학술논문

Improving the diagnosis and measurement of tropical lymphoedema in Ethiopia
Document Type
Electronic Thesis or Dissertation
Source
Subject
Language
English
Abstract
Background: In the last decade, though significant progress had been made on tropical lymphoedema (mainly podoconiosis research), little has been achieved on the diagnosis and volume measurement aspect, so podoconiosis remains a diagnosis of clinical exclusion. Therefore, the objectives of this PhD thesis were to improve the diagnosis and measurement of podoconiosis in clinical and research settings. The project validated a novel portable three-dimensional infrared imaging device for lymphoedema volume measurement, and a Digital Light Processing technology based on near infrared spectroscopy Analyser (DLP-based NIR spectrometry) and ZI MFIA digital impedence analyser devices for diagnostic purposes. Methods: To validate the novel portable three-dimensional infrared imaging device, 106 participants were recruited into the study. All the study participants were assessed first using the novel portable three-dimensional infrared imaging system and then by the gold standard water displacement method by two independent raters, with each rater performing duplicate measurements in quick succession. To test the diagnostic capacity of the DLP based NIR Spectrometry, we recruited patients with lymphoedema due to podoconiosis, lymphoedema due to lymphatic filariasis, lymphoedema due to other causes (other than podoconiosis and lymphatic filariasis) and healthy controls. The ZI MFIA digital impedence analyser study aimed to test whether it can acquire readings from the lower limbs of patients with podoconiosis and those who do not have podoconiosis. Furthermore, the project conducted a community based cross sectional study to estimate the burden of lymphatic filariasis on chronic lymphoedema patients. Results: The findings of the novel portable three-dimensional infrared imaging device indicated a strong positive correlation (r=0.96; p < 0.001) and good agreement between the methods. For inter-rater reliability, the ICC was 0.817 (95% CI: 0.738, 0.874) for the water displacement method and 0.9 (95% CI: 0.894, 0.951) for the novel portable threedimensional infrared imaging device. Intra-rater reliability gave an ICC of 0.969 (95% CI: 0.954, 0.979) for the water displacement method and 0.702 (95% CI: 0.585 to 0.791) for the novel portable three-dimensional infrared imaging device. The results of the DLP based NIR spectrometry showed the best sensitivity was 0.96, specificity was 0.93 and the area under the curve (AUC) was 0.945. The burden study showed an overall lymphatic filariasis prevalence of 13.3%. Sex and age were independent predictors. The results of the ZI MFIA digital impedence analyser showed that it could collect scans and the scans could be reconstructed in the form of graphs. Conclusion: The novel portable three-dimensional imaging device can substitute the water displacement technique. The DLP-based NIR spectrometry and the ZI MFIA digital impedance analyser appear to be promising for the diagnosis of tropical lymphoedema, however there are remaining further works.

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