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Self-demodulation effect on subharmonic response of ultrasound contrast agent

Verya Daeichin (Institutionen för signaler och system) ; T. Faez ; A. Needles ; G. Renaud ; J.G. Bosch ; A.F.W. Van Der Steen ; N. De Jong
Progress in Biomedical Optics and Imaging - Proceedings of SPIE. Medical Imaging 2012: Ultrasonic Imaging, Tomography, and Therapy, San Diego, CA, 5 - 6 February 2012 (1605-7422). Vol. 8320 (2012),
[Konferensbidrag, refereegranskat]

In this work the use of the self-demodulation (S-D) signal as a mean of microbubble excitation at the subharmonic (SH) frequency to enhance the SH emission of ultrasound contrast agent (UCA) is studied. SH emission from the UCA is of interest since it is produced only by the UCA and is free of the artifacts produced in harmonic imaging modes. The S-D wave is a low-frequency signal produced by nonlinear propagation of an ultrasound wave in the medium. Single element transducer experiments and numerical simulations were conducted at 10 MHz to study the effect of the S-D signal on the SH response of the UCA by modifying the envelope of the excitation bursts. For 6 and 20 transmitted cycles, the SH response is increased up to 25 dB and 22 dB because of the S-D stimulation for a burst with a rectangular envelope compared with a Gaussian envelope burst. Such optimized excitations were used in an array-based micro-ultrasound system (Vevo 2100, VisualSonics Inc., Toronto, ON, Canada) at 18 MHz for in vitro validation of SH imaging. This study suggests that a suitable design of the envelope of the transmit excitation to generate a S-D signal at the SH frequency can enhance the SH emission of UCA and real-time SH imaging is feasible with shorter transmit burst (6- cycle) and low acoustic pressure (-150 KPa) at high frequencies (>15 MHz).

Nyckelord: Contrast imaging, High frequency ultrasound, Self-demodulation, Subharmonic imaging, Ultrasound contrast agent



Denna post skapades 2012-05-29. Senast ändrad 2013-04-23.
CPL Pubid: 158198

 

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Institutioner (Chalmers)

Institutionen för signaler och system

Ämnesområden

Elektroteknik och elektronik