Clutter Filtering for Diagnostic Ultrasound Color Flow Imaging

Clutter filtering plays an important role in constructing a quality color flow map in ultrasound Doppler imaging. Signals from slow-moving tissues and vessel walls are clutter as they often mix with reflections from blood and should be suppressed for the further correct estimation of flow parameters. Their complete suppression in color flow imaging is difficult, because these signals on average are 40-60 dB more powerful than the signals from blood, the length of the Doppler sequence is very short, and there is always a demand for a real-time operation. This article provides a general model of the Doppler signal and discusses filters based on polynomial and adaptive regression, empirical mode decomposition, and prospective combined approaches to blood flow filtering.