OP12.04: A new algorithm for fetal cardiac scanning using volume reslicing modality (3D extended imaging) and spatiotemporal image correlation (STIC)

Abstract

To assess the value of a new ultrasound technology, named XI STIC, that is composed of volume reslicing modality 3D XI and STIC for routine fetal cardiac screening in the second trimester. Sixty-two volume datasets of fetuses without fetal heart defects were obtained using ACCUVIX XI (Medison Co Ltd, Korea) and reviewed with the help of 3D XI PC Viewer (laptop PC program). 3D XI modality associated with STIC enables a ‘slice-by-slice’ approach for ultrasound examination of the beating fetal heart and allows simultaneous visualization of transverse cardiac planes from the upper abdomen to the upper mediastinum. The complete offline fetal cardiac survey was based on the criteria of Dr Yagel and Dr Yoo (‘5 short axis’ planes: upper abdomen, four-chamber view, five-chamber view, main pulmonary artery, three-vessel and trachea view). Each volume was resliced to the 12 consecutive planes, whose distances were adjusted for an optimal visualization of the fetal cardiac landmarks. In addition, long-axis views of great outflows and their crisscrossing were acquired by revolving the volumes along the x- or y-axis on 30–45 degrees. The visualization rate of each diagnostic cardiac plane was calculated. In our preliminary study the ‘upper abdomen’ was not visualized in some cases due to the insufficient sweep angle that was not appropriate to capture the ‘stomach level’. The four-chamber view was obtained in all cases, as each volume sweep was initiated after imaging the view in the transverse plane of the fetal chest. The Table lists the diagnostic planes of the fetal heart and the frequency of visualization. With the help of XI STIC it was possible to generate standard diagnostic planes of the beating fetal heart from only a single volume. The new algorithm using XI STIC makes it feasible to evaluate ‘5 short axis’ planes and outflow crisscrossing simultaneously that is not available with the conventional ultrasound approach.