  disposed within the perturbation  706  may be monitored to detect patient motion as described herein. Other embodiments of the method  400  of  FIG. 4  may rely on other structures in detecting motion of at least a portion of the medical instrument that is indicative of patient motion. 
     Returning again to  FIG. 4 , after motion of the portion of the medical instrument as compared with a threshold motion value or several threshold motion values, the control system  112  may generate a communication or message for rendering or presentation in the display system  110  based on the comparison performed at operation  406 . At operation  408 , the message may be generated and rendered in a display as shown in  FIG. 8 .  FIG. 8  depicts an embodiment of the display system  110  which includes a rendering of a graphical user interface  800 . As shown in  FIG. 8 , the user interface  800  includes a rendering of the lungs  500 , which may be a surface model derived from preoperative or intraoperative image data or a rendering of the image data itself. A model of the elongate device  310  is also rendered in the illustrated embodiment of the user interface  800 . An exemplary communication, patient motion message  802 , may be overlaid on the user interface  800  to communicate to the physician O that the patient P has moved or is likely to have moved is determined by the control system  112 . For example, the patient motion message  802  may include text (e.g. “Warning: patient motion detected!”) and/or graphical elements to communicate to the physician O. In some embodiments, the message  802  may be displayed as a moving message or graphic across the bottom, middle, or top of a display. The patient motion message  802  may include one or more graphical user interface elements associated with options to be presented to the physician O. For example, the patient motion message  802  may include an interface element (e.g., a selectable button) associated with an option  804 A whereby the physician O may request that the control system  112  discard the existing registration and perform a new registration between the lungs  500  and a model of the lungs  500 . Selecting the option  804 A may also comprise a request to update an existing registration. The message  802  may include displaying a numerical value (or a graphical representation of the numerical value) indicating a detected magnitude of patient motion based on sensor measurements and/or differences in sequential images. In some embodiments, the patient motion message  802  may include an interface element associated with an option  804 B, the selection of which may cause the control system  112  to resume operation without updating the registration or performing a new registration. 
     Other communications or messages may be generated by the control system  112 . For example, the control system  112  may cause the screen or an element on the screen to flash or pulse. The message may include a sound emitted from a speaker coupled to the control system  112 , such as an alarm sound or a verbal message. The message may be interactive and provide options the physician O to take some action (for example request an update to a registration or request a new registration) or to ignore the detected motion. In some implementations, the control system  112  may ignore or filter out any movement commands or end effector actuation commands, until the physician O acknowledges the alert message by pushing a physical button, a virtual button, or speaks a verbal command. 
     Some implementations of the method  400  may include an operation that identifies a magnitude of the difference between the motion of the portion of the medical instrument and the threshold motion value or values. A threshold control value may be applied such that ignoring the patient motion message  802  by selecting the option  804 B is permitted by the control system  112  only when the difference is below the threshold control value. When the difference is greater than a threshold control value, the option  804 B may not be presented to the physician O. Additionally, when the difference exceeds the threshold control value, the control system  112  may alter control of the medical instrument at operation  410 . For example, the control system  112  may ignore subsequent motion commands received from the master assembly  106  until a new registration is performed or an existing registration is updated. In this manner, the control system  112  may prevent the physician O from relying on a registration that is likely to be unreliable due to a relatively large motion of the patient P or of the medical system  100 . Similarly, any commands associated with the performance of a treatment, such as the performance of a biopsy with a biopsy needle protruding from the distal tip  318 , may be ignored until a reliable registration is provided to compensate for the motion of the patient P. 
       FIG. 9  is a flowchart of a method  900  for monitoring patient movement during a medical procedure according to some embodiments.  FIG. 9  depicts the method  900  as a series or sequence of operations. Embodiments of the method may include additional or alternative operations before, after, in between, or as part of the enumerated operations. Some embodiments of the method  900  may include computer-readable instructions or programming that, when executed by a processor of the control system  112 , the processor causes the operations to be performed or implemented to improve the monitoring of patient movement during a medical procedure. 
     The illustrated embodiment of the method  900  begins at operation  902 , in which the processing device of a control system generates a first model of the medical instrument, also referred to as a current measured model. The first model may correspond to the medical instrument at a first insertion position of the anatomy. In one embodiment, the first model may be understood as characterizing the current measured state of the medical instrument. In some instances, the first model of the medical instrument may be understood as a set of data that represents the state (e.g., pose, shape, or motion) of the medical instrument, which may include the elongate device  202  of  FIGS. 2A and 2B , as well as the manipulator  252  of  FIG. 2C , and/or the carriage  306  and insertion stage  308  of  FIGS. 3A and 3B . The set of data may include measured data associated with points along the length of a catheter. As an example, the first model of the medical instrument may be generated by the control system  112  using data from a rotational or translational sensor indicative of a rotational or translational position, velocity, or acceleration of a capstan, rotational drive element, or linear drive element in the drive unit  204  or in manipulator assembly  102  of  FIG. 2 . As another example, the control system  112  may use tension sensors that monitor the tension on cables extending through a medical instrument to control a distal end thereof. As another example, the control system  112  may use data from the joint sensors described with respect to the medical instrument system  250  of  FIG. 2C . The data from the joint sensors may be combined with known component lengths in the control arm of manipulator  252  and/or of the length of the flexible body  216  to generate a model of the medical instrument. Alternatively or additionally, the control system may use a fiber optic shape sensor, like the shape sensor  314  of  FIGS. 3A and 3B , or a set of electromagnetic coils disposed at positions along the length of the medical instrument to generate at least some of the data used in producing the first model. In some instances, the first model of the medical instrument may model all of the moving components of a medical instrument system, such that the medical instrument can be fully modeled in a known reference frame. In some instances, the first model may describe only a portion of the medical instrument. For example, only the distal end  218  of the flexible body  216  of the elongate device  202  ( FIGS. 2A and 2B ) is included in the first model in some embodiments. In some embodiments, the data may be captured for a portion of the medical device that is in a measurement zone established by locations in anatomy. That measurement zone may be based on an insertion depth within the anatomy such as a landmark and a set retraction or insertion distance from that landmark. In a particular example, the measurement zone may include the main carina and/or areas within a particular distance proximal to the carina in the trachea. The measurement zone may be determined during registration. In an example, a retraction distance within the trachea proximally from the carina may be defined. When the carina is determined, the insertion depth is recorded and then the measurement zone is established as a fixed distance in the retraction direction as identified by the insertion axis encoder. The data is measured for the section of the catheter that is within that measurement zone. In some embodiments, the measurement zone is determined based on an endotracheal tube of the elongate instrument of an anti-bucking guide of the elongate instrument. 
     At operation  904 , a processing device generates a second model of the medical instrument. The second model may be produced by the control system  112  and may be based on a different data source than the first model, a subset of the sources incorporated in the first model, or a combination of the different data source and the subset of the sources incorporated in the first model. In this example, the second model may be understood as characterizing a predicted state (e.g., pose, shape, or motion) of the medical instrument, and is also referred to as a predicted model. 
     As described in connection with method  900 , the second model is a predicted model that indicates what the expected state (e.g., pose, shape, or motion) of the first model given certain assumptions. The assumptions may include many factors, such as the measured state of the medical instrument at one or more previous times. The measured state of the medical instrument at the one or more previous times may be measured at the one or more previous times and recorded by the processing device. The underlying assumptions may further include data from one or more rotational or translational sensors in the drive unit  204  of  FIG. 2  at the current time. The underlying assumptions may include a combination of assumptions. For example, the second model may combine the measured state(s) (e.g. using one or more corresponding reference models) of the medical instrument with the data from one or more rotational or translational sensors (such as insertion) in the drive unit  204  of  FIG. 2  at the current time. 
     As illustrated in  FIG. 9 , in some embodiments, operation  904  includes operation  905 A- 1 , where a processing device generates a first reference model of the medical instrument based on the measured state of the medical instrument at a first reference insertion position. The first reference insertion position of operation  905 A- 1  may be the same as or different from the first insertion position of operation  902 . The operation  904  further includes operation  905 A- 2 , where a processing device generates a second reference model of the medical instrument based on the measured state of the medical instrument at a second reference insertion position. The second reference insertion position of operation  905 A- 2  may be the same as or different from the first reference insertion position of operation  905 A- 1  and/or first insertion position of operation  902 . The measured states of the medical instrument of operations  905 A- 1  and  905 A- 2  may be measured at a time (also referred to as a previous time) before a time (also referred to as current time) of operation  902 . It is noted that while two reference models from operations  905 A- 1  and  905 A- 2  are described, operation  904  may include operations to generate any number (e.g., one, two, . . . , N) of reference models associated with reference insertion positions that are the same as or different from each other. 
     In some embodiments, operation  904  includes operation  905 B, where a processing device generates the predicted model of the medical instrument (e.g., at the first insertion position of operation  902 ) based on the one or more reference models of operations  905 A- 1  and  905 A- 2 . For example, the predicted model may be generated using the first insertion position of the first model of operation  902  and/or the reference insertion positions of reference models of operations  905 A- 1  and  905 A- 2 . In some embodiments, the predicted model may include a probability distribution of the possible expected state of the medical instrument, including for example, a mean and a standard deviation. 
     The time separation between the “current time” and the “previous time” may be short, e.g. milliseconds or seconds, but may also be longer. For example, the previous time may be the last time a registration algorithm was performed, which could be measured on the order of minutes. The assumptions may further include knowledge of the mechanical behavior of the medical instrument, for example the expected motion of the distal end of the flexible body  216  of the elongate device  202  based on measured motion of the proximal end. This expected motion may be based on the physical dimensions and properties of the components that make up the elongate device  218 , in addition to the measured motion of the proximal end. The underlying assumptions may further include knowledge of the tissues of the patient P that provide the environment surrounding the medical instrument when in use. For example, CT scans may be segmented and processed to categorize the tissue types around the work site and to define their dimensions. The control system  112  may include a table of physical properties associated with each of the tissue types and may use a three-dimensional model of patient anatomy and the physical properties of the tissue types in order to predict how the tissue will affect the medical instrument. For example, the patient anatomy may push on the medical instrument in one direction or another such that the control system  112  predicts a location of the pushed portion of the medical instrument based on the anatomy and its properties, e.g., its propensity to push the medical instrument in a particular direction with a particular force. 
     At operation  906 , the control system  112  compares the state (e.g., pose, shape, or motion) of the first model (e.g., generated at operation  902 ) and the predicted model (e.g., generated at operation  904 ). In some embodiments, the operation  906  may include a comparison of only a segment (e.g., a measurement zone) of the medical instrument, such as a segment extending through an endotracheal tube (ET tube) or laryngeal mask airway (LMA) or a segment of the medical instrument extending within the trachea of the patient P. Referring to the examples of  FIGS. 10A through 10F , graphical representations of first model, reference model, and predicted model are illustrated. The examples of  FIGS. 10A, 10B, and 10C  illustrate that a difference between the first model and predicted model is below a particular threshold (e.g., for determining a patient movement). In the examples of  FIGS. 10D, 10E, and 10F  illustrate that a difference between the first model and predicted model is above a particular threshold (e.g., for determining a patient movement). 
     Referring now to  FIGS. 10A and 10B , shown therein are graphical representations of system configurations with a medical instrument positioned within patient anatomy. Each of the models  1000  includes several components, which may be present or absent in the varying embodiments provided herein.  FIG. 10C  shows a graphical representation of a first model  1010  (also referred to as measured model  1010 ), and an exemplary predicted model  1012 . 
     In the example of  FIG. 10A , a first configuration  1000 A includes a first component  1002 , a second component  1004 , and a third component  1006 . The first component  1002  represents a manipulator like the manipulator  252 , having rigid segments connected by joints. The second component  1004  represents an insertion stage, like the insertion stage  308  of  FIGS. 3A and 3B . The second component  1004  may be coupled to the first component  1002  in a fixed manner or by a hinge having a sensor thereon such that the relationship between the component  1002  and  1004  is known to the control system  112 . The third component  1006  represents a medical instrument with a flexible body, like the flexible body  216  of the elongate device  202  shown in  FIGS. 2A and 2B . The flexible body of the third component  1006  may be coupled to the second component  1004  by a backend mechanism and may have a fixed or measured orientation with respect to the backend mechanism. The third component  1006  may further include a shape sensing system, such as a fiber-optic shape sensor or a series of electromagnetic sensors. By querying sensors distributed from the proximal end of the medical instrument to the distal end thereof, a set of data points along the length of the medical instrument may be collected and used to determine and store lengths and other geometric information associated with the included components, the state (e.g., pose, shape, or motion) of the medical instrument may be measured and modeled by the control system  112 . Additionally, the control system  112  may query tens, hundreds, or thousands of times a second to be able to measure motion of the medical instrument. 
     Similarly, a reference configuration  1000 B includes a first component  1002 , a second component  1004 , and a third component  1006 . The reference configuration  1000 B may be substantially similar to the first configuration  1000 A, except that the reference configuration  1000 B is generated based on a measured state of the medical instrument at a time (e.g., previous time) different from a time (e.g., current time) associated with the first configuration  1000 A. In the example of  FIGS. 10A and 10B , the first configuration  1000 A is associated with a first insertion position, the reference configuration  1000 B is associated with a reference insertion position, and there is a distance D 1  between the first insertion position and the reference insertion position. In the examples of  FIGS. 10A and 10B , the components  1002  and  1002 B and the components  1004 A and  1004 B have substantially similar poses.  FIGS. 10A and 10B  show the models  1000 A and  1000 B, according to some embodiments. Between these two figures, the position of the back end mechanism on the component  1004 A and  1004 B has changed. The movement D 1  of the backend mechanism results in the retraction of the flexible component modeled as  1006 A and  1006 B. 
     As shown in  FIG. 10C , the control system  112  may perform a comparison of multiple models including for example a predicted model  1012  and a first model  1010 . The first model  1010  and the predicted model  1012  can each be generated based on data representing the shape of the medical instrument  1006  within a specified zone, such as a measurement zone  1008 , each taken at different times and/or different insertion distances. 
     The first model first model  1010  may be generated from one or more current states or one or more currently measured models, for example, taken during the system configuration  1000 A. 
     The predicted model  1012  may be generated from one or more previous states or one or more previously measured models, for example taken during the system configuration  1000 B (e.g., reference configurations associated with reference models of operation  905 A- 1  and  905 A- 2 ), and one or more commands received from an operator while the medical instrument was in the previous state, such as an insertion command for an insertion distance. For example, the predicted model  1012  may be generated using the previous position of the backend mechanism of reference configuration  1000 B, and knowledge of the input commands and actuator commands received, issued, and implemented in connection with the movement D 1 . The predicted model  1012  may further include state information, such as input received from the user that described a desired motion to be implemented by actuators. The input may be defined in terms of the manipulation of an input device, such as the master assembly  106 , and/or as the translation of that into control signals for actuators such as a capstan that applies tension on a cable in order to move or otherwise actuate the medical instrument. While  FIG. 10C  illustrates a predicted model  1012  associated with the third component  1006  in the measurement zone  1008 , in various embodiments, the predicted model  1012  may also be associated with the entire length of the third component  1006 , e.g., using data for the entire length of the catheter. 
     Additionally, as noted herein the predicted model  1012  may further be based on anatomical information or other information that characterizes the surrounding environment of the medical instrument, such as tissue that is pushing against a portion of the medical instrument. Additionally, the predicted model may use data from the user input device. For example, if the user commands the system through the input device to bend left, the predicted model would show the catheter bending left in its prediction. In some instances, the predicted model would include the predicted result of movement commands included in state information characterizing the reference models of operation  905 A- 1  and  905 A- 2 . For example, the reference models of operation  905 A- 1  and  905 A- 2  may include the actual configuration of the medical instrument resulting from a movement command and/or the movement command itself, while the predicted model  1012  includes the predicted configuration of the medical instrument based on the movement command. The control system  112  may detect differences in the actual configuration and the predicted configuration. 
     In some embodiments, the measured model  1010  generated from the first configuration  1000 A and the predicted model  1012  generated at least in part from reference configuration  1000 B (and its corresponding reference model) have substantially overlapping shapes within the measurement zone  1008 , but differ in shape at the proximal and distance ends. Comparisons may include all components of the measured model  1010  and predicted model  1012  or a subset thereof. In some embodiments, as shown in  FIG. 10C , the comparison may be based on a measured model  1010  and a predicted model  1012 , in the measurement zone  1008 , ignoring the components  1002  and  1004 . In the example of  FIG. 10C , measured model  1010  and predicted model  1012  substantially overlap with each other. Thus, in the example of  FIG. 10C , it is determined that there is no patient movement because the difference between measured model  1010  and predicted model  1012  is less than a particular threshold. 
     Referring to the examples of  FIGS. 10D, 10E, and 10F , a difference in position of patient anatomy is illustrated, resulting in a difference between a first model and predicted model above a particular threshold (e.g., for determining a patient movement).  FIGS. 10D and 10E  illustrate graphical representations of a first system configuration  1000 D and a reference system configuration  1000 E.  FIG. 10F  illustrates an exemplary comparison of a first model  1010  (e.g., generated from first system configuration  1000 D) and a predicted model  1012  (e.g., generated from reference model generated from reference configuration  1000 E). The system configurations  1000 D and  1000 E are substantially similar to the system configurations  1000 A and  1000 B, while the comparison of  FIG. 10F  is substantially similar to the comparison of  FIG. 10C , except for the differences described below.  FIG. 10D  illustrates a shift in patient anatomy  502 .  FIG. 10F  shows that the first model  1010  and the predictive model  1012  diverge from each other. The comparison performed at operation  906  may identify this divergence (e.g., in terms of its magnitude and pose), between the first model  1010  and predicted model  1012 . Based on this, the control system  112  may determine a current state of the instrument represented by the system configurations  1000 A or  1000 D, or a current state of the patient, based on the comparison, at operation  908 . As described herein, the control system  112  may also determine whether the patient has moved based on the comparison and identification, at operation  910 . In the example of  FIG. 10F , the control system  112  may determine that the difference between measured first model  1010  and predicted model  1012  exceed a particular threshold, and thereby determine that the patient has moved. 
     The comparison performed at operation  906  may be a comparison of any or all of the components  1002 ,  1004 , and  1006  or of specific portions thereof, by for example, shifting the measurement zone  1008 . For example, some comparisons may include only a comparison of the portion of the component  1006  inside the anti-buckling guide  322  of  FIGS. 3A and 3B . In some embodiments, different weights may be assigned to different components of the medical instrument or of different portions of the different components. For example, some embodiments of the operation  906  may include a comparison of only a segment (e.g., a measurement zone  1008 ) of the measured component  1006 A and the predicted component  1006 C, such as a segment extending through an endotracheal tube (ET tube) or laryngeal mask airway (LMA) or a segment of the medical instrument extending within the trachea of the patient h. In some instances, comparing the models may include comparison of the measured and predicted motions or shapes in a particular direction or along or away from a particular place. For example, the models may be compared based on their motion in a direction normal to the table T, in a direction parallel to the table T, or in some other direction of interest. Determining the state of the patient may include determining that the patient has moved and may include determining a type of movement of the patient, such as an identification of a cough or of normal period motion, such as respiratory motion. Alternatively or additionally, determining the state of the patient or instrument may include determining an additional component used in the medical procedure. For example, the state may indicate that the medical instrument is introduced into the patient via a particular trocar cannula, through a particular ET tube, through a particular LMA, etc. Shape information included in the state may be matched to known geometries of a plurality of such entry devices. Determining the state of the patient may also include detecting buckling of the portion of the medical instrument disposed in the anti-budding guide  322 . 
       FIG. 11A  shows a representation of the measured model  1010  and the predicted model  1012  relative to a lung L of the patient P. In some instances, such graphical representations may be provided to an operator of the medical instrument in a display, such as the display system  110  of  FIG. 1 . FIG. HA shows multiple diverges along the length of the models. In some instances, the comparison may be performed at regular intervals along the lengths of the models. In some instances, only the divergences in a particular direction are noted. For example,  FIG. 11B  shows a side view of the models  1000 A and  1000 C, divergences or differences D 4 , D 5 , D 6 , and D 7  are labeled. These divergences may be numerically represented along an axis normal to the table T. 
     Returning to operation  910 , the control system  112  may determine whether the patient has moved based on the comparison of the measured model  1010  and the predicted model  1012 . As noted, in some instances only specific segments of the model may be compared. For example, only the area around the divergence D 4  in  FIG. 11B  may be compared in some embodiments and used to determine whether the patient P has moved. In order to determine whether the patient P has moved, the control system  112  may compare any identified divergences or differences with a threshold value. This threshold value may be different depending on the component of the models being compared or the specific portions of the models being compared. For example, when the divergence D 4  is greater than 10 mm, 5 mm, or 1 mm, the control system  112  may identify the divergence D 4  is indicating that the patient P has moved. In general, the divergence may be determined in many ways, such as an absolute magnitude, but also in the magnitude in a specific direction, or in terms of frequency of motion. The indication of the patient P has moved is determined relative to the medical instrument, such that a movement of the medical instrument relative to the patient (for example, the cart supporting the medical instrument may be accidentally pushed) is interpreted as patient movement. The thresholds applied in determining whether the patient P has moved may be dependent upon the approximate location of the medical instrument relative to the work site or environment surrounding the medical instrument. For example, the threshold for a divergence in the area of the trachea may be different than the threshold for a divergence in the area that is inside or likely to be inside the lungs. The threshold may also be different depending on the task being performed or the required level of accuracy. For example, the threshold may be set more stringent if the system is being used to access to a particular small region, if the target area is close to a sensitive body structure such as a vessel or the pleura, or if the nature of the tasks (for example ablation) requires more accuracy. The control system  112  may include such information and utilize it during comparison and determination operations. 
     In some embodiments, the difference between the measured model and the predicted model is determined by comparing the points of the measured model with the points of the predicted model (e.g., based on one or more comparison criteria). It may be determined that there is no patient movement if the difference is less than a corresponding threshold of the comparison criterion, and that there is patient movement if the difference is equal to or greater than the corresponding threshold. Various comparison criteria with corresponding thresholds may be used. In an example, the difference is based on a sum of amplitude differences between measured points of measured model  1010  and corresponding predicted points of predicted model  1012 , and the corresponding threshold is a total threshold distance (e.g., 15 mm). In another example, the difference is determined using an amplitude difference (e.g., in a radial direction) and/or a length difference (e.g., in a linear direction along the insertion axis). In yet another example, the difference is determined using an average amplitude difference or a maximum amplitude difference over the entire length of the measurement zone  1008 . In some examples, the amplitude is based on a maximum along the entire length of the measurement zone  1008 . In yet another example, the comparison criteria provide comparison of movement properties (e.g., frequency, velocity, acceleration, etc.) and shape properties (e.g., amplitude, peak numbers, dip numbers, curvature, etc.) with corresponding threshold. In some embodiments, the comparison criteria may provide that the threshold is based on the distribution of the predicted model  1012 . For example, it may be determined that there is a patient movement if the measured model  1010  in the measurement zone  1008  is outside of a standard deviation of the distribution of the predicted model  1012 . 
     As a result of the operation  910 , the control system  112  may take an action such as issuing an alert to an operator via the display system  110  and/or by altering control of the medical instrument based on the comparison and determination as shown in  FIG. 9  at operation  912 . In some embodiments, the control system  112  may display a patient motion message  802  as shown in  FIG. 8 . In some embodiments, the user may ignore or dismiss an alert or message, or may be unable to dismiss a message until an action is taken. The control system  112  may ignore, disregard, or not implement any movement commands or end effector actuation commands received from the operator until the message  802  is acknowledged or interface element options  804 A and/or  804 B are selected. In some embodiments, the control system  112  may actively attempt to maintain the actual location of the medical instrument or may allow the medical instrument to compliantly yield to pressures and forces applied by tissues and surrounding environment. In another embodiment, the control system may disable energy supply to an energized instrument, such as an ablation probe, that is used in the method  900  to treat a patient. Additionally, the control system  112  may instruct the user to perform a registration process or update an existing registration between the medical instrument, a model of the patient anatomy, and the actual patient anatomy when the control system determines that the patient P has moved. This is because movement of the patient P may cause an existing registration of these features to become unreliable and unsuitable for use by the operator. 
     Embodiments of the present disclosure may provide for the detection of patient motion using sensors disposed on structures required for the medical procedure being performed and using measured and predicted models of the pose and/or motion of the utilized medical instruments. For example, rather than use a dedicated system for monitoring motion of the patient (such as optical, EM, or fiber optic sensors) the existing sensors and systems such as the fiber optic shape sensor  314  of the elongate device  310  may be relied upon to obtain positioning, orientation, and/or shape information. This information may be primarily used by the control system  112  in characterizing the catheter for purposes of registration and use in image-guided medical procedures. As described herein such information may be used secondarily to monitor for patient motion to prevent use of unreliable registrations. In many embodiments, the systems described herein allow for such dedicated systems to be replaced, enabling more information to be obtained from fewer pieces of equipment. This can make a procedure more affordable and can remove clutter from the work site. 
     One of ordinary skill in the art may be able to identify combinations of disclosed embodiments and additional features that are within the scope of the present disclosure. Accordingly, the spirit and scope of the present disclosure may be best understood by reference to the following claims.