3D fusion echocardiography improves 3D left ventricular assessment: comparison with 2D contrast echocardiography

Abstract

Purpose: Real time 3D (RT3D) echocardiography has the potential to provide rapid acquisition of whole heart volumes for clinical use where fast, real time assessment of ventricular function is important, such as stress echocardiography. In clinical practice RT3D image quality is limited by echocardiographic windows and stitching artefacts. We hypothesised that fusion of multiple, sequential RT3D volume datasets may improve image quality. We compare this approach to the gold standard reference image for stress echocardiography, 2D contrast echocardiography.Methods: 60 patients had RT3D volumes (1 beat and 4beats) acquired according to 2 protocols. In Protocol A, the 4 chamber view on 2D imaging was visually assessed and a RT3D dataset acquired which was fused with a further two 3D volumes that were acquired following small probe manoeuvres. In protocol B the RT3D volumes (4 beat) were acquired of the optimal 4, 3 and 2 chamber views and these were fused together. Finally 2D contrast images were obtained of 4, 3 and 2 chamber view.The fused, standard RT3D and 2D contrast views were analysed to compare (i) quality (using the standard segmental approach) and (ii) contrast to noise ratio (CNR). Contrast-to-noise ratio (CNR) was used as a quantitative measurement of the image quality- defined as the ratio of the signal intensity differences between image regions (myocardium) and the image noise (blood pool). Each segment was assigned a rating 0-3 depending on the amount of visualised endocardial border defined as: 0 = {