Evaluation of First-Trimester Physiological Midgut Herniation Using Three-Dimensional Ultrasound.

INTRODUCTION: The aim of this study was to investigate the development of midgut herniation in vivo using three-dimensional (3D) ultrasonographic volume and distance measurements and to create reference data for physiological midgut herniation in ongoing pregnancies in a tertiary hospital population. MATERIALS AND METHODS: The transvaginal 3D ultrasound volumes of 112 women, seen weekly during the first trimester of pregnancy, were obtained and subsequently analysed in a virtual reality environment. The width of the umbilical cord insertion, the maximum diameter of the umbilical cord, and the volume of midgut herniation were measured from 6 until 13 weeks gestational age (GA). RESULTS: All parameters had a positive relation with GA, crown-rump length, and abdominal circumference. In approximately 1 of 10 volumes no midgut herniation could be observed at 9 and 10 weeks GA. In 5.0% of the fetuses the presence of midgut herniation could still be visualised at 12 weeks GA. CONCLUSION: Reference charts for several dimensions of physiological midgut herniation were created. In the future, our data might be used as a reference in the first trimester for comparison in case of a suspected pathological omphalocele.

Design and validation of a 3D virtual reality desktop system for sonographic length and volume measurements in early pregnancy evaluation.

PURPOSE: To design and validate a desktop virtual reality (VR) system, for presentation and assessment of volumetric data, based on commercially off-the-shelf hardware as an alternative to a fully immersive CAVE-like I-Space VR system. METHODS: We designed a desktop VR system, using a three-dimensional (3D) monitor and a six degrees-of-freedom tracking system. A personal computer uses the V-Scope (Erasmus MC, Rotterdam, The Netherlands) volume-rendering application, developed for the I-Space, to create a hologram of volumetric data. Inter- and intraobserver reliability for crown-rump length and embryonic volume measurements are investigated using Bland-Altman plots and intraclass correlation coefficients. Time required for the measurements was recorded. RESULTS: Comparing the I-Space and the desktop VR system, the mean difference for crown-rump length is -0.34% (limits of agreement -2.58-1.89, ±2.24%) and for embryonic volume -0.92% (limits of agreement -6.97-5.13, ±6.05%). Intra- and interobserver intraclass correlation coefficients of the desktop VR system were all >0.99. Measurement times were longer on the desktop VR system compared with the I-Space, but the differences were not statistically significant. CONCLUSIONS: A user-friendly desktop VR system can be put together using commercially off-the-shelf hardware at an acceptable price. This system provides a valid and reliable method for embryonic length and volume measurements and can be used in clinical practice.

First-trimester hand measurements in euploid and aneuploid human fetuses using virtual reality.

OBJECTIVE: Although second-trimester and third-trimester reference curves for human fetal hand growth allow for identification of several genetic syndromes, little is known about first-trimester hand growth. We investigated first-trimester hand growth in euploid and aneuploid fetuses. METHOD: Between 9 and 12 weeks' gestational age (GA), wrist width, hand width, hand length, and hand index were measured in three-dimensional (3D) ultrasound datasets of 112 euploid and 65 aneuploid pregnancies. We constructed reference curves for these measurements in euploid pregnancies and calculated z-scores for measurements in aneuploid pregnancies. Reproducibility was established in a subset of 20 datasets. RESULTS: While wrist width, hand width, and hand length increased with gestational age, hand index decreased. Intraobserver and interobserver intraclass correlation coefficient values were >0.97. In trisomy 21 cases, wider wrists and hands were observed compared with euploid pregnancies (mean z-scores 1.06, SD 2.04, p < 0.001 and 1.16, SD 1.30, p < 0.001, respectively). Trisomy 18 cases showed narrower and shorter hands (mean z-scores -0.74, SD 1.20, p = 0.009 and -0.97, SD 0.86, p = 0.005, respectively). In trisomy 13 cases, no differences were observed. CONCLUSION: Reference values are available for first-trimester studies on human hand development. First-trimester hand measurements in trisomies 21 and 18 differ significantly from those in euploid pregnancies and may be useful for early identification of abnormal development.

First-Trimester Detection of Surface Abnormalities: A Comparison of 2- and 3-Dimensional Ultrasound and 3-Dimensional Virtual Reality Ultrasound.

The aim was to determine the diagnostic performance of 3-dimensional virtual reality ultrasound (3D_VR_US) and conventional 2- and 3-dimensional ultrasound (2D/3D_US) for first-trimester detection of structural abnormalities. Forty-eight first trimester cases (gold standard available, 22 normal, 26 abnormal) were evaluated offline using both techniques by 5 experienced, blinded sonographers. In each case, we analyzed whether each organ category was correctly indicated as normal or abnormal and whether the specific diagnosis was correctly made. Sensitivity in terms of normal or abnormal was comparable for both techniques (P = .24). The general sensitivity for specific diagnoses was 62.6% using 3D_VR_US and 52.2% using 2D/3D_US (P = .075). The 3D_VR_US more often correctly diagnosed skeleton/limb malformations (36.7% vs 10%; P = .013). Mean evaluation time in 3D_VR_US was 4:24 minutes and in 2D/3D_US 2:53 minutes (P < .001). General diagnostic performance of 3D_VR_US and 2D/3D_US apparently is comparable. Malformations of skeleton and limbs are more often detected using 3D_VR_US. Evaluation time is longer in 3D_VR_US.

Diagnostic techniques and criteria for first-trimester conjoined twin documentation: a review of the literature illustrated by three recent cases.

OBJECTIVES: Conjoined twins are rare. High-quality imaging techniques are essential for proper first-trimester diagnosis. Technological development leads to new imaging techniques such as 3-dimensional virtual embryoscopy. The aim of this review was to explore imaging techniques used in the first-trimester diagnosis of conjoined twins and provide a systematic diagnostic table for making this diagnosis. DESIGN: A PubMed literature search was performed using the terms ultrasound, Doppler, MRI, and CT combined with first-trimester and conjoined twins. Three recent cases at our department are reviewed and examined additionally using 3-dimensional virtual embryoscopy. RESULTS: The different types of conjoined twins are summarized in a table for practical use during ultrasound examination. In evaluating conjoined twins, 2-dimensional ultrasound is the criterion standard. Three-dimensional and Doppler ultrasounds add anatomical and prognostic information. Virtual embryoscopy imaging reveals additional findings in our 3 cases not seen with routine 2-dimensionalultrasound examination. CONCLUSIONS: Each case of conjoined twins is unique and should be evaluated with the best possible imaging techniques. Three-dimensional and Doppler ultrasound should be added to the systematic diagnostic evaluation of conjoined twins. Virtual embryoscopy imaging may contribute to earlier, more appropriate counseling and management of these pregnancies.