Experimental comparisons of the impact of abdominal wall aberrators on linear and nonlinear beam patterns

An ultrasonic wavefront can suffer significant aberration as it passes through the abdominal or chest wall. The present work experimentally measures the impact of phase and amplitude aberrations resulting from an inhomogeneous tissue path on: the fundamental (1f), the nonlinearly generated second harmonic (2f), and the effective apodization signal, linearly propagated at the same (2f) frequency. While the nonlinearly generated second harmonic beam is found to be relatively more degraded by the aberration than the fundamental, it remains more compact.