Abstract:
Disclosed are systems, devices, and methods for marking a main carina and a trachea of a patient, an exemplary method comprising importing slice images of a chest of the patient, generating a three-dimensional (3D) model based on the imported slice images, displaying the 3D model in a graphical user interface (GUI), locating the main carina by viewing 2D images of the 3D model in an axial orientation, marking the main carina in one of the 2D images of the 3D model, adjusting a view plane of the 3D model around a rotation axis defined by the marked location of the main carina to adjust the view plane from an axial orientation to a coronal orientation while keeping the main carina in the view plane to thereby display the entire trachea on the GUI, and marking an upper end of the trachea in one of the 2D images of the 3D model.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 62/020,253 filed on Jul. 2, 2014, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to the treatment of patients with lung diseases and, more particularly, to devices, systems, and methods for marking the trachea in a three-dimensional (3D) model generated based on CT scan image data of a patient&#39;s lungs. 
     Discussion of Related Art 
     Visualization techniques related to visualizing a patient&#39;s lungs have been developed so as to help clinicians perform diagnoses and/or surgeries on the patient&#39;s lungs. Visualization is especially important for identifying a location of a diseased region. Further, when treating the diseased region, additional emphasis is given to identification of the particular location of the diseased region so that a surgical operation is performed at the correct location. 
     In the past, scanned two-dimensional images of the lungs have been used to aid in visualization. In order to visualize a lung from scanned two-dimensional images, it is important to determine whether or not an area of the two-dimensional images is a part of the lung. Thus, detecting a starting location where a navigation procedure will begin, for example, a location of an organ or other part that is connected to or is a part of the lung, is also important for identifying the lung. In one example, the trachea can be used as the starting location because the trachea has a substantially constant diameter along its length and is known to be connected to the lung. 
     SUMMARY 
     Provided in accordance with the present disclosure is a method of marking a main carina and a trachea of a patient. 
     According to an aspect of the present disclosure, the method includes importing, into an image processing computer, slice images of a chest of the patient from an imaging device, generating, by a graphics processor included in the image processing computer, a three-dimensional (3D) model based on the imported slice images, displaying, by the image processing computer, the 3D model in a graphical user interface (GUI), locating, by a user using the GUI, the main carina by viewing 2D images of the 3D model in an axial orientation, marking the main carina in one of the 2D images of the 3D model, adjusting a view plane of the 3D model around a rotation axis defined by the marked location of the main carina to adjust the view plane from an axial orientation to a coronal orientation while keeping the main carina in the view plane to thereby display the entire trachea on the GUI, and marking an upper end of the trachea in one of the 2D images of the 3D model. 
     According to another aspect of the present disclosure, the method includes importing, into an image processing computer, slice images of a chest of the patient from an imaging device, generating, by a graphics processor included in the image processing computer, a three-dimensional (3D) model based on the imported slice images, displaying, by the image processing computer, the 3D model in a graphical user interface (GUI), marking, by a user using the GUI, the main carina in one of a plurality of 2D images of the 3D model, adjusting, by the user using the GUI, a view plane of the 3D model to display the entire trachea on the GUI, and marking, by a user using the GUI, an upper end of the trachea in one of the plurality of 2D images of the 3D model. 
     In a further aspect of the present disclosure, the method further includes, prior to marking the main carina, locating the main carina in one of the 2D images of the 3D model. 
     In another aspect of the present disclosure, the user locates the main carina by viewing the 2D images of the 3D model in an axial orientation 
     In yet another aspect of the present disclosure, the 3D model is generated based on two dimensional images obtained by tomographic technique, radiography, tomogram produced by a computerized axial tomography scan, magnetic resonance imaging, ultrasonography, contrast imaging, fluoroscopy, nuclear scans, or positron emission tomography. 
     In a further aspect of the present disclosure, adjusting a view plane of the 3D model includes adjusting the view plane around a rotation axis. 
     In another aspect of the present disclosure, adjusting the view plane around the rotation axis includes adjusting the view plane from an axial orientation to a coronal orientation. 
     In a further aspect of the present disclosure, during the adjusting, the main carina is kept within the view plane. 
     In another aspect of the present disclosure, the method further includes verifying, by the user using the GUI, the marking of the trachea by reviewing a rendering of the 3D model displayed on the GUI. 
     In a further aspect of the present disclosure, the rendered 3D model includes the marking of the main carina and the marking of the upper end of the trachea. 
     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 schematic diagram of an example device which may be used to mark a trachea in a 3D model of a patient&#39;s lungs, in accordance with an embodiment of the present disclosure; 
         FIG. 2  depicts 2D slice images generated from the 3D model showing the trachea in the axial and coronal orientations, in accordance with embodiments of the present disclosure; 
         FIG. 3  is a flowchart illustrating an example method for performing an ENB procedure, in accordance with an embodiment of the present disclosure; 
         FIG. 4  is a flowchart illustrating an example method for manually marking a trachea in a 3D model of a patient&#39;s lungs, in accordance with an embodiment of the present disclosure; and 
         FIG. 5  is an example view which may be presented by electromagnetic navigation pathway planning software to enable a clinician to manually mark a trachea in a 3D model of a patient&#39;s lungs, in accordance with an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure is related to devices, systems, and methods for identifying and manually marking a trachea and main carina on slice images of a patient&#39;s lungs when automatic detection of the trachea fails. Identifying the trachea may be a necessary component of pathway planning for performing an ELECTROMAGNETIC NAVIGATION BRONCHOSCOPY® (ENB) procedure using an electromagnetic navigation (EMN) system. 
     An ENB procedure generally involves at least two phases: (1) planning a pathway to a target located within, or adjacent to, the patient&#39;s lungs; and (2) navigating a probe to the target along the planned pathway. These phases are generally referred to as (1) “planning” and (2) “navigation.” Prior to the planning phase, the patient&#39;s lungs are imaged by, for example, a computed tomography (CT) scan, although additional applicable methods of imaging will be known to those skilled in the art. The image data assembled during the CT scan may then be stored in, for example, the Digital Imaging and Communications in Medicine (DICOM) format, although additional applicable formats will be known to those skilled in the art. The CT scan image data may then be loaded into a planning software application (“application”) to be processed for generating a 3D model which may be used during the planning phase of the ENB procedure. 
     The application may use the CT scan image data to generate a 3D model of the patient&#39;s lungs. The 3D model may include, among other things, a model airway tree corresponding to the actual airways of the patient&#39;s lungs, and showing the various passages, branches, and bifurcations of the patient&#39;s actual airway tree. While the CT scan image data may have gaps, omissions, and/or other imperfections included in the image data, the 3D model is a smooth representation of the patient&#39;s airways, with any such gaps, omissions, and/or imperfections in the CT scan image data filled in or corrected. As described in more detail below, the 3D model may be viewed in various orientations. For example, if a clinician desires to view a particular section of the patient&#39;s airways, the clinician may view the 3D model represented in a 3D rendering and rotate and/or zoom in on the particular section of the patient&#39;s airways. Additionally, the clinician may view the 3D model represented in two-dimensional (2D) slice images generated along the axial, sagittal, and coronal planes, and may “scroll through” such 2D slice images to a “depth” showing the particular section of the patient&#39;s airways. The planning phase generally involves identifying at least one target nodule in the 3D model, and generating a pathway to the target. The pathway will generally run from the patient&#39;s mouth, through the trachea and connected airways, to the target. However, in order to generate the pathway to the target, the location of the trachea within the 3D model must be known. Generally, the application will automatically detect the trachea within the 3D model. This process is more fully described in commonly-owned U.S. Provisional Patent Application Ser. No. 62/020,257 entitled “Automatic Detection of Human Lung Trachea”, filed on Jul. 2, 2014, by Markov et al., the entire contents of which are hereby incorporated by reference. However, there may be instances where automatic detection of the trachea fails. The present disclosure is directed to devices, systems, and methods for manually marking the trachea in such instances. 
     The trachea provides a passage way for breathing. The trachea is connected to the larynx and the pharynx in the upper end. In particular, the upper part of the trachea extends substantially linearly from the larynx and pharynx and behind the sternum. The lower end of the trachea branches into a pair of smaller tubes, i.e., primary bronchi, each tube connecting to a lung. The main carina is a cartilaginous ridge formed by the branching of the trachea into the primary bronchi. The diameter of the trachea is substantially constant along its length (i.e., the axial direction), while the size of the lung changes substantially along the same direction as the length of the trachea. Thus, by analyzing 2D slice images of the 3D model, the trachea may be detected. For this reason, images generated along the axial plane may be analyzed to detect the trachea in the present disclosure. In other embodiments, images generated along other planes may also be used to detect the trachea. 
       FIG. 1  shows an image processing device  100  that may be used during the planning phase of an ENB procedure to manually mark the location of the trachea in the 3D model. Device  100  may be a specialized image processing computer configured to perform the functions described below. Device  100  may be embodied in any form factor known to those skilled in the art, such as, a laptop, desktop, tablet, or other similar computer. Device  100  may include, among other things, one or more processors  110 , memory  120  storing, among other things, the above-referenced application  122 , a display  130 , one or more specialized graphics processors  140 , a network interface  150 , and one or more input interfaces  160 . 
     As noted above, 2D slice images of the 3D model may be displayed in various orientations. As an example,  FIG. 2  shows 2D slice images of the 3D model of the patient&#39;s lungs in the axial and coronal orientations, with 2D slice image  210  generated along the axial plane and 2D slice image  220  generated along the coronal plane. Both 2D slice images  210  and  220  show the trachea  212  and the main carina  214 . 
     The 2D slice images of the 3D model may show a high density area with high intensity and a low density area with low intensity. For example, bones, muscles, blood vessels, or cancerous portions are displayed with higher intensity than an inside area of airways of the lung. The 2D slice images of the 3D model may be further processed to obtain binarized 2D slice images, which only includes black and white pixels. The binarized 2D slice images may show white regions as non-lung areas (e.g., bones, stomach, heart, blood vessels, walls of airways, etc.) and black regions as lung areas (e.g., the lung, the trachea, and connected components). 
       FIG. 3  is a flowchart illustrating an example method for performing the planning phase of an ENB procedure, in accordance with the present disclosure. Starting with step S 302 , image data of the patient&#39;s lungs are acquired. Image data may be acquired using any effective imaging modality, e.g., a CT scan, radiography such as an X-ray scan, tomogram produced by a computerized axial tomography (CAT) scan, magnetic resonance imaging (MRI), ultrasonography, contrast imaging, fluoroscopy, nuclear scans, and/or positron emission tomography (PET). Thereafter, at step S 304 , the acquired image data is loaded into ENB planning software. The ENB planning software then, at step S 306 , attempts to automatically detect the trachea from the image data. At step S 308  it is determined whether the trachea detection was successful. If the trachea has not successfully been detected, manual detection is necessary. One method of manually detecting the trachea in accordance with the present disclosure is detailed below with reference to  FIG. 4 . 
     When the trachea has successfully been detected, the ENB planning software enables a clinician, at step S 310 , to mark one or more target locations in the image data. Thereafter, at step S 312 , the ENB software generates a pathway from the trachea through the patient&#39;s airways to the target. At step S 314  it is determined whether a pathway has been generated for each target marked by the clinician. If not, processing returns to step S 312 . If yes, the planning phase of the ENB procedure is complete, and, at step S 316 , the generated pathways may be loaded into ENB navigation software to start the navigation phase of the ENB procedure, or stored for later use. 
       FIG. 4  is a flowchart of an example method for manually marking the trachea in the 3D model by using an example view of application  122  shown in  FIG. 5 . This example method will be processed if it is determined, at step S 308  of  FIG. 3 , that the trachea detection was unsuccessful. Application  122  may present various views of the 3D model to assist the clinician in marking the trachea. In an embodiment, the 2D slice images of the 3D model may be used. In other embodiments, other views of the 3D model may be used. Starting at step S 402 , a clinician may locate the main carina by viewing the 2D slice images of the 3D model in the axial orientation, as shown in subview  510  of  FIG. 5 . The clinician may have to view and “scroll through” multiple 2D slice images before finding the correct 2D slice image  511  showing the bifurcation of the trachea into the primary bronchi, and thus also the tip of the main carina. 
     Upon finding the 2D slice image showing the tip of the main carina, the clinician, at step S 404 , selects the tip of the main carina to mark a point of rotation  512 . Then, at step S 406 , using the marked point of rotation  512 , a rotation axis is defined passing through the point of rotation and parallel to the sagittal plane. Thereafter, at step S 408 , the clinician adjusts the view plane around the rotation axis, from an axial orientation to a coronal orientation, while keeping the main carina in the view plane, thereby exposing the length of the trachea  523 , as shown in subview  520  of  FIG. 5 . Thus, the clinician adjusts the view plane from a 2D slice image generated along the axial plane, such as 2D slice image  210  shown in  FIG. 2 , to a 2D slice image generated along the coronal plane, such as 2D slice image  220  shown in  FIG. 2 . The clinician may again have to view and “scroll through” multiple 2D slice images before finding a 2D slice image  521  showing the length of the trachea  523 . 
     Upon finding the 2D slice image showing the length of the trachea  523 , the clinician, at step S 410 , selects the upper end of the trachea  523  to mark a second point  522 . Subview  520  may then show the point of rotation  512  and the second point, respectively marking the lower and upper ends of the trachea  523 . Thereafter, the clinician may verify that the trachea  523  has been correctly identified by viewing a rendering  531  of the 3D model of the patient&#39;s airways looking down the trachea  523  from the second point  522  towards the main carina, as shown by subview  530  of  FIG. 5 . If, upon verification, the clinician determines at step S 414  that the trachea  523  has not been correctly identified, processing returns to step S 402 . If the clinician determines that the trachea  523  has been correctly identified, processing returns to step S 308  of  FIG. 3  and completes the planning phase of the ENB procedure. 
     Returning now to  FIG. 1 , memory  120  includes application  122  such as EMN planning and procedure software and other data that may be executed by processors  110 . For example, the data may be the CT scan image data stored in the DICOM format and/or the 3D model generated based on the CT scan image data. Memory  120  may also store other related data, such as medical records of the patient, prescriptions and/or a disease history of the patient. Memory  120  may be one or more solid-state storage devices, flash memory chips, mass storages, tape drives, or any computer-readable storage media which are connected to a processor through a storage controller and a communications bus. Computer readable storage media include 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 random access memory (RAM), read-only memory (ROM), erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory or other solid state memory technology, CD-ROM, DVD 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 desired information and which can be accessed by device  100 . 
     Display  130  may be touch-sensitive and/or voice-activated, enabling display  130  to serve as both an input device and an output device. Graphics processors  140  may be specialized graphics processors which perform image-processing functions, such as processing the CT scan image data to generate the 3D model, and process the 3D model to generate the 2D slice images of the 3D model in the various orientations as described above, as well as the 3D renderings of the 3D model. Graphics processors  140  may further be configured to generate a graphical user interface (GUI) to be displayed on display  130 . The GUI may include views showing the 2D image slices, the 3D rendering, among other things. In embodiments, graphics processors  140  may be specialized graphics processors, such as a dedicated graphics processing unit (GPU), which performs only the image processing functions so that the one or more general processors  110  may be available for other functions. The specialized GPU may be a stand-alone dedicated graphics card, or an integrated graphics card. 
     Network interface  150  enables device  100  to communicate with other devices through a wired and/or wireless network connection. In an embodiment, device  100  may receive the CT scan image data from an imaging device via a network connection. In other embodiments, device  100  may receive the CT scan image data via a storage device, such as a disk or other external storage media known to those skilled in the art. 
     Input interface  160  is used for inputting data or control information, such as setting values, text information, and/or controlling device  100 . Input interface  160  may include a keyboard, mouse, touch sensor, camera, microphone, or other data input devices or sensors used for user interaction known to those skilled in the art. 
     Although the present disclosure has been described in terms of specific illustrative embodiments, it will be readily apparent to those skilled in this art that various modifications, rearrangements and substitutions may be made without departing from the spirit of the present disclosure. The scope of the present disclosure is defined by the claims appended hereto. 
     Further aspects of image and data generation, management, and manipulation useable in either the planning or navigation phases of an ENB procedure are more fully described in commonly-owned U.S. patent application Ser. Nos. 13/838,805; 13/838,997; and 13/839,224, all entitled “Pathway Planning System and Method”, filed on Mar. 15, 2013, by Baker, the entire contents of which are hereby incorporated by reference. Further aspects of the planning phase as well as the navigation phase of an ENB procedure are more fully described in commonly-owned U.S. Provisional Patent Application Ser. No. 62/020,220 entitled “Real-Time Automatic Registration Feedback”, filed on Jul. 2, 2014, by Brown et al.; U.S. Provisional Patent Application Ser. No. 62/020,177 entitled “Methods for Marking Biopsy Location”, filed on Jul. 2, 2014, by Brown; U.S. Provisional Patent Application Ser. No. 62/020,240 entitled “System and Method for Navigating Within the Lung”, filed on Jul. 2, 2014, by Brown et al.; U.S. Provisional Patent Application Ser. No. 62/020,238 entitled “Intelligent Display”, filed on Jul. 2, 2014, by Kehat et al.; U.S. Provisional Patent Application Ser. No. 62/020,242 entitled “Unified Coordinate System for Multiple CT Scans of Patient Lungs”, filed on Jul. 2, 2014, by Greenburg; U.S. Provisional Patent Application Ser. No. 62/020,245 entitled “Alignment CT”, filed on Jul. 2, 2014, by Klein et al.; U.S. Provisional Patent Application Ser. No. 62/020,250 entitled “Algorithm for Fluoroscopic Pose Estimation”, filed on Jul. 2, 2014, by Merlet; U.S. Provisional Patent Application Ser. No. 62/020,261 entitled “System and Method for Segmentation of Lung”, filed on Jul. 2, 2014, by Markov et al.; U.S. Provisional Patent Application Ser. No. 62/020,258 entitled “Cone View—A Method of Providing Distance and Orientation Feedback While Navigating in 3D”, filed on Jul. 2, 2014, by Lachmanovich et al.; and U.S. Provisional Patent Application Ser. No. 62/020,262 entitled “Dynamic 3D Lung Map View for Tool Navigation Inside the Lung”, filed on Jul. 2, 2014, by Weingarten et al., the entire contents of all of which are hereby incorporated by reference. 
     Although embodiments have been described in detail with reference to the accompanying drawings for the purpose of illustration and description, it is to be understood that the inventive processes and apparatus are not to be construed as limited thereby. It will be apparent to those of ordinary skill in the art that various modifications to the foregoing embodiments may be made without departing from the scope of the disclosure.