JP4549462B2 - Method for improving image quality of fluoroscopic image and system for improving image quality of fluoroscopic image - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to pulsed cardiac fluoroscopy, and more particularly to improving the image quality of continuously displayed fluoroscopic images, in other words, for example, when an operator uses a control pedal of a fluoroscopic image acquisition device. The present invention relates to improving the image quality of fluoroscopic images that are continuously displayed when one's feet are removed.
[0002]
[Prior art]
The fluoroscopy method is to acquire a plurality of radiographic images (hereinafter referred to as fluoroscopic images) at high speed, and these images are displayed on a display screen. Fluoroscopy is used on blood vessels to display the path of a probe injected directly into a subject.
[0003]
There are several types of fluoroscopy. In this regard, it is called continuous fluoroscopy, a method characterized by continuously irradiating a patient with X-rays, and is called pulsed fluoroscopy, which has a predetermined time width and can take a picture. Mention may be made of methods characterized by X-ray pulses repeated at a frequency.
[0004]
Therefore, in the pulse fluoroscopy method, when an operator steps on the control pedal of the apparatus, X-ray pulses are sequentially emitted, and one fluoroscopic image can be acquired for each pulse.
[0005]
[Problems to be solved by the invention]
When the operator removes his foot from the pedal, a fluoroscopic image is then displayed continuously on the display screen, but this image should be as clear as possible. However, the heartbeat of the patient moves the patient's chest, which causes blurring of images displayed by cardiac fluoroscopy. The present invention is intended to display a clear image without the blur.
[0006]
[Means for Solving the Problems]
One embodiment of the present invention provides continuous display of fluoroscopic images having the best possible sharpness while minimizing stress on the X-ray tube so as not to shorten the life of the X-ray tube. .
[0007]
Accordingly, one embodiment of the present invention provides a method for improving the image quality of a fluoroscopic image displayed continuously after an image acquisition sequence in which images are acquired using a pulsed cardiac fluoroscopy device. An image satisfying a predetermined minimum operation criterion is stored from the sequence of images, and the stored image is continuously displayed.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Other advantages of the present invention will become apparent by considering the detailed description of embodiments in a generally non-limiting manner and the accompanying drawings in which a system for acquiring fluoroscopic images in a single view is shown very schematically. And features will be revealed.
[0009]
In this single figure (FIG. 1), reference numeral 1 denotes a platform that supports a patient P. The X-ray emitter 2 emits X-ray pulses at regular time intervals when the acquisition pedal 7 of the device is depressed. Each time a pulse is emitted, the X-ray beam 3 passes through the patient and is received by a detector 4 connected to the processing means 5. The architecture of the processing means 5 is based on a microcomputer. The acquired image is displayed on the display screen 6.
[0010]
According to the first embodiment of the present invention, when the operator steps on the pedal 7, X-ray pulses are continuously emitted at a predetermined time interval, for example, with a pulse width of about 15 milliseconds. The image acquired by the image acquisition sequence is directly displayed on the display screen 6 after being processed by the processing means 5. When the operator removes his foot from the pedal 7, the processing means 5 supplies a control signal to the X-ray emitter, so that the length of the emitted pulse is reduced from 15 milliseconds to about 5 milliseconds. Furthermore, since the X-ray dose per image must remain constant, the level of X-rays emitted during this last image is increased so that it is acquired and continuously displayed on the screen 6 To improve the sharpness of that image.
[0011]
The person skilled in the art will therefore realize that further heating of the X-ray tube due to the shortening of the pulse occurs only during the last image, and therefore this does not shorten the life of the X-ray tube.
[0012]
According to another embodiment of the present invention, the processing means 5 performs image processing on the images in the sequence and as a result stores images that meet the criteria for minimizing blur. More specifically, for example, correlation processing between images can be executed in a small area of the image. The maximum correlation between two consecutive images represents the minimum motion correlation between these two images. The image associated with the maximum correlation is then stored in real time.
[0013]
This image processing can be performed on an image-by-image basis, or alternatively, can be performed on all images of the last 10 cycles of the heart, which are stored continuously.
[0014]
According to another variant of the invention, a sensor 8, for example a blood pressure sensor, or another device for the electrocardiogram is used instead, so that the end of the diastole, i.e. when the heart movement is minimal, is detected. can do. The sensor then issues a control signal to the processing means 5 and then displays the images acquired at this time continuously at the end of the acquisition of the image sequence, i.e. continuously when the operator removes his foot from the pedal 7. To store in memory.
[0015]
The stored image can be the last image in the sequence, i.e., acquired when the operator removes his foot from the control pedal of the device. In this alternative embodiment, the present invention provides for an increase in the X-ray level emitted during this last image and subsequent storage of this image.
[0016]
In this different embodiment, increasing the x-ray level shortens the pulse length for such last image. This increase in stress experienced by the x-ray tube is limited to the time the last image is acquired. This pulse length is reduced to, for example, 5 milliseconds, whereas it is held at 15 milliseconds throughout the rest of the acquisition sequence.
[0017]
According to another variant of the invention, image processing is performed on the sequence image so as to store images that meet the criteria for minimizing blur. For example, this image processing is to correlate images on a small area. The maximum correlation between two consecutive images is then determined.
[0018]
According to another variant of the invention, a sensor, for example a blood pressure sensor or instead an electrocardiogram recording device, is used to detect the end of the diastole corresponding to a minute movement of the heart. In response to the control signal issued by, the image acquired when this control signal is received is stored.
[0019]
Various modifications may be made to the structure and / or function and / or steps by those skilled in the art to disclose the embodiments without departing from the scope and extent of the invention.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a system for acquiring a fluoroscopic image.
[Explanation of symbols]
1 unit 2 X-ray emitter 3 X-ray beam 4 detector 5 processing means 6 display screen 7 acquisition pedal 8 sensor

Claims (4)

A method for improving the image quality of a fluoroscopic image displayed continuously after an image acquisition sequence,
A sequence of images generated by a plurality of X-ray pulses emitted at a plurality of regular time intervals is displayed;
Storing an image satisfying a predetermined minimum operating criterion from the sequence of images, the criterion being satisfied by reducing the length of the last pulse of the sequence, wherein the last pulse is an image acquisition pedal ( Said storing step, determined by 7) being opened;
Increasing the level of x-ray (3) emitted during the last image of the sequence;
Storing the last image and continuously displaying (6) the stored image.  The method of claim 1, wherein the sequence of images is acquired using a pulsed cardiac fluoroscope. A system for improving the image quality of a fluoroscopic image displayed continuously after an image acquisition sequence,
Means for displaying a sequence of images generated by a plurality of X-ray pulses emitted at a plurality of regular time intervals;
Means for storing an image satisfying a predetermined minimum operating criterion from the sequence of images, the criterion being satisfied by reducing the length of the last pulse of the sequence, wherein the last pulse is an image acquisition pedal ( Said means for storing determined by opening 7);
Means for increasing the level of X-ray (3) emitted during the last image of the sequence;
A system comprising means for storing the last image and displaying (6) the stored image continuously. The system of claim 3, wherein the sequence of images is acquired using a pulsed cardiac fluoroscope.

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