Rousian, M.

Embryonic Development in Virtual Reality (Doctoral Thesis)

2011-11-24T00:00:00Z

The overall aim of this thesis is to establish an accurate and reliable description of new in vivo biometric and volumetric measurements in the first trimester of pregnancy using 3D ultrasound datasets, analyzed using an innovative VR system. These new measurements, which make optimal use of all three dimensions, will form a basis for follow-up studies describing the abnormal development of embryonic and early fetal life.

Virtual reality for embryonic measurements requiring depth perception (Article)

2011-02-01T00:00:00Z

Two real-time three-dimensional images of first-trimester pregnancies visualized using virtual reality (VR) are presented. Inherently three-dimensional structures, like the umbilical cord and limbs, can be efficiently and accurately measured using VR.

First trimester umbilical cord and vitelline duct measurements using virtual reality (Article)

2011-01-01T00:00:00Z

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 14 weeks 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.

An innovative virtual reality technique for automated human embryonic volume measurements (Article)

2010-09-01T00:00:00Z

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 mm3 and YSV ranged from 33 to 424 mm3. 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.

First trimester umbilical cord and vitelline duct measurements using virtual reality (Article)

2010-01-01T00:00:00Z

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 14 weeks 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.

Early pregnancy volume measurements: Validation of ultrasound techniques and new perspectives (Article)

2009-01-01T00:00:00Z

Objective: To investigate accuracy and reliability of four different ultrasound-related volume-measuring methods. Design: Observational study. Setting: Both in vitro and in vivo. Population or Sample: Ten phantoms for in vitro measurements and 28 pregnancies with gestational ages ranging from 6 to 11 weeks for in vivo measurements were included. Methods: Three-dimensional (3D) ultrasound images of phantoms (with known variable contents) and yolk sacs were used to calculate volumes using four different methods: Virtual Organ Computed-Aided AnaLysis (VOCAL), inversion mode, Sono Automatic Volume Calculation (SonoAVC) and V-Scope. V-Scope is a newly developed 3D volume visualisation application using a Barco I-Space virtual reality system. Intra- and interobserver agreement was established by calculating intraclass correlation coefficients (ICC). Main outcome measure: Evaluation of accuracy and reliability by comparing the different techniques with true volumes (in vitro) and with each other (in vitro and in vivo). Results: In the in vitro study, volume measurements by VOCAL, inversion mode and V-Scope proved to be accurate. SonoAVC measurements resulted in a substantial systematic underestimation. Correlation coefficients of measured versus true volumes were excellent in all four techniques. For all techniques, an intra- and interobserver agreement of at least 0.91 was found. Yolk sac measurements by the different techniques proved to be highly correlated (ICCs > 0.91). Conclusions: We demonstrated that VOCAL, inversion mode and V-Scope can all be used to measure volumes of hypoechoic structures. The newly introduced V-Scope application proved to be accurate and reliable.

Reliability of three-dimensional sonographic measurements in early pregnancy using virtual reality (Article)

2008-12-01T00:00:00Z

Objective: To establish the reliability of three-dimensional (3D) ultrasound measurements in early pregnancy using a virtual reality system (the Barco I-Space). Methods: The study included 28 pregnancies with gestational ages ranging from 6 to 14 (median, 10) weeks. 3D volumes were acquired and offline measurements were made, where possible, of the yolk sac diameter, crown-rump length, biparietal diameter, head circumference and abdominal circumference, using specialized 3D imaging software (4DView). The datasets were then transferred to the Barco I-Space, a virtual reality system that allows the observer to perceive depth and interact with volume-rendered (ultrasound) data. The 3D rendered volumes were measured using a virtual pointer, controlled by a wireless joystick. For intraobserver variability, 3D and virtual reality volumes were measured twice by one operator. For interobserver variability, another operator performed the same measurements once. All measurements were repeated three times and their mean values were used for comparisons. Results: All intraclass correlation coefficients (ICCs) comparing 4DView measurements with I-Space measurements were >0.97. Intra- and interobserver ICCs for the 4DView measurements were >0.96 and for the I-Space ones were >0.98, representing good agreement. Conclusions: The application of virtual reality is a novel method of visualizing 3D ultrasound data and perception of the depth in the I-Space offers possibilities for measuring non-planar structures. We have demonstrated that early pregnancy measurements in the I-Space are reliable. New areas of embryonic and fetal biometry can now be explored using this technique, which we tentatively name 'virtual embryoscopy'. Copyright