In this paper, a new elastographic method is proposed. Using this method, the propagation of a low-frequency transient shear wave can be imaged by means of an ultrafast imaging system (up to 10,000 frames/s) that we have developed. Ultrafast ultrasonic imaging is obtained with a linear array of transducers (3.5 MHz) connected to electronics that have 64 channels sampled at 30 MHz and 128 Kbytes for storing the backscattered signals. Displacements are measured using cross-correlation of the ultrasonic signals. Movies of the low central frequency (200 Hz) shear wave propagation through homogeneous and heterogeneous phantoms have been obtained with 1,000 and 2,000 frames per second.
OphirJ.CespedesE.I.PonnekantiH.YazdiY.LiX., Elastography: A method for imaging the elasticity in biological tissues, Ultrasonic Imaging13, 111–134 (1991).
2.
OphirJ.CespedesE.I.GarraB.PonnekantiH.HuangY.MakladN., Elastography: ultrasonic imaging of tissue strain and elastic modulus in vivo. Eur. J. Ultrasound3, 49–70 (1996).
3.
OphirJ.KallelF.VargheseT.BertrandM.CespedesE.I.PonnekantiH., Elastography: a system approach, Intern. J. lmag. Systems Tech.8, 89–103 (1997).
4.
LernerR.M.HuangS.R.ParkerK.J., “Sonoelasticity” images derived from ultrasound signals in mechanically vibrated tissues, Ultrasound Med. Biol.16, 231–239 (1990).
5.
ParkerK.J.HuangS.R.LernerR.M., Tissue response to mechanical vibrations for “sonoelasticity imaging”, Ultrasound Med. Biol.16, 241–246 (1990).
6.
LeeF.BronsonJ.P.LernerR.M.ParkerK.J.HuangS.R.RoachD.J., Sonoelasticity imaging: results in in vitro tissue specimens, Radiology, 237–239 (1991).
7.
GaoL.ParkerK.J.LernerR.M.LevinsonS.F., Imaging of the elastic properties of tissue - a review, Ultrasound Med. Biol.22, 959–977 (1996).
8.
ParkerK.J.FuD.GraceswkiM.YeungF.LevinsonS.F., Vibration sonoelastography and the detectability of lesions, Ultrasound Med. Biol.24, 1437–1447 (1998).
9.
YamakoshiY.SatoJ.SatoT., Ultrasonic imaging of internal vibration of soft tissue under forced vibration, IEEE Trans. Ultrason. Ferroelec. Freq. Contr.37, 45–53 (1990).
10.
FujiK.SatoT.KameyamaK.InoueT.YokoyamaK.KobayashiK., Imaging system of precise hardness distribution in soft tissue in vivo using vibration and ultrasonic detection, in Acoustical Imaging, Vol. 21 (1995).
11.
MuthupillaiR.LomasD.J.RossmanP.J.GreenleafJ.F.ManducaA.EhmanR. L., Magnetic resonance elastography by direct visualization of propagating acoustic strain waves, Science269, 1854–1857 (1995).
12.
DuttV.KinnickR.R.GreenleafJ.F., Acoustic shear wave displacement measurement using ultrasound, in Proc. IEEE Ultrason. Symp.2, pp. 1185–1193 (1996).
13.
CathelineS.WuF.FinkM., A solution to diffraction biases in sonoelasticity: the acoustic impulse technique, J. Acoust. Soc. Am.105, 2941–2950 (1999).
14.
CathelineS.ThomasJ.L.WuF.FinkM., Diffraction field of a low-frequency vibrator in soft tissues using transient elastography, IEEE Trans. Ultrason. Ferroelec. Freq. Contr.46, 1013–1020 (1999).
15.
MillerG.F.PurseyH., The field and radiation impedance of mechanical radiators on the free surface of a semi-infinite isotropic solid, Proc. Roy. Soc. LondonA233, 233–541 (1954).
16.
KawashimaK., Theory and numerical calculation of the acoustic field produced in metal by an electromagnetic ultrasonic transducer, J. Acoust. Soc. Am.60, 1089–1099 (1976).
17.
BabouxJ.C.KazysR., Analysis of the transient ultrasonic fields radiated in solids by circular and annular sources, J. Acoust. Soc. Am.92, 2942–2951 (1992).
18.
LhémeryA., Un modèle efficace pour prédire le champ transitoire rayonné dans un milieu élastique par les traducteurs ultrasonores, J. Phys. TV4 (1994).
19.
ShattuckD.P.WeinshenkerM.D.SmithS.W.Von RammO.T., Explososcan: A parallel processing technique for high speed ultrasound imaging with linear phased arrays, J. Acoust. Soc. Am.75, 1273–1282 (1984).
20.
BonnefousO.PesquéP.BertrandX., A new velocity estimator for color flow mapping, in Proc. IEEE Ultrason. Symp., pp. 855–860 (1986).
21.
O'DonnelM.SkovorodaA.R.ShapoB.M.EmelianovY., Internal displacement and strain imaging using ultrasonic speckle tracking, IEEE Trans. Ultrason. Ferroelec. Freq. Contr.41 (1994).
22.
JensenJ.A., Estimation of Blood Velocities Using Ultrasound, chap. 8 (Cambridge University PressCambridgem, UK, 1996).
23.
WalkerW.F.TraheyG.E., A fundamental limit on the performance of correlation based on phase correction and flow estimation technique, IEEE Trans. Ultrason. Ferroelec. Freq. Contr.41 (1994).
24.
Animations of the displacement images versus time in various phantoms can be observed on the LOA web site (www.loa.espci.fr).
