Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
1998-11-10
2001-05-22
Lateef, Marvin M. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
Reexamination Certificate
active
06234970
ABSTRACT:
BACKGROUND OF THE INVENTION
Echo-doppler is commonly applied for non-invasive imaging of the heart. Commercially available systems provide the user with several imaging modalities: 2D two-dimensional) image of a single plane through the heart; m-mode image of a single line through the heart; doppler image of a flow in a specific location (pulsed doppler) or in any location along a line (continuous doppler); color-doppler image which consists of superimposing information of flow direction and velocity on 2D image; and tissue-doppler imaging which provides tissue deformation data on a 2D image. Three-dimensional imaging of the heart, which currently provides off-line reconstruction of the heart from sequentially acquired multi-plans of the heart may soon provide real-time imaging of the heart.
A main limitation in the clinical application of echo-doppler imaging is the image quality. While about 20-30% of the studies have good technical quality and do not require image enhancement, about 40-60% are acceptable studies which can be enhanced to get more accurate evaluation, and about 20-30% are technically poor and usually do not provide the required image quality.
This limitation is either overcome by using oesophageal imaging, rather than the standard trans-thoracic imaging, or by using echo-contrast media which are injected intravenously. These techniques significantly improve the image quality but are semi-invasive and can only be used in a limited number of studies.
Accordingly, there exists a need for a system that will provide for image enhancement of trans-thoracic studies that can significantly improve the accuracy of echo-doppler imaging in the majority of studies which provide images that can be analyzed but need more time to optimize the image and to get the required clinical data.
OBJECTS AND SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a method and apparatus for image enhancement in cardiologic applications of echo-doppler imaging.
It is another object of the present invention to improve the image quality of the technically poor studies sufficiently to get the required data and to avoid the use of the semi-invasive trans-oesophageal and echo-contrast techniques.
Yet another object of the present invention is to enhance perfusion studies of the heart or other organs which are currently done with contrast-enhanced echo-doppler imaging.
According to the present invention, repetitive physiologic phenomena—the heart contraction/relaxation cycle and/or the breathing inspiration/expiration cycle, are divided into “m” equal sequences. Factors that determine “m” include the length of the physiologic cycle, the scanning rate of the echo-doppler apparatus, the image area to be enhanced and the amount of available memory in the processing apparatus. Typically, “m” equals 20-40. The image acquired during each sequence represents the heart shape at the specific time of the measurement with respect to a fixed reference point in the physiologic cycle (e.g. the initiation of heart contraction, signaled by the R-wave of the ECG, or the initiation of the breathing cycle, signaled by the initial portion of inspiration). This image is to be filtered with previous images at the same time, relative to the reference point, that were acquired in previous physiologic cycles. Thus the change of the heart shape due to these physiologic phenomena is eliminated and the images can be filtered to get an improved image.
The improved image is displayed on the monitor (either with the acquired raw image or as substitute) and is saved for filtering with future images. A simple embodiment of this filtering is weighted averaging, where the newly acquired image is multiplied by a certain factor, the image saved during previous cycles is multiplied by another factor and the two results are summed. The multiplying factors (the multipliers) determine the “memory” of the algorithm, or the effect of previous images versus the effect of the newly acquired image, and can be controlled by the operator.
More complex filtering requires more memory which can be used to save several weighted past images, and thus the newly acquired image can be filtered with several previous images. This approach can be applied with all modes of commercial echo-doppler systems, namely 2D, m-mode, doppler, color-doppler, tissue-doppler and 3D imaging.
The same approach can be used for perfusion studies of any organ in the body. Due to the pulsatile pattern of blood flow and pressure in the body, gating to the R-wave of the ECG enhances the quality of the perfusion images and may allow quantitated analysis of perfusion pulsatility in any organ. This may assist the delineation of abnormal tissue, for example a tumor, from neighboring normal tissue.
The invention also provides apparatus to enable the application of the described method either as an add-on device for commercial echo-doppler systems or as a built-in module for future echo-doppler systems. The apparatus comprises an interface to acquire the image from the echo-doppler system (e.g. video frame grabber), an interface to get the physiologic cycling signal (e.g. the ECG raw signals which can be processed to provide both heart contraction timing and breathing timing or the ECG tracing which is commonly recorded as part of the echo-doppler display), memory modules to save the gated images, user interface to control parameters of the algorithm (e.g. the multipliers for weighted averaging), micro-processor for mathematical processing of the imaging (e.g. array processor), and an interface to present the enhanced image (e.g. an additional screen or interface to the echo-doppler screen).
REFERENCES:
patent: 4887306 (1989-12-01), Hwang et al.
patent: 5235984 (1993-08-01), D'Sa
patent: 5409010 (1995-04-01), Beach et al.
patent: 5415171 (1995-05-01), Goh et al.
patent: 5450850 (1995-09-01), Iinuma
patent: 5883613 (1998-11-01), Averkiou et al.
Nevo Erez
Roth Abraham
Lateef Marvin M.
Patel Maulin
Robin Medical Technologies, Ltd.
LandOfFree
Method and apparatus for cardiologic echo-doppler image... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for cardiologic echo-doppler image..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for cardiologic echo-doppler image... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2494005