Automated retrieval of standard diagnostic fetal cardiac ultrasound planes in the second trimester of pregnancy: a prospective evaluation of software.

OBJECTIVE: To evaluate prospectively the performance of software that automatically retrieves, from a three-dimensional (3D) volume of the fetal chest, three diagnostic cardiac planes in the second trimester of pregnancy. METHODS: 3D static volumes of the fetal chest were acquired at the level of the four-chamber view in 72 fetuses between 18 and 23 weeks of gestation. Standardization of 3D volumes was performed in Plane A (the reference plane: four-chamber view) alone. Tomographic ultrasound imaging (TUI) was added to the display of each diagnostic plane. The left ventricular outflow plane (Cardiac plane 1: five-chamber view, aorta), the right ventricular outflow plane (Cardiac plane 2: pulmonary artery) and the abdominal circumference plane (Cardiac plane 3: abdominal circumference, stomach) were retrieved by the software from the 3D volumes and the data were analyzed to determine whether Cardiac planes 1-3 were displayed correctly in each volume. RESULTS: The automated software displayed, in at least one TUI plane, target Cardiac plane 1 in 94.4% of volumes, target Cardiac plane 2 in 91.7% of volumes and target Cardiac plane 3 in 97.2% of volumes. CONCLUSION: Our results validate the concept of automated sonography and its potential clinical applicability.

Spatio-temporal image correlation (STIC): new technology for evaluation of the fetal heart.

Spatio-temporal image correlation (STIC) is a new approach for clinical assessment of the fetal heart. It offers an easy to use technique to acquire data from the fetal heart and to aid in visualization with both two-dimensional and three-dimensional (3D) cine sequences. The acquisition is performed in two steps: first, images are acquired by a single, automatic volume sweep. Second, the system analyzes the image data according to their spatial and temporal domain and processes an online dynamic 3D image sequence that is displayed in a multiplanar reformatted cross-sectional display and/or a surface rendered display. The examiner can navigate within the heart, re-slice, and produce all of the standard image planes necessary for a comprehensive diagnosis. The advantages of STIC for use in evaluation of the fetal heart are as follows: the technique delivers a temporal resolution which corresponds to a B-mode frame rate of approximately 80 frames/s; it provides the examiner with an unlimited number of images for review; it allows for correlation between image planes that are perpendicular to the main image acquisition plane; it may shorten the evaluation time when complex heart defects are suspected; it enables the reconstruction of a 3D rendered image that contains depth and volume which may provide additional information that is not available from the thin multiplanar image slices (e.g. for pulmonary veins, septal thickness); it lends itself to storage and review of volume data by the examiner or by experts at a remote site; it provides the examiner with the ability to review all images in a looped cine sequence.