SECOND HARMONIC IMAGING FROM PULSE-ECHO SIGNALS OF CONTRAST-ASSISTED ULTRASOUND
Keywords:
Ultrasound contrast agents, harmonic imaging, linear bandpass filterAbstract
Increasing interest in extending the diagnostic capabilities of medical ultrasound imaging byutilizing ultrasound contrast agents (UCAs) has heightened the need for suitable harmonicseparation models. This article describes the second harmonic frequency characteristic and secondharmonic image generation from pulse-echo signals of UCA. Based on the differences in frequencyof ultrasound data from two different media, ultrasound signals are classified into two classes, i.e.,UCA and tissue. We show the frequency characteristic of the UCA signals from an in vivo target todemonstrate this nonlinear behavior. Then, the difference in frequency components of the UCA andtissue data is used as a reference to design a linear bandpass filter (LBF) in order to separate theUCA signals from tissue echoes. The LBF is designed using the Parks-McClellan algorithm. We findthat the appropriate fractional bandwidth (FB) and stopband attenuation of the LBF are 15% - 25%and 40 - 50 dB, respectively. The imaging quality for medical ultrasound purposes, by utilizing theinformation from the frequency contents of contrast-assisted ultrasound data, has been improved.Results show that the images produced from the output signals of the optimal LBF are superior tothe original B-mode images both in terms of contrast and spatial resolution.
References
Al-Mistarihi, M.F., Phukpattaranont, P., andEbbini, E.S. (2004a). A two-step procedurefor optimization of contrast sensitivity andspecificity of Post-Beamforming VolterraFilters. Proceedings of the 2004 IEEEInternational Ultrasonics Symposium;August 23-27, 2004; Montreal, Canada,p. 978-981.
Al-Mistarihi, M.F., Phukpattaranont, P., andEbbini, E.S. (2004b). Post-beamformingthird-order Volterra filter (ThOVF) forpulse-echo ultrasonic imaging. Proceedingsof the 2004 IEEE InternationalConference on Acoustics, Speech, andSignal Processing; May 17-21, 2004;Montreal, Canada, p. 97-100.
Cosgrove, D. (2006). Ultrasound contrastagents: An overview. Eur. J. Radiol., 60:324-330.
de Jong, N., Cornet, R., and Lancee, C.T. (1994a).Higher harmonics of vibrating gas filledmicrospheres. Part one: Simulations.Ultrasonics, 32(6):447-453.
de Jong, N., Cornet, R., and Lancee, C.T. (1994b).Higher harmonics of vibrating gas filledmicrospheres. Part two: Measurements.Ultrasonics, 32(6):455-459.
Er, M.H., Antoniou, A., Smith, L.M., Bomar,B.W., Lim, Y.C., and Saramaki, T. (2003).In: The Circuits and Filters Handbook.Chen W.K., (eds). CRC Press, NY, p. 2,603-2,677.
Feinstein, S.B., Shah, P.M., Bing, R.J., Meerbaum,S., Corday, E., Chang, B.L., Santillan, G.,and Fujibayashi, Y. (1984). Microbubbledynamics visualized in the intact capillarycirculation. J. Am. Coll. Cardiol., 4: 595-600.
Frinking, P.J.A., Bouakaz, A., Kirkhorn, J.,Ten Cate, F.J., and de Jong, N. (2000).Ultrasound contrast imaging: current andnew potential methods. Ultrasound inMedicine & Biology, 26(6):965-975.
Frischke, C., Lindner, J.R., Wei, K., Goodman,N.C., Skyba, D.M., and Kaul, S. (1997).Myocardial perfusion imaging in thesetting of coronary artery stenosis andacute myocardial infarction using venousinjection of a second-generationechocardiographic contrast agent. Circulation,96(3):959-967.
Parks, T.W. and McClellan, J.H. (1972).Chebyshev approximation for nonrecursivedigital filters with linear phase.IEEE Trans. Circuits Theory, 19:189-194.
Ramnarine, K.V., Kyriakopoulou, K., Gordon,P., McDicken, N.W., McArdle, C.S., andLeen, E. (2000). Improved characterizationof focal liver tumours: dynamic powerdoppler imaging using NC100100 echoenhancer.Eur. J. Ultrasound, 11(2):95-104.
Schilling, R.J. and Harris, S.L. (2005). Fundamentalsof digital signal processing usingmatlab. Thomson, p. 427-495.
Tanaka, S., Kitamra, T., Yoshioka, F., Kitamura,S., Yamamoto, K., Ooura, Y., and Imaoka,T. (1995). Effectiveness of galactose basedintravenous contrast medium on colordoppler sonography of deeply locatedhepatocellular carcinoma. Ultrasound inMedicine & Biology, 21(2):157-160.
