High-Volume-Rate 3-D Ultrasound Imaging Based on Motion Compensation: A Feasibility Study

International audience; Background, Motivation and ObjectiveEchocardiography is the most used modality for the evaluation of cardiac function. To obtain a time-resolved volumetric quantification of cardiac motion, ultrafast 3-D imaging is required. Ultrafast ultrasound imaging with diverging waves has demonstrated its potential for clinical 2-D echocardiography. It has been shown that MoCo (motion compensation)strategies based on a triangle transmit arrangement could produce high-contrast cardiac B-mode images at 500 fps [1]. With the purpose of developing high-volume-rate 3-D echocardiography, we introduced a transmit sequence enabling volumetric MoCo for spherical diverging wave imaging.Statement of Contribution/MethodsFour Verasonics scanners were combined to get 1024 channels connected to a 2-D 3-MHz phased array of 32x32 elements. A sequence of 49 spherical waves (PRF = 2250 Hz) whose steering angles followed a particular 2-D triangle arrangement was generated using the full aperture of the probe. Motion was compensated by using tissue color DopplerImaging to avoid destructive interferences issued from frame-to-frame tissue motion. High-frame-rate 3-D ultrasound imaging based on MoCo was evaluated in vitro with a rotating disk. The angle arrangements (cf. Fig.) were defined in the elevation (E) and azimuth (A) directions such that:- E and A angles increased then decreased linearly to sum the main lobes coherently and mitigate the side lobes- Small angle increments were used to preserve the frame-to-frame correlation to reduce Doppler variance- The E and A angles were allocated homogeneously to ensure high spatial resolutionResults/DiscussionA contrast loss due to tissue motion was observed when MoCo was not included in the coherent summation. When MoCo was integrated, the speckles were preserved in the whole field of view (cf. Fig). The estimated in vitro tissue Doppler velocities were consistent with the expected values (mean relative error = 4%). These preliminary results showed thatMoCo will be essential in high-volume-rate 3D echocardiography. Further works will help to determine if the temporal and spatial resolutions obtained with this 3-D MoCo method are adapted to 3-D speckle tracking echocardiography.[1] Porée et al. High-frame-rate echocardiography using coherent compounding with Doppler-based motion-compensation. IEEE TMI, 2016.