Robust adaptive beamforming for artifact suppression in gastrointestinal ultrasonography

Reverberation artifacts are well-known to degrade quality on ultrasound images. In gastrointestinal (GI) ultrasound, reverberation artifacts caused by intraluminal gas obscure details of the intestinal wall and any deeper structures, and are a main reason that ultrasound is used infrequently for imaging the GI tract in humans. We hypothesize that minimum variance adaptive beamforming (MVABF), which adaptively estimates and suppresses interfering signals, should be well suited to suppressing the reverberation caused by isolated bubbles in the bowel lumen. A key issue in MVABF is controlling the aggressiveness of adaptation via diagonal loading so the beamfomer is robust to calibration errors. In this context, we explore the potential benefits of applying a White Noise Gain Constraint (WNGC) to Minimum Variance Distortionless Response (MVDR) algorithms. WNGC has been widely applied in sonar, but to our knowledge has not been previously applied to medical ultrasound.