Abstract:
A review and analyze protocol is described. The protocol comprises the steps of performing a patient scan to collect scan data to be used in generating an image, performing at least one of a single exam review and a dual exam review of images generated using the scan data, and analyzing an area of interest identified in performing the exam review.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to medical imaging, and more particularly, to a protocol for reviewing and analyzing anatomical areas of interest. 
     As used herein, the term “protocol” refers to method steps performed in completing a task, such as reviewing and analyzing anatomical areas of interest. The term “lung screening” protocol refers to a method for detection and management of lung tumor growth. A lung screening protocol typically includes, for example, generating images of a lung and then reviewing the images to identify nodules. 
     In performing a review of images generated by computed tomography (CT), a physician can follow one of many protocols. The specific protocol followed by a particular physician may not necessarily be the fastest review protocol as compared to other protocols, and may not necessarily be the most efficient protocol as compared to other protocols. Rather, the particular physician may simply follow a protocol most familiar to the physician. 
     BRIEF SUMMARY OF THE INVENTION 
     In one aspect, a review and analyze protocol is provided. The protocol comprises the steps of performing a patient scan to collect scan data to be used in generating an image, performing at least one of a single exam review and a dual exam review of images generated using the scan data, and analyzing an area of interest identified in performing the exam review. 
     In another aspect, a method for examining a lung nodule is provided. The method comprises the steps of performing a scan to collect scan data of the nodule, performing at least one of a single exam review and a dual exam review of images of the nodule generated using the scan data, and analyzing the nodule after reviewing the nodule images. 
     In yet another aspect, a computer program for controlling operation of a computer workstation during a nodule exam and review is provided. The computer program is configured to control a processor to prompt an operator to enter patient history data into the station, prompt an operator to select whether to perform at least one of a single exam review and a dual exam review, and initiate an analyze mode. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a pictorial view of a CT imaging system. 
     FIG. 2 is a block schematic diagram of the system illustrated in FIG.  1 . 
     FIG. 3 is a simplified flow chart representative of one embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Although the protocol described below is sometimes described with specific reference to lung screening, it is contemplated that the protocol, or at least some aspects of the protocol, can be utilized in other applications. Of course, the particular analysis and imaging performed can vary from application to application. Therefore, the specific references to lung screening are by way of example only and do not limit use of the protocol to lung screening. 
     In addition, the protocol is described below in the context of computed tomography (CT). It is believed that the protocol, however, can be practiced in connection with other imaging systems such as ultrasound and magnetic resonance imaging systems. 
     Further, an example CT system is described below. The protocol can be practiced in connection with a CT system such as the LightSpeed imaging system, which is commercially available from the GE Medical Systems business of General Electric Company, Milwaukee, Wis. The protocol can, however, be used in connection with other CT systems and is not limited to practice with any one particular CT system. 
     Referring to FIGS. 1 and 2, a CT system  10  is shown as including a gantry  12  representative of a “third generation” CT scanner. Gantry  12  has an x-ray radiation source  14  that projects a beam of x-ray radiation  16  toward a detector array  18  on the opposite side of gantry  12 . Detector array  18  is formed by detector elements  20  that together sense the projected x-rays that pass through an object  22 , for example a medical patient. Each detector element  20  produces an electrical signal that represents the intensity of an impinging x-ray beam and hence the attenuation of the beam as it passes through patient  22 . During a scan to acquire x-ray projection data, gantry  12  and the components mounted thereon rotate about a center of rotation  24 . In one embodiment, detector array  18  is fabricated in a multi-slice configuration. In a multi-slice configuration, detector array  18  has a plurality of rows of detector elements or cells  20 , only one of which is shown in FIG.  2 . One or more additional rows of detector elements  20  in such configurations are arranged parallel to the illustrated row, and each row is transverse to the translation direction of patient  22  (i.e., the z-axis or patient axis). 
     Rotation of gantry  12  and the operation of x-ray source  14  are governed by a control mechanism  26  of CT system  10 . Control mechanism  26  includes an x-ray controller  28  that provides power and timing signals to x-ray source  14  and a gantry motor controller  30  that controls the rotational speed and position of gantry  12 . A data acquisition system (DAS)  32  in control mechanism  26  samples analog data from detector elements or cells  20  and converts the data to digital signals for subsequent processing. An image reconstructor  34  receives sampled and digitized x-ray data from DAS  32  and performs high speed image reconstruction. The reconstructed image is applied as an input to a computer  36  which stores the image in a mass storage device  38 . Computer  36  also receives commands and scanning parameters from an operator via console  40  that has a keyboard. An associated cathode ray tube display  42  allows the operator to observe the reconstructed image and other data from computer  36 . The operator supplied commands and parameters are used by computer  36  to provide control signals and information to DAS  32 , x-ray controller  28  and gantry motor controller  30 . In addition, computer  36  operates a table motor controller  44  which controls a motorized table  46  to position patient  22  in gantry  12 . Particularly, table  46  moves portions of patient  22  through gantry opening  48 . In a helical scan as performed in one embodiments of the present invention, table  46  moves while projection data is being collected and gantry  12  is rotating. The “helical pitch” is a measure of the amount of movement of table  46  per rotation of gantry  12 . 
     In one embodiment, computer  36  includes a device  50  for reading and writing onto removable media  52 . For example, device  50  is a floppy disk drive, a CD-R/W drive, or a magneto-optical drive (MOD). Correspondingly, media  52  is either a floppy disk, a compact disk, or a MOD. Device  50  and media  52  are used in one embodiment to transfer acquired projection data from imaging system  10  to another computer (e.g., a post processing workstation) for further processing, or in another embodiment to input machine readable instructions that are processed by computer  36 . 
     In one embodiment, a post processing workstation  54  is coupled to computer  36  and utilized as described below. Workstation  54  includes, for example, a separate computer or processor, or a process sharing one or more CPUs (central processing units) in computer  36 . In one embodiment, computer  36  is configured as required to perform a paging review utilizing display  42 . Workstation  54  communicates with computer  36  so that data from a CT scan of patient  22  is provided to workstation  54 . Also, workstation  54  communicates window/level settings to computer  36  so that a desired image is displayed on display  42 . Workstation  54  can also be provided with a separate display unit (not shown) on which images are displayed. 
     In another embodiment, a computer system separate from imaging system  10  (for example, a workstation, not shown in the figures) is provided. Acquired data and/or reconstructed images are transferred from imaging system  10  to the separate computer system via a network (not shown) or suitable media  52 . 
     FIG. 3 is a simplified flow chart  100  of an example protocol. Specifically, after starting  102  execution of the protocol, a patient scan  104  is performed. In the example embodiment, the scan is performed using CT system  10 . The specific type of scan performed depends on the region of interest. For example, if the region of interest is a lung, then the lung region can be scanned in a low dose mode, as is known in the art. 
     Once the scan is complete, the scan data is transmitted  106  to a workstation, e.g., workstation  54 . In the example embodiment, the scan data transferred is in the form of image data. Of course, and depending on the workstation configuration and processing capacity, the scan data could be in the form of raw data collected from the scan, projection data, image data, or a combination of all or some of the different types of data. The data is transmitted to workstation via external media (e.g., a compact disc) or via a local or wide area network. 
     Patient history data also is entered  108  into workstation. Patient history data includes, for example, patient information such as smoking habits, cholesterol levels, and risk factors. The patient history data also can include family history data, such as family history of disease. 
     After transmitting data to the workstation and entering patient data into the workstation, then an exam review is performed. The exam review can be performed in a single exam review mode  110  or a dual exam review mode  112 . In the single exam review mode, one exam is reviewed with multiple viewports. Manual synchronization of the viewports is performed. The operator can page through the images with the same or multiple windows/levels. For example, one set of images can be viewed with a lung window/level and another set of images can be viewed using a soft tissue window/level. 
     In the dual exam review mode, two or more exams (i.e., data from different scans) can be viewed simultaneously with the same manual synchronization tools as described above in the single exam review mode. In addition to bookmarking slices of interest, bookmarks, regions of interest, and annotation from previously viewed studies is saved on the images so that the operator has a roadmap as to where the areas of interest are located. Linking of nodules between old and new studies also can be performed in the dual exam review mode. 
     Upon completing the exam review, then an analyze mode  114  is initiated. In the analyze mode, the area of interest can be further analyzed. For example, in a lung scan, a nodule can be further analyzed. Example software tools that can be utilized in such analysis include a shutter tool that encompasses the nodule or other area of interest. Multiple axial view slicing can be used in connection with the shutter tool so that axial slices of the nodule above and below the bookmarked slice of interest can be viewed. 
     In addition, an image verification tool can be utilized. The image verification tool outlines the area of interest, e.g., a nodule, according to a selected threshold. Characteristics of the area of interest also can be assessed. For a nodule, for example, the nodule size, spiculation, smoothness, and extents can be visually assessed by an operator. It is contemplated that such assessment, or portions of the assessment, can be performed automatically by computer. 
     The protocol ends  116  upon exiting the analyze mode. The analyze mode can be exited manually by the operator simply selecting exit, or the program can automatically exit upon the occurrence of a predetermined event, e.g., upon completion of a predefined analysis sequence or passage of a predetermined period of time. The images displayed and data are stored in the workstation memory or imaging system memory, for example. 
     The protocol, or portions of the protocol, can be performed under the control of a computer. For example, in one embodiment, a workstation computer processor is programmed to prompt an operator to enter patient data into the workstation once the scan data has been transferred to the workstation. More specifically, a programmed stored in the workstation memory controls execution of a workstation computer processor to prompt the operator to perform a number of steps or make selections. For example, the processor is programmed to prompt an operator to select whether to perform at least one of a single exam review and a dual exam review, and to initiate the analyze mode. 
     While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.