Improved spatiotemporal voxel space interpolation for 3D echocardiography with irregular sampling and multibeat fusion

We developed a novel multi-beat image fusion technique using a special spatiotemporal interpolation for sparse, irregularly sampled data (ISI). It is applied to irregularly distributed 3D cardiac ultrasound data acquired with the fast rotating ultrasound (FRU) transducer developed in our laboratory, a phased array rotating mechanically at very high speed (240-480rpm). High-quality 2D images are acquired at ~100 frames/s over 5-10 seconds. ISI was compared quantitatively to spatiotemporal nearest neighbor interpolation (STNI) on synthetic data and compared qualitatively to classical trilinear voxel interpolation on 10 in-vivo cardiac image sets. ISI showed considerably lower absolute distance errors than STNI. For in-vivo images, ISI voxel sets showed reduced motion artifacts, suppression of noise and interpolation artifacts and better delineation of endocardium. In conclusion, ISI improves the quality of 3D+T images acquired with a fast rotating transducer in simulated and in-vivo data.