Patent Publication Number: US-10782862-B2

Title: Systems and methods for viewing medical images

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/799,657, filed on Oct. 31, 2017 and entitled “SYSTEMS AND METHODS FOR VIEWING MEDICAL IMAGES,” which is a continuation of U.S. patent application Ser. No. 14/540,830, filed on Nov. 13, 2014 and entitled “SYSTEMS AND METHODS FOR VIEWING MEDICAL IMAGES,” now U.S. Pat. No. 9,836,202, which is a continuation of U.S. patent application Ser. No. 13/477,853, filed on May 22, 2012 and entitled “SYSTEMS AND METHODS FOR VIEWING MEDICAL IMAGES,” now U.S. Pat. No. 8,913,808, which is a continuation of U.S. patent application Ser. No. 13/228,349, filed on Sep. 8, 2011 and titled “SYSTEMS AND METHODS FOR VIEWING MEDICAL IMAGES,” now U.S. Pat. No. 8,244,014, which is a continuation of U.S. patent application Ser. No. 12/702,976, filed on Feb. 9, 2010 and titled “SYSTEMS AND METHODS FOR VIEWING MEDICAL IMAGES,” now U.S. Pat. No. 8,019,138, which is a continuation of U.S. patent application Ser. No. 11/179,384, filed on Jul. 11, 2005 and titled “SYSTEMS AND METHODS FOR VIEWING MEDICAL IMAGES,” now U.S. Pat. No. 7,660,488, which claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application Ser. No. 60/625,690, filed on Nov. 4, 2004, each of which is hereby expressly incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates to management and viewing of medical images and, more particularly, to systems and methods of tracking which portions of medical images have been displayed using predetermined display parameters. 
     Description of the Related Art 
     Medical imaging is increasingly moving into the digital realm. This includes imaging techniques that were traditionally analog, such as mammography, x-ray imaging, angiography, endoscopy, and pathology, where information can now be acquired directly using digital sensors, or by digitizing information that was acquired in analog form. In addition, many imaging modalities are inherently digital, such as MRI, CT, nuclear medicine, and ultrasound. Increasingly these digital images are viewed, manipulated, and interpreted using computers and related computer equipment. Accordingly, there is a need for improved systems and methods of viewing and manipulating these digital images. 
     SUMMARY OF THE INVENTION 
     A pixel is the smallest changeable element of a digital image, where an image comprises a plurality of pixels. For example, a mammographic image may include an array of 4,000 horizontal by 6,000 vertical pixels. For all medical images, particularly for certain modalities such as mammography, for example, it is important that every image pixel is displayed on a display device and viewed by a viewer or reader, such as a doctor, nurse, or other medical staff member. For example, in the field of mammography, diagnosis of a cancer may only be detectable in a small number of pixels. Accordingly, if this small number of pixels is not viewed by the viewer or reader, a misdiagnosis may be given to the patient. If a mammography image comprises 16 million pixels (e.g., an image resolution of 4,000×4,000), all of the 16 million pixels cannot be simultaneously displayed on a display device with a resolution of 2,048×1,536 (a 3.2 Megapixel display). Thus, only about ⅕ of the 16 million pixels of the mammography image may be displayed simultaneously at full resolution on such a display device. In other words, if one elects to display the image at full resolution, the entire 4,000×4,000 pixel image cannot be simultaneously displayed on a 2,048×1,536 or smaller matrix monitor. If one elects to display the complete area of the image, the only alternative is to display the entire image at a reduced resolution, discarding a fraction of the pixels. 
     Because an entire medical image cannot be concurrently viewed at full resolution on a typical display device, software applications currently allow viewing of portions of medical images at full resolution on the display device. In some embodiments, a user may be required to adjust the portion of the medical image that is displayed at full resolution on the display device in an attempt to view all of the image pixels. For example, the viewer may select up to hundreds of portions of the image for sequential viewing at full resolution before the entire image has been viewed at full resolution. As those of skill in the art will appreciate, manually tracking which portions of an image have been viewed at full resolution is cumbersome and may not allow the viewer to accurately determine when all relevant portions of the image have been viewed at full resolution. Currently, there are no systems or methods for automatically tracking the portions of a medical image that have been displayed at full resolution, or for indicating those images for which all pixels have been presented on a display device at full resolution. Accordingly, portions of medical images may not be viewed at full resolution and important indicia in the medical image may be overlooked. Thus, systems and methods for tracking portions of a medical image that have been viewed at full resolution are desired. Furthermore, systems and methods for allowing a viewer of the medical image to visually distinguish those portions that have not been viewed at full resolution are desired. 
     In one embodiment, the invention comprises a method of viewing medical images on a display device coupled to a computing system, wherein the display device is configured to concurrently display N pixels of an image to a user. In one embodiment, the method comprises (a) receiving an image at the computing system, wherein the image comprises M pixels, wherein M is greater than N; (b) displaying on the display device a portion of the image comprising N pixels, wherein the image portion is displayed at full resolution; (c) determining whether each of the M pixels of the image has been displayed on the display device, and (d) in response to determining that not all of the M pixels of the image have been displayed on the display device, returning to step (b). 
     In another embodiment, the invention comprises a method of viewing a mammographic image in a viewing pane depicted on a display device, wherein the viewing pane is configured to display a predetermined number of pixels. In one embodiment, the method comprises displaying the mammographic image at a reduced resolution in the viewing pane, displaying a portion of the mammographic image at full resolution in the viewing pane, and displaying the mammography image at the reduced resolution in the viewing pane, wherein a portion of the reduced resolution image that corresponds with the portion of the mammographic image that was displayed at full resolution is visually distinguishable from the remaining portion of the reduced resolution image. 
     In another embodiment, the invention comprises a computing system for viewing a mammographic image. In one embodiment, the system comprises a display device depicting a viewing pane, means for displaying a portion of the mammographic image at full resolution in the viewing pane, and means for displaying the entire mammographic image at the reduced resolution in the viewing pane, wherein the portion of the mammographic image displayed at full resolution is visually distinguishable from the other portions of the reduced resolution mammographic image. 
     In another embodiment, the invention comprises a computing system for viewing a medical image. In one embodiment, the system comprises a display device having a predetermined number of pixels, an input interface configured to receive the medical image, an application module comprising software for initiating display of the medical image on the display device, and a processing unit configured to execute the software, wherein, in a first mode, the software initiates display of the entire medical image at a reduced resolution on the display device, in a second mode, the software initiates display of a portion of the medical image at full resolution on the display device, and, in a third mode, the software initiates display of the entire medical image at the reduced resolution on the display device, wherein a portion of the reduced resolution medical image corresponding to the portion of the medical image displayed at full resolution is visually distinguishable from the remaining portions of the reduced resolution medical image. 
     In another embodiment, the invention comprises a method of viewing medical images. In one embodiment, the method comprises selectively viewing portions of a high resolution image and verifying that the entire high resolution image has been viewed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an exemplary computing system in communication with a network and various networked devices. 
         FIG. 2  is a flowchart illustrating a method of tracking which portions of a medical image have been displayed at full resolution. 
         FIG. 3  is a mammographic image, wherein the entire medical image is displayed at a reduced resolution. 
         FIG. 4  is the mammographic image of  FIG. 3 , wherein a portion of the mammographic image is displayed at full resolution. 
         FIG. 5  is the mammographic image of  FIG. 3 , wherein portions of the image that have been displayed at full resolution are color inverted. 
         FIG. 6  is an exemplary mammographic image, wherein a portion of the image has been selected for display at full resolution and another portion of the image has already been displayed at full resolution. 
         FIG. 7  is a portion of a mammographic image that has been selected for display at full resolution displayed at full resolution. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     Embodiments of the invention will now be described with reference to the accompanying figures, wherein like numerals refer to like elements throughout. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner, simply because it is being utilized in conjunction with a detailed description of certain specific embodiments of the invention. Furthermore, embodiments of the invention may include several novel features, no single one of which is solely responsible for its desirable attributes or which is essential to practicing the inventions herein described. 
       FIG. 1  is a block diagram of an exemplary computing system  100  in communication with a network  160  and various network devices. The computing system  100  may be used to implement certain systems and methods described herein. The functionality provided for in the components and modules of computing system  100  may be combined into fewer components and modules or further separated into additional components and modules. 
     The computing system  100  includes, for example, a personal computer that is IBM, Macintosh, or Linux/Unix compatible. In one embodiment, the exemplary computing system  100  includes a central processing unit (“CPU”)  105 , which may include a conventional microprocessor, an application module  145  that comprises one or more various applications that may be executed by the CPU  105 . The application module  145  may include, by way of example, components, such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. 
     The computing system  100  further includes a memory  130 , such as random access memory (“RAM”) for temporary storage of information and a read only memory (“ROM”) for permanent storage of information, and a mass storage device  120 , such as a hard drive, diskette, or optical media storage device. Typically, the modules of the computing system  100  are connected to the computer using a standards-based bus system. In different embodiments of the present invention, the standards based bus system could be Peripheral Component Interconnect (PCI), Microchannel, SCSI, Industrial Standard Architecture (ISA) and Extended ISA (EISA) architectures, for example. 
     The computing system  100  is generally controlled and coordinated by operating system software, such as the Windows 95, 98, NT, 2000, XP or other compatible operating systems. In Macintosh systems, the operating system may be any available operating system, such as MAC OS X. In other embodiments, the computing system  100  may be controlled by a proprietary operating system. Conventional operating systems control and schedule computer processes for execution, perform memory management, provide file system, networking, and I/O services, and provide a user interface, such as a graphical user interface (“GUI”), among other things. 
     The exemplary computing system  100  includes one or more of commonly available input/output (I/O) devices and interfaces  110 , such as a keyboard, mouse, touchpad, and printer. In one embodiment, the I/O devices and interfaces  110  include one or more display devices, such as a monitor, that allows the visual presentation of data to a user. More particularly, display devices provide for the presentation of GUIs, application software data, and multimedia presentations, for example. In one embodiment, a GUI includes one or more display panes in which medical images may be displayed. According to the systems and methods described below, medical images may be stored on the computing system  100  or another device that is local or remote, displayed on a display device, and manipulated by the application module  145 . The computing system  100  may also include one or more multimedia devices  140 , such as speakers, video cards, graphics accelerators, and microphones, for example. 
     In the embodiment of  FIG. 1 , the I/O devices and interfaces  110  provide a communication interface to various external devices. In the embodiment of  FIG. 1 , the computing system  100  is coupled to a network  160 , such as a LAN, WAN, or the Internet, for example, via a communication link  115 . The network  160  may be coupled to various computing devices anchor other electronic devices. In the exemplary embodiment of  FIG. 1 , the network  160  is coupled to imaging devices  170 , an image server  180 , and a medical facility  190 . In addition to the devices that are illustrated in  FIG. 1 , the network  160  may communicate with other computing, imaging, and storage devices. 
     The imaging devices  170  may be any type of device that is capable of acquiring medical images, such as an MRI, x-ray, mammography, or CT scan systems. The image server  180  includes a data store  182  that is configured to store images and data associated with images. In one embodiment, the imaging devices  170  communicate with the image server via the network  160  and image information is transmitted to the image server  160  and stored in the data store  182 . In one embodiment, the image data is stored in Digital Imaging and Communications in Medicine (“DICOM”) format. The complete DICOM specifications may be found on the National Electrical Manufactures Association Website at &lt;medical.nema.org&gt;. Also, NEMA PS 3—Digital imaging and Communications in Medicine, 2004 ed., Global Engineering Documents, Englewood Colo., 2004, provides an overview of the DICOM standard. Each of the above-cited references is hereby incorporated by reference in their entireties. In one embodiment, the data store  182  also stores the user-defined display parameters associated with one or more of the images stored on the data store  182 . As discussed in further detail below, the user-defined display parameters may vary depending of the type of image, area imaged, clinical indication, source of image, display device, user, or other factors. Accordingly, any type of user-defined display parameter is expressly contemplated for use in conjunction with the systems and methods described herein. 
     The exemplary image server  160  is configured to store images from multiple sources and in multiple formats. For example, the image server  160  may be configured to receive medical images in the DICOM format from multiple sources, store these images in the data store  182 , and selectively transmit medical images to requesting computing devices. 
     The medical facility  190  may be a hospital, clinic, doctor&#39;s office, or any other medical facility. The medical facility  190  may include one or more imaging devices and may share medical images with the image server  180  or other authorized computing devices. In one embodiment, multiple computing systems, such as the computing system  100  may be housed at a medical facility, such as medical facility  190 . 
     Definition of Terms 
     Below is a definition of certain terms used herein. 
     “Medical image” is defined to include an image of an organism. It may include but is not limited to a radiograph, computed tomography (CT), magnetic resonance imaging (MRI), Ultrasound (US), mammogram, positron emission tomography scan (PET), nuclear scan (NM), pathology, endoscopy, ophthalmology, or many other types of medical images. While this description is directed to viewing and tracking of medical images, the methods and systems described herein may also be used in conjunction with non-medical images, such as, images of circuit boards, airplane wings, and satellite images, for example. 
     “Modality” is defined as a medical imaging device (a patient who undergoes an MRI is said to have been examined with the MRI modality). 
     “Patient” refers to an individual who undergoes a medical imaging examination. 
     “Viewing” is defined to include the process of visually observing one or more medical images associated with exams. 
     “Viewer” is defined as any person who views a medical image. 
     “Reading” is defined to include the process of visually observing one or more medical images for the purpose of creating a professional medical report, also called an interpretation. When reading is complete, an exam may be labeled “read,” indicating that the medical professional has completed observation of the one or more medical images for purposes of creating a medical report. 
     “Reader” is defined to include one who is authorized to perform the reading process. 
     “User” is defined to include any person that is a viewer and/or a reader. 
     “Display parameters” are defined to include methods of display of an image or exam. For example, an image or exam may be displayed with a certain pixel window level or width (similar to brightness and contrast), in color, based on a certain color map, opacity map, or other display parameters. 
     “Full pixel display” is defined to include display on a monitor or other display system of every pixel of a medical image. 
     “Full Resolution” is defined to include the concurrent display of all pixels of a medical image portion on a display device. 
     “Reduced Resolution” is defined to include display of less than alt of the pixels of a medical image portion on a display device. 
     “User-defined display parameter” refers to rules that a user can establish and store in a database that establish criteria for image display that is considered adequate. For example, a user-defined display parameter might store a rule that triggers certain warnings or displays if all pixels are not displayed or alternatively if at least half the pixels are not displayed, or alternatively, if some determined fraction of the pixels are not viewed with a certain display method (such as image window, level, brightness, contrast, opacity, color look-up table, or other parameters). User-defined display parameters may also refer to other image processing functions, such as edge enhancement and automated image analysis functions, e.g., computer-aided detection (CAD) techniques 
       FIG. 2  is a flowchart illustrating a method of tracking which pixels of a medical image have been displayed according to user-defined display parameters. In one embodiment, the method described with respect to  FIG. 2  is performed by a computing system  100 , a medical facility  190 , or an image server  190 , for example. For ease of description, the method will be discussed below with reference to a computing system  100  performing the method. Depending on the embodiment, certain of the blocks described below may be removed, others may be added, and the sequence of the blocks may be altered. 
     In one embodiment, the user-defined display parameters specify that an entire medical image must be viewed at full resolution before a reader may mark the image as read. However, the user-defined display parameters may have different requirements, such as requiring that at least a defined portion of the pixels are displayed at full resolution and/or a defined portion of the pixels are viewed with a certain display method, for example. In another embodiment, the user-defined display parameters may specify that the medical image is viewed at a resolution that is less than full resolution. In other embodiments, the user-defined display parameters may specify additional display settings that must be satisfied in order to allow the reader to mark the image as read. For example, the display parameters may be set to require that every n th  pixel is displayed. Thus, various user-defined display parameters may be established on a user, modality, or facility basis, for example. In one embodiment, such as when viewing CT images, the display parameters specify that the CT images must be viewed using a specified series of display parameters, such as lung windows, bone windows, and/or other types of windows, for example. In this embodiment, if the user forgets to view the images separately using all the required display parameters, the CT images may be misinterpreted. For ease of description, the following description refers to user-defined display parameters specifying that every pixel of the image is displayed at full resolution before it may be marked as read. However, the methods described herein are not limited to these display parameters and application of these methods using other user-defined display parameters are expressly contemplated. Any reference to tracking pixels at full resolution should be interpreted to cover similar systems and methods for monitoring and/or tracking of any other user-defined display parameter or combination of display parameters. 
     In some embodiments, it may be important and/or required that a user view all of a medical image at full resolution. Thus, a user may be required to adjust the portion of the medical image that is displayed at full resolution on the display device in an attempt to view all of the image pixels. However, currently there are no systems or methods for automatically tracking the portions of a medical image that have already been displayed at full resolution, or for indicating those images for which all pixels have been presented on a display device at full resolution (“full pixel display”). Accordingly, there is a need for image viewing devices and computing systems that monitor the portions of the medical image that are displayed on the display device, notate those portions that have been displayed at full resolution (or other user-defined display parameters), and provide the user with information indicating portions that have not been viewed at full resolution and/or provide information indicating for which images of a multiple image examination full pixel display has been accomplished. These processes are referred to herein as “visual pixel tracking.” 
     In one embodiment, visual pixel tracking applies to the display of an individual image. In another embodiment, visual pixel tracking applies to a volume rendering, wherein after 3-D slicing, the computing system  100  indicates which pixels in a volume have not been displayed at full resolution or meeting other user-defined display parameters.  FIG. 2 , described in detail below, is a flowchart illustrating an exemplary method of tracking which pixels of a medical image are displayed according to user-defined display parameters. When volume rendering is performed, the method of  FIG. 2  may be applied to each slice of the imaging volume. The user interface may provide a real time status of viewing each of the slices at full resolution. 
     In one embodiment, the computing system  100  is configured to determine a portion of the medical image on which visual pixel tracking is to be applied. Many medical images comprise areas surrounding the area of interest that are not important for a user, such as a doctor, to view and mark as read. For example, a medical image of a breast typically includes areas, such as air around the breast, that are irrelevant to the analysis by the user. Accordingly, viewing of these irrelevant portions of the image according to the user-defined display parameters is not necessary. In one embodiment, the computing system  100  analyzes the medical image and determines those areas that are irrelevant to the user&#39;s analysis. These irrelevant areas are then excluded from the user-defined display parameters and a viewer may mark an image as read without viewing the irrelevant areas at full resolution, for example. In another embodiment, the user may define the irrelevant areas of an image prior to viewing portions of the image at full resolution. For example, the user may use the keyboard, mouse, or other input device, to select areas surrounding the area of interest that do not require viewing according to the user-defined display parameters. In yet another embodiment, the user may determine that the relevant portions of an image have been viewed according to the display parameters, without the need to pre-select portions that should be viewed according to the display parameters. By providing for automatic and/or manual selection of irrelevant portions of a medical image, the viewer is not required to display those irrelevant portions of the medical image according to the user-defined display parameters, such as full resolution. 
     In a block  210 , one or more medical images are received from an image source. Although the process described below is directed to processing one image, it is possible to use the process in conjunction with multiple images. The image source may comprise one or more of the imaging devices  170 , the image server  180 , the medical facility  190 , or any other device that is capable of transmitting medical images. The medical image may be received via the network  160 , or by other means, such as transferred on a floppy disk or CD-ROM. For ease of description, in the description that follows the exemplary computing system  100  will be the device that receives and displays the medical image. However, other computing devices may perform the methods described herein. The received medical image comprises more pixels that the display device and, thus, the entire image may not be concurrently displayed at full resolution. 
     Continuing to a block  220 , a portion of the medical image is selected for display on the display device. As discussed above, many medical images contain more pixels than are capable of being displayed concurrently on a display device. Accordingly, the user of the medical image may select a portion of the image to display at full resolution on the display device. Alternatively, the computing system  100  may automatically determine a portion of the image to display on the display device. For example, in one embodiment the computing system  100  may initially display a top, left portion of received medical image first and then proceed to display adjacent portions of the image in response to an input from the user. 
     Moving to a block  230 , the portion of the image that was selected for display at full resolution is displayed on the display device. More particularly, all of the image pixels for the selected portion of the medical image are concurrently displayed on the display device. In one embodiment, depending on the resolution of the medical image and the resolution of the display device, about 1-25% of the image may be concurrently displayed at full resolution on the display device. 
     Continuing to a block  240 , an indication of the portion of the image that is displayed at full resolution is recorded. For example, if ⅛ of the total pixels of an image are displayed at full resolution, an indication of these pixels is recorded, such as by storing pixel information in a memory  130  of the computing system  100 . Alternatively, the information regarding displayed pixels may be stored on a central server, such as the image server  180 , which may then be accessible to other medical facilities and imaging devices. 
     In a decision block  250 , the computing system  100  determines if another portion of the image has been selected for display at full resolution. In one embodiment, the user is presented with a reduced resolution representation of the medical image and is allowed to select another portion of the image for display at full resolution. Selection of an image portion may be accomplished by pressing certain keys on a keyboard, such as the arrow keys, for example. In another embodiment, the user may change the selected portion for viewing by moving a mouse, or other input device. For example, a pan tool may be invoked by the user, allowing the user to adjust the portion of the image displayed at full resolution so that areas of the images that are above, below, or to the sides of the current displayed portion are displayed at full resolution. In another embodiment, the computing system  100  may be configured to periodically updated the display with a portion of the image that has not yet been displayed at full resolution, or update the display in response to an input from the user. 
     If in the decision block  250 , the computing device  100  determines that instructions have been received to display another portion of the image on the display device, at a block  280  the requested portion of the image is selected for display at full resolution. In one embodiment, such as when a panning tool is used, the selected portion comprises much of the currently displayed portion of the image. In another embodiment, the selected portion comprises a portion of the image that is entirely different than the portion of the image that is currently displayed. 
     Moving to a block  290 , one or more display characteristics of the selected portion of the image that is displayed at full resolution is altered. Thus, when the entire image is displayed on the display device at a reduced resolution, those portions of the image that have not been displayed at full resolution can be identified. These portions of the image may then be selected for display at full resolution. 
     In one embodiment, the adjustment of a display characteristic comprises changing a color of the image portion. In another embodiment, other indicators, such as a line surrounding those image portions already displayed at full resolution, may be used to discriminate between portions of the image that have been displayed at full resolution and portions that have not been displayed at full resolution. Accordingly, when the entire image is viewed at a reduced resolution, such as by displaying only every n th  image pixel, where n is less than or equal to the ratio of image pixels to display pixels, areas of the image that have not been viewed at full resolution are distinguished from those that have been viewed at full resolution. Based on the distinguishing display characteristic, the user may select for display a portion of the image that has not yet been displayed at full resolution. In one embodiment, coloring of the viewed pixels may be toggled on and off by the user. In another embodiment, a text message, icon, or other indication, may be displayed at the bottom of the display, for example, indicating that the image has been viewed according to the user-defined display parameters. In yet another embodiment, the outside margins of the viewing pane may change color or the system could beep or provide some other audible feedback when the image has been displayed according to the user-defined display parameters. 
     Moving from block  290 , the selected portion of the image is displayed at full resolution in block  230 , and the method continues to block  240  and block  250 . Accordingly, blocks  230 ,  240 ,  250 ,  280 , and  290  may be repeated multiple times in the process of selecting and displaying portions of an image at full resolution. 
     Referring again to the decision block  250 , if the computing device  100  determines that instructions to display another portion of the image at full resolution have not been received, the method continues to a decision block  260 , wherein the computing device  100  determines whether all of the image has been displayed at full resolution. If it is determined that not all of the image has been displayed at full resolution, the method continues to a block  295 , wherein an indication is provided to the user that not all of the image has been viewed at full resolution. If, however, in the decision block  260 , the computing device  100  determines that the entire image has been displayed at full resolution, the method continues to a block  270 , wherein an indication is provided to the user that the entire image has been displayed at full resolution. 
     As noted above, the flowchart of  FIG. 2  illustrates an exemplary process of tracking pixels viewed by a user according to exemplary user-defined display parameters. In particular, the user-defined display parameters in the example of  FIG. 2  specify that the entire image is viewed at full resolution. However, in other embodiments the user-defined display parameters may require that, for example, only a portion of the image is displayed at full resolution, or any other predetermined reduced resolution. For example, many images contain non-rectangular areas of interest. The portions outside of the areas of interest, such as a breast in a mammography image, may include air, other body portions, or imaging equipment, for example. Those of skill in the art will recognize that is not important to analyze every pixel of the air surrounding an area or interest. Accordingly, in one embodiment, the user or the software may select portions of the image that must be displayed according to the user-defined display parameters. In another embodiment, the display parameters may specify that the viewer determines when the image has been viewed according to the user-defined display parameters. In this embodiment, the system may track the viewed pixel of the image, present the viewer with a view of the image that distinguishes portions of the image that have not been viewed at full resolution, or according to any other user-defined display parameters, and the viewer can determine whether the image can be marked as read. 
     In one embodiment, the user can establish user-defined display parameters and store those parameters in a database. For example, the user may establish a rule linked to the individual user, user type, exam type, modality, system or other links that triggers the above described automatic warnings and/or visual pixel tracking if a user-defined fraction of the pixels are displayed. The user may, alternatively or additionally, establish other rules linked to the individual user, user type, exam type, modality, and/or system that trigger the above-described automatic warnings and/or visual pixel tracking if an image is not viewed using one or more specified display parameters or combination of display parameters. For example, the computing system  100  may be configured to automatically direct the user to any pixels or images that have not been displayed with specific display parameters. 
     In another embodiment, rules may be generated to automatically designate when the pixel tracking process should be turned on and off. For example, rules may designate that visual pixel tracking applies to only certain viewers or users. In one embodiment, one type of display parameters can apply to one modality and another set of display parameters can apply to another modality. 
     In one embodiment, the user is not able to notate an image as being read, or completely viewed, until the entire image has been displayed at full resolution. Accordingly, in the exemplary method of  FIG. 2 , if not all of the image has been displayed at full resolution, the method indicates that the entire image has not been viewed at full resolution in block  295 , and the method returns to block  250 , wherein another portion of the image may be selected for viewing. 
     In one embodiment, the computing system  100  automatically displays portions of the image that have not yet been displayed at full resolution, and/or that have not been displayed such that user-defined display parameters have been met. For example, a user interface may include visual indications as to which portions of an image include pixels that have not been displayed, or which pixels have not been displayed using a user-defined display parameter, such as a specified window or level setting. In one embodiment, the computing system  100  automatically displays a message indicating which one or more of several images has not displayed with full pixel display and/or meeting user-defined display parameter criteria. In another embodiment, the computing system  100  automatically directs the user to any image positions or images, that have not been displayed at full resolution and/or meeting user-defined display parameter criteria. 
       FIG. 3  is an exemplary graphical user interface (GUI)  300  including a menu bar  320 , multiple toolbars  310 , and an image viewing pane  330 . In the example of  FIG. 3 , a mammographic image is displayed in the viewing pane  330 , wherein the entire image is displayed at a reduced resolution. For example, if the mammography image comprises 16 million pixels (e.g., an image resolution of 4,000×4,000), all of the 16 million pixels cannot be simultaneously displayed on a display device with a resolution of 2,048×1,536 (a 3.2 Megapixel display). Thus, only about ⅕ of the 16 million pixels of the mammography image may be displayed simultaneously at full resolution on such a display device. Accordingly, in order to view the entire mammographic image on a display device, the number of pixels in the image is reduced by removing about 4 of every 5 pixels. Those of skill in the art will recognize that there are many systems and methods for reducing the resolution of a digital image. These systems and methods are contemplated for use in generating a reduced resolution image, such as the image displayed in the viewing pane  330  of  FIG. 3 . 
     As noted above, because many medical images, such as mammography images, for example, may include features or abnormalities that are only detectable by viewing only 1, or a few, pixels, a viewer of the image  340  may not be able to detect all features and abnormalities. Importantly, the viewer of a mammographic image displayed at less than full resolution, such as image  340 , may not be able to detect an abnormality related to breast cancer. For example, the area  350  shown in  FIG. 3  may include many times more pixel than are displayed in the area  350 . 
       FIGS. 4 and 5  illustrate a method of sequentially viewing portions of a medical image at full resolution and related methods of tracking and indicating the portions of the image that have been viewed at full resolution. In the embodiment of  FIGS. 4 and 5 , the reduced resolution image remains in the viewing pane  330  while a portion of the image is also displayed at full resolution within the viewing pane  330 . 
       FIG. 4  is the GUI  300  with the mammographic image  340  ( FIG. 3 ) displayed in the viewing pane  330  at a reduced resolution, where a window  410  displays a portion of the image at full resolution. In one embodiment, the portion of the mammographic image that is displayed at full resolution in the window  410  is selected by the user, such as by allowing the user to move a cursor, or other icon, over portions of the mammographic image. In this embodiment, when the cursor is over an area of the mammographic image, the window  410  displays at full resolution the portion of the mammographic image currently covered by the cursor. Thus, in the example of  FIG. 4 , the window  410  display all of the pixels of a portion of the reduced resolution image  340 . 
     In one embodiment, the portion of the image displayed at full resolution in the window  410  is updated as the user moves the cursor across the reduced resolution mammographic image  340 . Thus, the user may determine the order in which portions of the reduced resolution image are viewed at full resolution and may control the speed at which portions of the image are viewed at full resolution. 
       FIG. 5  is the GUI  300  with the reduced resolution mammographic image  340  ( FIG. 3 ) displayed in the viewing pane  330 , wherein portions of the image that have been displayed at full resolution are distinguished from portions of the image that have not yet been displayed at full resolution. In the embodiment of  FIG. 5 , for example, the portions of the image that have already been viewed at full resolution, such as via the window  410  ( FIG. 4 ) are color inverted from those portions that have not been viewed at full resolution. In  FIG. 5 , the non inverted image portion  510  indicates that this portion has been displayed at full resolution. The inverted image portion  520 , which substantially surrounds the non-inverted image portion  510 , indicates that portion  520  has not been viewed at full resolution. Accordingly, if the viewer is required to view all of the image at full resolution, the portion  520  would need to be viewed at full resolution. 
     In another embodiment, the portions of the image that have been viewed at full resolution are distinguished from those portions that have not been viewed at full resolution in other manners. For example, in one embodiment a border may be displayed around those portions of the image  340  that have been displayed at full resolution. In another embodiment, the portion that has been viewed at full resolution is color-inverted. In another embodiment, the coloring of the portion that has been viewed at full resolution is adjusted, such as by adding a yellow tint to that portion. 
       FIGS. 6 and 7  illustrate another method of sequentially viewing portions of a reduced resolution medical image at full resolution and related methods of tracking and indicating the portions of the image that have been viewed at full resolution. 
       FIG. 6  is the GUI  300  with the reduced resolution mammographic image  640  displayed in the viewing pane  330 , wherein a portion of the image has already been displayed at full resolution and another portion of the image is selected for display at full resolution. More particularly, the inverted portion  610  of the image (shaped generally as two overlapping rectangles), indicates that portion  610  has already been displayed at full resolution. As described above, other methods of indicating portions of an image that have been viewed at full resolution may be used also. 
     In one embodiment, a portion of the mammographic image  640  is selected for display at full resolution. The portion that is selected is sized so that the selected portion may be displayed at full resolution in the viewing pane  330 . In  FIG. 6 , for example, the selection window  620  has approximately the same vertical to horizontal proportions as the viewing pane  330 . In addition, the selection window  620  is sized so that a portion of the image covered by the selection window  620  substantially fills in the viewing pane  330  when displayed at full resolution. 
     In one embodiment, the viewer may move the selection window  620  to any portion of the viewing pane  330 , such as by moving a mouse or pressing designated keys on a keyboard. Once the selection window  620  is over a portion of the image that the user would like to view at full resolution, the user selects the portion by pressing a button on the mouse or pressing a designated key on the keyboard, for example. In one embodiment, after selecting a portion for viewing at full resolution, the viewing pane  330  is updated to display the selected portion at full resolution in the viewing pane  330 . After viewing the selected portion at full resolution for a predetermined period of time or until the user indicates, the viewing pane  330  is updated with the reduced resolution image  330 , updated with an indication of the portion of the image that was viewed at full resolution. Alternatively, the viewing pane  330  may be sequentially filled with full resolution portions of the image without returning to the reduced resolution image. 
       FIG. 7  is the GUI  300  with a portion of a mammographic displayed at full resolution in the viewing pane  330 . As noted above, many medical images, such as mammographic images, are taken at resolutions that are higher than resolutions of typical display and, thus, all pixel of these medical images may not concurrently be displayed. As illustrated in  FIG. 7 , a portion of a mammographic image is displayed at full resolution  710  in the viewing pane  330  of the GUI  300 . The portion of the image displayed at full resolution in the viewing pane may be selected by the user (such as is described with reference to  FIG. 6 ) or may be selected by the computing device according to predetermined display criteria. 
     In another embodiment, a viewing pane includes two panes, where a first pane, or selection pane, displays the image at a reduced resolution and a second pane, or display pane, displays at least a portion of the image at full resolution, or other user-defined display parameters. For example, a single display device could concurrently display an image such as the mammographic image  640  in the selection pane and a selected portion of the mammographic image  640  may be viewed in the display pane at full resolution, such as the full resolution image portion  710 . In one embodiment, the selection pane may be sized to correspond to the size and shape that will accommodate a full resolution display pane. In one embodiment, the user may be provided with at least two methods of selecting portions of the reduced resolution image for viewing in the display pane. In particular, the user may move a selection window, such as the selection window  620  ( FIG. 6 ), in the selection pane and the corresponding image area may be updated in the display pane. Alternatively, the user may use a pan function in the display pane and the position of the selection window in the selection pane is dynamically updated. In either case, areas that have been viewed at full resolution, or according to other user-defined display parameters, are dynamically adjusted so that they may be distinguished from the remaining portions. In an embodiment incorporating a selection and display pane, the relative sizes of the panes may be adjusted by the user or, alternatively, may be automatically adjusted by the software according to predetermined criteria. 
     In yet another embodiment, the selection pane may include multiple pares that each display a different image at a reduced resolution. For example, the multiple panes may display various images in a single image series. In one embodiment, the reduced resolution images are adjusted so that portions of the images that have been viewed at full resolution, or other user-defined display parameters, are visually distinguishable from the remaining portions. Accordingly, the display may provide an overview of the viewing status of multiple images. 
     The foregoing description details certain embodiments of the invention. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the invention can be practiced in many ways. For example, the above-described pixel checking method may be performed on other types of images, in addition to medical images. For example, images of circuit boards, airplane wings, and satellite imagery may be analyzed using the described systems and methods for monitoring whether an image has been viewed according to predefined display parameters. As is also stated above, it should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the invention with which that terminology is associated. The scope of the invention should therefore be construed in accordance with the appended claims and any equivalents thereof.