Klinische Untersuchung der plazentaren Hämodynamik eines Normalkollektivs mittels des Echtzeit-Demonstrators im Angio-Modus (Powerdoppler) zur Vorhersage einer Risikoschwangerschaft bis zur 22. Schwangerschaftswoche

The assessment of a pregnancy depends on many different factors. Not only does the pregnant woman’s anamnesis play a decisive role but also diseases, former pregnancies and medical findings during the current pregnancy. In case of an uncomplicated pregnancy, three ultrasound examinations are prescribed in the guidelines for confinement. Usually, the placenta is examined in the second pregnancy trimester. However, because possible damage to the placenta cannot be remedied at that time, we think examination of the placenta at that time is far too late. Furthermore, with the established methods of ultrasound examination, it is impossible to examine the placenta’s slow blood flow. These concerns motivated us to examine the proportion of the blood flow in the placenta with the help of ultrasound in the so-called angio-modus, or Power-Doppler. With this method it is possible to examine blood flows in basins with the qualities which aforesaid. Within this survey 109 pregnant women between the 17th and 22nd week of pregnancy were examined. On the basis of due date and the baby’s birth weight, the women were divided into a risk-group of 5 patients and a risk-free group of 104 patients. The pregnant women were examined in the dorsal position. The placenta was demonstrated with the help of sonography and the measurement performed in the angio-modus. We videotaped the sequences of ultrasound. We analyzed the results with the help of a computer program called Power-Doppler-Analyse, which was designed in conjunction with this survey. Within this program, different parameters can be configured. The parameters can be differentiated in terms of mathematical background, color system, ”Farbgewichtung” and the acquisition time. For this survey we defined 21 different parameters. Each patient’s ultrasound sequence was analysed with the help of these 21 parameters. On the basis of these parameters statements can be made about the proportion of the blood flow (homogeneous blood flow/ inhomogeneous blood flow, local flow differences, quantity of perfusion) in the placenta. It is important to find out which proportion of blood flow is particularly favourable and which is unfavourable for the fetus’ growth. Furthermore, it was important to consider the question of which parameter adjustment best illustrates these proportions of blood flow. Our ideas were mostly based on the Papenfuss‘ and Schmid-Schönbein’s model. In this modell blood flow is regard as percolation of a “porous medium” which based on the Carman Kozeny equation. We assume that homogeneous proportions of blood flow within the placenta are the best for the fetus’ growth, whereas strong local blood flow differences, so-called “hot-spots” are not good for the fetus. This theory could neither be verified nor negated on the basis of these results. The different parameters that, for example, give evidence on the homogeneity of the blood flow but have different mathematical backgrounds, sometimes deliver differing results about which flow conditions in the placenta best serve the development of the age-appropriate fetuses. It was not the task of this thesis to deliver definite values but much more to make a selection of parameters that are to be analyzed in follow-up studies. The results of the parameters 9, 16 and 19 that make a statement about the existence of blood-flow in the placenta, may lead to the conclusion that extended blood-flow does have a positive impact on the fetus’ development. These should be analyzed in a second step rather than depending on the maternal respiration. These tendencies manifesting our theory can also be see at the parameters 7, 8 and 17. It also seems that parameters of the YUV-System (see parameter 15 and 18) and the parameters concerning progressive color grading (see parameter 1 and 21) do allow differentiation between normal populations and populations at risk (OK) taking insights gained within this thesis into account. Further study should assess which level of inhomogeneity and perfusion does support or damage the intrauterine development.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2009

Author dc:creator

• Weiler, Christine

Contributors dc:contributor

• Jörn, Hendrik Horst

• info:eu-repo/classification/ddc/610
• Plazenta
• Durchblutung
• Risikoschwangerschaft
• Frühdiagnostik
• Ultraschall
• Perkolation
• Medizin
• Powerdoppler
• Angiomodus
• bloodflow

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-113773%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A51484