Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
1999-11-16
2001-06-26
Jaworski, Francis J. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
Reexamination Certificate
active
06251074
ABSTRACT:
This invention relates to ultrasonic diagnosis and imaging of the body and, in particular, to new methods and apparatus for ultrasonically imaging with a response frequency which differs from the transmitted frequency.
Ultrasonic diagnostic imaging systems have been used to image the body with the enhancement of ultrasonic contrast agents. Contrast agents are substances which are biocompatible and exhibit uniquely chosen acoustic properties which return readily identifiable echo signals in response to insonification. Contrast agents can have several properties which enables them to enhance an ultrasonic image. One is the nonlinear characteristics of many contrast agents. Agents have been produced which, when insonified by an ultrasonic wave at one frequency, will exhibit resonance modes which return energy at other frequencies, in particular, harmonic frequencies. A harmonic contrast agent, when insonified at a fundamental frequency, will return echoes at the second, third, fourth, and higher harmonics of that frequency.
It has been known for some time that tissue and fluids also have inherent nonlinear properties. Tissue and fluids will, even in the absence of a contrast agent, develop and return their own non-fundamental frequency echo response signals, including signals at harmonics of the fundamental. Muir and Carstensen explored these properties of water beginning in 1980, and Starritt et al. looked at these properties in human calf muscle and excised bovine liver.
While these non-fundamental frequency echo components of tissue and fluids are generally not as great in amplitude as the harmonic components returned by harmonic contrast agents, they do exhibit a number of characteristics which may be advantageously used in ultrasonic imaging. One of us (M. Averkiou) has done extensive research into these properties in work described in his doctoral dissertation. In this exposition and other research, the present inventors have seen that the main lobe of a harmonic beam is narrower than that of its fundamental, which they have found has implications for clutter reduction when imaging through narrow orifices such as the ribs. They have seen that the sidelobe levels of a harmonic beam are lower than the corresponding sidelobe levels of the fundamental beam, which they have found has implications for off-axis clutter reduction. They have also seen that harmonic returns from the near field are also relatively less than returning energy at the fundamental frequency, which they have found has implications for near field clutter rejection. As will be seen, these properties may be exploited in the methods and constructed embodiments of the present invention.
In accordance with the principles of the present invention, an ultrasonic imaging system and method are provided for imaging tissue and fluids from response frequencies which differ from the transmitted frequency, in particular echoes returned from the tissue or fluids at a harmonic of a transmitted fundamental frequency. The imaging system comprises a means for transmitting an ultrasonic wave at a fundamental frequency, means for receiving echoes at a harmonic frequency, and an image processor for producing an ultrasonic image from the harmonic frequency echoes.
In a preferred embodiment of the present invention the transmitting and receiving means comprise a single ultrasonic probe. In accordance with a further aspect of the present invention, the probe utilizes a broadband ultrasonic transducer for both transmission and reception.
In accordance with yet another aspect of the present invention, partially decorrelated components of received harmonic echoes are produced and utilized to remove artifacts from the harmonic image, providing clearly defined images of tissue boundaries such as that of the endocardium. In a preferred embodiment the partially decorrelated components are produced by processing the harmonic echoes through different passbands.
The methods of the present invention include the use of harmonic echoes to reduce near-field or multipath clutter in an ultrasonic image, such as that produced when imaging through a narrow acoustic window such as the ribs. In accordance with yet a further aspect of the present invention, harmonic and fundamental echoes are blended in a common image to reduce clutter, image at appreciable depths, and overcome the effects of depth-dependent attenuation.
REFERENCES:
patent: 4702258 (1987-10-01), Nicolas
patent: 4714846 (1987-12-01), Pesque
patent: 5158071 (1992-10-01), Umemura
patent: 5255683 (1993-10-01), Monaghan
patent: 5410516 (1995-04-01), Uhlendorf et al.
patent: 5415171 (1995-05-01), Goh
patent: 5419328 (1995-05-01), Goh
patent: 5435311 (1995-07-01), Umemura
patent: 5608690 (1997-03-01), Hossack et al.
patent: 5740128 (1998-04-01), Hossack et al.
patent: WO 98/20361 A1 (1998-05-01), None
patent: WO 98/46139 (1998-10-01), None
patent: WO 98/57583 (1998-12-01), None
Starritt, Evidence for ultrasonic finite amplitude distortion in muscle using medical equipment, JASA 77(1), Jan. 1985 at 302-06.
Muir, Prediction of nonlinear acoustic effects at biomedical frequencies and intensities, Ult. in Med. & Biol., Bol. 6 at 345-57 (1980).
Carstensen, Demonstration of nonlinear acoustical effects at biomedical frequencies and intensities, Ult. in Med. & Biol. vol. 6 at 359-68 (1980).
Starritt, The development of harmonic distortion in pulsed finite-amplitude ultrasound passing through liver, Phys. Med. Biol., vol. 31, No. 12, 1401-09.
Ward, Non-linear propagation applied to the improvement of lateral resolution in medical ultrasound scanners, 1995 World Cong. on Ult. at 965-68.
Law, Ultrasonic determination of the nonlinearity parameter B/A for biological media, JASA 69(4), Apr. 1981 at 1210-12.
Dunn, et al., Nonlinear Ultrasonic Wave Propagation in Biological Materials, 1981 Ultrasonics Symposium at 527-32 (IEEE).
Muir, Nonlinear Effects In Acoustic Imaging, Acoustical Imaging, vol. 9 at 93-109 (Plenum Press, NYC, 1980).
Ichida et al., Imaging the Nonlinear Parameter of a Medium, Ultrasonic Imaging, vol. 5 at 295-99 (Academic Press, 1983).
Christopher, Finite Amplitude Distortion-Based Inhomogeneous Pulse Echo Ultrasonic Imaging, IEEE Tras. Ult., Ferro. & Freq. Contr., vol. 44, Jan. 1997 at 123 and particularly p. 138.
Burns et al., Harmonic Power Mode Doppler Using Microbubble Contrast Agents, J.E.M.U., vol. 16, No. 4 at 132-42 (Masson, Paris, 1995).
Burns, et al., Harmonic Imaging Principles and Preliminary Results, Angiology, vol. 47, No. 7. Part 2 at 563-574 (Jul. 1996 New York).
Burns, Presentation of Papers Nos. 241, 243, 1046, 1438, 1682, 166, 169 Supplements to Radiology (Nov. 1992, vol. 185, Nov. 1993, vol. 193, Nov. 1995, vol. 197, Nov. 1996, vol. 201).
Averkiou, et al., Measurements of Harmonic Generation in a Focused Finite-Amplitude Sound Beam, J. Acoust. Soc. Am. 98(6) at 3439-42 (Dec. 1995).
Ward, et al., Nonlinear Propagation Applied to the improvement of Resolution in Diagnostic Medical Ultrasound, J. Acoust. Soc. Am. 101(1) at 143-54 (Jan. 1997), particularly p. 143.
Schrope, et al., Simulated Capillary Blood Flow Measurement Using a Nonlinear Ultrasonic Contrast Agent, Ultrasonic Imaging 13 at 134-58 (Acu. Press 1992).
Schrope, et al., Second Harmonic Ultrasonic Blood Perfusion Measurement, Ult. in Med. & Biol. 19(7) at 567-79 (Pergamon Press 1993).
Levy, et al., Harmonic Power Mode Doppler Using Microbubble Constrast Agents: An Improved Method for Small Vessel Flow Imaging, 1994 Ultrasonic Symposium, vol. 3, at 1547-1550.
Averkiou Michalakis
Burns Peter N.
Hwang Juin-Jet
Powers Jeffry E.
Roundhill David N.
ATL Ultrasound
Jaworski Francis J.
Yorks, Jr. W. Brinton
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