Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reissue Patent
1998-05-13
2001-03-06
Manuel, George (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
Reissue Patent
active
RE037088
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a method for generating anatomical M-Mode displays in ultrasonic investigation of living biological structures during movement, for example a heart function, employing an ultrasonic transducer.
The invention describes a technique for obtaining anatomically meaningful M-Mode displays by data extraction from 2D (two dimensional) and 3D (three dimensional) ultrasonic imaging. Conventional M-Mode is acquired along one acoustical beam of an ultrasonic transducer employed, displaying the
tide-variant
time-
variant
data in a display unit with time along the x-axis and depth along the y-axis. The localization of the M-Mode line in conventional M-Mode is limited to the set of beam directions that can be generated (scanned) by the transducer.
In cardiology, the use of the M-Mode method is fairly standardized, requiring specific cuts through the heart at standard positions and angles. To be able to perform a good M-Mode measurement, important criteria are:
1. Image quality. The borders and interfaces between different structures of the heart must be clearly visible. One of the most important factors to achieve this, is to position the ultrasound transducer on the body concerned at a point where the acoustic properties are optimum. These places are often referred to as “acoustic windows”. On older patients, these windows are scarce, and hard to find.
2. Alignment. The standardized M-Mode measurements require that the recording is taken at specific angles, usually 90 degrees relative to the heart structure being investigated.
3. Motion. As the heart moves inside the chest during contraction and relaxation, a correct M-Mode line position at one point in the heart cycle may be wrong at another point in the same heart cycle. This is very difficult to compensate for manually, since the probe must be moved synchronous to the heartbeats. Therefore, most sonographers settle for a fixed, compromise direction of the M-Mode line, i.e. transducer beam.
4. Wall thickening analysis. With coronary diseases, an important parameter to observe is the thickening of the left ventricular muscle at various positions.
In many cases there can be problems getting the correct alignment at a good acoustical window. Often, the good acoustic windows give bad alignment, and vice versa. Hence, the sonographer or user spends much time and effort trying to optimize the image for the two criteria (alignment, image quality).
SUMMARY OF THE INVENTION
With the advent of high-performance digital front-end control for phased transducer array probes, the possibility exists for acquiring 2D images at very high framerates (<10 ms per 2D image). These 2D data are stored in a computer RAM, with storage capacity enough to hold one or more full heart cycles worth of 2D data recordings. M-Mode displays can be generated based on these recordings with an adequate temporal resolution. According to the present invention this allows for complete flexibility in the positioning of the M-Mode lines. The invention describes how this flexibility can be utilized to improve the anatomical information content in the extracted M-Mode displays.
The invention also applies to extraction of M-Mode displays from a time series with 3D images. In 3D it is possible to compensate for the true 3D motion of the ventricle. Based on 2D recordings the operator will be limited to compensate for the movements that can be measured in the imaged plane. The invention also describes how local M-Mode information extracted from 3D acquisitions can be utilized to obtain a color encoding of the ventricle wall providing information about wall thickening.
The anatomical M-Mode displays can be generated in real-time during scanning of a 2D image or during real-time volumetric scanning. The invention then describes how multiple M-Mode displays can be maintained together with the live 2D or 3D image. These M-Mode displays can also be freely positioned and even allowed to track the location and direction of the ventricle wall during the cardiac cycle. During real-time scanning, time resolution of anatomical M-Mode displays may be increased by constraining the 2D or volumetric scanning to the area defined by the ultrasound probe and the M-Mode line. This requires complete control of the ultrasound scanner front-end.
The anatomical M-Mode can also be used as a post-processing tool, where the user acquires the 2D/3D image sequence at super-high framerates, without making any M-Mode recordings. As long as the 2D data includes an adequate cut/view through the heart, the user may use the anatomical M-Mode to do the M-Mode analysis later.
The computer processing of data sets are previously known, as for example described in: J. D. Foley, A van Dam, S. K. Seiner, J. F. Hughes “Computer Graphics: Principles and Practice”, Addison Wesley U.S.A. (1990). Among other things line drawing algorithms are described in this reference. Thus, such computer processing, operations and steps are not explained in detail in the following description. Other references relating more specifically to techniques of particular interest here are the following:
B. Olstad, “Maximizing image variance in rendering of volumetric data sets,” Journal of Electronic Imaging, 1:245-265, July 1992.
E. Steen and B. Olstad, “Volume rendering in medical ultrasound imaging”. Proceedings of 8th Scandinavian Conference on Image Analysis. Tromsø, Norway May 1993.
G. Borgefors, “Distance transformations in digital images”, Computer vision, graphics and image processing 34, 1986, pp. 344-371.
Peter Seitz, “Optical Superresolution Using Solid State Cameras and Digital Signal Processing”, Optical Engineering 27(7) July 1988.
On the background of known techniques this invention takes as a starting-point methods for computation of conventional M-Mode and established clinical procedures for utilization of M-Mode imaging. The invention includes new techniques for the computation of anatomical M-Mode displays based on a time series of 2D or 3D ultrasonic images. The anatomical M-Mode is derived as a virtual M-Mode measurement along an arbitrary or virtual, tilted M-Mode line. What is novel and specific in the method according to the invention is defined more specifically in the appended claims.
Some of the advantages obtained with this invention can be summarized as follows: Multiple M-Mode displays with arbitrary positioning can be computer on the basis of a 2D or 3D acquisition. The position of the M-Mode line is not limited to the scanning geometry and can be freely positioned. Global heart movements can be compensated for by moving the M-Mode line according to the motion of the heart during the cardiac cycle. Wall thickening analysis is improved due to the possibility of keeping the M-Mode line perpendicular to the ventricle wall during the entire cardiac cycle. Reference points in the scene can be fixed at a given y-coordinate in the M-Mode display, hence improving the visual interpretability of relative motion/thickening phenomenons. 3D acquisitions can be visualized by mapping properties extracted from local M-Mode lines in a color encoding of the ventricle wall.
REFERENCES:
patent: 3955561 (1976-05-01), Eggleton
patent: 4271842 (1981-06-01), Specht et al.
patent: 4413521 (1983-11-01), Van Kemenade
patent: 4501277 (1985-02-01), Hongo
patent: 4735211 (1988-04-01), Takasugi
patent: 4932414 (1990-06-01), Coleman et al.
patent: 5097836 (1992-03-01), Yamada et al.
patent: 5105813 (1992-04-01), Shikata
patent: 5127409 (1992-07-01), Daigle
patent: 5195521 (1993-03-01), Melton, Jr. et al.
patent: 5285788 (1994-02-01), Arenson et al.
patent: 5355887 (1994-10-01), Iizuka et al.
patent: 5375599 (1994-12-01), Shimizu
Foley, et al., “Computer Graphics: Principles And Practice,” Addison Wesley USA (1990) (only bibliographic pages included).
Olstad, B., “Maximizing Image Variance In Rendering Of Columetric Data Sets”, Journal Of Electronic Imaging, 1:256-265, Jul. 1992.
Borgefors, G., “Distance Transformations In Digital Images”., Computer Vision, Graphics And Image Processing 34,
Ashman James
Holm Eivind
Olstad Bjorn
Blakely , Sokoloff, Taylor & Zafman LLP
Manuel George
Vingmed Sound A/S
LandOfFree
Method for generating anatomical M-mode displays 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 for generating anatomical M-mode displays, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for generating anatomical M-mode displays will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2503947