System and method for processing and visualizing tube current modulation in a medical imaging device - Patents.com

Abstract

When performing an imaging scan on a patient, the x-ray tube current is modulated as the scan is performed. The x-ray tube current values ​​and modulation can be recorded and accessed. The accessed values ​​are processed to generate overlays and displays to identify patient and diagnostic equipment problems.

Description

[Technical field]

[0001] The present invention relates to the field of medical diagnostic imaging, and more particularly to the processing and visualization of X-ray tube current values. [Background technology]

[0002]

[0002] Computed tomography (CT) scans are commonly performed on patients as part of a medical examination. A typical CT scan involves taking multiple x-ray images from different angles around the patient. These x-ray images are then combined and processed to generate cross-sectional data of the scanned patient. In effect, a composite image is generated from the multiple x-ray images.

[0003]

[0003] However, from generating a CT scan, additional information in addition to X-ray image data can be obtained that can be useful in treating a patient. Moreover, this additional information can be presented in an intuitive and easily understandable manner that avoids introducing friction or inefficiencies into the workflow of a medical practitioner. Summary of the Invention [Problem to be solved by the invention]

[0004] It is an object of the present invention to provide a system and method as claimed. [Means for solving the problem]

[0005]

[0004] In one example, a computer-implemented method for visualizing tube current modulation includes: accessing one or more x-ray tube current values ​​for a portion of a patient scan, where the one or more x-ray tube current values ​​correspond to an x-ray tube used to perform the portion of the patient scan; mapping the one or more accessed x-ray tube current values ​​to a region of a scout scan associated with the patient scan; and applying a transformation function based on the accessed x-ray tube current values ​​to the region of the scout scan to generate a transformed scout scan, where the region of the scout scan contrasts (stands out) from other adjacent regions of the scout scan when displayed to a user.

[0006] In some examples of the computer-implemented method, the conversion function includes converting pixel colors of the pixels of the scout scan to new colors corresponding to the accessed one or more x-ray tube current values.

[0007] In some examples of the computer-implemented method, the transformation function includes a saturation transformation function for modulating the opacity of the new color.

[0008] In some examples of the computer-implemented method, the accessed x-ray tube current values ​​are normalized.

[0009] In some examples of the computer-implemented method, the one or more x-ray tube current values ​​are placed in a metadata field of a DICOM header file.

[0010]

[0009] In some examples of the computer-implemented method, the method further includes: accessing a plurality of other patient scans related to the patient scan based on one or more of the patient information or the scanned anatomical structures, the plurality of other patient scans including other X-ray tube current values; identifying other X-ray tube current values ​​that correspond to the one or more X-ray tube current values, the correspondence being based on the other X-ray tube current values ​​and the anatomical region from which the one or more X-ray tube current values ​​were generated; and displaying the identified other X-ray tube current values ​​to a user.

[0011]

[0010] In some examples of the computer-implemented method, the method further includes: generating one or more tube current fingerprints based on one or more of the X-ray tube current values ​​or identified other X-ray tube current values, each fingerprint including sequential colored line segments, each line segment corresponding to an anatomical region, each color being based on the X-ray tube current value or identified other X-ray tube current value; and displaying the one or more tube current fingerprints to a user in a stacked format, each fingerprint being aligned according to its respective sequential colored line segment.

[0012]

[0011] In some examples of the computer-implemented method, the method further includes: determining an average X-ray tube current value for one of the anatomical regions based on the identified other X-ray tube current values; applying a transformation function to the determined average X-ray tube current value to obtain a transformed value; and displaying the transformed value to a user in association with one of the anatomical regions of the scout scan and the displayed region.

[0013]

[0012] In one example, a system for visualizing tube current modulation in a patient scan includes: a medical diagnostic imaging device; a display communicatively coupled to the medical diagnostic imaging device; and a computing device; the computing device is configured to: access one or more x-ray tube current values ​​for a portion of the patient scan, where the one or more x-ray tube current values ​​correspond to an x-ray tube of the medical diagnostic imaging device used to perform the portion of the patient scan; map the accessed one or more x-ray tube current values ​​to a region of a scout scan associated with the patient scan; apply a transformation function based on the accessed x-ray tube current values ​​to the region of the scout scan to generate a transformed scout scan; and display the transformed scout scan on the display; where the region of the scout scan contrasts with other adjacent regions of the scout scan when displayed to a user.

[0014] In some examples of the system, the conversion function includes converting pixel colors of the pixels of the scout scan to new colors corresponding to one or more of the accessed x-ray tube current values.

[0015] In some examples of the system, the transformation function includes a saturation transformation function for modulating the opacity of the new color.

[0016] In some examples of the system, the computing device is further configured to normalize the accessed x-ray tube current values.

[0017] In some examples of the system, the one or more x-ray tube current values ​​are placed in a metadata field of a DICOM header file.

[0018]

[0017] In some examples of the system, the computing device is further configured to: access a plurality of other patient scans related to the patient scan based on one or more of the patient information or the scanned anatomical structure, where the plurality of other patient scans include other X-ray tube current values; identify other X-ray tube current values ​​that correspond to the one or more X-ray tube current values, where the correspondence is based on the other X-ray tube current values ​​and the anatomical region from which the one or more X-ray tube current values ​​were generated; and display the identified other X-ray tube current values ​​to the user.

[0019]

[0018] In some examples of the system, the computing device is further configured to: generate one or more tube current fingerprints based on one or more of the X-ray tube current values ​​or identified other X-ray tube current values, where each fingerprint includes sequential colored line segments, each line segment corresponding to an anatomical region, and each color is based on the X-ray tube current values ​​or identified other X-ray tube current values; and display the one or more tube current fingerprints to a user in a stacked format, where each fingerprint is aligned according to its respective sequential colored line segment.

[0020]

[0019] In some examples of the system, the computing device is further configured to: determine an average X-ray tube current value for one of the anatomical regions based on the identified other X-ray tube current values; apply a transformation function to the determined average X-ray tube current value to generate a transformed value; and display the transformed value to a user in association with one of the anatomical regions of the scout scan and the displayed region.

[0021]

[0020] In one example, a non-transitory computer-readable medium stores instructions that, when executed by one or more processors, cause the one or more processors to: access one or more x-ray tube current values ​​for a portion of a patient scan, where the one or more x-ray tube current values ​​correspond to an x-ray tube used to perform the portion of the patient scan and are located within a metadata field of a DICOM header file; map the one or more accessed x-ray tube current values ​​to a region of a scout scan associated with the patient scan; and apply a transformation function based on the accessed x-ray tube current values ​​to the region of the scout scan to generate a transformed scout scan; the transformation function includes: a pixel color transformation of pixels of the scout scan to a new color corresponding to the one or more accessed x-ray tube current values; and a saturation transformation function for modulating the opacity of the new color, such that the region of the scout scan contrasts with other adjacent regions of the scout scan when displayed to a user.

[0022]

[0021] In some examples of the non-transitory computer-readable medium, the instructions further cause the one or more processors to: access a plurality of other patient scans associated with the patient scan based on one or more of the patient information or the scanned anatomical structure, where the plurality of other patient scans include other X-ray tube current values; identify other X-ray tube current values ​​that correspond to the one or more X-ray tube current values, where the correspondence is based on the other X-ray tube current values ​​and the anatomical region from which the one or more X-ray tube current values ​​were generated; and display the identified other X-ray tube current values ​​to a user.

[0023]

[0022] In some examples of the non-transitory computer-readable medium, the instructions further cause the one or more processors to: generate one or more tube current fingerprints based on one or more of the X-ray tube current values ​​or identified other X-ray tube current values, where each fingerprint includes sequential colored line segments, each line segment corresponding to an anatomical region, and each color is based on the X-ray tube current values ​​or identified other X-ray tube current values; and display the one or more tube current fingerprints to a user in a stacked format, where each fingerprint is aligned according to its respective sequential colored line segment.

[0024]

[0023] In some examples of the non-transitory computer-readable medium, the instructions further cause the one or more processors to: determine an average X-ray tube current value for one of the anatomical regions based on the identified other X-ray tube current values; apply a transformation function to the determined average X-ray tube current value to generate a transformed value; and display the transformed value to a user in association with one of the anatomical regions and the displayed region of the scout scan. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a system diagram illustrating an example computer system in accordance with some embodiments of the present technology. [Figure 2A] FIG. 2A is a system diagram illustrating an example of a tube current modulation overlay system, in accordance with some embodiments of the present technique. [Figure 2B]

[0026] FIG. 2B is a flow chart illustrating an example method for generating a tube current modulation view, in accordance with some embodiments of the present technique. [Figure 2C]

[0027] FIG. 2C is a system diagram illustrating an example of a tube current value statistics engine, in accordance with some embodiments of the present technology. [Figure 2D]

[0028] FIG. 2D is a flow chart illustrating an example method for generating a context tube current modulation view, in accordance with some embodiments of the present technology. [Figure 3A]

[0029] FIG. 3A is an exemplary view of a tube current modulation overlay in accordance with some embodiments of the present technology. [Figure 3B]

[0030] FIG. 3B is an exemplary view of a tube current modulation overlay, in accordance with some embodiments of the present technology. [Figure 4]

[0031] FIG. 4 is an exemplary view of a tube current modulation overlay with identification of anatomical structures, in accordance with some embodiments of the present technology. [Figure 5A]

[0032] FIG. 5A is an exemplary view of a stacked tube current modulation display in accordance with some embodiments of the present technique. [Figure 5B]

[0033] FIG. 5B is an exemplary view of a comparative tube current modulation display, in accordance with some embodiments of the present technology. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026]

[0034] A CT scan is produced by taking multiple x-ray images at or near the same time as one another. These x-ray images are then used via computer algorithms to generate tomographic data to produce a composite image of the cross-section of the scanned patient. In many instances, the x-rays that produce the x-ray images are set at multiple varying angles relative to the patient. Nevertheless, typically an x-ray tube is used to produce the x-rays and x-ray images.

[0027]

[0035] A standard X-ray tube converts electrical energy into X-rays (e.g., via an anode). The electrical energy is supplied to the tube in the form of an electric current, and the X-rays produced are proportional to the current supplied to the X-ray tube. Conversely, the tube current is proportional to the number of X-ray photons produced (also called photon flux). However, although the signal-to-noise ratio (SNR) increases as the photon flux increases, the correlation is not strictly proportional.

[0028]

[0036] In many x-ray scanners, the electrical current (i.e., tube current) can be modulated to adjust the x-rays produced. Often, the tube current is modified to maintain a consistent signal to SNR throughout the scanning process. Different tube currents can result in different SNRs, especially when different volumes of dense tissue (e.g., muscle, fat, bone, etc.) are x-rayed. As a result, the tube current can be modulated accordingly for x-raying different organs, body parts, etc.

[0029]

[0037] In some examples, tube current modulation is performed automatically (e.g., in response to monitoring the SNR in real time throughout the entire CT scan process). For example, the tube current can be modulated based on the amount and density of tissue to be penetrated by the resulting x-rays. A scan of a patient's lungs and abdomen may include decreasing the z-portion of the scan that runs over the lungs and increasing the same portion of the scan that runs over the abdominal region. Additionally, the tube current applied for each cross-sectional slice (e.g., x-ray image) of a CT scan can be stored in a corresponding DICOM file that is typically generated and associated with each cross-sectional slice.

[0030]

[0038] Some CT scanner suppliers provide tube current data for verification of scanner settings and functionality. In some instances, the provided tube current data can be displayed to the end user as a graph overlaid on the scout scan image. However, such a representation may obstruct parts of the scout scan image, making it difficult to visually evaluate local tube current values ​​at the level of individual pixels or groups of pixels. Furthermore, detailed estimates of organ location and extent are often difficult to determine due to various factors, such as the superposition of organs with different absorption characteristics. In fact, displayed information regarding tube current modulation that can be determined requires the reader to collate and decompose the displayed information to understand the relationship between the anatomical regions and the characteristics of the applied modulation, thus taking time and distracting attention from medically interpreting the reading. What is disclosed is a solution to the technical problem of determining the relationship between tube current modulation and the corresponding anatomical regions and displaying the determination in an intuitive and efficient manner that allows the user to keep their attention on more relevant tasks, such as medical interpretation of the scan.

[0031]

[0039] In particular, the tube current can be determined and converted into a color code. The color code can then be used to convert the grayscale scout scan image into a colorized version (e.g., RGB) that corresponds to the tube current value. As a result, a clinician can quickly determine the approximate tube current value and the tube current value modulation throughout the scanning process by evaluating the colorized scout scan image. Visual clutter is reduced and the risk of obstructing the graphic user interface in a way that would obscure the features of the scout scan image is avoided.

[0032]

[0040] Additionally, the tube current modulation information can be associated with a particular anatomical region of interest, such as, but not limited to, the lungs, abdomen, pelvis, etc. In some instances, associated information can be collected and derived values, such as, but not limited to, the average tube current, minimum tube current, and / or maximum tube current, can be calculated for each region of interest. The location and extent of the anatomical region can be estimated using image segmentation algorithms and / or region of interest regression techniques well known in the art for scout scans and / or CT images.

[0033]

[0041] In some cases, the axial extent of the scout image may differ from the axial extent of the reconstructed 3D CT image (for which DICOM slices are exported from the scanner). As a result, the extent of the color overlay may not match perfectly with the underlying image. This difference may be either positive if the axial extent of the CT volume is smaller than the axial extent of the scout image, or negative if the axial extent of the scout image is smaller than the axial extent of the CT volume, and thus the overlap may be different at each end (e.g., top and / or bottom) of the axial image extent.

[0034]

[0042] To account for axial extent misalignment, the tube current modulation information may be overlaid over only a portion of the vertical extent of the image. Additionally, in some examples, but not by way of limitation, a horizontal bar (relative to the axial extent) may be aligned with the axial position of the 3D CT scout image to display a color bar representing the tube current modulation.

[0035]

[0043] In addition to or instead of color-coded bands, various visualization and evaluation techniques can be applied using the collected and derived tube current modulation values ​​to generate useful overlays, for example, graphic elements in the form of tables, plots and overlays can be added to the images of the scan.

[0036]

[0044] A quantitative representation of the statistical characteristics of the tube current modulation for an anatomical region of interest (e.g., minimum, maximum, average, median, etc.) can be displayed to the user as a table (e.g., together with a scan output image, etc.). The table can include information related to patient history (longitudinal) or a larger patient population (global) for comparison with the current scan, for example, but not limited to, to identify drift warnings in cases where a large difference in the current patient's value from the long-term or global value is detected. Statistical plots can be provided, for example, in the form of box plots to visualize the tube current modulation per region of interest. Additional overlays, such as the color overlays described above, can be combined with the tabular and / or box plot displays to quickly evaluate scans in one view. In some examples, an ensemble of studies can include one or more of the above visualizations and can be anatomically aligned to provide an easily comparable view of multiple studies.

[0037]

[0045] A description of certain exemplary embodiments of the present technology follows. Although architectures, systems, methods and / or devices are disclosed, those skilled in the art will understand that these are examples for general understanding and clarity. Thus, variations on the disclosed embodiments, such as more or less steps, alternative architectures, and other modifications, may still fall within the spirit and scope of the present disclosure.

[0038]

[0046] 1 is an exemplary computing system (computer system) 100 in which various systems and methods described herein can be implemented. Computer system 100 includes one or more computing elements communicating via bus 102. In one implementation, computing system 100 includes one or more processors 114. Processor 114 may include one or more internal level caches 116 and a bus controller or bus interface. Processor 114 may specifically perform various methods described herein. Main memory 108 may include one or more memory cards and control circuits (not shown), or other forms of removable memory, and may store various software applications that include computer executable instructions that, when executed on processor 114, implement the methods and systems described herein. Other forms of memory, such as storage device 110 and mass storage device 112, may also be included and are accessible by processor (or processors) 114 via bus 102. Storage device 110 and mass storage device 112 may each include any or all of the methods and systems described herein.

[0039]

[0047] The computer system 100 may further include a communications interface 118, which may enable the computer system 100 to connect to a network, receive data useful for implementing the methods and systems described herein, and transmit information to other devices. The computer system 100 may also include an input device 106, through which information may be input. The input device 106 may be a scanner, keyboard, and / or other input device, as will be apparent to one of ordinary skill in the art. The computer system 100 may also include an output device 104, through which information may be output. The output device 104 may be a monitor, printer, USB, and / or other output device or port, as will be apparent to one of ordinary skill in the art.

[0040]

[0048] 1 is merely one possible example of a computer system that may be employed or configured in accordance with aspects of the present disclosure, and it will be appreciated that other non-transitory, tangible, computer-readable storage media that store computer-executable instructions for implementing the disclosed techniques on a computing system may also be utilized.

[0041]

[0049] In this disclosure, the disclosed methods may be implemented as a set of device-readable instructions or software. It is further understood that the specific order or hierarchy of steps in the disclosed methods is an example of an exemplary approach. Based on design preferences, it is understood that the specific order or hierarchy of steps in the methods can be rearranged while remaining within the scope of the disclosed subject matter. The accompanying method claims present elements of the various steps in a sample order, and are not necessarily meant to be limited to the specific order or hierarchy presented.

[0042]

[0050] The described disclosure may be provided as a computer program product or software, which may include a computer-readable storage medium having stored thereon instructions that may be used to program a computer system (or other electronic device) to perform processes according to the present disclosure. A computer-readable storage medium includes any mechanism for storing information (e.g., software, processing applications) in a form readable by a computer. The computer-readable storage medium may include, but is not limited to, optical storage media (e.g., CD-ROM), magneto-optical storage media, read-only memory (ROM), random access memory (RAM), erasable programmable memory (e.g., EPROM, EEPROM, etc.), flash memory, or other types of media suitable for storing electronic instructions.

[0043]

[0051] 2A illustrates an example of a tube current modulation overlay system 200. Although the tube current modulation overlay system 200 is illustrated as a standalone system, it is understood that this is for illustrative purposes only and that the tube current modulation overlay system 200 can be deployed as a monolithic architecture, a separated architecture, a cloud service, and various other deployment configurations, as would be apparent to one skilled in the art.

[0044]

[0052] Nevertheless, the tube current modulation overlay system 200 includes various interfaces for interacting with external systems, including a scanner data receiver 208, an image searcher 206, and an interface 214. The scanner data receiver 208 receives scanner information in the form of image data from a medical diagnostic device, either as individual image files or as image file stacks of slices. In one example, the medical diagnostic device is a CT scanner, and the scanner data receiver 208 is configured to receive image data from the CT scanner in the form of DICOM files. In some examples, the scanner data receiver 208 is directly connected to each medical diagnostic device. In some examples, the scanner data receiver 208 can intercept or otherwise receive DICOM files transmitted over a hospital network.

[0045]

[0053] The scanner data receiver 208 provides the tube current values ​​to the tube current monitor 202. DICOM files include the tube current values ​​in the metadata of each file header, which can be extracted, for example, by a packet parser. The tube current monitor 202 receives and tracks the extracted tube current values ​​from the scanner data receiver 208. The tube current monitor 202 also receives tracking values ​​included in the DICOM header, such as "slice position", "image position", "image orientation" and / or "pixel spacing". For example, slice position can be defined as a relative position in the image plane and can include a value stored as "(0020,1401)"; image position can include a patient identifier and z, y and z axis coordinate values ​​(e.g., using the center of the first voxel transmitted as the top left reference point); image orientation can include direction cosines of the first row and first column relative to the patient; pixel spacing can provide the physical distance between adjacent pixels. In general, the special values ​​can be defined in millimeters.

[0046]

[0054] The scanner data receiver 208 can process the DICOM files using parsers known in the art to identify the various fields and corresponding values. The pydicom Python package is one example, although several alternative DICOM parsers can be used to process the DICOM files.

[0047]

[0055] In some examples, the tube current monitor 202 can normalize the tube current values ​​to a specified range. The normalized values ​​can then be used by the current-to-image mapper 210 to convert corresponding scout scan color values ​​to represent tube current. The current-to-image mapper 210 applies a color scale to the corresponding scout scan based on the normalized tube current values. In some examples, the color scale can be set by a user via the interface 214 and customized to user preferences, clinical situation, patient history, etc. While any color scale can be used, a scale ranging from blue to red is provided in this disclosure for illustrative purposes only. Other color scales can include ranges from green to red, green to yellow, yellow to red, etc.

[0048]

[0056] The image data pre-processor 204 can receive image data files from a scanner data receiver 208 and / or an image retriever 206. The image retriever 206 may include picture archiving and communication system (PACS) integration. Patient images, such as scout scans, may be retrieved from the image retriever 206 and prepared by the image data pre-processor 204. In some examples, the image data pre-processor 204 adds metadata or modifies the retrieved scout scan image files to allow the current / image mapper 210 to apply color transformations.

[0049]

[0057] In some examples, additional or alternative values ​​can be generated by the image data pre-processor 204 either through extraction information from the DICOM header metadata or through calculated derivatives of the image or metadata, or both. For example, "exposure", "dose saving", and / or "CTDI_vol" can be extracted from the DICOM header metadata and provided to the current-to-image mapper 210 for correlating the values ​​to a scout scan. Exposure is the product of the tube current in milliamps (mA) and the corresponding exposure time provided in seconds. Dose saving is the percentage of dose saved due to the corresponding applied tube current modulation compared to a scan acquired at maximum tube current. CTDI_vol is a volumetric dose index, a standardized measure of the radiation dose output of a CT scanner. Similarly, the image data pre-processor 204 can calculate values ​​such as "water equivalent diameter" from the image content of the DICOM file, for example, but not limited to, using image processing algorithms and / or trained classifiers. The calculated values ​​can likewise be provided to the current-to-image mapper 210 for correlation with a scout scan.

[0050]

[0058] The visualizer 212 compiles the mapped tube current information from the current / image mapper 210 and generates graphical content that is displayed to the user via the interface 214. A user can configure certain visualization settings of the visualizer 212, such as thresholds, color scales, what data is visualized, etc., by interacting with the interface 214. Additionally, in some examples, the visualizer 212 can receive various statistical or other global information from a statistical engine or database, which is further described below with reference to FIG. 2C. This additional information can be integrated into the visual elements prepared by the visualizer 212 and provided to the user via the interface 214.

[0051]

[0059] 2B illustrates, by way of example and not limitation, a method 250 for generating and visualizing mapped tube current values ​​from a CT scan. Method 250 may be performed by one or more processors executing stored instructions and / or on a system such as that shown in FIGURE 2A and described above. Nonetheless, method 250 is provided for purposes of illustration and understanding, and it will be understood that steps illustrated in method 250 may be modified, substituted, or added without departing from the spirit and scope of the present disclosure.

[0052]

[0060] In step 252, tube current values ​​are extracted from the image data. In some examples, the image data is received by the scanner data receiver 208 described above with reference to FIGURE 2A. The tube current values ​​include x-ray current values ​​for one slice or image of a CT scan. If the image is provided as part of a DICOM file, the tube current values ​​can be extracted from metadata in a header portion of the DICOM file.

[0053]

[0061] In step 254, the extracted tube current values ​​are mapped to corresponding coordinates in a scout scan. The mapping of the extracted tube current values ​​can be performed using coordinate information in a DICOM header file that indicates slice location, image location, image orientation, and pixel spacing. The scout scan can be retrieved, for example, from a network PACS via the image retrieval unit 206.

[0054]

[0062] The scout scan may then be copied into each channel of the multi-channel image. For example, if an RGB image is used, the scout scan is copied into each of the three channels of the RGB image. This allows the RGB image of the scout scan to be color modified along each primary color channel (e.g., red, green, blue, etc.). Additionally, the tube current values ​​may be normalized, and in one example, the tube current values ​​are normalized to a range of -1 to 1.

[0055]

[0063] In step 256, a color transformation function is applied to each vertical pixel column in the scout scan. In some examples, the color scale can be selected from various options by the user via interface 214 or can be input by the user. For example, the minimum tube current value can be mapped to "blue" and the maximum tube current value can be mapped to "red". Using the normalized tube current values, the following mapping function (1) can be applied to each vertical pixel column to achieve a scout scan image color-mapped to tube current. Color mapping function (1): If TC_n(z)<0: R(z)=(1+TC_n(z))*R(z);G(z)=(1+TC_n(z))*G(z) If TC_n(z)>0: R(z)=(1-TC_n(z))*R(z);B(z)=(1-TC_n(z))*B(z)

[0056]

[0064] In the mapping function (1), TC_n(z) represents the tube current value that is mapped to the z coordinate of the scout scan and normalized to a span ranging from -1 to 1. R(z), G(z) and B(z) represent the red, green and blue channel pixel values ​​at the corresponding z coordinate in the RGB image of the scout scan, respectively. In effect, the mapping function (1) proportionally modifies (corrects) the red and green channel pixels at a coordinate of the RGB scout scan image if the corresponding normalized tube current value is greater than 0. If the corresponding normalized tube current value is less than 0, the mapping function (1) instead proportionally modifies the red and blue channels of the pixel at each coordinate. In this way, the resulting RGB scout scan image will be colored according to a scale that is closely tied to and represents the tube current value for imaging the corresponding location by the corresponding CT scan.

[0057]

[0065] In step 258, a saturation conversion factor is applied to each vertical pixel column in the scout scan. The saturation conversion factor, an example of which is shown integrated in mapping function (2) below, ensures that color saturation does not overwhelm the underlying scout scan image, effectively rendering feature structures and image textures unintelligible. In effect, the saturation conversion factor softens the colorization of the image. Mapping Function (2): If TC_n(z)<0: R(z)=(1+s*TC_n(z))*R(z);G(z)=(1+s*TC_n(z))*G(z) If TC_n(z)>0: R(z)=(1-s*TC_n(z))*R(z);B(z)=(1-s*TC_n(z))*B(z)

[0058]

[0066] Mapping function (2) integrates the saturation transformation coefficient and can be used in place of mapping function (1). In mapping function (2), an additional saturation coefficient, denoted by s, is applied directly to the normalized tube current values ​​to generate modified RGB values. Typically, the saturation coefficient s has values ​​0 and 1. Once the saturation function has been applied, a transformed scout scan image can be displayed with the three color channels mapped to the tube current values, an example of which is shown in FIG. 3A below.

[0059]

[0067] At step 260, the transformed scout scan is displayed to the user for review. In some examples, the displayed transformed scout scan provides the user with a colorized view of the scanned patient. The colorized view may include bands of color that correspond to the tube current values ​​recorded in each anatomical region of the scan and are superimposed on the scout scan so as to not obscure the underlying features of the scan while still providing detailed tube current information. In some examples, the user can switch between the colorized view and a conventional view 350 as shown in FIG. 3.

[0060]

[0068] 3A and 3B respectively show a colorized view 300 such as that produced by the method 250 described above, and a conventional view 350 which the colored view 300 improves by, among other things, providing a non-intrusive view of tube current values ​​mapped to corresponding anatomical regions. In particular, the conventional view 350 includes a 2D image 354 (e.g., a scout scan) overlaid with a series of graph lines 356A-D corresponding to various relevant values ​​from the scan. Additionally, a legend 352 consumes available display space. Here, the graph line 356A shows the tube current values ​​along the longitudinal axis of the scan corresponding to the region of the scan over which the graph is overlaid. Similarly, the graph lines 356B-D represent the exposure, dose savings and CT dose index (CTDI_vol), respectively, and are overlaid directly on the scan.

[0061]

[0069] In contrast, the colorized view 300 illustrated by FIGURE 3A illustrates some of the improvements of the present disclosure over the conventional view 350. In particular, the colorized view 300 includes a scout scan image 302 providing a longitudinal scan 304 of a patient being examined by a CT scanner. Colored bands 306A-D are non-obstructively overlaid on the longitudinal scan 304 of the patient. Each color band 306A-D is generated according to a mapping of tube current values ​​to RGB channel values, such as by method 250 described above.

[0062]

[0070] As shown in Figure 3A, the color bands 306A-D are mapped such that blue corresponds to the minimum tube current value and red corresponds to the maximum tube current value. The mapped colors are linearly scaled. It will be understood that the above mapping is an example and that other mappings and scalings can be used without departing from the spirit and scope of the present disclosure.

[0063]

[0071] Here, each color band 306A-D clearly corresponds to an anatomical region, and a modulation of the tube current can be seen over these regions as a whole: the red color band 306A shows maximum tube current values ​​in the upper part of the lung region, and the blue color band 306B shows an abrupt shift to minimum tube current values ​​over most of the lung region.

[0064]

[0072] In comparison, the red color bands 306C and 306D each show a rise in tube current values ​​back to a maximum value as the scan progresses from the lung region to the abdominal region and then to the pelvic region, respectively. This visualization can be used, for example, by a medical professional responsible for monitoring dose and in assessing the performance and functionality of tube current modulation in a scan. As another example, if the dose is higher than expected for a given exam type (e.g., a dose warning), a medical professional can perform an immediate visual check to identify where the high dose values ​​occurred in relation to the patient's anatomy.

[0065]

[0073] In some examples, the tube current modulation overlay system 200 can supplement the overlay information with a statistical engine 270 to generate further information related to a particular patient's tube current modulation across multiple exams or for population-level values. The statistical engine 270 shown in FIG. 2C is one such example. The statistical engine 270 can be directly integrated into the tube current modulation overlay system 200, or in some examples, can be made accessible to the tube current modulation overlay system 200 as a microservice or the like. Depending on the evaluation considered, different visualization and evaluation techniques can also be implemented. For example, a tabular format can be displayed to provide a quantitative representation of the statistical characteristics (e.g., minimum, maximum, average, median, etc.) of the tube current modulation for the anatomical region of interest. The visualization of the tube current modulation for each region of interest can also be displayed as a statistical plot (e.g., a box plot to visualize distribution parameters for individual organs such as the lungs). Additionally, overlays combining scout visualization with curves or color coding may facilitate advanced visualization that takes anatomical structures into account (e.g., by providing interactive visualization that allows visualization of only curves in the scout that indicate anatomical landmarks and region boundaries or curves specific to anatomical structures).

[0066]

[0074] The statistical engine 270 includes an aggregator 272 and an analysis engine 274. The aggregator 272 can access patient history (e.g., via an electronic medical record (EMR) or the like) and the hospital PACS (e.g., as a networked repository 276) to capture either or both of the patient's previous scans and / or scans of other patients. The aggregated information can then be used to generate time series and population comparison data, which can be provided to the user as additional overlays such as those shown in Figures 5A-B, further described below.

[0067]

[0075] The statistical engine 270 can determine statistical characteristics (e.g., minimum, maximum, mean, median, etc.) of tube current modulation for an anatomical region of interest for a larger population or for all or a portion of the patient's recorded scans. In some examples, the statistical engine 270 can also automatically detect if a scan deviates significantly from the determined statistical characteristics and alert the user to check for possible flaws in the scan and / or scanning procedure.

[0068]

[0076] Furthermore, the visualizer 212 can use the determined statistical features to display the tube current modulation values ​​for the region of interest in terms of a statistical plot. For example, as shown in FIG 4, which is further described below, a box plot can be used to visualize distribution parameters for individual organs or regions such as the lungs, pelvis, abdomen, etc.

[0069]

[0077] The visualizer 212 can integrate data generated by the statistical engine 270 into the overlay. For example, the visualizer can take anatomical structures into account by providing interactive visualization that allows visualization of curves indicating anatomical landmarks and region boundaries in the scout scan image or curves specific to the anatomical structures only. In fact, the tube current modulation information can be anatomically aligned across multiple exams based on the landmarks, thus compensating for variations in anatomical and / or imaging parameters (e.g., field of view (FOV) etc.).

[0070]

[0078] 2D illustrates one example of a method 280 for generating enhanced tube current modulation visualization. Method 280 may be performed by one or more processors executing stored instructions and / or on a system such as that shown in FIG. 2C and described above. Nonetheless, method 280 is provided for purposes of illustration and understanding, and it will be understood that steps illustrated in method 280 may be modified, substituted, or added without departing from the spirit and scope of the present disclosure.

[0071]

[0079] In step 282, multiple DICOM files associated with the current patient scan are accessed. The DICOM files may be related to the patient, such as when obtaining previous scans of the same patient, or may be related to scans of the patient, such as when obtaining DICOM files for scans of the same anatomical region from other patients. The DICOM files may include one or more images or slices stored in a stack, which may include tags in the form of metadata fields.

[0072]

[0080] In step 284, corresponding tube current values ​​are identified across the multiple DICOM files. In one example, the DICOM tags of the DICOM files are checked to ensure that the corresponding scans were performed across the same anatomical regions as the current patient's scan. If the scanned anatomical regions match, then each tube current value can be obtained from the DICOM tag.

[0073]

[0081] Based on the use of the data, method 280 may proceed from step 284 to step 288 or to step 286. For example, if a user wishes to visually review corresponding tube current values ​​to compare many values ​​at once, method 280 may proceed to step 286 and modify and / or normalize the data to facilitate comparison. In other examples, a user may wish to perform a numerical review, in which case the data may be provided in unmodified form and method 280 may proceed directly to step 280.

[0074]

[0082] Nevertheless, in step 286, the mapping information of the multiple DICOM files with corresponding tube current values ​​is rescaled based on the current patient scan. For example, the axial extent of the scout image of the current patient scan may be different from the axial extent of the reconstructed 3D CT image of each of the accessed DICOM slices. As a result, the extent of the color overlay of the accessed DICOM slice may not perfectly match the color overlay of the scout scan (as described above). The difference may be positive if the axial extent of the CT volume is smaller than that of the scout image, or negative if the axial extent of the scout image is smaller than that of the CT volume, and / or the overlap may be different at each end (e.g., top or bottom) of the axial extent of the scout image. Thus, the tube current modulation information may be rescaled to fit, for example, a horizontal bar aligned with the axial arrangement of the scout image, and display a color bar with a representation of the tube current modulation, as shown in FIG. 5A, which will be further described below.

[0075]

[0083] In step 288, a display mode is determined, which may be selected by a user via a GUI such as interface 214 described above, determined by a user setting, automatically determined based on the scan the patient is undergoing, predicted based on user and / or patient characteristics, or determined by a variety of other mechanisms.

[0076]

[0084] In step 290, visualization information is generated according to the display mode and corresponding tube current values. The visualization information may be generated by the visualizer 212 and may provide the user with additional interactable options, such as options to change the display mode, filter the display results, perform additional searches and / or comparisons, etc. For example, the user may switch between views 400, 500, and 550 shown in Figures 4 and 5A-B, respectively, described below.

[0077]

[0085] 4 shows a box plot view 400 of a colorized scout scan supplemented with information from the statistical engine 270. In the box plot view 400, anatomical detection information is visualized and overlaid on the colorized scout scan based on tube current values ​​as described above. The colorized tube current values ​​are provided adjacent to the scout scan to provide intuitive and comparable information to the user, for example, to assist the user in identifying abnormal or concerning tube current values ​​on the scout scan.

[0078]

[0086] The box plot view 400 includes a colorized scout scan 402. Overlaid on the colorized scout scan 402 are anatomical structure boxes 406A, 408A, and 410A. Anatomical structure box 406A indicates the region of the scout scan 402 that corresponds to the pelvis. Anatomical structure box 408A indicates the region of the scout scan 402 that corresponds to the abdomen. Anatomical structure box 410A indicates the region of the scout scan 402 that corresponds to the lungs.

[0079]

[0087] In addition, colored average tube current value bars 406B, 408B, and 410B are set below the scout scan 402 in vertical alignment with the anatomical structure boxes 406A, 408A, and 410A. The colored average tube current value bars 406B, 408B, and 410B are color-mapped according to the same mapping function as the scout scan 402 to represent the average tube current of the corresponding anatomical region across multiple DICOM files. Here, the lung colored average tube current value bar 410B is blue, while the abdomen colored average tube current value bar 408B and the pelvis colored average tube current value bar 406B are light red and dark red, respectively. In fact, a user can quickly compare the color bands of the scout scan 402 with the corresponding local colored average tube current value bars to determine whether the tube current value of the patient scan is within the acceptable average range.

[0080]

[0088] 5A shows a stacked view 500 of multiple exams, which uses stacked "fingerprints" to display the changes in tube current values ​​across multiple exams for the same anatomical region. Registration of each exam can be performed according to step 286 described above. The stack 500 allows the user to quickly spot outliers.

[0081]

[0089] The stacked view 500 includes a stack 502 of exam fingerprints 504. Each exam fingerprint 504 is a horizontally distributed line segment characterized by an anatomical region that is colored and rescaled according to the respective tube current value during the exam. Here, each exam fingerprint 504 includes a lung region 506A, an abdominal region 506B, and a pelvic region 506C. The exam ID axis 504 provides an associated identifier for each exam fingerprint 504. In some examples, by interacting with an identifier in the exam ID axis 504, a user can navigate to the corresponding original exam file and / or access a DICOM file to review each information unmodified for the stacked view 500.

[0082]

[0090] 5B shows a patient context view 550 for comparing tube current modulation values ​​of a current scan of a current patient with other patients (e.g., inter-patient comparison) or with previous scans of the current patient (e.g., intra-patient comparison). The patient context view 550 includes a background scan image 552 aligned with a tube current axis 554. A tube current value line 556 is overlaid on the background scan image 552 and in combination with the tube current axis 554 indicates relative tube current values ​​associated with different scans. Organ bars 558A-B are set below the background image scan 552 and indicate particular regions related to values ​​of the tube current value line 556, such as a lung bar 558B and an abdomen bar 558A.

[0083]

[0091] The background scan image 552 may be a past image, a default normative image, or an artificial image, depending on the comparison being considered in the patient context view 550. For example, when comparing between different patients, a schematic anatomy diagram or a phantom scan may be used for the background scan image 552. In contrast, when the patient context view 550 is being used to compare tube current modulation values ​​across multiple scans of the same patient, a preferred actual scan may be used, such as an earlier scan or the patient scan that best meets a particular image quality threshold.

[0084]

[0092] Although the present technology has been described in detail for purposes of illustration based on what are presently considered to be the most practical and preferred embodiments, it is to be understood that such details are for illustrative purposes only and that the technology is not limited to the disclosed embodiments, but on the contrary, is intended to cover modifications and equivalent arrangements within the spirit and scope of the appended claims. For example, it should be understood that the present technology contemplates that, to the extent possible, one or more features of any configuration can be combined with one or more features of any other configuration.

Claims

1. 1. A computer-implemented method for visualizing tube current modulation in a patient scan, the computer-implemented method comprising: accessing one or more x-ray tube current values ​​for a portion of the patient scan, the one or more x-ray tube current values ​​corresponding to an x-ray tube used to perform the portion of the patient scan; mapping the accessed one or more x-ray tube current values ​​to a region of a scout scan associated with the patient scan; applying a transformation function based on the accessed x-ray tube current values ​​to the region of the scout scan to generate a transformed scout scan. having A computer-implemented method for contrasting the region of the transformed scout scan with other adjacent regions of the scout scan when displayed to a user.

2. The computer-implemented method of claim 1 , wherein the transformation function comprises converting pixel colors of pixels of the scout scan to new colors corresponding to the accessed one or more x-ray tube current values.

3. The computer-implemented method of claim 2 , wherein the transformation functions further comprise a saturation transformation function for modulating the opacity of the new color.

4. The computer-implemented method of claim 1 , further comprising the step of normalizing the accessed x-ray tube current values.

5. The computer-implemented method of claim 1 , wherein the one or more x-ray tube current values ​​are located in a metadata field of a DICOM header file.

6. accessing a plurality of other patient scans related to the patient scan based on one or more of patient information or scanned anatomy, the plurality of other patient scans having other x-ray tube current values; identifying other x-ray tube current values ​​that correspond to the one or more x-ray tube current values, the correspondence being based on the other x-ray tube current values ​​and the anatomical region in which the one or more x-ray tube current values ​​were generated; displaying the identified other x-ray tube current values ​​to a user; The computer-implemented method of claim 1 , further comprising:

7. generating one or more tube current fingerprints based on one or more of the x-ray tube current values ​​or the identified other x-ray tube current values, each fingerprint having sequential colored line segments, each line segment corresponding to an anatomical region, each color being based on the x-ray tube current values ​​or the identified other x-ray tube current values; displaying the one or more tube current fingerprints to a user in a stacked format, each fingerprint being aligned according to a respective successive colored line segment; The computer-implemented method of claim 6 further comprising:

8. determining an average x-ray tube current value for one of the anatomical regions based on the identified other x-ray tube current values; applying the transformation function to the determined average x-ray tube current value to obtain a transformed value; displaying the transformed values ​​to a user relative to one of the anatomical region and a displayed region of the scout scan; The computer-implemented method of claim 6 further comprising:

9. 1. A system for visualizing tube current modulation in a patient scan, comprising: a medical diagnostic imaging device having one or more x-ray tubes; a display communicatively coupled to the medical diagnostic imaging device; a computing device executing the computer-implemented method of any one of claims 1 to 8 and displaying the transformed scout scan on the display; The system has:

10. A non-transitory computer readable medium storing instructions that, when executed by one or more processors, cause the one or more processors to perform the computer-implemented method of claim 3 or any one of claims 6-8.

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