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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., (© 2014 Wiley Periodicals, Inc.)

Objectives: To examine whether embryonic volume (EV), as measured using three-dimensional (3D) ultrasound and a virtual reality approach, is a better measure of growth restriction than is crown-rump length (CRL) in aneuploid fetuses., Methods: We retrospectively measured CRL and EV in prospectively collected 3D ultrasound volumes of 55 aneuploid fetuses using the Barco I-Space VR system. The gestational age ranged from 11 + 2 to 14 + 4 weeks. We compared our measured data with previously published reference curves for euploid fetuses. Delta-values were calculated by subtracting the expected mean for euploid fetuses of the same gestational age from observed values. The one-sample t-test was used to test the significance of differences observed., Results: The CRL measurements of fetuses with trisomy 21 (n = 26), trisomy 13 (n = 5) and monosomy X (n = 5) were comparable with those of euploid fetuses, but in fetuses with trisomy 18 (n = 19) the CRL was 14.5% smaller (P < 0.001). The EV in fetuses with trisomies 21, 18 and 13 and monosomy X was smaller than in euploid fetuses (-27.8%, P < 0.001; -39.4%, P < 0.001; -40.9%, P = 0.004; and -27.3%, P = 0.055, respectively)., Conclusions: When relying on CRL measurements alone, first-trimester growth restriction is especially manifest in trisomy 18. Using EV, growth restriction is also evident in trisomies 21 and 13 and monosomy X. EV seems to be a more effective measurement for the assessment of first-trimester growth restriction in aneuploid fetuses., (Copyright © 2012 ISUOG. Published by John Wiley & Sons Ltd.)

Objectives: Virtual reality is a novel method of visualizing ultrasound data with the perception of depth and offers possibilities for measuring non-planar structures. The levator ani hiatus has both convex and concave aspects. The aim of this study was to compare levator ani hiatus volume measurements obtained with conventional three-dimensional (3D) ultrasound and with a virtual reality measurement technique and to establish their reliability and agreement., Methods: 100 symptomatic patients visiting a tertiary pelvic floor clinic with a normal intact levator ani muscle diagnosed on translabial ultrasound were selected. Datasets were analyzed using a rendered volume with a slice thickness of 1.5 cm at the level of minimal hiatal dimensions during contraction. The levator area (in cm(2)) was measured and multiplied by 1.5 to get the levator ani hiatus volume in conventional 3D ultrasound (in cm(3)). Levator ani hiatus volume measurements were then measured semi-automatically in virtual reality (cm(3) ) using a segmentation algorithm. An intra- and interobserver analysis of reliability and agreement was performed in 20 randomly chosen patients., Results: The mean difference between levator ani hiatus volume measurements performed using conventional 3D ultrasound and virtual reality was 0.10 (95% CI, - 0.15 to 0.35) cm(3). The intraclass correlation coefficient (ICC) comparing conventional 3D ultrasound with virtual reality measurements was > 0.96. Intra- and interobserver ICCs for conventional 3D ultrasound measurements were > 0.94 and for virtual reality measurements were > 0.97, indicating good reliability for both., Conclusion: Levator ani hiatus volume measurements performed using virtual reality were reliable and the results were similar to those obtained with conventional 3D ultrasonography., (Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.)

Background: the umbilical cord and vitelline duct are of vital importance to the fetus, but they are rarely the subject of first trimester two-dimensional (2D) ultrasound evaluation due to the complexity of their shape and morphology. Virtual reality (VR) allows efficient visualisation and measurement of complex structures like the umbilical cord and vitelline duct., Aim: to measure normal first trimester human growth of the umbilical cord length (UCL) and vitelline duct length (VDL) using a VR system; and to correlate both measurements with the gestational age (GA) and crown-rump length (CRL) and the VDL with the yolk sac volume (YSV)., Study Design: prospective cohort study. Serial three-dimensional (3D) ultrasound measurements were performed from six to 14weeks GA, resulting in 125 3D volumes. These volumes were analysed using an I-Space VR system., Subjects: Thirty-two healthy pregnant women with an ongoing, normal pregnancy., Outcome Measures: the UCL, VDL, YSV and other related structures were measured., Results: The UCL, measurable in 55% of cases, was positively correlated to advancing GA and CRL (p<0.001). The VDL could be measured in 42% of cases and showed a positive relationship with GA and CRL (p<0.001). There was a significant (p<0.001) relationship between YSV and VDL., Conclusions: the present study, facilitated by a VR system, is the first to provide an in-vivo longitudinal description of normal first trimester growth of the human umbilical cord and vitelline duct. Further studies will reveal whether these parameters can be used in detection of abnormal fetal development., (2010 Elsevier Ltd. All rights reserved.)

Background: The recent introduction of virtual reality (VR) enables us to use all three dimensions in a three-dimensional (3D) image. The aim of this prospective study was to evaluate an innovative VR technique for automated 3D volume measurements of the human embryo and yolk sac in first trimester pregnancies., Methods: We analysed 180 3D first trimester ultrasound scans of 42 pregnancies. Scans were transferred to an I-Space VR system and visualized as 3D 'holograms' with the V-Scope volume-rendering software. A semi-automatic segmentation algorithm was used to calculate the volumes. The logarithmically transformed outcomes were analysed using repeated measurements ANOVA. Interobserver and intraobserver agreement was established by calculating intraclass correlation coefficients (ICCs)., Results: Eighty-eight embryonic volumes (EVs) and 118 yolk sac volumes (YSVs) were selected and measured between 5(+5) and 12(+6) weeks of gestational age (GA). EV ranged from 14 to 29 877 mm(3) and YSV ranged from 33 to 424 mm(3). ANOVA calculations showed that when the crown-rump length (CRL) doubles, the mean EV increases 6.5-fold and when the GA doubles, the mean EV increases 500-fold (P < 0.001). Furthermore, it was found that a doubling in GA results in a 3.8-fold increase of the YSV and when the CRL doubles, the YSV increases 1.5-fold (P < 0.001). Interobserver and intraobserver agreement were both excellent with ICCs of 0.99., Conclusion: We measured the human EV and YSV in early pregnancy using a VR system. This innovative technique allows us to obtain unique information about the size of the embryo using all dimensions, which may be used to differentiate between normal and abnormal human development.

Background: Innovative imaging techniques, using up-to-date ultrasonic equipment, necessitate specific biometry. The aim of our study was to test the possibility of detailed human embryonic biometry using a virtual reality (VR) technique., Methods: In a longitudinal study, three-dimensional (3D) measurements were performed from 6 to 14 weeks gestational age in 32 pregnancies (n = 16 spontaneous conception, n = 16 IVF/ICSI). A total of 125 3D volumes were analysed in the I-Space VR system, which allows binocular depth perception, providing a realistic 3D illusion. Crown-rump length (CRL), biparietal diameter (BPD), occipito-frontal diameter (OFD), head circumference (HC) and abdominal circumference (AC) were measured as well as arm length, shoulder width, elbow width, hip width and knee width., Results: CRL, BPD, OFD and HC could be measured in more than 96% of patients, and AC in 78%. Shoulder width, elbow width, hip width and knee width could be measured in more than 95% of cases, and arm length in 82% of cases. Growth curves were constructed for all variables. Ear and foot measurements were only possible beyond 9 weeks gestation., Conclusions: This study provides a detailed, longitudinal description of normal human embryonic growth, facilitated by a VR system. Growth curves were created for embryonic biometry of the CRL, BPD, HC and AC early in pregnancy and also of several 'new' biometric measurements. Applying virtual embryoscopy will enable us to diagnose growth and/or developmental delay earlier and more accurately. This is especially important for pregnancies at risk of severe complications, such as recurrent late miscarriage and early growth restriction.

In this paper we present a new implementation of the virtual reality workstation concept. Based on an application originally developed for immersive virtual environments such as CAVEs, V-Scope allows clinicians and researchers to investigate their three dimensional (3D) imaging data with truly 3D views and interactions. This greatly improves the understanding of the data, and allows the efficient measurement of volumes and distances in a way that was previously not possible.

Objective: The utility of a virtual reality system was examined in the visualization of three-dimensional (3D) ultrasound images of fetal ambiguous genitalia., Methods: In 2005, fetal ambiguous genitalia were diagnosed in four patients referred to our department for prenatal ultrasound assessment. The patients were examined by two-dimensional (2D) and 3D ultrasound and, subsequently, the volumes obtained on 3D ultrasound were visualized in the BARCO I-Space virtual reality system. This system projects stereoscopic images on three walls and the floor of a small 'room', allowing several viewers to see a 3D 'hologram' of the data being visualized. The results of 2D and 3D ultrasound examination and the virtual reality images of the I-Space were compared with diagnoses made postpartum., Results: In all cases, prenatal diagnosis was unclear based on 2D ultrasound alone. Surface rendering of 3D data provided an impression of ambiguity, but diagnosis based on these data proved incorrect at birth in three cases. Conclusions based on the evaluation of 3D volumes in virtual reality best fitted the postpartum diagnosis in all cases., Conclusions: This study suggests that by evaluation of the genitals in the I-Space, a better impression of genital ambiguity can be established. Binocular depth perception appeared particularly useful in distinguishing either a micropenis or enlarged clitoris from labia minora, since it helps in the estimation of size and position. Therefore, we see potential for the application of virtual reality not only for the evaluation of fetal ambiguous genitalia, but in all those cases where depth perception would improve the visualization of anatomical structures.

Background: This study was done to investigate the potential additional role of virtual reality, using three-dimensional (3D) echocardiographic holograms, in the postoperative assessment of tricuspid valve function after surgical closure of ventricular septal defect (VSD)., Methods: 12 data sets from intraoperative epicardial echocardiographic studies in 5 operations (patient age at operation 3 weeks to 4 years and bodyweight at operation 3.8 to 17.2 kg) after surgical closure of VSD were included in the study. The data sets were analysed as two-dimensional (2D) images on the screen of the ultrasound system as well as holograms in an I-space virtual reality (VR) system. The 2D images were assessed for tricuspid valve function. In the I-Space, a 6 degrees-of-freedom controller was used to create the necessary projectory positions and cutting planes in the hologram. The holograms were used for additional assessment of tricuspid valve leaflet mobility., Results: All data sets could be used for 2D as well as holographic analysis. In all data sets the area of interest could be identified. The 2D analysis showed no tricuspid valve stenosis or regurgitation. Leaflet mobility was considered normal. In the virtual reality of the I-Space, all data sets allowed to assess the tricuspid leaflet level in a single holographic representation. In 3 holograms the septal leaflet showed restricted mobility that was not appreciated in the 2D echocardiogram. In 4 data sets the posterior leaflet and the tricuspid papillary apparatus were not completely included., Conclusion: This report shows that dynamic holographic imaging of intraoperative postoperative echocardiographic data regarding tricuspid valve function after VSD closure is feasible. Holographic analysis allows for additional tricuspid valve leaflet mobility analysis. The large size of the probe, in relation to small size of the patient, may preclude a complete data set. At the moment the requirement of an I-Space VR system limits the applicability in virtual reality 3D echocardiography in clinical practice.

Background: This pilot study was performed to evaluate whether virtual reality is applicable for three-dimensional echocardiography and if three-dimensional echocardiographic 'holograms' have the potential to become a clinically useful tool., Methods: Three-dimensional echocardiographic data sets from 2 normal subjects and from 4 patients with a mitral valve pathological condition were included in the study. The three-dimensional data sets were acquired with the Philips Sonos 7500 echo-system and transferred to the BARCO (Barco N.V., Kortrijk, Belgium) I-space. Ten independent observers assessed the 6 three-dimensional data sets with and without mitral valve pathology. After 10 minutes' instruction in the I-Space, all of the observers could use the virtual pointer that is necessary to create cut planes in the hologram., Results: The 10 independent observers correctly assessed the normal and pathological mitral valve in the holograms (analysis time approximately 10 minutes)., Conclusion: this report shows that dynamic holographic imaging of three-dimensional echocardiographic data is feasible. However, the applicability and use-fullness of this technology in clinical practice is still limited.