Patent Publication Number: US-2018049808-A1

Title: Method of using soft point features to predict breathing cycles and improve end registration

Description:
BACKGROUND 
     Technical Field 
     The present disclosure relates to modeling movement with an area of interest of a patient&#39;s body and, more particularly, to devices, systems, and methods for automatically registering and updating a three-dimensional model of the area of interest , with a patient&#39;s real features, throughout a breathing cycle. 
     Description of Related Art 
     A common device for inspecting the airway of a patient is a bronchoscope. Typically, the bronchoscope is inserted into a patient&#39;s airways through the patient&#39;s nose or mouth and can extend into the lungs of the patient. A typical bronchoscope includes an elongated flexible tube having an illumination assembly for illuminating the region distal to the bronchoscope&#39;s tip, an imaging assembly for providing a video image from the bronchoscope&#39;s tip, and a working channel through which instruments, e.g., diagnostic instruments such as biopsy tools, therapeutic instruments can be inserted. 
     Bronchoscopes, however, are limited in how far they may be advanced through the airways due to their size. Where the bronchoscope is too large to reach a target location deep in the lungs, a clinician may utilize certain real-time imaging modalities such as fluoroscopy. Fluoroscopic images, while useful, present certain drawbacks for navigation as it is often difficult to distinguish luminal passageways from solid tissue. Moreover, the images generated by the fluoroscope are two-dimensional whereas navigating the airways of a patient requires the ability to maneuver in three dimensions. 
     To address these issues, systems have been developed that enable the development of three-dimensional models of the airways or other luminal networks, typically from a series of computed tomography (CT) images. One such system has been developed as part of the ILOGIC® ELECTROMAGNETIC NAVIGATION BRONCHOSCOPY® (ENB™), system currently sold by Medtronic PLC. The details of such a system are described in commonly assigned U.S. Pat. No. 7,233,820, entitled ENDOSCOPE STRUCTURES AND TECHNIQUES FOR NAVIGATING TO A TARGET IN BRANCHED STRUCTURE, filed on Mar. 29, 2004, by Gilboa, and commonly assigned U.S. patent application Ser. No. 13/836,203, entitled SYSTEM AND METHOD FOR NAVIGATING WITHIN THE LUNG, by Brown, the entire contents of which are incorporated herein by reference. 
     While the system as described in U.S. Pat. No. 7,233,820 is quite capable, there is always a need for development of improvements and additions to such systems. 
     SUMMARY 
     Provided in accordance with the present disclosure is a method of registering an area of interest to images of the area of interest. In an aspect of the present disclosure, the method includes generating a model of the area of interest based on images of the area of interest, determining a location of a soft point in the area of interest, tracking a location of the location sensor while the location sensor is navigated within the area of interest, comparing the tracked locations of the location sensor within the area of interest , navigating the location sensor to the soft point, confirming the location sensor is located at the soft point, and updating the registration of the model with the area of interest based on the tracked locations of the location sensor at the soft point. 
     In a further aspect of the present disclosure, the method further includes displaying guidance for navigating a location sensor within the area of interest. 
     In an additional aspect of the present disclosure, the method further includes displaying guidance for navigating a location sensor within the area of interest. The location sensor includes magnetic field sensors configured to sense the magnetic field and to generate position signals in response to the sensed magnetic field. 
     In another aspect of the present disclosure, confirming the location sensor is located at the soft point includes imaging the soft point using CT, ultrasonic, or elastographic imaging. 
     In yet another aspect of the present disclosure, the method further includes identifying a static point on the patient, comparing the location of the soft point to a static point on the patient, and updating the registration of the model with the area of interest based on the comparison of the tracked location of the soft point to the static point. 
     In a further aspect of the present disclosure, the static point is a vertebral body, a main carina, sternum, thyroid cartilage, rib or an esophagus. 
     In another aspect of the present disclosure, the area of interest is an airway of a patient and the model is a model of the airway of the patient. 
     In yet another aspect of the present disclosure, the method further includes generating patient tidal volume breathing movement data, comparing the patient tidal volume breathing movement data with location sensor movement over a respiratory cycle, and updating the registration of the model with the area of interest based on the comparison of the patient volume breathing movement data with location sensor over a respiratory cycle to further enhance registration and localization of the sensor or tool as well as its position to an area of interest. 
     In a further aspect of the present disclosure, the method further includes placing a second location sensor on the patient&#39;s chest and tracking a location of the second sensor over time. 
     In another aspect of the present disclosure, the method further includes imaging the patient&#39;s chest from a position approximately parallel to the patient&#39;s nipple line and monitoring a location of an edge of the patient&#39;s chest over time. 
     In another aspect of the present disclosure, the location sensor is navigated through a luminal network. 
     In a further aspect of the present disclosure, the location sensor is further navigated through a wall in the luminal network after navigating through the luminal network. 
     In yet another aspect of the present disclosure, the location sensor is navigated percutaneously into and through the area of interest to the soft point. 
     Provided in accordance with the present disclosure is a system for registering an area of interest to a model of the area of interest. In an aspect of the present disclosure, the system comprises a location sensor capable of being navigated within the area of interest inside a patient&#39;s body, an electromagnetic field generator configured to detect the location of a location sensor as it is navigated within the area of interest, a monitor configured to determine external patient motion, a display capable of displaying an image of the location sensor within a soft point, and a computing device including a processor and a memory. The a memory stores instructions which, when executed by the processor, causes the computing device to generate a model of the area of interest based on images of the area of interest, identify a soft point within the model of the area of interest, display guidance for navigating the location sensor within the area of interest, track the location of the location sensor while the location sensor is navigated within the area of interest, compare the tracked location of the location sensor within the area of interest and the external patient motion while the sensor is located at the soft point, and update the registration of the model with the area of interest based on the comparison of the tracked locations of the location sensor and the external patient motion while the location sensor is at the soft point. 
     In a further aspect of the present disclosure, the area of interest is an airway of a patient and the model is a model of the airway of the patient. 
     In a further aspect of the present disclosure, the instructions, when executed by the processor, further cause the computing device to identify a known static point on the patient, compare the location of the known soft point about the patient&#39;s chest to a known static point, and update the registration of the model with the area of interestbased on the comparison of the tracked location of the soft point to the static point. 
     In another aspect of the present disclosure, the static point is on a vertebral body, a main carina, rib, sternum, thyroid cartilage, or an esophagus. 
     In yet another aspect of the present disclosure, the compared tracked location of the location sensor within the area of interest and the external patient motion are saved in a database to generate a predictive model according to patient characteristics. 
     Any of the above aspects and embodiments of the present disclosure may be combined without departing from the scope of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects and features of the present disclosure are described herein below with references to the drawings, wherein: 
         FIG. 1  is a perspective view of an electromagnetic navigation system in accordance with the present disclosure; 
         FIG. 2  is a flowchart illustrating a method of using soft points to improve registration of a luminal network to a model of the luminal network, provided in accordance with and embodiment of the present disclosure 
         FIG. 3  is a flowchart illustrating a method of using soft points and tidal volume calculations to improve registration of a luminal network to a model of the luminal network, provided in accordance with and embodiment of the present disclosure. 
         FIG. 4  is yet a flowchart illustrating a method of using soft points and static points to improve registration of a luminal network to a model of the luminal network, provided in accordance with and embodiment of the present disclosure. 
         FIG. 5A  is a graphical illustration of the target management mode in accordance with embodiments of the present disclosure; 
         FIG. 5B  is a subsequent graphical illustration of the target management mode in accordance with embodiments of the present disclosure after a ; 
         FIG. 6  is an illustration of a user interface of the workstation of  FIG. 7  presenting a view for performing navigation to a target further presenting a central navigation tab; 
         FIG. 7  is a schematic diagram of a workstation configured for use with the system of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure is directed to devices, systems, and methods for performing localized registration of a bronchial tree to improve an initial registration and better depict a patient&#39;s airways and lung movement due to patient breathing. The localized registration methods of the present disclosure involve navigating a sensor to a soft point target, confirming the location of the sensor with an imaging system, and initiating a tracking protocol to track the location of the sensor over a period of time, such as a period encompassing a breathing cycle. The tracked location of the sensor over time allows a localized registration of various points with respect to a previously imaged and previously model registration of a bronchial tree. 
     With reference to  FIG. 1 , an electromagnetic navigation (EMN) system  10  is provided in accordance with the present disclosure. Among other tasks that may be performed using the EMN system  10  are planning a pathway to target tissue, navigating a catheter assembly to the target tissue, navigating a biopsy tool or treatment tool, such as an ablation catheter, to the target tissue to obtain a tissue sample from the target tissue using the biopsy tool, digitally marking the location where the tissue sample was obtained, and placing one or more echogenic markers at or around the target. 
     EMN system  10  generally includes an operating table  40  configured to support a patient; a bronchoscope  50  configured for insertion through the patient&#39;s mouth and/or nose into the patient&#39;s airways; monitoring equipment  60  coupled to bronchoscope  50  for displaying video images received from bronchoscope  50 ; a tracking system  70  including a tracking module  72 , a plurality of reference sensors  74 , and an electromagnetic field generator  76 ; a workstation  80  including software and/or hardware used to facilitate pathway planning, identification of target tissue, navigation to target tissue, and digitally marking the biopsy location 
       FIG. 1  also depicts two types of catheter guide assemblies  90 ,  100 . Both catheter guide assemblies  90 ,  100  are usable with EMN system  10  and share a number of common components. Each catheter guide assembly  90 ,  100  includes a handle  91 , which is connected to an extended working channel (EWC)  96 . EWC  96  is sized for placement into the working channel of a bronchoscope  50 . In operation, a locatable guide (LG)  92 , including an electromagnetic (EM) sensor  94 , is inserted into EWC  96  and locked into position such that EM sensor  94  extends a desired distance beyond a distal tip  93  of EWC  96 . The location of EM sensor  94 , and thus the distal end of EWC  96 , within an electromagnetic field generated by electromagnetic field generator  76  can be derived by tracking module  72 , and workstation  80 . Catheter guide assemblies  90 ,  100  have different operating mechanisms, but each contain a handle  91  that can be manipulated by rotation and compression to steer distal tip  93  of LG  92  and EWC  96 . Catheter guide assemblies  90  are currently marketed and sold by Covidien LP under the name SUPERDIMENSION® Procedure Kits. Similarly, catheter guide assemblies  100  are currently sold by Covidien LP under the name EDGE™ Procedure Kits. Both kits include a handle  91 , EWC  96 , and LG  92 . For a more detailed description of the catheter guide assemblies  90 ,  100 , reference is made to commonly-owned U.S. patent application Ser. No. 13/836,203 entitled MICROWAVE ABLATION CATHETER AND METHOD OF UTILIZING THE SAME, filed on Mar. 15, 2013, by Ladtkow et al., the entire contents of which are hereby incorporated by reference. 
     As illustrated in  FIG. 1 , the patient is shown lying on operating table  40  with bronchoscope  50  inserted through the patient&#39;s mouth and into the patient&#39;s airways. Bronchoscope  50  includes a source of illumination and a video imaging system (not explicitly shown) and is coupled to monitoring equipment  60 , e.g., a video display, for displaying the video images received from the video imaging system of bronchoscope  50 . 
     Catheter guide assemblies  90 ,  100  including LG  92  and EWC  96  are configured for insertion through a working channel of bronchoscope  50  into the patient&#39;s airways (although the catheter guide assemblies  90 ,  100  may alternatively be used without bronchoscope  50 ). LG  92  and EWC  96  are selectively lockable relative to one another via a locking mechanism  99 . A six degrees-of-freedom electromagnetic tracking system  70 , e.g., similar to those disclosed in U.S. Pat. No. 6,188,355, entitled WIRELESS SIX-DEGREE-OF-FREEDOM LOCATOR, filed on Dec. 14, 1998, by Gilboa, and published PCT Application Nos. WO 2000/10456 entitled INTRABODY NAVIGATION SYSTEM FOR MEDICAL APPLICATIONS, filed on Jul. 7, 1999, by Gilboa et al. and WO 2001/67035, entitled OBJECT TRACKING USING A SINGLE SENSOR OR A PAIR OF SENSORS, filed on Sep. 3, 2001, by Gilboa et al., the entire contents of each of which is incorporated herein by reference, or any other suitable positioning measuring system, is utilized for performing navigation, although other configurations are also contemplated. Tracking system  70  is configured for use with catheter guide assemblies  90 ,  100  to track the position of EM sensor  94  as it moves in conjunction with EWC  96  through the airways of the patient, as detailed below. 
     As shown in  FIG. 1 , electromagnetic field generator  76  is positioned beneath the patient. Electromagnetic field generator  76  and the plurality of reference sensors  74  are interconnected with tracking module  72 , which derives the location of each reference sensor  74 . One or more of reference sensors  74  are attached to the chest of the patient. One or more reference sensors  74  may also be attached to a plurality of locations including those at static points such as i.e. a vertebral body, a main carina, sternum, thyroid cartilage, rib, an esophagus, etc. or at soft points such as i.e. a nipple line, an esophagus, a rib outline, a secondary carina, etc. The coordinates of reference sensors  74  are sent to workstation  80 , which includes and application  81  which uses data collected by sensors  74  to calculate a patient coordinate frame of reference. 
     Also shown in  FIG. 1  is a catheter biopsy tool  102  that is insertable into catheter guide assemblies  90 ,  100  following navigation to a target and removal of LG  92 . Biopsy tool  102  is used to collect one or more tissue samples from the target tissue. As detailed below, biopsy tool  102  is further configured for use in conjunction with tracking system  70  to facilitate navigation of biopsy tool  102  to the target tissue, tracking of a location of biopsy tool  102  as it is manipulated relative to the target tissue to obtain the tissue sample, and/or marking the location where the tissue sample was obtained. 
     Although navigation is detailed above with respect to EM sensor  94  being included in LG  92  it is also envisioned that EM sensor  94  may be embedded or incorporated within biopsy tool  102  where biopsy tool  102  may alternatively be utilized for navigation without need of LG  92  or the necessary tool exchanges that use of LG  92  requires. A variety of useable biopsy tools are described in Pub. Nos. U.S. 2015/0141869 and U.S. 2015/0265257 both entitled DEVICES, SYSTEMS, AND METHODS FOR NAVIGATING A BIOPSY TOOL TO A TARGET LOCATION AND OBTAINING A TISSUE SAMPLE USING THE SAME, filed May 21, 2015 and Sep. 24, 2015, respectively, by Costello et al., and in Pub. No. WO2015076936having the same title and filed Sep. 30, 2014, by Costello et al., the entire contents of each of which is incorporated herein by reference and useable with EMN system  10  as described herein. 
     During procedure planning, workstation  80  utilizes computed tomographic (CT) image data for generating and viewing the 3D model of the patient&#39;s airways, enables the identification of target tissue on the 3D model (automatically, semi-automatically or manually), and allows for the selection of a pathway through the patient&#39;s airways to the target tissue. More specifically, the CT scans are processed and assembled into a 3D volume, which is then utilized to generate the 3D model of the patient&#39;s airways. The 3D model may be presented on a display monitor associated with workstation  80 , or in any other suitable fashion. Using workstation  80 , various slices of the 3D volume and views of the 3D model may be presented and/or may be manipulated by a clinician to facilitate identification of a target and selection of a suitable pathway through the patient&#39;s airways to access the target. The 3D model may also show marks of the locations where previous biopsies were performed, including the dates, times, and other identifying information regarding the tissue samples obtained. These marks may also be selected as the target to which a pathway can be planned. Once selected, the pathway is saved for use during the navigation procedure. An example of a suitable pathway planning system and method is described in Pub. Nos. U.S. 2014/0281961; U.S. 2014/0270441; and 2014/0282216, all entitled PATHWAY PLANNING SYSTEM AND METHOD, filed on Mar. 15, 2014, by Baker, the entire contents of each of which is incorporated herein by reference. During navigation, EM sensor  94 , in conjunction with tracking system  70 , enables tracking of EM sensor  94  and/or biopsy tool  102  as EM sensor  94  or biopsy tool  102  is advanced through the patient&#39;s airways. 
     Referring now to  FIG. 2 , there is shown a flowchart of an example method for updating the registration of the 3D model with a patient&#39;s airways. As described above, at step  202 , an area of interest, for instance the chest and lungs, of a patient is imaged using imaging methods such as, for example, a CT scan. At step  204 , a target is identified in the images generated in step  202 . Once a target is established, at step  206 , a path through the branches of the airways to the target is generated in the CT image data. Once the pathway plan has been developed and is accepted by the clinician, the pathway plan can be utilized in a navigation procedure using the EMN system  10 . The pathway plan is loaded into an application on workstation  80  and displayed. Then, at step  208 , application  81  performs the registration of the CT scan with the patient&#39;s airways, as described above, and in particular as described in co-pending U.S. patent application Ser. No. 14/790,581, entitled REAL TIME AUTOMATIC REGISTRATION FEEDBACK, filed on Jul. 2, 2015, by Brown et al., the entire contents of which is incorporated herein by reference. During registration, the location of EM sensor  94  within the patient&#39;s airways is tracked, and a plurality of points denoting the location of EM sensor  94  within the EM field generated by EM generator  76  is generated. When sufficient points have been collected, the application  81  compares the locations of these points to the 3D model and seeks to fit all the points within the lumens of the 3D model. When a fit is established, signifying that the majority if not all of the points have been fit within the area defined by the 3D model of the airway, the patient and the 3D model are registered to one another. As a result, detected movement of the EM sensor  94  within the patient can be accurately depicted on the display of the workstation  80  as a sensor  94  traversing the 3D model or a 2D image from which the 3D model was generated. 
     At step  210 , a physician or application  81  may identify one or more soft point targets, e.g., a nipple line, an esophagus, a rib outline, a secondary carina, etc. Once a soft point is established, at step  212 , a path to the target is generated in the CT image data by Application  81 . The path may provide guidance for navigation of the EM sensor through the bronchial network of the lung to or near the soft point. The path may then further provide for the EM sensor to be guided from a location near the soft point, through a bronchial wall of the lungs to a soft point located outside of, but near the bronchial tree. In the alternative, the path may provide guidance for the EM sensor to be inserted percutaneously through the patient&#39;s skin to the location of the soft point with or without additional guidance through the bronchial tree. After the pathway plan has been developed and is accepted by the clinician, the pathway plan can be utilized in a navigation procedure using the EMN system  10 . Application  81  begins navigation process, at step  214  by displaying guidance for navigating EM sensor proximate to a soft point target, such as i.e. a nipple line, an esophagus, a rib outline, a secondary carina, etc., while tracking the location of EM sensor  94 . In the alternative, by viewing a live video feed from a camera located proximate EM sensor  94  (e.g., in a bronchoscope) a soft point target may be detected visually by a clinician. Thereafter, at step  216 , the clinician or application  81  may determine whether the sensor is located proximate to a determined soft point target. Unless the clinician or application  81  determines that EM sensor  94  is proximate a soft point target, processing returns to step  214  where further guidance is displayed. 
     At step  218 , the soft point target is imaged while EM sensor  94  is located proximate the soft point using, for example, CT imaging, cone beam CT imaging, or ultrasonic imaging. Using the image generated in step  218 , at step  220 , a clinician or application  81  confirms EM sensor&#39;s  94  location at the soft point. If it is determined that the EM sensor  94  is not at the soft point target, processing returns to step  214  where further guidance is displayed. If EM sensor  94  is confirmed to be proximate the soft point, processing proceeds to step  222 . 
     At step  222 , application  81  uses the stored points denoting the location of EM sensor  94  to perform localized registration to update the 3D model with the patient&#39;s airways proximate the soft point target. For example, localized registration may be performed based on a range of interpolation techniques, such as Thin Plates Splines (TPS) interpolation. In embodiments, TPS interpolation may be used for non-rigid registration of the points denoting the location of EM sensor  94  within the EM field generated by EM generator  76  stored during automatic registration with the 3D model, and may be augmented by additional points stored during localized registration. 
     At step  224 , application  81  or a clinician determines updating registration to be complete if there are no remaining soft point targets for which localized registration is to be performed. If updating registration is not complete, processing returns to step  214 , where application  81  displays guidance for navigating EM sensor  94  proximate the next soft point target. If updating registration is complete, the processing ends. 
     Turning to  FIG. 3 , there is shown another flowchart of an example method for updating a registration of the 3D model with a patient&#39;s airways. At step  302 , application  81  displays guidance for navigating, through the a luminal network, through a wall of a luminal network, or percutaneously through a patient&#39;s skin, EM  94  sensor proximate to a soft point target, such as i.e. a nipple line, an esophagus, a rib outline, a secondary carina, etc., near a treatment target, while tracking the location of EM sensor  94 . In the alternative, by viewing a live video feed from a camera located proximate EM sensor  94  (e.g., in a bronchoscope) a soft point target may be detected visually by the clinician. Thereinafter, at step  304 , a clinician or application  81  determines whether EM sensor  94  is proximate to the soft point target. If no, processing returns to step  302 , where application  81  resumes displaying guidance for navigating EM sensor  94  proximate the soft point target. If yes, processing proceeds to step  306 . 
     At step  306 , the soft point target is imaged while EM sensor  94  is located proximate the soft point using, for example, CT imagining, cone beam CT imaging, or ultrasonic imaging. Using the image generated in step  306 , at step  308 , a clinician or application  81  may confirm EM sensor&#39;s  94  location at the soft point. In confirming whether EM sensor  94  is located at the soft point, the image generated in step  406  may be displayed on display  706  ( FIG. 7 ). If it is determined that the EM sensor  94  is not at the soft point target, processing returns to step  302  where further guidance is displayed. If EM sensor  94  is confirmed to be proximate the soft point, processing proceeds to step  310 . 
     At step  310 , the movement of the patient&#39;s chest caused by tidal volume breathing is sampled throughout one or more cycles of the patient&#39;s breathing cycle. Movement caused by tidal volume breathing may be sampled using one or more optical cameras positioned to view and record the movement of the patient&#39;s chest. The movement of the patient&#39;s chest may be used to estimate the movement caused by tidal breathing. In the alternative, sensors  74  may be sampled to determine the movement of the patient&#39;s chest during the patient&#39;s tidal breathing. The movement of the patient&#39;s chest sensed using sensors  74  similarly maybe be used to estimate the movement cause by tidal breathing. 
     At step  312 , application  81  receives the patient&#39;s tidal volume movement data and location data from EM sensor  94  and correlates the data sets. By correlating the data sets, the present disclosure seeks to apportion the observed chest movement to movement of the EM sensor  94 . That is, if the chest is observed moving a distance in one direction (e.g., normal to the longitudinal axis of the spine) a determination can be made as to the magnitude of the movement that could be observed in the airway of the lungs proximate EM sensor  94 . Application  81  saves the data and correlates the patient&#39;s volume breathing movement data and location data from EM sensor  94  according to the time the data points were received. 
     The saved data may be transferred and saved to a larger database and conglomerated with similar saved data from other patients in order to be utilized in future procedures. The database also includes additional factors of each patient such as height, weight, sex, gender, peak expiratory flow rate, and forced expiratory volume. By analyzing the saved data of many patients saved on the database, a predictive model may be generated to determine a likely location of a target within the lungs or to update a model of the patient&#39;s lungs without performing an invasive procedure. The predictive model may further incorporate additional factors to create a comprehensive estimation of movement throughout the breathing cycle. 
     In practice, a physician performs a CT scan on a patient&#39;s lungs and generates a model. Then, the physician measures movement caused by tidal volume breathing using, for example, one or more optical cameras positioned to view and record the movement of the patient&#39;s chest, and generates data. Finally, the measured movement data and patient&#39;s additional factors are input into the predictive model in order to generate a predicted estimation of points within the lungs or to improve the model generated in the CT scan throughout the breathing cycle. 
     At step  314 , application  81  uses the correlated tidal movement volume data and EM sensor  94  location data to perform localized registration to update the 3D model with the patient&#39;s airways proximate the soft point target. For example, localized registration may be performed based on a range of interpolation techniques, such as Thin Plates Splines (TPS) interpolation. In embodiments, TPS interpolation may be used for non-rigid registration of the points denoting the location of EM sensor  94  within the EM field generated by EM generator  76  stored during automatic registration with the 3D model, and may be augmented by additional points stored during localized registration. As a result of the correlation in step  312  and the registration updating in step  314 , the detected movement of the EM sensor  94 , which otherwise would be depicted on the display of static CT images, or the 3D model derived therefrom, is modified to more accurately display the location of the EM sensor  94  and any tool it is operatively connected to within the airways of the patient. Without such correlation and localized registration, the detected location of the EM sensor  94  can appear to be outside of the airways of the patient during certain portions of the patient&#39;s breathing cycle. 
     At step  316 , the updated registration is incorporated into the model and guidance is display to enable a physician to navigate to the treatment target. Upon reaching the treatment target, at step  318 , a procedure is performed. The updated registration provides a more accurate representation of the location of the treatment target. All updates to the registration are performed as background processes as the user only view the results of the updated registration. 
     At step  320 , application  81  or a clinician determines if there are additional treatment targets. If treatment targets remain, processing returns to step  302 , where application  81  displays guidance for navigating EM sensor  94  proximate the next soft point near the next treatment target. If no treatment targets remain, the process is complete and processing ends. 
     Referring now to  FIG. 4 , there is shown a flowchart of an example method for updating a registration of the 3D model with a patient&#39;s airways. As described above, at step  502 , an area of interest, for instance the chest and lungs, of a patient is imaged using imaging methods such as, for example, a CT scan. At step  404 , application  81  displays guidance for performing the registration of the CT scan with the patient&#39;s airways, as described above. During registration, the location of EM sensor  94  within the patient&#39;s airways is tracked, and a plurality of points denoting the location of EM sensor  94  within the EM field generated by EM generator  76  is stored. 
     At step  406 , a physician or application  81  may identify one or more soft point targets, such as i.e. a nipple line, an esophagus, a rib outline, a secondary carina, etc. Application  81  begins the localized registration process by displaying guidance for navigating, through the a luminal network, through a wall of a luminal network, or percutaneously through a patient&#39;s skin, EM sensor  94  proximate to a soft point target, such as i.e. a nipple line, an esophagus, a rib outline, a secondary carina, etc., while tracking the location of EM sensor  94 . In the alternative, by viewing a live video feed from a camera located proximate EM sensor  94  (e.g., in a bronchoscope) a soft point target may be detected visually by the clinician. Thereafter, at step  408 , the clinician or application  81  may determine whether the sensor is located proximate to a determined soft point target. If the clinician or application  81  determines that EM sensor  94  is not proximate a soft point target, processing returns to step  406  where further guidance is displayed. 
     At step  410 , the soft point target is imaged while EM sensor  94  is located proximate the soft point using, for example, CT imagining, cone beam CT imaging, or ultrasonic imaging. Using the image generated in step  410 , at step  412 , a clinician or application  81  may confirm EM sensor&#39;s  94  location at the soft point. If it is determined that the EM sensor  94  is not at the soft point target, processing returns to step  406  where further guidance is displayed. If EM sensor  94  is confirmed to be proximate the soft point, processing proceeds to step  414 . 
     At step  414 , the movement of the patient&#39;s chest caused by tidal volume breathing is sampled throughout one or more cycles of the patient&#39;s breathing cycle. Movement caused by tidal volume breathing may be sampled using one or more optical cameras positioned to view and record the movement of the patient&#39;s chest. The movement of the patient&#39;s chest may be used to estimate the movement caused by tidal breathing. n the alternative, sensors  74  may be sampled to determine the movement of the patient&#39;s chest during the patient&#39;s tidal breathing. The movement of the patient&#39;s chest sensed using sensors  74  similarly maybe be used to estimate the movement cause by tidal breathing. 
     At step  416 , a clinician or application  81  may identify a static point, a point that moves minimally during a patient breathing cycle, such as, for example, a vertebral body, a main carina, thyroid cartilage, or an esophagus. Many of these static points will appear and will be cognizable and measureable on the initial CT scans and 3D generated model. Others may be monitored with sensors  74  placed on or near the identified static point. At step  418 , the patient&#39;s tidal volume movement data is sampled throughout one or more cycles of the patient&#39;s breathing cycle. 
     At step  420 , application  81  receives location data from EM sensor  94  throughout the patient&#39;s breathing cycle. The patient&#39;s breathing cycle is determined and monitored using the tidal volume monitor activated in step  414  and sampled in step  418 . The location data from EM sensor  94  is converted into location data within the 3D model and compared to the location of the identified static point by application  81  to determine the location of the soft point relative to the static point throughout the breathing cycle. The relative location of the static point may be determined using, for example, triangulation. Potential methods of triangulation include, for example, direct linear transformation, mid-point determination of the Euclidean distance, essential matrix transformation, and optimal triangulation performed by determining the minimum-weight of various potential triangles from a set of points in a Euclidean plane. The relative soft point locations are stored as soft point data denoting the location of EM sensor  94 . 
     At step  422 , application  81  uses the soft point location data denoting the location of EM sensor  94  to perform localized registration to update the 3D model with the patient&#39;s airways proximate the soft point target. For example, localized registration may be performed based on a range of interpolation techniques, such as Thin Plates Splines (TPS) interpolation. In embodiments, TPS interpolation may be used for non-rigid registration of the points denoting the location of EM sensor  94  within the EM field generated by EM generator  76  stored during automatic registration with the 3D model, and may be augmented by additional points stored during localized registration. 
     At step  424 , application  81  or a clinician determines if updating registration is complete if there are no remaining soft point targets for which localized registration has not been performed. If updating registration is not complete, processing returns to step  406 , where application  81  displays guidance for navigating EM sensor  94  proximate the next soft point target. If updating registration is complete, the localized registration updating processing ends. 
       FIGS. 5A and 5B  illustrate various windows that user interface  716  can present on the display  706  ( FIG. 7 ) in accordance with embodiments of the present disclosure. Display  706  may present specific windows based on a mode of operation of the endoscopic navigation system  10 , such as, for example, a target management mode, a pathway planning mode, and a navigation mode. 
       FIGS. 5A and 5B  also illustrate the target management mode in accordance with embodiments of the present disclosure. After a target is identified, clinicians may review and manage to prioritize or confirm a location or size of each target. The target management mode may include a 3D map window  510  and three windows including the axial view window  530 , the coronal view window  550 , and the sagittal view window  570 . The 3D map window  510  may be located on the left side and show a target  215 . Three windows  530 ,  550 , and  570  are selected based on the location of the target. 
       FIG. 5A  shows a possible interface display after an initial registration. The initial registration allows for the physician to create a navigation plan to navigate to a soft spot near a treatment target. Upon reaching the soft spot and performing any of the localized registration methods described in  FIGS. 2-4  at the site, the 3D Map view  510 , the axial view window  530 , the coronal view window  550 , and the sagittal view window  570  automatically update.  FIG. 5B  shows an updated display following a localized registration ( FIG. 5A and 5B  are shown in stark contrast merely for illustration purposes). As a physician navigates using any of the 2D or 3D displays  510 ,  530 ,  550 , and  570 , the displays further automatically update in order to present a stable image as the patient&#39;s chest moves during breathing cycles. The updating of the displays, as viewed from the perspective of the physician will remain unchanged, thus allowing the physician to navigate and apply treatment with a steady and accurate view. 
     During navigation, user interface  716  ( FIG. 7 ) may also present the physician with a view  650 , as shown, for example, in  FIG. 6 . View  650  provides the clinician with a user interface for navigating to a target, such as a soft point target or a treatment target, including a central navigation tab  654 , a peripheral navigation tab  656 , and a target alignment tab  658 . Central navigation tab  654  is primarily used to guide the bronchoscope  50  through the patient&#39;s bronchial tree. Peripheral navigation tab  456  is primarily used to guide the EWC  96 , EM sensor  94 , and LG  92  toward a target, including a soft point target and a treatment target. Target alignment tab  658  is primarily used to verify that LG  92  is aligned with a target after LG  92  has been navigated to the target using the peripheral navigation tab  656 . View  650  also allows the clinician to select target  652  to navigate by activating a target selection button  660 . 
     Each tab  654 ,  656 , and  658  includes a number of windows  662  that assist the clinician in navigating to the soft point target. The number and configuration of windows  662  to be presented is configurable by the clinician prior to or during navigation through the activation of an “options” button  664 . The view displayed in each window  662  is also configurable by the clinician by activating a display button  666  of each window  662 . For example, activating the display button  666  presents the clinician with a list of views for selection by the clinician including a bronchoscope view  670 , virtual bronchoscope view  672 , 3D map dynamic view  682 , MIP view (not shown), 3D map static view (not shown), sagittal CT view (not shown), axial CT view (not shown), coronal CT view (not shown), tip view (not shown), 3D CT view (not shown), and alignment view (not shown). 
     Bronchoscope view  670  presents the clinician with a real-time image received from the bronchoscope  50 , as shown, for example, in  FIG. 6 . Bronchoscope view  670  allows the clinician to visually observe the patient&#39;s airways in real-time as bronchoscope  50  is navigated through the patient&#39;s airways toward a target. 
     Virtual bronchoscope view  672  presents the clinician with a 3D rendering  674  of the walls of the patient&#39;s airways generated from the 3D volume of the loaded navigation plan, as shown, for example, in  FIG. 6 . Virtual bronchoscope view  672  also presents the clinician with a navigation pathway  676  providing an indication of the direction along which the clinician will need to travel to reach a target. The navigation pathway  476  may be presented in a color or shape that contrasts with the 3D rendering  674  so that the clinician may easily determine the desired path to travel. 
     3D map dynamic view  682  presents a dynamic 3D model  684  of the patient&#39;s airways generated from the 3D volume of the loaded navigation plan. Dynamic 3D model  684  includes a highlighted portion  686  indicating the airways along which the clinician will need to travel to reach a target. The orientation of dynamic 3D model  684  automatically updates based on movement of the EM sensor  94  within the patient&#39;s airways to provide the clinician with a view of the dynamic 3D model  684  that is relatively unobstructed by airway branches that are not on the pathway to the target. 3D map dynamic view  682  also presents the virtual probe  679  to the clinician as described above where the virtual probe  679  rotates and moves through the airways presented in the dynamic 3D model  684  as the clinician advances the LG  92  through corresponding patient airways. 
     After performing any of the registration update methods shown in  FIGS. 2-4 , program  81  controls bronchoscope view  670 , virtual bronchoscope view  672 , 3D map dynamic view  682  according to the updated registration throughout the breathing cycle. As the patient&#39;s chest moves during breathing cycles, the updated registration accounts for the movement in order to show stable bronchoscope view  670 , virtual bronchoscope view  672 , and 3D map dynamic view  682 . Stable views allow a clinician to navigate EWC  96 , EM sensor  94 , and LG  92  toward a treatment target or an additional registration target without continually disruptive chest movements causing as unstable view. Thus, the clinician is provided with more control and a simpler user experience navigating EWC  96 , EM sensor  94 , and LG  92  to the treatment target. 
     When a treatment target is reached, catheter biopsy tool  102  may be guided through EWC  96  and LG  92  so that treatment may be provided at the treatment target. While at the target, the improved localized registration allows for the target to be tracked more accurately in real time throughout the breathing cycle. As the procedure is carried out, the updated registration allows a physician to maintain treatment at the treatment target and avoid applying unwanted treatment on health tissue which may be adversely affected. 
     The improved localized registration additionally improves application of treatment to a treatment target outside of the airways. An access tool may be guided through EWC  96  or LG  92  to a location near a treatment or biopsy target. While near the treatment target, the improved localized registration allows for the target to be tracked more accurately through the walls of the tracheobronchial wall in real time throughout the breathing cycle. The improved tracking of the target reduces risk of increased damage to the bronchial tree when the access tool punctures the tracheobronchial wall to provide access to the treatment target. 
     The improved localized registration further aids percutaneous navigation and approach planning. The improved localized registration informs the location of the target as well as the location of other internal body features throughout the breathing cycle. A physician or application  81  may then determine a path for guiding a percutaneous needle to avoid puncturing internal body features while creating an accurate path to the treatment target to apply treatment throughout the breathing cycle. 
     Turning now to  FIG. 7 , there is shown a system diagram of workstation  80 . Workstation  80  may include memory  702 , processor  704 , display  706 , network interface  708 , input device  710 , and/or output module  712 . 
     Memory  702  includes any non-transitory computer-readable storage media for storing data and/or software that is executable by processor  704  and which controls the operation of workstation  80 . In an embodiment, memory  702  may include one or more solid-state storage devices such as flash memory chips. Alternatively or in addition to the one or more solid-state storage devices, memory  702  may include one or more mass storage devices connected to the processor  704  through a mass storage controller (not shown) and a communications bus (not shown). Although the description of computer-readable media contained herein refers to a solid-state storage, it should be appreciated by those skilled in the art that computer-readable storage media can be any available media that can be accessed by the processor  704 . That is, computer readable storage media includes non-transitory, volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules or other data. For example, computer-readable storage media includes RAM, ROM, EPROM, EEPROM, flash memory or other solid state memory technology, CD-ROM, DVD, Blu-Ray or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by workstation  80 . 
     Memory  702  may store application  81  and/or CT data  214 . Application  81  may, when executed by processor  704 , cause display  706  to present user interface  716 . Network interface  708  may be configured to connect to a network such as a local area network (LAN) consisting of a wired network and/or a wireless network, a wide area network (WAN), a wireless mobile network, a Bluetooth network, and/or the internet. Input device  710  may be any device by means of which a clinician may interact with workstation  80 , such as, for example, a mouse, keyboard, foot pedal, touch screen, and/or voice interface. Output module  712  may include any connectivity port or bus, such as, for example, parallel ports, serial ports, universal serial busses (USB), or any other similar connectivity port known to those skilled in the art. 
     While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto. 
     Detailed embodiments of such devices, systems incorporating such devices, and methods using the same are described above. However, these detailed embodiments are merely examples of the disclosure, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting but merely as a basis for the claims and as a representative basis for allowing one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. While the example embodiments described above are directed to the bronchoscopy of a patient&#39;s airways, those skilled in the art will realize that the same or similar devices, systems, and methods may also be used in other lumen networks, such as, for example, the vascular, lymphatic, and/or gastrointestinal networks.