Thesis (MTech (Radiography))--Peninsula Technikon, 2000. / Word processed copy. Summary in English. Includes bibliographical references (leaves 51-61). Also available online.

Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 1999. / Includes bibliographical references.

Thesis (MTech (Radiography))--Peninsula Technikon, Cape Town, 2000 / Ultrasound has, until recently, been regarded as a sophisticated diagnostic modality, reserved for tertiary health care. In reality, it is a cost-effective, reliable and safe modality that is highly suited to primary health care. Secondary level centres provide the only access to ultrasound for many of the obstetric primary health care patients, as primary health care has limited ultrasound resources. The increasing monthly statistics, at one secondary centre, bares witness to the need for ultrasound in primary health care. At the time of this study ultrasound scans were not routine for every obstetric patient. Experience indicates that only the patients who clinically suggest a possible risk are referred for ultrasound to confirm, or rule out problems. However, there are a number of complications, which have little or no early clinical indications. [Palmer, 1995:285] This means that many of the problems encountered are often in late gestation and they have a marked bearing on the obstetric management of the patient. This was a retrospective study, of approximately 1000 patients attending an ultrasound department at a secondary centre. Most of the obstetric patients that were sent for an ultrasound examination came from the primary health care centres in the region.

In this thesis the use of real-time ultrasound in the assessment and management of preterm labour has been studied, with particular reference to the observation of fetal breathing movements, gross fetal body movements and the state of the uterine cervix. In addition, a longitudinal analysis of the trends in preterm labour in the John Radcliffe Hospital in Oxford between 1973 and 1981 has been performed. Finally, an attempt has been made to clarify the relationship between prostaglandin E2 and fetal breathing movements. The analysis of the trends in preterm labour in Oxford has shown that the incidence of preterm delivery remains unaltered. Of these patients, however, those eligible for tocolytic therapy (unexplained spontaneous preterm labour) form a small proportion. The incidence of extreme prematurity in this group is very low and the neonatal outcome is good. The presence or absence of Fetal Breathing Movements (FBM) by defined criteria is shown to be a highly sensitive index of whether the preterm labour is going to progress to delivery or not in singleton pregnancies with intact membranes. Its significance is lost when the membranes are ruptured and in multiple pregnancies. In pregnancies complicated by antepartum haemorrhage the presence or absence of Fetal Breathing Movements does not predict further haemorrhage leading to delivery. Fetal Breathing Movement status on admission bears no relationship to neonatal outcome and gives no indication of the presence of intrauterine infection. Silent chorioamnionitis has been highlighted as an important cause of "unexplained" preterm labour. Gross Fetal Body Movements (FM) are shown to give no early indication of impending preterm delivery. Evidence is presented to suggest that significant diminution in Fetal Movements is related to poor neonatal outcome. Ultrasonic measurement of the uterine cervix has been found to be technically feasible but of no benefit in the diagnosis of ongoing preterm labour. The relationship between prostaglandin E2 (PGE2) and the cessation of fetal breathing movement has been approached by elucidating the maternal absorption of PGE2 from a vaginal pessary. This then enabled me to sample fetal blood at the time of maximal maternal concentrations (the time we expect the fetal concentration to be greatest). This was performed by fetoscopy and demonstrated that a significant rise in fetal bicycleprostaglandin-E-metabolite (bicyclo-PGEM) occurs following maternal vaginal administration of PGE2. Using this information FBM has been assessed two and a half hours following the vaginal administration of PGE2. Although inconclusive, no reduction in FBM was demonstrated. as the bicyclo-PGE metabolite is used to assess PGE levels, this evidence decreases the probability that PGE mediates the reduction in FBM with the onset of labour.

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Three-dimensional (3D) sonography is regarded as a further development of ultrasound imaging technology and its application has greatly increased in recent years. This thesis summarizes the original research findings of the application of 3D ultrasonography for biometry measurement, morphology screening, prenatal diagnosis of abnormalities, ultrasound training and the application of 3D volumetry in the early diagnosis of homozygous α-thalassemia and birth weight prediction in term pregnancy. In a study involving 50 singleton pregnancies at 17-34 weeks' gestation, fetal biometric measurements obtained by an inexperienced operator using both two-dimensional (2D) and 3D ultrasound were reproducible and showed good agreement with those obtained by an experienced operator (all intraclass correlation coefficients were ≥ 0.991). The use of 3D ultrasound by an inexperienced operator allowed faster measurement of fetal biometric parameters than the use of 2D ultrasound, and also seemed to facilitate the acquisition of higher-quality images for the measurement of abdominal circumference. In basic central nervous system and cardiac screening examination, for the inexperienced operator, 3D/four-dimensional(4D) volume acquisition yielded a quicker but less optimal anatomic examination of the fetal central nervous system and heart structures compared to 2D. The diagnostic accuracy of 3D ultrasonography in central nervous system abnormalities was also investigated. The results illustrated that 3D agreed with 2D ultrasonography in the prenatal diagnosis of intracranial malformations. Homozygous α0-thalassemia is very common in South-east Asia and its prenatal diagnosis is essential due to increased fetal and maternal mortality and morbidity. Placental volume/CRL quotient measured by 3D volumetry was significantly higher in pregnancies with α0-thalassemia major cases, and 1.49 may be regarded as a cut-off for early prediction of α0-thalassemia major. In a cross-sectional study of 290 Hong Kong Chinese women with a singleton pregnancy at 37-42 weeks of gestation, the birth weight prediction models based on 3D thigh volume and conventional 2D biometric measurements were developed. It was found that with 3D thigh model, the precision of birth weight prediction to within 5 and 10% of actual birth weight in a Chinese population at term gestation could be achieved. Previous studies have shown that there is a difference in the learning curve of fetal biometry measurement by 2D ultrasound among trainees. Whether there is any difference in the learning curve between 2D and 3D ultrasound is unknown. The study included three trainees and each of them performed 90 scans in biometry measurements. By using cumulative sum analysis graphs, it could be shown that there was no difference in the learning curve between 2D and 3D ultrasound. In conclusion, the above studies have demonstrated that the use of 3D ultrasound has diversified and provided much additional information in selected indications. / published_or_final_version / Obstetrics and Gynaecology / Doctoral / Doctor of Philosophy

Thesis (Ph.D.)--Duquesne University, 2005. / Title from document title page. Abstract included in electronic submission form. Includes bibliographical references (p. 226-240) and index.

Thesis (M.D.)--University of Hong Kong, 1995. / Includes bibliographical references (leaf 208-230).

Thesis (Ph. D.)--University of Chicago, Dept. of Anthropology, August 1999. / Includes bibliographical references. Also available on the Internet.