Biomedical subjects

Y Tovbin

Publications and source records attributed to Y Tovbin.

9 recordsLinked to original sources

PubMed2006

A model for second-trimester Down syndrome sonographic screening based on facial landmarks and digit length measurement.

OBJECTIVE: To determine whether Down syndrome can be detected by combining measurements of fetal nasal bone (NB) length, prenasal thickness (PT) and digits 2 and 3 of the hand. METHODS: Two hundred and fifty-four normal and 25 Down-syndrome fetuses were scanned between 15 and 33 weeks' gestation. Physicians performing the scans were not blinded to the fetal karyotype. Both PT and NB were measured in a mid-sagittal plane. For PT measurement calipers were placed between the frontonasal angle and the outer skin edge. Digits 2 and 3 of one hand were also measured. The results (except for PT/NB ratio) were expressed in multiples of the normal gestation-specific median (MoM). A logistic regression model was used to estimate the odds of the fetus having Down syndrome given different combinations of NB, PT, PT/NB ratio, and digits 2 and 3 measurements. The odds were used to calculate the risk of Down syndrome for each pregnant woman from her age and measurements. RESULTS: The median PT MoM for unaffected fetuses and Down-syndrome fetuses was 1.12 vs. 1.35 (P < 0.0001). The median NB MoM for unaffected and Down-syndrome fetuses was 1.03 vs. 0.81 (P < 0.001) and the PT/NB ratio MoM for unaffected and Down-syndrome fetuses was 0.63 vs. 0.96 (P < 0.001). The respective median MoM values for digits 2 and 3 of the Down-syndrome fetuses were significantly smaller (0.81 vs. 0.93 and 0.89 vs. 0.95, respectively, P = 0.003). Only the PT/NB ratio and digit 2 were finally included in the logistic regression equation. Using a 1 in 200 risk cut-off, the observed sensitivity and false-positive rate were 76% and 6.7%, respectively. CONCLUSION: Combining the PT/NB ratio and digit 2 measurements yielded a promising screening detection rate. Confirmation of our findings in a prospective study is needed before the method can be used clinically.

Adult↗

PubMed2004

All five digits of the hands of fetuses with Down syndrome are short.

OBJECTIVE: To compare mid-gestation sonographic measurements of all five digits of the hands of fetuses with Down syndrome with those of normal controls. METHODS: Twenty-nine fetuses between 17 and 26 weeks' gestation which had been confirmed by karyotyping to have Down syndrome were included in this prospective study. Each fetus was scanned once and the digits of only one hand were measured. Measurements were compared with those of 302 previously reported normal controls matched for gestational age. All measurements were expressed in multiples of the gestation-specific normal median (MoM) for each digit. RESULTS: Compared to 1 MoM for the length of Digits 1 to 5 from the normal population, the respective values in the Down syndrome digits were: 0.94, 0.85, 0.92, 0.88 and 0.85 MoM, representing values significantly lower than normal (P < 0.05; t-test). CONCLUSIONS: All five digits of the hands of fetuses with Down syndrome are shorter than are those of euploid fetuses. Integration of fetal digit measurement into the antenatal assessment of selected high-risk cases may be of value although confirmation of our findings should be obtained before this measurement is incorporated into Down syndrome screening in the general population.

Cross-Sectional Studies↗

PubMed2002

Down-up sequential separation of the placenta.

OBJECTIVE: To characterize the patterns of placental separation during the third stage of labor. METHODS: Continuous real-time ultrasound was performed during the third stage of labor in 101 normal deliveries. The sequence of placental separation was recorded for determining whether the process was multiphasic, the site from which separation commenced and the mode of its progression. RESULTS: Separation in 97 cases was multiphasic. Monophasic separation in which all parts of the placenta appeared to separate simultaneously occurred in two cases only. Pathological prolongation of the third stage precluded determination of separation in two cases. Ninety-two cases had a uterine wall placenta (anterior or posterior); the separation commenced at one pole and progressed sequentially towards the opposite side in 89 of them. The process started at the lower pole (down-up separation) in 83/92 cases (90.2%) and began from the upper pole (up-down separation) in only 6/92 cases (6.5%). Nine cases had a fundal placenta; of these the separation was also multiphasic but began sequentially from either the anterior or posterior pole, or simultaneously from both, in 8 (88.9%) cases so that the fundal part was separated last (bipolar separation). CONCLUSIONS: Placental separation is usually an orderly multiphasic phenomenon that begins mostly from the lower pole of the placenta and propagates sequentially upwards. Fundal placentae, however, separate first at their poles with the fundal part being separated last. Recognition of the sequence of events and understanding of the mechanism of placental separation may aid in detecting cases prone to third-stage complications and in managing pathological ones.

Adult↗

PubMed2001

Reconstructed measurements produced from ultrasound images using a computerized system.

OBJECTIVE: The aim of this study was to evaluate the feasibility and accuracy of reconstructed measurements produced from video-printed ultrasound images. DESIGN: Reproduction of reconstructed measurements using designated software and comparison of the results with regular measurements derived from the same images. SUBJECTS: Seventy regular sonographic examinations of biparietal diameter (BPD) and nuchal translucency (NT) thickness. METHODS: The study included 35 conventional-size (BPD) and 35 small-size (NT) measurements. Each image was measured twice during a dynamic ultrasound examination (regular measurements) and twice using a computerized system (reconstructed measurements). The latter comprised three steps: (i) computerization (computer-generated images by scanning); (ii) calibration (using the scale located alongside the image); (iii) measurement (placing the calipers at the desired points). RESULTS: All images were successfully scanned, and the computer-generated images were of sufficient quality for proper measurement. There was no difference between mean values of regular and reconstructed BPD measurements, 63.9 mm (3.7 mm, SE) and 63.6 mm (3.8 mm, SE), respectively. Similarly, mean values of regular NT measurements were similar to the reconstructed ones, 1.48 mm (0.09 mm, SE) and 1.49 mm (0.09 mm, SE), respectively. Repeated regular BPD and NT measurements exhibited repeatability coefficients of 1.6 mm and 0.4 mm, respectively. These values were smaller than those obtained by repeated reconstructed measurements of 2.1 mm and 0.52 mm, respectively. CONCLUSIONS: Reconstructed measurements of ultrasound video-printed images are feasible, require modest facilities and exhibit more than reasonable accuracy. This option may contribute to medical research, audit, quality control and training, as well as to medico-legal issues.

Feasibility Studies↗

PubMed1999

[Pregnancy outcome in fetuses with increased nuchal translucency thickness at 10-14 weeks of pregnancy].

Increased thickness of fetal nuchal translucency (TNT) measured at 10-14 weeks of gestation, may suggest underlying fetal chromosomal defects, structural abnormalities or genetic syndromes. We examined the relationship between increased TNT and pregnancy outcome, especially in fetuses with normal karyotypes. 1400 pregnant women underwent first trimester scanning and screening for chromosomal abnormalities and measurement of fetal TNT. 25 fetuses (2%) with increased TNT (> 3 mm) were identified. 8 (30%) had an abnormal karyotype. Of these, 5 pregnancies were aborted, 3 ended in spontaneous abortions before karyotyping, and 2 were terminated, all before detailed cardiac scanning. There was a high association between increased TNT and karyotype abnormalities. The total incidence of favorable outcome in fetuses with normal chromosomal and cardiac features but enlarged TNT was 56%.

Abortion, Induced↗

PubMed1999

Implementation of nuchal translucency image-scoring method during ongoing audit.

OBJECTIVE: The aim of this study was to evaluate the contribution of an ongoing audit, using the image-scoring method, to the quality of nuchal translucency images and to set the basic standards required from the examiners. DESIGN: Evaluation of nuchal translucency images, before, during and after the implementation of an ongoing audit, without knowledge of the time period or the examiner. SUBJECTS: A total of 315 nuchal translucency scans were performed by three examiners. METHODS: Each of the retrospective, intermediate and prospective time periods included blind scoring of 105 images. The effect of the ongoing audit was examined by comparing the distribution of the quality groups and the mean final score between the time periods, for all cases and for each examiner separately. Improvement of the criteria was assessed by comparing the rate of scans meeting the demands between the time periods. RESULTS: The quality of the images improved significantly as the mean final score changed from 4.62 +/- 0.21 to 6.19 +/- 0.19 and to 6.91 +/- 0.16 (p < 0.0001) and the rate of obtaining acceptable scans rose from 72% to 88% and to 92% (p < 0.001), respective to the three time periods. Whereas the three major criteria improved significantly before and after implementation of the audit (mid-sagittal section from 48% to 94%, caliper placement from 60% to 75% and skin line from 19% to 77%), the minor criteria remained unchanged (image size 90%, amnion demonstration 25% and head position 77%). The average scores of two examiners, for whom improvement was more pronounced, were used to determine the basic standards required from examiners subjected to the audit as follows: unacceptable, none; intermediate, 5%; reasonable, 65%; excellent, 30%; with a mean final score of 7.25. CONCLUSIONS: Implementation of an ongoing audit, using the image-scoring method, proved to be an efficient method for surveillance and improving the quality of nuchal translucency images. We recommended centers or individuals practicing first-trimester ultrasound screening to consider its routine utilization, in an unbiased and strict manner.

Analysis of Variance↗

PubMed1999

Can nuchal cord cause transient increased nuchal translucency thickness?

When detected in a first trimester scan, an increased thickness of nuchal translucency (NT) may be associated with chromosomal, cardiac or genetic disorders. However, less attention has been devoted to the outcome of those fetuses who have confirmed normal anatomies and karyotyping, but have abnormal first trimester scans. Thus, a challenging new issue is how to counsel such cases of transient increased NT in which the translucency rapidly vanishes with no evidence of other underlying abnormalities. Two cases of transient increased thickness of NT are reported. In both, a nuchal cord was ultrasonographically demonstrated and a thorough work-up revealed chromosomally and anatomically normal fetuses. The pathophysiological theories behind these observations and their significance are discussed. Based on these observations, we suggest that transvaginal sonography combined with Doppler flow studies should be utilized for the presize detection of cord patterns to accomplish the work-up in cases of increased NT.

Adult↗

PubMed1999

The feasibility of nuchal translucency measurement in higher order multiple gestations achieved by assisted reproduction.

Nuchal translucency (NT) measurement for screening chromosomal abnormalities and detecting fetal anomalies is an effective ultrasonographic marker, originally developed for singleton pregnancies. This study sought to evaluate the feasibility of NT measurements in higher order multiple gestations. Pregnant patients who conceived following assisted reproduction and were carrying three or more fetuses were enrolled in the study. Each fetus was ultrasonographically assessed, a NT measurement was obtained, and the findings were used for counselling prior to any invasive procedure. In all, 24 pregnant patients, initially carrying 79 fetuses aged 10-14 weeks of gestation, were compared with 79 consecutively matched, singleton controls, naturally conceived, having similar crown-rump lengths (+/- 3 mm). NT measurements were feasible for both study and control fetuses, which exhibited similar NT measurements for 5th, 50th and 95th centiles. Also, mean NT thicknesses [measurements in mm or multiple of the medians (MOM)] were similar for both groups (1.41 +/- 0.41 and 1.35 +/- 0.39 mm respectively and 0.87 +/- 0.23 and 0.83 +/- 0.25 MOM respectively). Prenatally no chromosomal abnormalities were detected in either group, and, of those infants who had no karyotyping, no traits were observed that warranted chromosomal analysis. NT measurements are feasible in higher order multiple gestations. Since there is no other effective screening modality for these pregnancies, it seems reasonable to recommend NT measurement for antenatal screening services for higher order multiple gestations.

Chromosome Aberrations↗

PubMed1994

Ultrasonic antepartum assessment of a classical Cesarean uterine scar and diagnosis of dehiscence.

Prior classic incision through the uterine corpus carries the most significant risk of catastrophic uterine rupture and subsequent maternal and fetal morbidity or mortality. A trial of labor is not carried out in this group of patients, but the risk of uterine rupture exists during the antepartum period. An accurate and prospective method for diagnosing the presence of uterine defects or documenting their absence would be clinically useful. Our unusual case emphasizes the obvious need for antepartum sonographic scans of the classic uterine scar, starting from the third trimester to term, using the high-frequency (> 5 MHz) transducer.

Journal Article↗