Eigen-based clutter filters for color flow imaging: Single-ensemble vs. multi-ensemble approaches

In designing eigen-based clutter filters for color flow imaging, one of the challenges is to develop an accurate way of estimating the eigen-components that represent clutter in slow-time ensembles. To provide new insights on the problem, this paper presents a comparative analysis on how eigen-filters perform when using eigen-estimation methods that involve multiple ensembles or a single ensemble. The analysis consists of two parts: 1) a comparative review on the principles behind different eigen-estimation methods; 2) an eigen-filtering experiment done with coronary flow imaging data acquired from a porcine during bypass graft operation. For an imaging case containing tissue motion due to myocardial contraction, our analysis showed that the single-ensemble eigen-filter shared similar performance with a multi-ensemble eigen-filter that uses small (5×5) ensemble windows (with about 1 dB difference in clutter suppression level). Results also showed that a multi-ensemble eigen-filter with large (20x20) ensemble windows yielded poorer performance (clutter suppression level was 3 to 6 dB lower). © 2007 IEEE.published_or_final_versionThe 2007 IEEE Ultrasonics Symposium, New York, N.Y., 28-31 October 2007. In Conference Proceedings of IEEE Ultrasonics Symposium, 2007, p. 1101-110