Normal and Abnormal Embryonic Development in Virtual Reality
Normale en abnormale embryonale ontwikkeling in virtuele realiteit
Research of the past years indicates that the periconception period, the period including gametogenesis and embryogenesis, determines growth and development of the embryo and subsequent pregnancy outcome. Prenatal care starts to focus more on the first-trimester of pregnancy, where growth and development rates are the highest. The main aim of this thesis is to describe normal and abnormal development of embryonic and early fetal life using the innovative I-Space Virtual Reality (VR) system. Part I is an introduction to the research performed in this thesis. Chapter 1.1 compromises the general introduction of the research subject and provides the aims and the outline of this thesis. Chapter 1.2 describes the technical details and the applications of the I-Space VR system in the early pregnancy. In part II new applications of the I-Space VR system are described. In chapter 2.1 the design and validation of a desktop VR system is described. The desktop VR system is a new application that runs the same software, the V-Scope software, as the fully immersive I-Space. The development of a desktop system, due to its smaller size and its lower costs, is an important step towards the availability of VR in clinical practice. This study also demonstrates that length and volume measurements can be performed at least as reliable on the desktop system as in the I-Space. Future research can therefore as well be performed using the desktop VR system. In chapter 2.2 the I-Space VR technique is evaluated for the use of first-trimester diagnosis of structural congenital abnormalities. Detection rates of congenital abnormalities were compared between the I-Space and conventional two- and three-dimensional ultrasound. Five blinded observers scored abnormalities in 40 cases, once using the I-Space and once by means of conventional ultrasound. Furthermore, evaluation time was recorded and a questionnaire was filled out by the observers. The overall detection rates for both the I-Space and conventional ultrasound were comparable. However, abnormalities of skeleton and limbs were more often detected using the I-Space, whereas the detection rate for holoprosencephaly was higher using conventional ultrasound. The evaluation time was about two minutes longer for the I-Space. The reviewers reported a more clear presentation of the ultrasound images when VR is used as compared to conventional ultrasound. The results of this study show an additional value of VR in specific cases. Part III describes the use of embryonic volume measurements in the quantification of growth restriction in embryo’s and fetuses with structural congenital abnormalities (chapter 3.1), and in pregnancies that will subsequently end in a miscarriage (chapter 3.2). Embryonic volume (EV) measurements proved to be more informative than standard crown-rump length (CRL) measurements in the analysis of growth restriction in pregnancies diagnosed with first-trimester structural congenital abnormalities (chapter 3.1). EV measurements can therefore be used to diagnose abnormal first-trimester growth earlier and more accurately. In chapter 3.2 we analyzed the use of EV measurements in pregnancies that will subsequently end in a miscarriage. In these cases EV does not improve the assessment of growth restriction when compared to CRL measurements. A different growth pattern therefore seems to exist between miscarriage cases and pregnancies that are diagnosed with (chromosomal)congenital abnormalities. In part IV both non-standard in vivo biometric measurements and volume measurements in first-trimester aneuploid pregnancies are described. Chapter 4.1 provides unique normative data, related to gestational age and crown-rump length, on first-trimester hand growth. Different parameters of hand growth are measured; wrist width, hand width, and hand length. The depth perception of the I-Space enabled us to measure these structures. The newly developed growth charts were used to analyze hand growth in aneuploid pregnancies. It was shown that hand growth is significantly different in trisomy 21 (Down syndrome) and trisomy 18 (Edwards syndrome) already in the first trimester of pregnancy. In chapter 4.2 it was demonstrated that also in case of aneuploid pregnancies EV measurements is a better indicator of growth restriction when compared to conventional CRL measurements. Only in cases with trisomy 18 a smaller than expected CRL was seen, whereas EV was significantly smaller in trisomy 21, trisomy 18, and trisomy 13. In part V the use of VR in the diagnosis of first-trimester structural congenital abnormalities is evaluated. Chapter 5.1 describes the applicability of VR in the diagnosis of conjoined twins. In this review all imaging techniques used in the diagnosis of conjoined twins are evaluated. The review is illustrated by three cases of conjoined twins that were diagnosed using two- and three-dimensional ultrasound and that were additionally evaluated using VR. As VR provided extra diagnostic clues to all three cases, VR can contribute to earlier and more appropriate diagnosis of these rare cases. In chapter 5.2 VR facilitated the earliest diagnosis of thrombocytopenia-absent radius (TAR) syndrome reported in the literature. We believe that the application of VR can be useful in evaluating complex anatomical relationships requiring depth perception. In chapter 5.3 it was demonstrated that different types of cranial neural tube defects can be distinguished in vivo using three-dimensional ultrasound. The third dimension aided in relating our cases to previously published ex vivo documentation on cranial neural tube defects. Different types of cranial neural tube defects differ in their prognosis. Discerning the different types is of particular importance in understanding etiology and developing prevention strategies. In part VI, the general discussion, the results of all studies presented in this thesis are discussed and put in a broader perspective. The I-Space VR technique provides true depth perception and allows for intuitive visualization of the early pregnancy in detail. Structures that cannot be analyzed or measured in two-dimensions were studied in this thesis using VR. In conclusion we can say that first-trimester growth is associated with pregnancy outcome. The new applications of this VR technique and the new biometric and volume measurements enable earlier and more accurate diagnosis of abnormal embryonic growth and development. Since developmental problems early in pregnancy have major implications for pregnancy outcome, the embryonic period should be monitored very precisely. Diagnosis of congenital malformations or the detections of markers that indicate abnormal embryonic development may lead to a better understanding of embryonic health and adjustments in obstetrical management.
|Keywords||obstetrics, embryonic development, virtual reality, first-trimester, ultrasound|
|Promotor||E.A.P. Steegers (Eric) , P.J. van der Spek (Peter)|
|Publisher||Erasmus University Rotterdam|
|Sponsor||The printing of this thesis has been financially supported by the Department of Obstetrics and Gynaecology and the Department of Bioinformatics, Erasmus MC Rotterdam, MPluz, BMA Mosos, Chipsoft, ABN Amro.|
Baken, L. (2014, December 9). Normal and Abnormal Embryonic Development in Virtual Reality. Erasmus University Rotterdam. Retrieved from http://hdl.handle.net/1765/77227