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The aim of our study was to evaluate the thermal index (TI) and mechanical index (MI), during the assessment of the fetal heart at the time of first-trimester scan, with different ultrasound machines. This was part of an observational study conducted in patients undergoing routine first-trimester screening. Cases were examined with Voluson E8 or 730Pro scanners using 2–8 MHz transabdominal probes. TI and MI were retrieved from the saved displays while in gray mode, color flow mapping and pulsed-wave (PW) Doppler examinations of the fetal heart and also from the ductus venosus (DV) assessment. We evaluated 552 fetal cardiac examinations, 303 (55%) performed with Voluson E8 and 249 (45%) with Voluson 730Pro ultrasound machines. The gray-scale exam of the heart and the PW Doppler DV assessment had TI values significantly lower for the Voluson E8 group (median, 0.04 vs. 0.2 and 0.1 vs. 0.2, respectively). The MI values from gray-scale and color flow mapping of the heart were significantly lower (median, 0.6 vs, 1.2 and 0.7 vs. 1) and for PW Doppler exam of the tricuspid flow were significantly higher (median 0.4 vs. 0.2) in the Voluson E8 group. The TI values from Doppler examinations of the heart, either color flow or PW imaging and MI values from DV assessment were not significantly different between the two groups. A different (newer) generation of ultrasound equipment provides lower or at least the same safety indices for most of the first-trimester heart examinations.

Aims: The aim of our study was to analyze the variation of acoustic output, as expressed by the thermal (TI) and mechanical index (MI), during the learning curve for a fetal heart scan at 11-13 gestational weeks, with the introduction of a new ultrasound system. Material and methods: This was a prospective, observational study on 303 normal fetuses. The fetal heart was examined transabdominally using B-Mode and high definition (HD) color Doppler to obtain standard parameters: fourchamber, outflow tracts and three-vessel-trachea views. Data were analyzed in groups of 20 consecutive examinations and the percentage of successful examinations was calculated. TI and MI were retrieved from HD color Doppler examinations of the fetal heart and from pulsed-wave Doppler assessment of the tricuspid flow and ductus venosus. Results: MI values from the color Doppler examination of the fetal heart showed a continuous decrease (0.81 to 0.75, p<0.001), along the learning phase. TI and MI indices from pulsed-wave Doppler evaluation of the tricuspid flow increased at the beginning of the learning phase and stabilized afterwards (0.34 to 0.36, p<0.05 and 0.37 to 0.4, p<0.001, respectively). TI from color Doppler exam of the heart and indices from ductus venosus assessment were very constant and did not change along the studied periods. The length of Doppler examination of the heart increased after about 80 cases by 25%, to a mean of 4 minutes (p<0.05). Conclusions: Safety indices from Doppler evaluation of the fetal heart and tricuspid flow vary during the learning curve for fetal heart assessment. Also, the occurrence of constant values suggests the potential for their supplementary active reduction. For a better adaptation to a new ultrasound technology, the sonographer should scan the fetal heart longer in the first trimester and follow displayed safety indices along the first 80 cases.

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The purpose of this study was to evaluate first trimester biochemical screening benefit with and without adding NT in enlarged measurements on screening performances. Methods: Nine thousands five hundreds and twenty-three patients underwent first trimester screening performing NT measurement and first trimester serum screening. Clinical management was decided on the basis of NT/biochemistry risk calculation. Retrospectively enlarged NT were evaluated and risk calculation was evaluated with and without NT measurements when above 2.0 MoM. Results: One hundred and seven fetuses presented at 11-14 weeks' gestation NT measurement above 2.0 MoM. 87 presented positive ultrasound-biochemical screening whilst only 21 had a positive risk calculation using only PAPP-A and free beta hCG. 24 patients were lost at follow-up. The whole population with adverse obstetric outcome (27 patients) where within the 87 with combined screen positive (Detection rate 100%; 87-100% CI 95%), while only nine were detected by biochemical screen (Detection rate 33%; 17-54% CI 95%). Seven cases of trisomy 21 were identified by combined screen (Detection rate 100%; 59-100% CI 95%) and only five by biochemistry alone (detection rate 71%; 29-96% CI 95%). Conclusions: NT measurements above 2.0 MoM increase significantly the risk from biochemistry having 4 times positive screen patients. Whilst an increase of OAPR, the detection rate is reduced significantly not considering NT measurements above 2.0 MoM. Larger population is needed in order to confirm our population result and screening policy.