Magnitude, origins, and reduction of abdominal ultrasonic clutter

Clutter is a noise artifact in ultrasound images, from multiple sources. Experiments were conducted urine-filled in vivo bladders to differentiate among various sources. Successive-frame image acquisitions with varying PRFs were used to determine the clutter contributions echoes of previously sent pulses and random electronic /or acoustic noise. Images acquired during axial displacement the abdominal wall were assessed to distinguish clutter due to field reverberation from clutter due to off-axis scattering. results indicate that clutter contributions from random and echoes of previously sent pulses are weak, while arising from sound reverberation in abdominal tissues dominant distal to the abdominal wall. Clutter adjacent to distal and lateral bladder walls is mainly due to off-axis. Clutter was reduced in fundamental and harmonic images by applying Finite Impulse Response (FIR) and Source Separation (BSS) motion filters to images acquired during axial displacement of the abdominal wall.