JP2012223255A - Medical image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medical image display device capable of displaying MR images collected in different time periods with more equal contrast easily and uniformly.SOLUTION: A medical image display device includes an image data acquisition means and a contrast adjustment means. The image data acquisition means acquires two or more pieces of magnetic resonance image data corresponding to different time periods of the same subject by acquiring at least one piece of the image data of the communication standard of medical image data through a network. The contrast adjustment means adjusts a window parameter for at least one of the two or more pieces of magnetic resonance image data so as to display areas corresponding to each other with luminance equal to each other on the basis of respective pixel values in the areas corresponding to each other respectively set for the two or more pieces of magnetic resonance image data.

Description

  Embodiments described herein relate generally to a medical image display apparatus.

  Magnetic Resonance Imaging (MRI), one of the medical image display devices, magnetically analyzes the nuclear spin of a subject placed in a static magnetic field with a radio frequency (RF) signal of Larmor frequency. It is an apparatus that excites and reconstructs MR (magnetic resonance) image data from NMR (nuclear magnetic resonance) signals generated by the excitation.

  In examinations using an MRI apparatus, images are often compared before and after surgery for a patient and for follow-up of a lesion site. When comparing images, image data is repeatedly collected from the same position as the imaging position of image data collected in the past. That is, the image data collection conditions are set with reference to the imaging conditions of the image data collected in the past.

  MR image data collected by an MRI apparatus is normally transferred to a medical image server and managed as medical image data of DICOM (Digital Imaging and Communication in Medicine) standard, which is a communication standard for medical image data. For this reason, MR image data may be compared using not only the MRI apparatus but also the image display function of the medical image server, or may be imported from the medical image server to a medical image processing workstation for comparison. is there.

  In view of this, a technique has been devised that enables information associated with medical image data such as imaging conditions and image processing conditions to be recognized as DICOM image data and processed in a plurality of medical systems connected to each other via a network. ing. According to this technique, positioning image data of the DICOM standard with an imaging condition such as coordinate information used for collecting medical image data is generated. For this reason, if past imaging condition information incidental to positioning image data is acquired from a medical image server or the like via a network and referenced, image data is collected from the same position as the imaging position of image data collected in the past. It is possible to set an imaging condition for this purpose.

JP 2007-167634 A JP 2010-142462 A

  However, even if image data is collected from the same imaging region under the same imaging conditions as the image data collected in the past, the contrast of the image data may change. This is due to various factors such as a change in the imaging region between before and after the operation, a difference in the degree of staining of the contrast agent, and a difference in the apparatus.

  In addition, the DICOM standard has a limit on the data size of image data. For this reason, even if high-resolution MR image data is collected by the MRI apparatus, it is transferred to the medical image server as image data compressed to a low resolution. As a result, the contrast of MR image data may change.

  In particular, when past MR image data that has been converted to the DICOM standard is imported from a medical image server to an MRI apparatus and compared with high-resolution MR image data immediately after collection, past low-resolution past image data is acquired by image processing. It is necessary to restore MR image data to high-resolution MR image data. In such a case, the contrast of past image data may change from the contrast immediately after being collected by the MRI apparatus.

  For this reason, when performing a comparison inspection of MR images collected at different times, the operator compares the images and manually fine-tunes the contrast. As a result, the operator needs time for adjusting the contrast. In addition, there is a problem that the contrast may be adjusted depending on the subjectivity of the operator.

  An object of the present invention is to provide a medical image display device that can display MR images collected at different times with a more equal contrast in a simpler and uniform manner.

  A medical image display apparatus according to an embodiment of the present invention includes an image data acquisition unit and a contrast adjustment unit. The image data acquisition means acquires a plurality of magnetic resonance image data corresponding to different times of the same subject by acquiring at least one image data of a communication standard of medical image data via a network. The contrast adjusting unit is configured to display the plurality of regions corresponding to each other with the same brightness based on the pixel values in the regions corresponding to each other set for the plurality of magnetic resonance image data. The window parameter is adjusted for at least one of the magnetic resonance image data.

  The medical image display apparatus according to the embodiment of the present invention includes an image data acquisition unit and a contrast adjustment unit. The image data acquisition means collects a plurality of magnetic resonance image data corresponding to different times from the same subject. The contrast adjusting unit is configured to display the plurality of regions corresponding to each other with the same brightness based on the pixel values in the regions corresponding to each other set for the plurality of magnetic resonance image data. The window parameter is adjusted for at least one of the magnetic resonance image data.

FIG. 1 is a functional block diagram of a magnetic resonance imaging apparatus which is an example of a medical image display apparatus according to an embodiment of the present invention. The sequence chart which shows the flow at the time of imaging multiple times from the same subject at different time with the magnetic resonance imaging apparatus shown in FIG. 1, and comparatively reading image data. The figure explaining the adjustment method of the window parameter by the contrast adjustment part shown in FIG. The figure which shows the example which displayed the image by applying the several window parameter adjusted for every contrast adjustment area | region by the contrast adjustment part shown in FIG.

  A medical image display apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a functional block diagram of a magnetic resonance imaging apparatus which is an example of a medical image display apparatus according to an embodiment of the present invention.

  The medical image display device is a device that acquires and displays MR image data. Here, a case where the medical image display apparatus is a magnetic resonance imaging apparatus including an imaging system for collecting MR image data will be described as an example. However, the medical image display apparatus is simply an MR image acquired via a network. It may be a medical image processing apparatus such as a workstation that displays data or a medical image server.

  As shown in FIG. 1, the magnetic resonance imaging apparatus 1 is connected to a medical information management system 3 and a medical image server 4 via a network 2. Further, another magnetic resonance imaging apparatus 1 </ b> A can be connected to the network 2.

  The network 2 is not limited to a local area network (LAN) such as a hospital network in a single medical institution, but may be the Internet or a dedicated wide area network used between a plurality of medical institutions. If medical image display apparatuses such as the magnetic resonance imaging apparatus 1 are connected to each other through a network 2 between a plurality of medical institutions, telemedicine using the medical image display apparatus becomes possible.

  The medical information management system 3 is a radiology information system (RIS) or a hospital information system (HIS) that manages examination order information including patient information such as patient identification information and imaging condition designation information such as an imaging region. hospital information system).

  The medical image server 4 is an image data management system such as a picture archiving and communication system (PACS) that stores medical image data as DICOM standard image data, which is a communication standard for medical image data. The medical image server 4 includes an image database 4A and a database control unit 4B. The database control unit 4B can be constructed by causing a computer to read a control program. A circuit can also be used to configure the database control unit 4B.

  The image database 4A is a database for storing DICOM standard medical image data. The database control unit 4B has a function of writing and storing image data transmitted from a transmission source such as the magnetic resonance imaging apparatus 1 or 1A via the network 2 in the image database 4A, and a function from the magnetic resonance imaging apparatus 1 via the network 2 When the image data or the transmission request of the examination information included in the image data is transmitted, the corresponding image data or the examination information included in the image data is acquired from the image database 4A as a response to the transmission request, and the magnetic resonance imaging apparatus 1 to the transmission function.

  The magnetic resonance imaging apparatus 1 includes a patient information acquisition unit 5, an imaging condition setting unit 6, an imaging system 7, a contrast adjustment unit 8, an image data transmission unit 9, an input device 10, and a display device 11. The contrast adjustment unit 8 includes an area setting unit 8A, a past image acquisition unit 8B, a resolution conversion unit 8C, and a WL / WW adjustment unit 8D. Of the patient information acquisition unit 5, the imaging condition setting unit 6, the imaging system 7, the contrast adjustment unit 8, and the image data transmission unit 9, components that process digital information can be constructed by reading a program into a computer. However, a circuit may be used to configure these components.

  The patient information acquisition unit 5 has a function of registering examination order information when examination order information for each patient and examination is given from the medical information management system 3 to the magnetic resonance imaging apparatus 1 via the network 2.

  The imaging condition setting unit 6 has a function of setting imaging conditions such as a pulse sequence and an imaging region based on examination order information registered in the patient information acquisition unit 5 and instruction information input from the input device 10.

  In particular, the imaging condition setting unit 6 acquires past examination information corresponding to patient information included in examination order information from the medical image server 4 and collects image data at a position equivalent to image data collected in the past. A function for setting an imaging condition for this purpose. That is, the imaging condition setting unit 6 is configured to set an imaging area that can be regarded as the same as or the same as an imaging area set in the past as an imaging condition.

  For desired image data such as image data collected in the past and positioning image data used for image data collected in the past, coordinates for specifying the imaging area of the image data collected in the past as incidental information Information can be attached. Therefore, the imaging condition setting unit 6 has a function of transmitting a coordinate information corresponding to past image data or a transmission request of image data accompanying the coordinate information to the medical image server 4 via the network 2, and responding to the transmission request. Thus, the coordinate information or image data transmitted from the medical image server 4 is received and acquired. And the imaging condition setting part 6 is comprised so that the same coordinate range can be set as an imaging region based on the acquired coordinate information.

  The imaging condition setting unit 6 also collects past image data for imaging parameters such as an echo time (TE), a repetition time (TR), a data collection position, and a matrix size other than the imaging region. An equivalent imaging condition can be set with reference to the used imaging condition. In this case, in the imaging condition setting unit 6, information that is referred to for setting the imaging conditions is actually acquired from the medical image server 4 in addition to the coordinate information. Imaging conditions other than the coordinate information can also be acquired from the medical image server 4 as supplementary information of desired image data.

  The imaging system 7 has a function of collecting MR image data of a subject as a patient by performing imaging according to the imaging conditions set in the imaging condition setting unit 6 and a function of displaying the collected MR image data on the display device 11. And have. For this purpose, the imaging system 7 includes a static magnetic field magnet for collecting NMR signals as imaging data from a subject, hardware such as a gradient magnetic field coil and an RF coil, a static magnetic field power source for controlling these hardware, and a gradient magnetic field. A control device such as a power source, an RF transmitter, an RF receiver, a sequence controller, and a computer, and a computer that generates MR image data by image reconstruction processing and image processing on the collected NMR signals are provided.

  The contrast adjustment unit 8 is configured to display a window width (WW: Window) so that areas designated for image data for a plurality of frames collected from the same subject at different times are displayed on the display device 11 with the same luminance. Width) and window level (WL: Window Level) adjustment, and a function of causing the display device 11 to display image data of a plurality of frames after adjustment of WW and WL. That is, the contrast adjustment unit 8 has a function of adjusting the contrast so that a plurality of image data collected at different times can be compared as they are based on the luminance value by setting appropriate window parameters.

  Based on the information from the input device 10, the area setting unit 8 </ b> A acquires the area to be displayed with the same luminance as the contrast adjustment area from the image data collected in the imaging system 7 or the medical image server 4 via the network 2. A function for setting the image data.

  It should be noted that a plurality of contrast adjustment regions can be set for a single slice image data. Further, not only slice image data, but also three-dimensional (3D) images such as maximum intensity projection (MIP) image data and volume rendering (VR) image data displayed on the display device 11. A two-dimensional (2D) or 3D contrast adjustment region may be set through the data.

  The setting information of the contrast adjustment area can be added to the image data as supplementary information. In particular, when image data is converted into DICOM standard image data, setting information of a contrast adjustment area can be attached to the image data as private tag information.

  Private tag information is information that can be uniquely defined and attached to image data by a manufacturer of a device that outputs DICOM standard image data such as an image diagnostic device. On the other hand, among the incidental information of DICOM standard image data, the common incidental information regardless of the manufacturer is called standard tag information.

  The past image acquisition unit 8B acquires the past image data to be displayed for comparative interpretation from the medical image server 4 as DICOM standard image data via the network 2, and magnetic resonance is performed on the received DICOM standard image data. A function of converting the image data into image data having a data structure that can be processed by the imaging apparatus 1.

  The resolution conversion unit 8C has a function of converting the resolution of the image data acquired from the medical image server 4 by the past image acquisition unit 8B according to the resolution of the image data collected in the imaging system 7. That is, in the DICOM standard, there is an upper limit on the data size of the image data, so the resolution of the image data acquired from the medical image server 4 is often lower than the resolution of the image data collected in the imaging system 7. Therefore, the resolution conversion unit 8 </ b> C has a function of increasing the resolution of the image data acquired from the medical image server 4 in accordance with the resolution of the image data collected in the imaging system 7. Resolution conversion can be performed by known image processing such as interpolation processing.

  The WL / WW adjustment unit 8D has a function of comparing representative values of pixel values of each contrast adjustment region between image data of a plurality of frames collected at different times as objects of comparative interpretation, and each contrast adjustment region is equivalent to each other. The window parameter adjustment conditions for displaying in brightness are determined according to the function obtained based on the comparison result of the representative value of the pixel value in each contrast adjustment region and the window parameter attached to the image data of each frame, and the window parameter adjustment condition. And a function of adjusting WL.

  When the contrast adjustment area is set for the image data of a certain frame, the window parameter adjustment condition can be set using the corresponding area of the other frame image data as the contrast adjustment area in the image data of the other frame. .

  That is, if the image data for which the contrast adjustment area is not set is image data at the same slice position as the slice image data for which the contrast adjustment area is set, the contrast adjustment area is set to the same area as the contrast adjustment area. This can be a contrast adjustment region of image data that is not present.

  On the other hand, when the image data for which the contrast adjustment area is not set is not the image data at the same slice position as the slice image data for which the contrast adjustment area is set, the corresponding area such as the same shape closest to the contrast adjustment area is supported. The area can be a contrast adjustment area of image data in which no contrast adjustment area is set.

  Furthermore, when the contrast adjustment area is set as the same area or an area that can be compared in the image data of a plurality of frames to be subjected to comparative interpretation, each of the set contrast adjustment areas is a window parameter adjustment condition. This is a comparison area of representative values of pixel values for obtaining.

  The image data transmission unit 9 has a function of converting image data into DICOM standard image data and transmitting the converted DICOM standard image data to a transmission destination designated by the input device 10. The image data generated in the magnetic resonance imaging apparatus 1 is normally transferred to the medical image server 4 and stored in the medical image server 4 as DICOM standard image data.

  Note that the specific information of the contrast adjustment area set in the area setting unit 8A can be transferred to the medical image server 4 together with the image data as supplementary information identified by the private tag of the DICOM standard image data. In this case, the specific information of the contrast adjustment area is not limited to the image data for which the contrast adjustment area is set, but is transferred to the medical image server 4 as supplementary information of any DICOM standard image data such as positioning image data. Can do.

  In addition, the window parameters set in the image data are added to the DICOM standard image data as supplementary information identified by the standard tag in accordance with the DICOM standard, but the DICOM standard image data is supplementary information identified by the private tag. You may make it add to. Therefore, the window parameter after adjustment in the WL / WW adjustment unit 8D can be transferred to the medical image server 4 as incidental information in the DICOM standard image data.

  Furthermore, the other magnetic resonance imaging apparatus 1A can be provided with components such as the contrast adjustment unit 8 included in the magnetic resonance imaging apparatus 1.

  Next, the operation and action of the magnetic resonance imaging apparatus 1 will be described. Here, for simplification of description, image data corresponding to the same imaging region as the past image data acquired from the medical image server 4 in the magnetic resonance imaging apparatus 1 is collected by the imaging system 7, and the past image data and the imaging are collected. A case of comparative interpretation of image data collected by the system 7 will be described.

  FIG. 2 is a sequence chart showing a flow when the magnetic resonance imaging apparatus 1 shown in FIG. 1 performs multiple imaging from the same subject at different times and comparatively interprets image data.

  First, in step S1, examination order information is transmitted from the medical information management system 3 to the magnetic resonance imaging apparatus 1 via the network 2.

  Then, in step S2, the patient information acquisition unit 5 of the magnetic resonance imaging apparatus 1 receives the examination order information and obtains patient information such as a patient ID included in the examination order information. That is, patient information is registered as an imaging target. The examination order information is given from the patient information acquisition unit 5 to the imaging condition setting unit 6.

  Next, in step S3, imaging for the imaging region designated by the examination order information is executed. For this purpose, the imaging condition setting unit 6 sets imaging conditions based on the examination order information received by the patient information acquisition unit 5 and the instruction information input from the input device 10. The imaging system 7 performs imaging according to the imaging conditions set in the imaging condition setting unit 6. Thereby, MR image data of the subject specified by the patient ID is collected.

  Next, in step S4, the region setting unit 8A sets a region to be displayed with the same luminance when imaging the same subject in the future as a contrast adjustment region for the image data based on information from the input device 10. Set. In other words, the user can observe the image data and designate a desired area of the desired slice image data by operating the input device 10 as a contrast adjustment area.

  The image data that sets the contrast adjustment area can be sliced image data that includes a region of interest (ROI) that is to be repeatedly collected and compared and read. From the viewpoint of observing with high contrast. In addition, it is desirable from the viewpoint of observing the ROI with the same contrast that the contrast adjustment region is set to a position and a range in which the change in the pixel value is determined to be sufficiently small after or after the operation of the subject. .

  As described above, a plurality of contrast adjustment areas can be set for a single slice image data. In this case, even if the pixel value changes in a certain contrast adjustment region, it is possible to repeatedly collect image data having an equivalent contrast based on the pixel value in another contrast adjustment region.

  In step S5, the image data transmission unit 9 converts the image data including the imaging conditions such as the imaging region and the contrast adjustment region set in the region setting unit 8A as supplementary information into DICOM standard image data, thereby obtaining a medical image. It transmits to the server 4 via the network 2. That is, the imaging condition and the contrast adjustment area are transmitted to the medical image server 4 as incidental information identified by the standard tag and the private tag attached to the DICOM standard image data.

  Then, in step S6, the database control unit 4B of the medical image server 4 receives the DICOM standard image data transmitted from the magnetic resonance imaging apparatus 1 via the network 2, and uses the image database as examination information corresponding to the patient ID. Write to 4A.

  Then, according to the medical plan, the subject can be operated and treated. Further, when image data is collected and it is necessary to follow the subject, such as after the operation of the subject, reexamination by the magnetic resonance imaging apparatus 1 is performed.

  In this case, reexamination order information is transmitted from the medical information management system 3 to the magnetic resonance imaging apparatus 1 via the network 2 in step S7.

  Next, in step S8, the patient information acquisition unit 5 of the magnetic resonance imaging apparatus 1 receives reexamination order information and acquires patient information such as a patient ID included in the reexamination order information. That is, patient information is registered as an imaging target. The reexamination order information is given from the patient information acquisition unit 5 to the imaging condition setting unit 6.

  Next, in step S9, since the order information given from the patient information acquisition unit 5 is reexamination order information, the imaging condition setting unit 6 uses the imaging used for collecting past image data corresponding to the patient information. A transmission request for image data accompanying conditions or imaging conditions is transmitted to the medical image server 4 via the network 2.

  Next, in step S10, the database control unit 4B of the medical image server 4 searches for past imaging conditions stored as examination information in the image database 4A or image data incidental to past imaging conditions.

  Next, in step S <b> 11, the database control unit 4 </ b> B transmits the past imaging conditions obtained as a search result or image data accompanying the past imaging conditions via the network 2.

  Next, in step S <b> 12, the imaging condition setting unit 6 receives past imaging conditions or image data transmitted from the medical image server 4. Then, the imaging condition setting unit 6 sets the same imaging area as the imaging area of the image data collected in the past as the imaging condition for reexamination imaging based on the coordinate information included in the past imaging conditions. In addition, the imaging condition setting unit 6 refers to past imaging conditions and sets other imaging conditions based on the instruction information input from the input device 10.

  Next, in step S <b> 13, imaging for the imaging region designated by the reexamination order information is executed. That is, the imaging condition setting unit 6 outputs the imaging conditions set for reexamination to the imaging system 7. Then, the imaging system 7 performs imaging in accordance with imaging conditions for reexamination that collects image data of the same imaging region. Thereby, image data of the same imaging region is collected again from the same subject.

  Next, in step S14, the WL / WW adjustment unit 8D of the contrast adjustment unit 8 determines that the past image data corresponding to the patient information has already been acquired from the medical image server 4 by the magnetic resonance imaging apparatus 1. Are compared with image data collected by imaging for reexamination. At this time, the resolution conversion unit 8C converts the resolution of the past image data before the comparison of the image data in the WL / WW adjustment unit 8D as necessary.

  On the other hand, when past image data has not been acquired from the medical image server 4, the past image acquisition unit 8 </ b> B transmits a search request to the database control unit 4 </ b> B of the medical image server 4 via the network 2. The past DICOM standard image data transmitted from the medical image server 4 via the network 2 in response to the search request is received by the past image acquisition unit 8B. Then, the past image acquisition unit 8B converts past DICOM standard image data into image data having a data structure that can be processed by the magnetic resonance imaging apparatus 1.

  Next, if necessary, the resolution conversion unit 8C converts the resolution of the past image data acquired from the medical image server 4 according to the resolution of the image data collected by re-examination imaging by the imaging system 7. To do. As a result, the high-resolution past image data and the image data collected by the reexamination are prepared for comparison, and the WL / WW adjustment unit 8D compares the past image data and the image data collected by the reexamination. The

  Further, when the contrast adjustment area set for the past image data is displayed in luminance, the WL / WW adjustment unit 8D is equivalent to the past image data and the image data collected in the reexamination. The window parameter of at least one of the past image data and the image data collected in the reexamination is adjusted so as to obtain the luminance. The contrast adjustment area can be acquired as incidental information of past image data.

  Past image data is collected under imaging conditions that provide a contrast suitable for observation of a lesion site at the time of collection. For this reason, it is often desirable to match the image data collected in the reexamination with the contrast of past image data.

  Therefore, here, an example will be described in which the contrast of image data collected in reexamination is adjusted in accordance with the contrast of past image data. Of course, it is also possible to adjust the contrast of past image data according to the contrast of the image data collected in the reexamination, or to adjust the contrast of both the past image data and the image data collected in the reexamination. .

  FIG. 3 is a diagram for explaining a window parameter adjustment method by the contrast adjustment unit 8 shown in FIG.

In FIG. 3, the vertical axis indicates the relative luminance value when image data is displayed on the display device 10. For example, as shown on the left side of FIG. 3, if the window level WL ₀ and the window width WW ₀ are set to WL ₀ = 10000 and WW ₀ = 20000, respectively, in accordance with the pixel value of the past image data I ₀ , the window parameter corresponds to the window parameter. The past image data I ₀ is displayed with the luminance value.

On the other hand, when the pixel value of the image data I ₁ collected by the reexamination changes from the past image data I ₀ due to various factors such as a decrease in the lesion site and a decrease in the effect of the contrast agent, the image data I ₁ The window level WL ₁ ′ and the window width WW ₁ ′ that match the pixel value of the image data also change from the window level WL ₀ and the window width WW ₀ for the past image data I ₀ . In the example shown in FIG. 3, the window level WL ₁ ′ and the window width WW ₁ ′ matched with the image data I ₁ collected by the reexamination are WL ₁ ′ = 7500 and WW ₁ ′ = 15000, respectively.

As a result, even if there is no change between the past collection of image data I _{0 and} the collection of image data I ₁ in the reexamination, it will be displayed with different brightness due to differences in pixel values and window parameters. . Therefore, the luminance changes in the contrast adjustment area that can be regarded that there is no the image data I ₁ collected by such re-examination becomes equivalent between the image data I ₁ collected by the re-examination of the past image data I ₀ The window level WL ₁ ′ and the window width WW ₁ ′ are adjusted.

In other words, the WL / WW adjustment unit 8D has been collected by re-examination to display the contrast adjustment region with the same luminance in both the past image data I ₀ and the image data I ₁ collected by re-inspection. Request window level WL ₁ and the window width WW ₁ for the image data I _1. Then, if the display image data I ₁ collected by the re-examination by applying a window level WL ₁ and the window width WW ₁ after adjustment, the image data I ₁ of the re-examination change in pixel values is canceled ' The image data I ₁ can be displayed with the same luminance.

  The adjustment value of the window parameter for the image data of the reexamination for displaying the contrast adjustment area with the same luminance is the representative value of each pixel value in the contrast adjustment area of the past image data and the image data collected by the reexamination. It can be obtained based on window parameters set for past image data. Note that window parameters set for past image data can be acquired as supplementary information such as past image data or corresponding positioning image data.

  However, the contrast adjustment region can be set at a plurality of locations as described above. In this case, even if it can be displayed with the same brightness between the past image data and the image data collected by the reexamination for one contrast adjustment area by adjusting the window parameter, it is different in other contrast adjustment areas. There is a possibility of brightness.

  Therefore, if it is not possible to display all the contrast adjustment areas with the same luminance even if one adjustment value of the window parameter is obtained, the window parameter can be adjusted for each contrast adjustment area. That is, the adjustment value of the window parameter is obtained for each contrast adjustment region, and a plurality of image data obtained by applying the plurality of window parameters can be displayed.

  FIG. 4 is a diagram showing an example in which an image is displayed by applying a plurality of window parameters adjusted for each contrast adjustment region by the contrast adjustment unit 8 shown in FIG.

  FIG. 4 shows an example in which past image data and image data for reexamination after contrast adjustment are displayed in parallel on the display device 10. That is, a past image is displayed on the left side of the display device 10 shown in FIG. 4, and an image of re-examination after contrast adjustment is displayed on the right side.

  A plurality of contrast adjustment areas can be set in the past image data. FIG. 4 shows an example in which three contrast adjustment regions R1, R2, and R3 are set around the ROI. In the example shown in FIG. 4, the ROI of the image data obtained by the reexamination is smaller than the ROI of the past image data. Three contrast adjustment regions R1, R2, and R3 are displayed at corresponding positions around the ROI of the image data obtained by the reexamination.

  When a plurality of contrast adjustment areas are set in this way, window parameters are adjusted so that all contrast adjustment areas are displayed with the same brightness in past image data and image data obtained by reexamination. It may not be possible.

  Therefore, window parameters can be adjusted for each contrast adjustment region. In the example of FIG. 4, the three images can be switched so that the three contrast adjustment regions R1, R2, and R3 are displayed with the same luminance in both the past image data and the image data obtained by the reexamination. Is displayed.

  That is, the first contrast adjustment region R1 is applied by applying an adjustment value of the window parameter for displaying the same contrast in both the past image data and the image data obtained by the reexamination. The adjusted image can be displayed. Similarly, the adjustment values of the window parameters for displaying the second and third contrast adjustment regions R2 and R3 with the same luminance in both the past image data and the image data obtained by the reexamination, respectively. By applying this, it is possible to display images after adjusting the second and third contrasts. Each image after the first, second, and third contrast adjustments can be switched and displayed using tabs TAB1, TAB2, and TAB3 as shown in FIG.

  On the other hand, even if a plurality of contrast adjustment areas are set, if each contrast adjustment area can be displayed with the same brightness in the past image data and the image data obtained by the reexamination, the plurality of contrast adjustment areas are displayed. An image after adjusting the common contrast can be displayed. In this case, images smaller than the number of contrast adjustment areas are switched and displayed.

The window parameter adjustment processing when a plurality of contrast adjustment areas are set can be performed by the following algorithm (1), for example.
If (| I ₀₁ / I ₁₁ |, | I ₀₂ / I ₁₂ |, | I ₀₃ / I ₁₃ | ≦ T)
{
WL ₁₁ = WL ₁₂ = WL ₁₃ = WL ₀
WW ₁₁ = WW ₁₂ = WW ₁₂ = WW ₀
}
else
{
WL ₁₁ = WL ₀ × | I ₀₁ / I ₁₁ |
WW ₁₁ = WW ₀ × | I ₀₁ / I ₁₁ |
WL ₁₂ = WL ₀ × | I ₀₂ / I ₁₂ |
WW ₁₂ = WW ₀ × | I ₀₂ / I ₁₂ |
WL ₁₃ = WL ₀ × | I ₀₃ / I ₁₃ |
WW ₁₃ = WW ₀ × | I ₀₃ / I ₁₃ |
}
(1)
However, in algorithm (1),
I ₀₁ : representative pixel value of the first contrast adjustment region R1 in the past image data
I ₀₂ : representative pixel value of the second contrast adjustment region R2 in the past image data
I ₀₃ : representative pixel value of the third contrast adjustment region R3 in the past image data
I ₁₁ : representative pixel value of the first contrast adjustment region R1 in the image data obtained by re-examination
I ₁₂ : representative pixel value of the second contrast adjustment region R2 in the image data obtained by re-examination
I ₁₃ : representative pixel value of the third contrast adjustment region R3 in the image data obtained by the reexamination
T: Threshold value
WL ₀ : Window level for past image data
WW ₀ : Window width for past image data
WL ₁₁ ': Window level adjusted to the first contrast adjustment area R1 in the image data obtained by re-examination
WW ₁₁ : Window width adjusted in accordance with the first contrast adjustment region R1 in the image data obtained by re-examination
WL ₁₂ : Window level adjusted in accordance with the second contrast adjustment region R2 in the image data obtained by re-examination
WW ₁₂ : Window width adjusted to the second contrast adjustment area R2 in the image data obtained by re-examination
WL ₁₃ : Window level adjusted in accordance with the third contrast adjustment region R3 in the image data obtained by re-examination
WW ₁₃ : The window width adjusted in accordance with the third contrast adjustment region R3 in the image data obtained by the reexamination.

That is, the representative pixels of the past image data with respect to the representative pixel values I ₁₁ , I ₁₂ , and I ₁₃ of the image data obtained by the reexamination in the first, second, and third contrast adjustment regions R1, R2, and R3. If the ratio of the values I ₀₁ , I ₀₂ , I ₀₃ is less than or equal to the threshold value T (or less than the threshold value T), the amount of change from the past image data in the pixel value range in the image data obtained by re-examination is small.

Therefore, by applying the window parameters applied to the past image data as they are to the image data obtained by the reexamination, the first, second and third contrast adjustment regions R1, R2 and R3 are respectively equivalent. It can be displayed with brightness. That is, the common window levels WL ₁₁ , WL ₁₂ , WL ₁₃ and window width WL for displaying image data obtained by re-inspecting the window level WL ₀ and window width WW ₀ used for displaying past image data are displayed. ₁₁ , WL ₁₂ , WL ₁₃ can be used as they are.

On the other hand, the past image data for the representative pixel values I ₁₁ , I ₁₂ , and I ₁₃ of the image data obtained by re-examination in the first, second, and third contrast adjustment regions R1, R2, and R3. If any of the ratios of the representative pixel values I ₀₁ , I ₀₂ , I ₀₃ exceeds the threshold T (or exceeds the threshold T), the amount of change in the pixel value range of the image data obtained by the re-examination Is big. For this reason, the window parameter is adjusted using the ratio of the representative pixel values I ₀₁ , I ₀₂ , I ₀₃ as an index representing the amount of change in the pixel value range.

That is, by multiplying the ratio of the representative pixel values I ₀₁ , I ₀₂ , I ₀₃ as the coefficients respectively to the window level WL ₀ and the window width WW ₀ used as the reference for displaying the past image data, the first, Obtaining appropriate window levels WL ₁₁ , WL ₁₂ , WL ₁₃ and window widths WL ₁₁ , WL ₁₂ , WL ₁₃ corresponding to the second and third contrast adjustment regions R1, R2, R3 as window parameter adjustment values Can do.

  The threshold value T can be arbitrarily set by the user. An appropriate value for the threshold T can be determined empirically.

  Then, the past image data after the contrast adjustment in the contrast adjustment unit 8 and the image data for the reexamination are displayed on the display device 10. That is, the past image data in which the contrast adjustment area is displayed with the same brightness and the image data obtained by the re-examination are displayed on the display device 10.

  For this reason, the user can perform comparative interpretation of image data corresponding to different times. Contrast adjustment is performed on image data to be interpreted based on the pixel value of the contrast adjustment area. Therefore, the ROI can be compared in the same column between the past image data and the image data obtained by the reexamination. As a result, the follow-up of ROI can be appropriately executed.

  If necessary, the image data for reexamination including the specific information of the contrast adjustment area can be transmitted to the medical image server 4 and stored again in step S5. In addition, re-inspection can be performed repeatedly. In that case, reexamination order information is transmitted from the medical information management system 3 to the magnetic resonance imaging apparatus 1 in step S7. Then, comparative interpretation of image data at different times with adjusted contrast can be repeatedly performed in the same flow.

  That is, the magnetic resonance imaging apparatus 1 as described above sets a contrast adjustment region corresponding to each other in a plurality of image data collected at different times, and the set contrast adjustment regions are equivalent to each other. The window parameters are adjusted so as to be displayed with luminance.

  Therefore, according to the magnetic resonance imaging apparatus 1, when a plurality of image data collected at different times are comparatively interpreted, the plurality of image data can be easily displayed with the same contrast. That is, since the contrast adjustment is automatically performed, it is possible to avoid the user's manual contrast adjustment. This simplifies the user workflow and shortens the inspection time.

  In addition, it is possible to display image data whose contrast is uniformly adjusted without depending on the subjectivity or skill of the user for comparative interpretation. For this reason, it is possible to appropriately perform comparative inspection of images. As a result, the burden on not only the user but also the patient can be reduced.

  Although specific embodiments have been described above, the described embodiments are merely examples, and do not limit the scope of the invention. The novel methods and apparatus described herein can be implemented in a variety of other ways. Various omissions, substitutions, and changes can be made in the method and apparatus described herein without departing from the spirit of the invention. The appended claims and their equivalents include such various forms and modifications as are encompassed by the scope and spirit of the invention.

  For example, in the above-described embodiment, the case where image data collected mainly in the magnetic resonance imaging apparatus 1 is compared with image data acquired from the medical image server 4 has been described. Similarly, when comparing a plurality of stored image data, it is possible to adjust window parameters by setting a single or a plurality of contrast adjustment regions.

  On the other hand, even when comparing a plurality of image data collected in different magnetic resonance imaging apparatuses 1 and 1A, it is possible to similarly adjust the window parameter by setting a single or a plurality of contrast adjustment regions. In this case, the image data collected by the 1.5T magnetic resonance imaging apparatus and the image data collected by the 3T magnetic resonance imaging apparatus can be compared as a plurality of image data having the same contrast.

DESCRIPTION OF SYMBOLS 1, 1A Magnetic resonance imaging apparatus 2 Network 3 Medical information management system 4 Medical image server 4A Image database 4B Database control part 5 Patient information acquisition part 6 Imaging condition setting part 7 Imaging system 8 Contrast adjustment part 8A Area setting part 8B Past image acquisition 8C Resolution conversion unit 8D WL / WW adjustment unit 9 Image data transmission unit 10 Input device 11 Display device

Claims (5)

Image data acquisition means for acquiring a plurality of magnetic resonance image data corresponding to different times of the same subject by acquiring at least one image data of a communication standard of medical image data via a network;
The plurality of magnetic resonance image data so that the corresponding regions are displayed with the same luminance based on the pixel values in the corresponding regions set for the plurality of magnetic resonance image data, respectively. Contrast adjustment means for adjusting window parameters for at least one of the following:
A medical image display device comprising: The contrast adjustment unit is configured to display a plurality of window parameters corresponding to the plurality of regions so that the plurality of regions corresponding to the plurality of magnetic resonance image data are displayed with the same luminance. The medical image display apparatus according to claim 1, wherein the medical image display apparatus is configured to obtain an adjustment value. The contrast adjusting unit is configured such that the corresponding region of the magnetic resonance image data after the conversion of the resolution obtained based on the communication standard image data of the medical image data has the same luminance as the corresponding region of the other magnetic resonance image data. The medical image display apparatus according to claim 1, wherein the window parameter is adjusted so that the window parameter is displayed. The contrast adjustment unit obtains an adjustment value of the window parameter by multiplying the window parameter serving as a reference by the ratio when the ratio between the representative values of the pixel values in the corresponding regions is equal to or greater than the threshold value or exceeds the threshold value. The medical image display device according to claim 1 configured as described above. Image data acquisition means for collecting a plurality of magnetic resonance image data corresponding to different times from the same subject;
The plurality of magnetic resonance image data so that the corresponding regions are displayed with the same luminance based on the pixel values in the corresponding regions set for the plurality of magnetic resonance image data, respectively. Contrast adjustment means for adjusting window parameters for at least one of the following:
A medical image display device comprising:

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