Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
1999-09-10
2001-03-13
Lateef, Marvin M. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C600S463000, C600S467000
Reexamination Certificate
active
06200268
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to the intravascular ultrasound analysis arts. It finds particular application to a method and system for quantitative component identification within a vascular object including characterization of plaque. It will be appreciated that the present invention will also find application to other types objects which can be scanned with an ultrasonic device.
Ultrasonic imaging of portions of a patient's body provides a useful tool in various areas of medical practice for determining the best type and course of treatment. Imaging of the coronary vessels of a patient by ultrasonic techniques can provide physicians with valuable information. For example, the image data may show the extent of a stenosis in a patient, reveal progression of disease, help determine whether procedures such as angioplasty or atherectomy are indicated or whether more invasive procedures may be warranted.
In a typical ultrasound imaging system, an ultrasonic transducer is attached to the end of a catheter that is carefully maneuvered through a patient's body to a point of interest such as within a blood vessel. The transducer is a single-element crystal or probe which is mechanically scanned or rotated back and forth to cover a sector over a selected angular range. Acoustic signals are transmitted during the scanning and echoes from these acoustic signals are received to provide data representative of the density of tissue over the sector. As the probe is swept through the sector, many acoustic lines are processed building up a sector-shaped image of the patient. After the data is collected, images of the blood vessel are reconstructed using well-known techniques and the images are visually analyzed by a cardiologist to assess the vessel components and plaque content.
Typically, the ultrasonic image data is transferred to a VHS videotape, digitized and then analyzed. This process, however, loses image resolution since the videotape has a lower resolution than the originally collected ultrasound data. Losing image resolution may result in an inaccurate evaluation of a vessel and its plaque content. Furthermore, certain image characteristics like brightness and contrast will be different for different patients or could vary for the same patient if the cardiologist varies the settings on the IVUS console. The images that are recorded on the videotapes are the same images viewed on the IVUS console screen and, thus, subject to the settings on the console. Since plaque is identified by its appearance on the screen, errors may occur in the analysis if the screen settings have been modified.
The present invention provides a new and unique intravascular ultrasonic analysis method and system with cures the above problems and others.
SUMMARY OF THE INVENTION
In accordance with the present invention, a new and unique method of identifying components within a vascular object from an ultrasonic signal is provided. An ultrasonic signal is transmitted within a selected region of the vascular object and a backscatter signal reflected from the vascular object is collected. An IVUS image of the selected region is reconstructed from the backscatter signal. A histology image of the selected region of the vascular object is prepared which distinguishes different components of the vascular object. A region of interest is selected from the histology image which represents one component from the different components of the vascular object. The region of interest is at a coordinate location on the histology image. The coordinate location is mapped to a location on the IVUS image which corresponds to the coordinate location. The location on the IVUS image is then translated to a signal portion in the backscatter signal which corresponds to the IVUS location. The signal portion represents a signal signature of the one component of the vascular object which is then correlated to the one component.
In accordance with a more limited aspect of the present invention, the method further includes performing a signal analysis on the signal portion to determine signal properties of the signal portion where the signal signature includes the signal properties.
In accordance with another aspect of the present invention, a method of identifying components of a vascular object from an ultrasonic signal is provided. An ultrasonic signal is transmitted within the vascular object where the vascular object reflects portions and absorbs portions of the ultrasonic signal. The reflected portions are collected as a backscatter signal which includes signal properties. A database is provided which associates vascular components to signal properties. The signal properties of the backscatter signal are compared to the signal properties in the database to determine a match. A vascular component is then assigned to the signal properties of the backscatter signal if a match is determined, thus, identifying the signal.
In accordance with a more limited aspect of the present invention, an intravascular ultrasound image is generated from the backscatter signal which distinguishes different vascular components based on the vascular component assigned to the signal properties of the backscatter signal.
In accordance with a more limited aspect of the present invention, the database is pregenerated by correlating vascular components from a histology image to corresponding signal properties from a backscatter signal.
In accordance with a more limited aspect of the present invention, a relationship is determined between two vascular components within the backscatter signal based on a location of the components along the backscatter signal.
In accordance with another aspect of the present invention, a method for characterizing a plaque component within a vascular object based on an ultrasonic backscatter signal collected from a selected section of the vascular object is provided. A histology image of the selected section is prepared. An area in the histology image is selected which represents a plaque component. The area in the histology image is then corresponded to a segment of the backscatter signal where the segment includes signal properties. The plaque component is then associated to the signal properties of the segment.
One advantage of the present invention is that it can automatically identify plaque components from a raw backscatter signal.
Another advantage of the present invention is that a blood vessel can be analyzed in real-time to identify plaque content while a patient is on the operating table. The present invention provides a database which identifies signal properties for each type of plaque component, thus, eliminating the need to perform image analysis by an operator.
Another advantage of the present invention is that it accurately identifies segments of a backscatter signal scan line based on previously generated histology information.
Yet another advantage of the present invention is that the distance of a plaque component from the vessel wall can be determined directly from a backscatter signal. Therefore, it can be determined whether a plaque component is stable or unstable.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.
REFERENCES:
patent: 5582171 (1996-12-01), Chornenky et al.
patent: 5885218 (1999-03-01), Teo et al.
patent: 6019726 (2000-02-01), Webb
patent: 6095976 (2000-08-01), Nachtomy et al.
patent: 6102862 (2000-08-01), Grunwald et al.
patent: 6120445 (2000-09-01), Grunwald
patent: PCT/GB97/03259 (1998-06-01), None
Imaging Systems and Technology—John Wiley & Sons, Inc. vol. pp. 5, 52-60 (1997).
Histopathologic Validation of Intracoronary Ultrasound Imaging—Peters, et al. pp. 230-pp. 241 (Date May-Jun. 1994) Journal of the American Society of Echocardiography.
High Resolution Ultrasonic Backscatter Coefficient Estimation Based on Autoregressive Spectral Estimation Using Burg's Algorithm—Wear, Wagner and Garra (IE
Kuban Barry D.
Nair Anuja
Vince D. Geoffrey
Calfee Halter & Griswold LLP
Imam Ali M.
Lateef Marvin M.
The Cleveland Clinic Foundation
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