Enhanced ultrasound harmonic imaging using the filtered-delay multiply and sum beamformer

Ultrasound Tissue Harmonic Imaging (THI) exploits the second harmonic component of backscattered signals generated by non-linear propagation in tissues. Compared to standard fundamental imaging mode, THI provides images with improved resolution and contrast, but with lower signal-to-noise ratio (SNR). The Filtered-Delay Multiply And Sum (F-DMAS) non-linear beamformer was recently demonstrated able to produce images with significantly superior contrast resolution and noise rejection than conventional Delay And Sum (DAS). In this work we experimentally investigate whether the combination of THI with F-DMAS can further suppress beam side-lobes and noise to provide enhanced image quality. Experimental images acquired on phantoms show that, when F-DMAS is applied, resolution and contrast improve and the SNR increases.