The role of spatio-temporal image correlation (STIC) with tomographic ultrasound imaging (TUI) in the sequential analysis of fetal congenital heart disease.

OBJECTIVE

Spatio-temporal image correlation associated with the tomographic ultrasound imaging mode (TUI-STIC) is a new modality that allows a complete sequential analysis of cardiac structures to be displayed on a single panel by showing all echocardiographic transverse views at the same time. The aims of this study were to identify the best settings for displaying the classic echocardiographic views at different gestational ages and to investigate the role of TUI-STIC in the sequential segmental analysis of complex congenital heart disease (CHD).

METHODS

Four-dimensional volumes from 103 cases of confirmed fetal CHD diagnosed and managed at our referral center were evaluated using TUI-STIC. To select the best interslice distance for adequate display of the central cardiovascular connections, each volume was opened and the TUI mode activated, having as a reference the apical four-chamber view. The number of slices was set at nine. The volume was then scrolled until the most significant echocardiographic views were displayed on the screen windows. Then, if too many windows showed intermediate non-diagnostic views, the slice distance was adjusted finely until all key echocardiographic views showed up in the various windows. The interslice distance was regressed against gestational age and the best-fitting curve was identified.

RESULTS

A sequential segmental analysis could be shown with TUI-STIC in all cases. A linear regression equation best fitted the correlation between interslice distance and advancing gestational age (r(2) = 0.9042), with the mean interslice distance being 2.7 (SD, 0.3) mm at 19-23 gestational weeks, and 4.0 (SD, 0.4) mm at 30-33 weeks. These settings allowed a complete sequential analysis in all cases.

CONCLUSIONS

TUI-STIC allows a complete sequential analysis of CHD in the fetus. The most suitable interslice distances for all gestational ages could be identified. These data may be used while adopting this imaging modality in the four-dimensional evaluation of fetal CHD.