Examination of the fetal heart by four-dimensional ultrasound with spatiotemporal image correlation during routine second-trimester examination: the 'three-steps technique'.
OBJECTIVE
To prospectively analyze the accuracy and rapidity of four-dimensional (4D) ultrasonography with spatiotemporal image correlation (STIC) in the assessment of four-chamber view and outflow tracts in unselected fetuses and in fetuses with congenital heart defects (CHD) at 19-23 weeks of gestation.


METHODS
112 consecutive pregnancies undergoing routine second-trimester ultrasonographic scan and 10 pregnancies with fetuses with CHD affecting the great arteries formed the study group. From the four-chamber view, volumes of the fetal heart were acquired by the STIC technique and stored for a later offline analysis that was performed by two examiners blinded to the characteristics of the fetuses. Offline analysis was performed using a simplified multiplanar approach based on 3 different steps and one rotation finalized to visualize the four-chamber view and the left and right outflow tracts.


RESULTS
Adequate recognition of four-chamber view and outflow tracts was obtained in more than 80% of the volumes. There were no false-positives and only one observer had a false-negative (interrupted aortic arch classified as normal). The mean time required to interpret 4D volumes was 3.7 min.


CONCLUSIONS
The standard fetal cardiac anatomy survey can be performed in the second-trimester fetus by 4D STIC in both normal and abnormal hearts. This approach may reduce the operator's dependency in diagnosis of CHD.
Rizzo
Giuseppe
G
Department of Obstetrics and Gynecology, Università di Roma Tor Vergata, Rome, Italy. giuseppe.rizzo@uniroma2.it
Capponi
Alessandra
A
Muscatello
Andrea
A
Cavicchioni
Ottavia
O
Vendola
Marianne
M
Arduini
Domenico
D
D019561:Echocardiography, Four-Dimensional; D005188:False Negative Reactions; D005240:Feasibility Studies; D005260:Female; D005318:Fetal Heart / Q000000981:diagnostic imaging*; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging* / Q000196:embryology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D015588:Observer Variation; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies; D015203:Reproducibility of Results; D013997:Time Factors; D016216:Ultrasonography, Prenatal / Q000379:methods*