Paper
30 May 2001 New method of aberration correction for ultrasonic brain imaging
Jean-Francois Aubry, Jamie Gerber, Mickael Tanter, Jean-Louis Thomas, Mathias Fink
Author Affiliations +
Abstract
Ultrasonic imaging systems capabilities are strongly dependent on the focusing quality of the ultrasonic beam. In the case of brain imaging, the skull strongly degrades the ultrasonic focusing pattern by introducing strong phase and amplitude aberrations of the wavefront. In previous work, this degradation of the beam focus has been partially corrected by coupling the time reversal focusing process to an amplitude compensation of the emitted signals. In that case, the optimal focus was reproduced down to -20 dB, but the sidelobe level remained at about -25 dB. We propose here a new focusing technique, called spatio- temporal inverse filter, based on the inversion of the propagation operator at each frequency within the bandwidth of our transducers. Simulations and experiments will be presented that show the effectiveness of the technique. Experimental focusing through the skull is now comparable to the optimal focusing in homogeneous medium. It will be explained how the set of emission signals can be used in order to achieve both transmit and receive focusing. In the transmit-receive mode, focusing through the skull reaches the optimal level obtained in water down to -70 dB (i.e. constrained only by experimental noise levels). This could lead to high quality real time brain imaging and Doppler flow mapping.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jean-Francois Aubry, Jamie Gerber, Mickael Tanter, Jean-Louis Thomas, and Mathias Fink "New method of aberration correction for ultrasonic brain imaging", Proc. SPIE 4325, Medical Imaging 2001: Ultrasonic Imaging and Signal Processing, (30 May 2001); https://doi.org/10.1117/12.428195
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KEYWORDS
Skull

Transducers

Electronic filtering

Brain imaging

Signal processing

Ultrasonics

Wavefronts

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