Search

EP-4020381-B1 - X-RAY DIAGNOSIS APPARATUS, AND MEDICAL IMAGE PROCESSING METHOD

EP4020381B1EP 4020381 B1EP4020381 B1EP 4020381B1EP-4020381-B1

Inventors

  • ABE, SHINGO

Dates

Publication Date
20260506
Application Date
20200820

Claims (15)

  1. An X-ray diagnostic apparatus comprising: an acquisition unit (21) configured to acquire a plurality of time-series X-ray images (I n ) of an object within which a moving target is provided, the apparatus characterized by : a motion suppression image generation unit (22) configured to generate, based on two or more of the plurality of time-series X-ray images (I n ), a motion suppression image A in which motion related components regarding the moving target are suppressed more than components in the two or more of the plurality of time-series X-ray images (I n ), wherein, in the motion suppression image (A), each pixel has a representative value of pixel values of the two or more X-ray images (I n ) so that the moving target is suppressed; characterized in that the apparatus further comprises a subtraction image generation unit (23) configured to generate a difference image (M n ) by difference processing between the motion suppression image (A) and one of the time-series X-ray images (I n ); and an emphasis processing image generation unit (24) configured to generate an emphasis processing image (SI n ) in which the moving target is emphasized in the one of the time-series X-ray images (I n ) based on the generated difference image (M n ), a size of the emphasis processing image (SI n ) being the same as that of the motion suppression image (A).
  2. The X-ray diagnostic apparatus according to claim 1, wherein the emphasis processing image generation unit (24) is configured to generate an emphasis processing image from an X-ray image by compositing the X-ray image and the difference image.
  3. The X-ray diagnostic apparatus according to claim 1 or 2, further comprising an extraction unit (23) is configured to extract motion related components in each of the plurality of X-ray images by subtracting the motion suppression image from the each of the plurality of X-ray images.
  4. The X-ray diagnostic apparatus according to any preceding claim, the motion suppression image generation unit (22) is configured to generate, as the motion suppression image, a mean value image or a median value image of two or more of the plurality of X-ray images.
  5. The X-ray diagnostic apparatus according to any preceding claim, wherein when an X-ray irradiation is switched from ON to OFF and then returned to ON, the motion suppression image generation unit (22) is configured to update the motion suppression image based on the motion suppression image generated before switched to OFF and the X-ray image obtained after returned to ON.
  6. The X-ray diagnostic apparatus according to any preceding claims, wherein when an irradiation field in X-ray imaging of the object is changed, the motion suppression image generation unit (22) is configured to generate the motion suppression image of the changed irradiation field such that the motion suppression image based on two or more of the plurality of time-series X-ray images imaged in the irradiation field before the change is used for the part of the changed irradiation field that overlaps with the irradiation field before the change.
  7. The X-ray diagnostic apparatus according to claim 2, wherein the emphasis processing image generation unit (24) is adapted to multiply the extracted motion related component by a factor to generate an intermediate emphasis image, and composite the intermediate emphasis image and the X-ray image to generate the emphasis processing image.
  8. The X-ray diagnostic apparatus according to claim 7, further comprising: an extraction unit (23) is configured to extract motion related components in each of the plurality of X-ray images by subtracting the motion suppression image from the each of the plurality of X-ray images; and an emphasis processing unit configured to: convert the X-ray image into a plurality of frequency band data; assign the emphasis coefficient to each of the plurality of frequency band data in accordance with a ratio of the extracted motion related component by cooperating with the extraction unit (23) and the emphasis processing image generation unit (24); and generate image data of the intermediate emphasis image for the each of the plurality of frequency bands based on the assigned emphasis coefficient, wherein the emphasis processing image generation unit (24) is configured to generate the emphasis processing image based on the image data of the intermediate emphasis image for the each of the plurality of frequency bands.
  9. The X-ray diagnostic apparatus according to any one of claims 1 to 8, wherein the emphasis processing image (ESIn) generation unit (24) is adapted to narrow a window width of the emphasis processing image (SIn) such that the target is emphasized.
  10. The X-ray diagnostic apparatus according to any one of claims 1 to 9, wherein the motion related components include movement derived from at least one of pulsation and respiration of the object and/or, when the target moves in the object, movement derived from movement of the target.
  11. The X-ray diagnostic apparatus according to any one of claims 1 to 10, wherein: the motion suppression image generation unit (22) is configured to generate a representative value image as the motion suppression image in which each pixel has a representative value of pixel values in the two or more X-ray images, based on the two or more X-ray images of the plurality of time-series X-ray images and the emphasis processing image generation unit (24) is configured to generate the emphasis processing image of the target depicted in the difference image by adding the generated difference image and the X-ray image corresponding to the difference image.
  12. The X-ray diagnostic apparatus according to claim 11, wherein the emphasis processing image generation unit (24) is configured to generate the emphasis processing image by adding the difference image multiplied by a factor and the X-ray image corresponding to the difference image.
  13. The X-ray diagnostic apparatus according to any one of claims 11 to 12, wherein the emphasis processing image generation unit (24) is configured to narrow a window width of the emphasis processing image such that the target is emphasized.
  14. A medical image processing method comprising: acquiring a plurality of time-series X-ray images of an object within which a moving target is provided, the method characterized by : generating, based on two or more of the plurality of time-series X-ray images, a motion suppression image in which motion related components regarding the moving target are suppressed more than components in the two or more of the plurality of time-series X-ray images, wherein, in the motion suppression image, each pixel has a representative value of pixel values of the two or more X-ray images so that the moving target is suppressed; generating a difference image by difference processing between the motion suppression image and one of the time-series X-ray images; and generating an emphasis processing image in which the moving target is emphasized in the one of the time-series X-ray images based on the generated difference image, a size of the emphasis processing image being the same as that of the motion suppression image.
  15. The medical image processing method according to claim 14, wherein: the acquiring the X-ray images is executed by any one of a client and a server both of which a medical image processing system includes; the extracting the motion related component is executed by any one of the client and the server; and the generating the emphasis processing image is executed by any one of the client and the server.

Description

FIELD Embodiments described herein relate generally to a medical image processing apparatus, an x-ray diagnostic apparatus, and a medical image processing method. BACKGROUND X-ray diagnostic apparatuses such as an X-ray fluoroscopic apparatus and an X-ray angiography apparatus have been provided recently in which the inside of an object can be observed in real time by irradiating the object with X-rays and sequentially displaying the acquired images like moving images in real time. Further, the time-series X-ray images acquired by the X-ray diagnostic apparatus can be observed as moving images a plurality of time-series X-ray images acquired by the X-ray diagnostic apparatus can be observed as a moving image in the X-ray diagnostic apparatus or other modality after the scan in the post process. Such X-ray diagnostic apparatus may be used for angiography using a catheter of IVR (Interventional Radiology). For example, when performing a catheter treatment, a user may display an X-ray fluoroscopic image based on X-ray imaging by an X-ray diagnostic apparatus in real time, and the procedure may be performed while checking positions of a catheter and a treatment device such as a balloon (including the indwelling position) depicted in the X-ray image. Further, after the procedure, the X-ray image may be used to confirm whether the treatment device such as the balloon has been placed at a desired position. Generally, image processing such as background compression, signal enhancement, and gradation conversion is performed on the X-ray image in order to improve the visibility of instruments such as contrast agents and catheters depicted on X-ray images. By performing image processing such as gradation conversion, it is possible to emphasize in the X-ray image the shade of a device such as a contrast agent or a catheter, which is the target to be observed for the user. However, when there are non-target components such as bones and diaphragms depicted in the same X-ray image, the shades of these non-target components are also emphasized by the image processing such as gradation conversion. In this case, as a result of performing image processing such as gradation conversion, the visibility of the target may be worsened by the non-target components. US 2015/139394 A1 discloses an X-ray imaging apparatus including an X-ray source configured to radiate X-rays onto an object region, an X-ray detector configured to detect the radiated X-rays and obtain image frames of the object region based on the detected X-rays, and a filter configured to filter X-rays radiated from the X-ray source such that the X-rays incident on a region of interest (ROI) of the object region have a lower dose than a dose of X-rays incident on a non-ROI of the object region. US 2018/082420 A1 discloses methods and systems for generating regional digital subtraction angiography (DSA) images and roadmap images with landmarks. In one embodiment, a method comprises generating a mask from a set of mask images of an anatomy of a subject, and generating a masked image by applying the mask to acquired image data of the anatomy of the subject, including weighting the mask differently inside a region of interest (ROI) of the image than outside the ROI, the weighting inside ROI independent of the weighting outside the ROI. A user may be able to adjust a relative magnitude of subtraction inside and outside the ROI, and thus be able to visualize both vasculature and landmarks within the same image frame. SUMMARY OF THE INVENTION The invention is set out in the appended set of claims. One of the problems to be solved by the embodiments described herein is to appropriately perform an emphasis processing of a target to be observed in an X-ray image. The problems to be solved by the embodiments described herein are not limited to the above-mentioned problem. The problem corresponding to each effect of each configuration shown in the embodiment described later can be another problem. According to an embodiment, there is provided an apparatus according to claim 1. The emphasis processing image generation unit may generate an emphasis processing image from an X-ray image by compositing the X-ray image and the extracted motion related component. The motion suppression image generation unit may generate, as the motion suppression image, a mean value image or a median value image of two or more of the plurality of X-ray images. When an X-ray irradiation is switched from ON to OFF and then returned to ON, the motion suppression image generation unit may update the motion suppression image based on the motion suppression image generated before switched to OFF and the X-ray image obtained after returned to ON. When an irradiation field in X-ray imaging of the object is changed, the motion suppression image generation unit may generate the motion suppression image of the changed irradiation field such that the motion suppression image based on two or more of the plurality of