First-trimester Down Syndrome Research Articles

EXTRACTION OF FETAL FEATURES FROM B MODE ULTRASONOGRAMS FOR EFFICIENT DIAGNOSIS OF DOWN SYNDROME IN FIRST AND SECOND TRIMESTER

Segmentation of ultrasound images has been found to be a tedious task due to the presence of speckle and other artifacts. The random nature of the multiplicative speckle noise and lack of demarcation of information in ultrasound images makes the segmentation a highly complex one. In this paper a modified watershed based method has been proposed for segmentation of features from Ultrasound images towards efficient diagnosis of Down Syndrome in first and second trimester. The pixels are grouped based on the pixel differences and the co- occurrence matrix is formed based on the energy and contrast. If global scheme is adopted for segmentation the high frequency edges may appear as artifacts. Hence to overcome this the wavelet transform of co-occurrence matrix is obtained and each decomposed band is subjected to an averaging filter. The process bands are thresholded using Otsu’s method and a binary image is obtained. The isolated pixels are removed by using suitable morphological operations. Then inverse wavelet transform is performed to obtain the image skeleton. The resultant image is subjected to watershed segmentation using gradients. Using the above mentioned approach we can see that the regions of interest are clearly segmented and is producing reproducible results.

First trimester screening for pre-eclampsia in Chinese pregnancies: case-control study.

To assess the potential of screening for pre-eclampsia (PE) in a Chinese population. Case-control study. Teaching hospital in Hong Kong. A total of 3330 women having a viable singleton pregnancy attending first-trimester Down-syndrome screening. Mean arterial pressure (MAP), bilateral uterine artery pulsatility index (UtA-PI), and placental growth factor (PlGF) were measured. Screening markers were transformed to multiples of the gestational median (MoM) and adjusted for maternal and pregnancy characteristics. MoM distributions in PE and non-PE pregnancies were compared with published expected values. PE screening performance was assessed using area under receiver operating curves (AUROC). PE detection rate. A total of 30 (0.9%) women developed either early (<34weeks) or late (≥34weeks) onset PE. MAP was dependent on maternal BMI, UtA-PI on fetal crown rump length, uterine artery peak systolic velocity (UtA-PSV) on maternal age and gestation, and PlGF on gestation in non-PE pregnancies. MoM distributions determined using published Fetal Medicine Foundation models deviated significantly from one for both MAP (P<0.0001) and PI (P<0.0001), but not PlGF (P=0.52) in non-PE pregnancies, whilst PlGF MoM distributions in those who developed early as opposed to late onset PE were significantly higher (P=<0.05). AUROC for any PE using multiple markers was 0.72 (95% CI: 0.64-0.81) with detection rates of 72 and 55% for early and late PE, respectively, for a 10% false positive rate. Detection rates for PE in our Chinese population were lower than the expected 90-95% even after adjusting MoM for local women's characteristics. General Research Fund (Project number 470513). Pre-eclampsia screening in the Chinese population had detection rates lower than previously published results.

Comparison of combined, biochemical and nuchal translucency screening for Down syndrome in first trimester in Northern Finland

To compare the efficacy of fetal nuchal translucency screening, maternal serum screening and combined screening for Down syndrome. A prospective study. University hospital and its public health care district in Northern Finland. A total of 35,314 women participated in the first-trimester screening for Down syndrome within the public healthcare system in 2002-08. There were 95 pregnancies involving Down syndrome. Serum samples were obtained from 35,314 women, nuchal translucency was measured in 27,144 pregnancies and full combined screening was performed in those pregnancies, including 76 involving Down syndrome. The adjusted estimated risk for Down syndrome was calculated using the Perkin Elmer AutoDELFIA® time-resolved fluoroimmunoassay kit for the measurement of pregnancy-associated plasma protein-A and free β-human chorionic gonadotropin. Nuchal translucency was measured by trained personnel in a university or district hospital. Risk cut-off figures 1:250 and 1:300 at term were used. Differences in detection rate, false-positive rate, positive and negative predictive values between nuchal translucency screening, serum screening and combined screening. Using the risk cut-off figure 1:250, the detection rates for serum screening, nuchal translucency screening and combined screening were 64.2, 64.5 and 72.4%, respectively and the false-positive rates were 7.8, 4.4 and 4.0%, respectively. Combined screening is the method of choice for Down syndrome screening in Finland.

First‐trimester maternal serum progesterone in aneuploid pregnancies

First-trimester maternal serum screening for Down syndrome (DS) can be improved by the use of additional serum markers. We examined whether progesterone (P), synthesized by placenta, might be a first-trimester maternal serum marker for fetal DS. P was quantified in first-trimester maternal serum from 42 DS, six trisomy 18 and two trisomy 13 pregnancies and 115 controls. Log-regression of P versus gestational age in days was used to convert P concentrations into multiples of the median (MoM). The P concentrations in controls increased with gestational age (p = 9.5 x 10(-7)). The log10MoM P distribution in DS pregnancies was not significantly different from that in controls. However, from day 58-67, the log10MoM P was elevated in DS pregnancies (n = 10) with a mean (SD) of 0.1040 (0.0956), compared to a mean (SD) of - 0.0109 (0.1661) in controls (n = 24) (p = 0.05). Five out of six trisomy 18 and both trisomy 13 pregnancies had a P MoM < 1. P is not a useful marker for DS in first trimester, except perhaps in a narrow gestational age window from day 58 to 67. P is a trisomy 18/13 marker.

A model for disclosing the first trimester part of an integrated Down's syndrome screening test.

This study was designed to evaluate a model for disclosing the first part of an integrated Down's syndrome (DS) test without affecting its low false-positive results. Parturient women underwent sequential DS-screening tests. They included nuchal translucency (NT) and biochemistry assessments in the first trimester and a mid-gestation triple test. Although screening tests results were given following each test, fetal karyotyping was performed by means of mid-gestation amniocentesis. The proposed approach for disclosure refers to either (a) cases picked by a statistical model (this is based on a logistic regression analysis and a receiver-operated curve that was set to a specificity of 100% of first-trimester markers pointing on at very high probability of aneuploidy) or (b) cases demonstrating a first trimester DS risk > or = 1 : 40 (a threshold level at which the integrated test results will always be screen positive). The results of the sequential screening and pregnancy outcome were available for 372 normal and 22 chromosomal affected singletons. NT and pregnancy-associated placental protein A emerged as the most sensitive marker combination. The statistical model picked up seven of 22 abnormal cases (32%), and a first-trimester DS risk > or = 1 : 40 was detected in 11 (50%) (there was an overlap of five cases). The combined strategy yields a 60% detection rate (13/22) of the affected pregnancies and without any increase in the false-positive results. This can be achieved immediately following the first part of the integrated DS test. This model obviates the ethical, clinical, and financial implications of further assessing about 60% of the affected pregnancies.

SP1 in pregnancies with Down syndrome in the first trimester of pregnancy

SP1 in pregnancies with Down syndrome in the first trimester of pregnancy

Schwangerschafts protein 1 (SP1) adds little to the age‐related detection of fetal Down syndrome in the first trimester of pregnancy

Schwangerschafts protein 1 (SP1) adds little to the age‐related detection of fetal Down syndrome in the first trimester of pregnancy