JP2001112746A - Method for improving quality of fluoroscopic image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for improving the quality of successively displayed fluoroscopic images. SOLUTION: The method for improving the quality of fluoroscopic images includes storing from an image sequence those images meeting a predetermined criterion for minimal action, and displaying the stored images in succession. The images are obtainable by use of a pulsed cardiac fluoroscopy apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to pulsed cardiac fluoroscopy, and more particularly to improving the quality of continuously displayed fluoroscopic images; The present invention relates to improving the quality of a fluoroscopic image that is continuously displayed when the user releases his / her foot from a control pedal of an image acquisition device.

[0002]

2. Description of the Related Art Fluoroscopy is a method in which a plurality of radiographic images (hereinafter, referred to as radiographic images) are used.
(Referred to as fluoroscopic images) at high speed, and these images are displayed on the display screen. Fluoroscopy is
Used on blood vessels to display the path of a probe injected directly into a subject.

There are several types of fluoroscopy. In this regard, a method characterized by continuously irradiating a patient with X-rays, which is called continuous fluoroscopy, and a pulsed fluoroscopy, which has a predetermined time width and can take a picture There may be mentioned a method characterized by an X-ray pulse repeated at a high frequency.

Therefore, in the pulse-type 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]

When the operator removes his foot from the pedal, a fluoroscopic image is then displayed continuously on the display screen, but this image must be as clear as possible. However, the heartbeat causes the patient's chest to move, which causes blurring of the images displayed by cardiac fluoroscopy. An object of the present invention is to eliminate the blur and display a clear image.

[0006]

According to one embodiment of the present invention, there is provided:
It is intended to continuously display a fluoroscopic image having the best possible sharpness while minimizing stress applied to the X-ray tube so as not to shorten the life of the X-ray tube.

Accordingly, one embodiment of the present invention provides a method for improving the quality of a fluoroscopic image that is displayed continuously after an image acquisition sequence in which the image is acquired using a pulsed cardiac fluoroscope. An image which satisfies a predetermined minimum operation criterion from a sequence of images is stored, and the stored images are continuously displayed.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS By reviewing the detailed description of the non-limiting embodiments in general, and the accompanying drawings in which the system for acquiring a fluoroscopic image by means of a single drawing is shown very schematically. Other advantages and features of the invention will become apparent.

In this single view (FIG. 1), reference numeral 1 indicates a platform for supporting 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, an X-ray beam 3 passes through the patient and is received by a detector 4 connected to a 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.

According to the first embodiment of the present invention, when the operator steps on the pedal 7, X-ray pulses are continuously emitted at predetermined time intervals, 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 the foot from the pedal 7, the processing means 5
Supplies a control signal to the X-ray emitter, thereby reducing the length of the emitted pulse from 15 ms to about 5 ms. Further, since the X-ray dose for each image must remain constant, the X-ray emitted during this last image
Increasing the level of lines, thereby improving the sharpness of the image that is acquired and displayed continuously on the screen 6.

Thus, those skilled in the art will note that further heating of the X-ray tube due to the shortened pulse only occurs during the last image, and thus this does not shorten the life of the X-ray tube. There will be.

According to another embodiment of the invention, the processing means 5 performs image processing on the images of the sequence and, as a result, stores the images that meet the criteria for minimizing blurring. More specifically, for example, correlation processing between images can be performed on a small area of an 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.

This image processing can be performed on an image-by-image basis, or alternatively, can be performed on all of the images of the last ten cycles of the heart, and these are stored continuously.

According to another variant of the invention, the sensor 8,
For example, a blood pressure sensor or, alternatively, another device for an electrocardiogram can be used, so that the end of diastole, i.e. when the heart movement is minimal, can be detected. 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, ie continuously when the operator releases the foot from the pedal 7. So that it is stored in the memory.

[0015] The stored image may be the last image in the sequence, that is, may have been acquired when the operator removed his foot from the control pedal of the device. In this alternative embodiment, the invention provides for an increase in the level of X-rays emitted during this last image and subsequent storage of this image.

In this different embodiment, as the X-ray level increases, the pulse length for such last image decreases. This increase in stress experienced by the x-ray tube is limited to when the last image is acquired. This pulse length is reduced to, for example, 5 ms, while being kept at 15 ms throughout the remaining acquisition sequence.

According to another variant of the invention, image processing is performed on the sequence images so as to store images that meet the criteria for minimizing blur. As an example, this image processing is to correlate images on a small area. The maximum correlation between two consecutive images is then determined.

According to another variant of the invention, a sensor, for example a blood pressure sensor, or alternatively a device for recording electrocardiograms is used to detect the end of diastole corresponding to minute movements of the heart. In response to a control signal emitted by the sensor, an image acquired when the control signal is received is stored.

Various modifications may be made to structure and / or function and / or steps by those skilled in the art in order to disclose an embodiment 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

Continued on the front page (72) Inventor Hubert Aquar, France, 91570 Beevre-Luval Profon 29 (72) Inventor François Cocien, France, 78390 Bore d'Assy, Allée, Corval, 5F Terms (reference) 4C093 AA07 CA04 CA08 DA02 EA02 FA47 FF04 FH02

Claims (5)

[Claims] 1. A method for improving the quality of a fluoroscopic image that is displayed continuously after an image acquisition sequence, comprising: storing an image from a sequence of images that satisfies a predetermined minimum operating criterion; Continuously displaying (6). 2. The method according to claim 1, wherein the level of the emitted X-rays (3) is increased during the last image of the sequence and the image is stored. 3. The method according to claim 1, wherein image processing (5) is performed on the sequence images to store images that meet the criteria for minimizing blur. 4. Using a sensor (8) to detect the end of diastole and storing an image acquired when receiving the control signal in response to a control signal emitted by the sensor. The method of claim 1. 5. The method of claim 1, wherein the image is acquired using a pulsed cardiac fluoroscope.