Introduction and objectives: To compare fetal images obtained at the first- and second-trimester ultrasound scan when applying the Cardiovascular System Sonographic Evaluation Algorithm (CASSEAL).
Methods: Using the CASSEAL protocol, nine sequential axial views were acquired in B-mode and color Doppler at the first- and second-trimester ultrasound scans, visualizing the main components of the extended fetal cardiovascular system. Images were compared qualitatively between both trimesters.
Results: We obtained comparable images for all the nine axial views described in the CASSEAL protocol, with few differences and limitations.
Conclusions: The CASSEAL protocol is reproducible in the first trimester, and could help in the early detection of fetal cardiovascular abnormalities. It represents a promising additional tool in order to increase the CHD detection rate.
Keywords: congenital heart diseases; extended cardiovascular system; first trimester; prenatal ultrasonic diagnosis; sonographic protocol.