Measurement of nuchal skin fold thickness in the second trimester: influence of imaging angle and fetal presentation

Prenatal Diagnosis of Mucopolysaccharidosis-Plus Syndrome (MPSPS)

Mucopolysaccharidosis-plus syndrome (MPSPS) is an autosomal-recessive disorder caused by c.1492C>T (p.R498W) in the VPS33A gene. MPSPS is a severe disorder that causes a short lifespan in patients. Currently, there is no specific treatment for patients. The Yakut population is more prone to this disease than others. Diagnosing MPSPS relies on clinical manifestations, and genetic testing (GT) is used to confirm the diagnosis. In this research, we examined two pregnancy cases, one of which involved a prenatal diagnosis for MPSPS. Notably, neither pregnant woman had a known family history of the disorder. During their pregnancies, both women underwent prenatal ultrasonography, which revealed increased prenasal thickness during the second trimester. In the first case, ultrasonography indicated increased prenasal thickness in the second trimester, but a definitive diagnosis was not made at that time. The patient was eventually diagnosed with MPSPS at 11 months of age. On the contrary, in the second case, GT uncovered that the parents were carriers of MPSPS. Consequently, a placental biopsy was performed, leading to an early diagnosis of MPSPS. This study emphasizes the importance of ultrasonography findings in prenatal MPSPS diagnosis. Combining ultrasonography with GT can be a valuable approach to confirming MPSPS at an early stage, allowing for the appropriate planning of delivery methods and medical care. Ultimately, this comprehensive approach can significantly enhance the quality of life of both affected patients and their parents.

Interpreting the role of nuchal fold for fetal growth restriction prediction using machine learning

The objective of the study is to investigate the effect of Nuchal Fold (NF) in predicting Fetal Growth Restriction (FGR) using machine learning (ML), to explain the model's results using model-agnostic interpretable techniques, and to compare the results with clinical guidelines. This study used second-trimester ultrasound biometry and Doppler velocimetry were used to construct six FGR (birthweight < 3rd centile) ML models. Interpretability analysis was conducted using Accumulated Local Effects (ALE) and Shapley Additive Explanations (SHAP). The results were compared with clinical guidelines based on the most optimal model. Support Vector Machine (SVM) exhibited the most consistent performance in FGR prediction. SHAP showed that the top contributors to identify FGR were Abdominal Circumference (AC), NF, Uterine RI (Ut RI), and Uterine PI (Ut PI). ALE showed that the cutoff values of Ut RI, Ut PI, and AC in differentiating FGR from normal were comparable with clinical guidelines (Errors between model and clinical; Ut RI: 15%, Ut PI: 8%, and AC: 11%). The cutoff value for NF to differentiate between healthy and FGR is 5.4 mm, where low NF may indicate FGR. The SVM model is the most stable in FGR prediction. ALE can be a potential tool to identify a cutoff value for novel parameters to differentiate between healthy and FGR.

Fetal nuchal skin-fold thickness during the 2nd trimester of pregnancy

A prospective study was conducted to determine the cut-off values of nuchal skin-fold thickness (NFT) with false-positive rates for each gestational week (GW) for chromosomal abnormalities during the 2nd trimester of pregnancy. A total of 2,313 women with normal singleton pregnancies were included in the study. Cases of multiple gestations, aneuploidy and major congenital malformations were excluded. The distribution of NFT between the 15th and 24th GW and the cut-off values of NFT with false-positive rates for chromosomal abnormalities were determined. A significant positive correlation was noted between NFT and GW. Statistically significant differences were observed in NFT for the each GW. The 95th percentile values of NFT between 15 and 24 weeks' gestation were 4.7, 4.77, 5.0, 5.5, 5.76, 5.9, 6.0, 6.1, 6.5 and 6.8 mm, respectively. In all fetuses, if the cut-off value of NFT was considered as 6 mm, the false-positive rate ranged from 1.8% to 37% in 15-24 weeks' gestation. Evaluation of NFT according to cut-off values determined by population-based percentiles for each GW might be a more appropriate screening method for chromosomal abnormalities than accepting NFT ≥ 6 mm for all fetuses as abnormal, regardless of gestational age.

Impact of gestational age on nuchal fold thickness in the second trimester

OBJECTIVES

The purpose of this study was to establish gestational age (GA)-specific nomograms for nuchal fold thickness between 16 and 24 weeks.

METHODS

This retrospective cross sectional study included 32,207 women who underwent a second-trimester anomaly scan at the Fetal Care Center of National University Hospital from January 2005 to April 2011. Nomograms were plotted for nuchal fold thickness at each gestation to study its variation with GA.

RESULTS

Nuchal fold thickness increased with GA in a linear manner from 3.13 ± 0.68 mm (mean ± SD) at 16 weeks to 5.08 ± 0.76 mm at 24 weeks. The 95th percentile measurement at 24 weeks remained less than 6 mm.

CONCLUSIONS

A threshold of 6 mm appears to be appropriate for the diagnosis of a thick nuchal fold even for gestations between 20 and 24 weeks.

Enhancement of Cerenkov luminescence imaging by dual excitation of Er(3+),Yb(3+)-doped rare-earth microparticles

Cerenkov luminescence imaging (CLI) has been successfully utilized in various fields of preclinical studies; however, CLI is challenging due to its weak luminescent intensity and insufficient penetration capability. Here, we report the design and synthesis of a type of rare-earth microparticles (REMPs), which can be dually excited by Cerenkov luminescence (CL) resulting from the decay of radionuclides to enhance CLI in terms of intensity and penetration.

METHODS

Yb(3+)- and Er(3+)- codoped hexagonal NaYF4 hollow microtubes were synthesized via a hydrothermal route. The phase, morphology, and emission spectrum were confirmed for these REMPs by power X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectrophotometry, respectively. A commercial CCD camera equipped with a series of optical filters was employed to quantify the intensity and spectrum of CLI from radionuclides. The enhancement of penetration was investigated by imaging studies of nylon phantoms and nude mouse pseudotumor models.

RESULTS

the REMPs could be dually excited by CL at the wavelengths of 520 and 980 nm, and the emission peaks overlaid at 660 nm. This strategy approximately doubled the overall detectable intensity of CLI and extended its maximum penetration in nylon phantoms from 5 to 15 mm. The penetration study in living animals yielded similar results.

CONCLUSIONS

this study demonstrated that CL can dually excite REMPs and that the overlaid emissions in the range of 660 nm could significantly enhance the penetration and intensity of CL. The proposed enhanced CLI strategy may have promising applications in the future.

Follow-up of sonographically detected soft markers for fetal aneuploidy

Sonographic soft markers of fetal Down syndrome were first reported in the 1980s. With improvements in aneuploidy screening, detection rates of 90% and higher are possible, and such screening is offered to women of all ages. The utility of sonographic detection and reporting of soft markers, particularly to women at low risk of fetal aneuploidy, is controversial. Some soft markers have no additional significance beyond an association with aneuploidy, while some potentially indicate other pathology, and therefore require sonographic follow-up or other evaluation. The definitions of soft markers vary among reported series, and any practice using such markers to adjust the risk of aneuploidy should carefully determine the most appropriate definitions as well as likelihood ratios and how to apply these in practice.

Detailed ultrasound screening in the second trimester: pictorial essay of normal fetal anatomy

Today, ultrasound is the main diagnostic tool in the prenatal detection of congenital abnormalities. Therefore, ultrasound examination should be offered to all pregnant women. A detailed sonographic examination of the fetus is usually performed between 18 and 22 weeks of pregnancy. The accurate recognition of normal fetal anatomy is very important for the detection of both minor and major defects. The purpose of this pictorial essay is to show fetal anatomic structures, which have to be examined between the 18(th) and 22(nd) weeks of pregnancy, and present their standard measurements systematically and thoroughly in accordance with sonographically obtained ideal sections.

Comparison of Fetal Nuchal Fold Thickness Measurements by Two- and Three-Dimensional Ultrasonography (3DXI Multislice View)

Purpose. To compare the measurements of fetal nuchal fold (NF) thickness by two-dimensional (2D) and three-dimensional (3D) ultrasonography using the three-dimensional extended imaging (3DXI). Methods. A cross-sectional study was performed with 60 healthy pregnant women with a gestational age between 16 and 20 weeks and 6 days. The 2D-NF measurements were made as the distance from the outer skull bone to the outer skin surface in the transverse axial image in the suboccipital-bregmatic plane of the head. For the 3D we employed the 3DXI multislice view software, in which 3 × 2 tomographic planes was displayed on the screen and the distance between the tomographic slices was 0.5 mm. Maximum, minimum, mean, and standard deviation were calculated for 2D and 3D ultrasonography, as well the maximum and minimum, mean, and standard deviation for the difference between both methods. The Wilcoxon signed-rank test was used to compare the two different techniques. Results. 2D-NF showed a mean of thickness of 3.52 ± 0.95 mm (1.69–7.14). The mean of 3D-NF was 3.90 ± 1.02 mm (2.13–7.72). The mean difference between the methods was 0.38 mm, with a maximum difference of 3.12 mm. Conclusion. The NF thickness measurements obtained by 3D ultrasonography were significantly larger than those detected with 2D ultrasonography.