Optimal pulse-inversion imaging for microsphere contrast agents
Abstract
Microbubbles are used as contrast agents because they scatter incident ultrasound (US) efficiently. Pulse-inversion imaging makes use of the asymmetrical difference in response of a bubble to an US pulse and its symmetrical opposite to obtain improved contrast. In this theoretical work, the principle of pulse-inversion imaging is expanded upon by finding the optimal pulse shape to maximize the signal from a bubble. Given a limit on driving intensity, a suitable norm of the bubble response is maximized using optimal control theory to identify the proper pulse/antipulse driving protocol for a single bubble. The optimal pulse yields a several-fold increase in the normed response over the best sinusoidal pulse of the same driving intensity. It was found that the optimal driving for a single bubble also maximizes the nonlinear response of the cloud if its mean bubble size is the same as that of the single bubble. (E-mail: aszeri@me.berkeley.edu)
Keywords: Pulse inversion, Optimal control, Ultrasonic imaging, Contrast agents
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PII: S0301-5629(02)00494-5
© 2002 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.
