Usefulness of color Doppler mode for fetal cardiac ultrasound screening in the second trimester: a study at a single perinatal center.

Objectives:To evaluate the usefulness of color Doppler in fetal cardiac ultrasound screening in the second trimester. Methods:Fetuses who underwent ultrasound screening at 18-20 weeks' gestation at Showa University Hospital between 2011 and 2016 were evaluated. After delivery, neonatal congenital heart abnormalities were reviewed and compared with the antenatal ultrasound findings. Since 2014, we have added color Doppler to the routine B mode evaluation of the fetal heart. Congenital heart diseases (CHDs) found antenatally and postnatally were compared before and after protocol alternation. Medical records of all fetuses who underwent ultrasound screening at 18-20 weeks' gestation at Showa University Hospital between 2011 and 2016 were retrospectively reviewed. Results:There were 47 cases of CHDs confirmed postnatally. The detection rates of CHDs were 45.0% (9/20) in 2011-2013 and 55.6% (15/27) in 2014-2016. In 2011-2013, cases with antenatal diagnosis showed obvious abnormal findings of three-vessel view and four-chamber view with the B mode. In 2014-2016, the detection rate of isolated ventricular septal defect (VSD) was elevated from 10 to 42.9% using color Doppler. Conclusions:In this study, color Doppler improved the detection rate of CHDs. Color Doppler could give us additional information on blood flow although the canal or vessel is too small to detect morphological changes in the second trimester. It might be a useful tool for screening of CHDs with stenosis, regurgitation, and shunt that are difficult to detect by only the B mode in the second trimester.