First-trimester presentation of ultrasound findings in trisomy 13 and validation of multiparameter ultrasound-based risk calculation models to detect trisomy 13 in the late first trimester.

OBJECTIVES: To identify the most common ultrasound patterns of markers and anomalies associated with Patau syndrome (PS), to explore the efficacy of multiparameter sonographic protocols in detecting trisomy 13 (T13) and to analyze the influence of maternal age (MA) on screening performance. METHODS: The project was a prospective study based on singleton pregnancies referred for a first-trimester screening examination. The scan protocol included nuchal translucency (NT), fetal heart rate (FHR), secondary ultrasound markers [nasal bone (NB), tricuspid regurgitation (TR), ductus venosus reversed a-wave (revDV)] and major anomaly findings. RESULTS: The study population comprised 6133 pregnancies: 6077 cases of euploidy and 56 cases of T13. Statistically significant differences were found in MA, FHR, NT, absence of NB, presence of revDV, TR and single umbilical artery. Fourteen cases of T13 (25%) demonstrated no markers of aneuploidy. The best general detection rate (DR) (DR of 78.6% with an false positive rate (FPR) of 1.2%) was obtained for a cutoff of 1/300 utilizing the "NT+T13" algorithm. The logistic regression model revealed that the central nervous system (CNS) anomalies had the greatest odds ratio (of 205.4) for T13. CONCLUSIONS: The effectiveness of the multiparameter sonographic protocol used for T13 screening showed promising results in patients older than 36 years and suboptimal results in patients between 26 and 36 years old. When screening for T13 left heart defects, CNS anomalies, abdominal anomalies, FHR above the 95th percentile, increased NT, revDV and lack of NB should receive specific attention.

Clinical article: screening for trisomy 13 using traditional combined screening versus an ultrasound-based protocol.

AIMS: To compare the screening capability of ultrasonography in detecting trisomy 13 (T13) using a multiparameter sonographic protocol (NT+) with a classical combined screening test (CST) protocol. METHODS: The project was a prospective, multicenter study based on a nonselected mixed-risk population of women referred for a first-trimester screening examination. Each subject was offered a choice between either the gold standard, traditional combined screening test (CSG arm) or the ultrasound-based screening protocol (USG arm). General and MA-based screening performances were checked. RESULTS: The study population comprised 20,887 pregnancies: 12,933 in the CSG arm, including 27 cases of T13, and 7954 in the USG arm, including 30 cases of T13. The DR for T13 was higher in the CSG arm than in the USG arm for all tested cutoff points: 1/50 (88.5 versus 63.3%, respectively), 1/100 (88.5 versus 70%, respectively) and 1/300 (92.3 versus 83.3%, respectively). Using the ROC curves for fixed FPRs of 3 and 5%, the T13 detection rate in our study reached 90 and 93%, respectively, in the USG arm and 92 and 96%, respectively, in the CSG arm. MA influenced the T13 screening performance in the USG arm and reduced the DR in patients <31 years. Such influence was not detected in the CSG arm. CONCLUSIONS: Classic CST was more effective in detecting T13 than the ultrasound-only approach. However, the recommended cutoff of 1/50 showed unsatisfactory results for both traditional CST and the multiparameter sonographic test we proposed.

Early fetal cardiac scan as an element of the sonographic first-trimester screening.

Early fetal cardiac scan (EFCS) is becoming an increasingly common element of the first trimester ultrasound screening carried out at 11-14 gestational weeks. It offers the first possibility to detect congenital heart defects (CHD) or, in ambiguous cases, to identify those pregnancies where a more detailed cardiac scan would be required later in pregnancy. The size of the fetal heart at the end of the first trimester and the associated relatively low image resolution make it impossible to capture all cardiac data to inform the ultimate picture. However, even at this stage, cues of anatomical and functional abnormalities can be picked up, which suggest not only a CHD, but also a likelihood of cardiovascular symptoms typical of genetic disorders. EFCS should focus on cardiac position, atrioventricular (AV) connections, AV valve function, initial assessment of ventriculo-arterial (VA) connections and the presence of red flag signs in the three vessel and trachea view (3VTV). Proper use of color Doppler mapping makes it possible to overcome the low resolution of B-mode to a certain extent. Here we present our long-term experience in EFCS.