Measurement of fetal automated fractional shortening using two-dimensional tracking in multiple centers

Purpose: To establish a normal reference range for automated fractional shortening (Auto FS) in normal singleton fetuses measured at multiple centers.

Methods: This study was conducted from May 2017 to March 2019. It was undertaken on normal singleton fetuses. First, a four-chamber view of the fetal heart was recorded in the B-mode. Then, the region of interest was set on the edge of the ventricular septum and on the edge of the ventricular muscle at a point one-third away from the atrioventricular valve and toward the cardiac apex. Tracking was automatically performed. Values measured in the right ventricle were defined as R-Auto FS, and in the left ventricle as L-Auto FS. Furthermore, combined-Auto FS was defined as the measurement across both ventricles.

Results: A total of 442 normal fetuses were assessed. R-Auto FS decreased significantly with gestational age, and L-Auto FS showed a similar tendency (Spearman's correlation analysis: r_s = - 0.415 and r_s = - 0.252, respectively). Combined-Auto FS showed a similar decline as the gestational age increased (r_s = - 0.451).

Conclusion: In this study, we succeeded in defining a reference Auto FS value not only at one institution but also multiple centers. This study suggests that Auto FS can be used clinically and effectively.