Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
1999-04-02
2001-03-06
Lateef, Marvin M. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
Reexamination Certificate
active
06196971
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to ultrasound imaging systems, and more particularly, to a chord propagation velocity measurement (CPVM) system and method for producing a chord propagation velocity (CPV) associated with a part in a body, for example but not limited to, a blood vessel in a living thing. In the context of a blood vessel, the CPV is indicative of the vessel stiffness, which is an important determinant of vessel health.
BACKGROUND OF THE INVENTION
The stiffness of a blood vessel in a living thing, particularly, a human being, can be used in assessing the health of the blood vessel. Presently, there are at least two known techniques for estimating vessel stiffness.
One technique involves assessing vessel stiffness by measuring the internal pressure within a vessel and dimensional changes resulting from pressure changes. However, it is very difficult to measure internal pressure within a vessel inside a body, and moreover, systems and apparatus to make external pressure measurements are not easily calibrated and require compressing the vessel.
Another technique for estimating vessel stiffness entails measuring a pressure propagation velocity. The pressure propagation velocity is a measure that is known to be very closely correlated with vessel stiffness and is a measure of the velocity with which a pressure pulse propagates along a vessel.
Both of the foregoing techniques require one or more pressure measurements of some sort that is very difficult to implement in vivo. To make these measurements, pressure transducers are placed externally on the body, e.g., on the skin of a person's body, and are monitored by an appropriate monitoring system in order to estimate pressure changes in vessels under the skin. There are many corrupting influences and limitations of this procedure. Because the pressure transducers are usually placed a large distance apart, for example, a half of a meter in some cases, local regions of vessels cannot be effectively isolated and analyzed for, for example, plaque formation, thrombi (blood clots), aneurysms, etc. Furthermore, when pressure transducers are used externally on a body, only vessels near the surface of the body can be analyzed. In other words, internal vessels, such as the important abdominal aorta associated with the heart, which degrades in most elderly people, cannot be analyzed.
Thus, a heretofore unaddressed need exists in the industry for a way to better quantitatively measure vessel stiffness, to thereby assess vessel health in a living thing.
SUMMARY OF THE INVENTION
The present invention provides a chord propagation velocity measurement (CPVM) system and method used in connection with, for example, a brightness-mode (B-mode) or doppler ultrasound imaging system. The CPVM system monitors ultrasound data provided to it by the ultrasound imaging system and enhances the functionality of the ultrasound imaging system by providing a chord propagation velocity (CPV) associated with a body part, such as a blood vessel in a living thing. The CPV is indicative of the stiffness of the body part.
In architecture, the CPVM system includes a tissue processor connected to the scanner of the ultrasound system designed to analyze each acoustic scan line and to determine a category (type of region, for example, blood or tissue) for each point along each acoustic scan line. A display produces an image generated from acoustic scan lines. A user input mechanism permits a user to identify a region of interest in the image. The tissue processor produces samples from different subregions of the region of interest in the image. In the context of a B-mode ultrasound imaging system, the samples are cross sectional areas A
i
and/or chords h
i
. In the context of a doppler ultrasound imaging system, the samples are changes in the cross sectional areas &Dgr;A
i
and/or chords &Dgr;h
i
.
A CPV determination system, which is connected to the tissue processor, acquires a plurality of the samples along a longitudinal span of the region for each of a plurality of different cycles, derives a plurality of composites, one for each subregion, by combining corresponding samples from different cycles, and produces a CPV based upon the plurality of composites. The CPV can be displayed, printed, or otherwise output by the CPVM system to the user of the ultrasound imaging system, optionally, continuously updated in real time, to permit immediate analysis, and evaluation of the body part by the user.
The present invention can also be conceptualized as providing a method for quantifying stiffness of a part of a body. In this regard, the method can be broadly stated by the following steps: acquiring a plurality of measured samples from different subregions along a longitudinal span of the body part for each of a plurality of different cycles; deriving a plurality of composites, one for each subregion, by combining corresponding samples from different cycles; and producing a CPV based upon the plurality of composites, the CPV being indicative of the stiffness.
Other features of the invention will become apparent to one with skill in the art upon examination of the following drawings and detailed description. These additional features and advantages are intended to be included herein within this description and protected by the claims.
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patent: 5474070 (1995-12-01), Ophir et al.
patent: 5517995 (1996-05-01), Klepper et al.
patent: 5830131 (1998-11-01), Caro et al.
patent: 6023977 (2000-02-01), Langdon et al.
Friedman Joel
Prater David M
Agilent Technologie,s Inc.
Imam Ali M.
Lateef Marvin M.
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