A Spatial Near-Field Clutter Reduction Filter Preserving Tissue Speckle in Echocardiography

M. Sjoerdsma, S. Bouwmeester, P. Houthuizen, F. N. van de Vosse, R. G. P. Lopata
2020 IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control  
Near-field clutter in echocardiography is depicted as a diffuse haze hindering the visualization of the myocardium and the blood-pool, thereby degrading its diagnostic value. Several clutter filters have been developed, which are limited in patients with contraction motion and rhythm anomalies, and in threedimensional ultrasound. This study introduces a new near-field clutter reduction method, which preserves ultrasound speckles required for strain imaging. The filter developed detects the
more » ... field clutter region in the spatial frequency domain. The filter employs an oriented, multi-scale approach, and assumes the near-field clutter to be predominantly present in the highest and lowest bandpass images. These bandpass images were filtered, whilst sparing features in the myocardium and near-field clutter free regions. The performance of the filter was assessed in a volunteer study, in ten 3D apical and parasternal view acquisitions, and in a retrospective clinical study composed of twenty cardiac patients with different indications for echocardiography. The filter reduced near-field clutter in all datasets, whilst preserving all or most of the myocardium. Additionally, it demonstrated a consistent enhancement of image quality, with an increase in contrast of 4.3 dB on average, and generated a clearer myocardial boundary distinction. Furthermore, the speckles were preserved according to the quality index based on local variance, the structural similarity index method, and normalized cross-correlation values, being 0.82, 0.92, and 0.95 on average, respectively. Global longitudinal strain measurements on near-field clutter reduced images were improved or equivalent compared to the original acquisitions, with an average increase in strain signal-to-noise ratio of 34%.
doi:10.1109/tuffc.2020.3028155 pmid:33001799 fatcat:44yf2lourvfopjj74ycgx75kxa