Second-harmonic aberration correction

Abstract

A simulation study is performed to present results concerning 3D aberration correction for harmonic imaging. Two different correction schemes (a pure time-delay correction and a time-delay and amplitude correction) are employed along with estimation based on either the received first- or second-harmonic frequency. An aberrating body wall is implemented as a 20 mm delay-screen body wall using eight screens, and is tuned to match human abdominal wall characteristics. The transmit pressure of the first harmonic is set to not succeed a mechanical index of 1.1 for the uncorrected case and a pure time-delay correction. Using a time-delay and amplitude correction, the total acoustic energy transmitted is equal to that of the uncorrected case. The total amount of generated second-harmonic energy increases with approximately 1 dB for a pure time-delay correction and about 2 dB for a time-delay and amplitude correction, both estimated at the received first-harmonic frequency. The general side-lobe level of the first- and second-harmonic focal point beam profile averaged over circles around the transducer axis is lowered with 2-10 dB for both correction schemes relative to the uncorrected case.