Diploma and Master Theses (authored and supervised):

H. Schuster:
"Finding the Homeostatic Set Point of the Hypothalamus-Pituitary-Thyroid Axis with Different Modelling Approaches";
Supervisor: A. Körner; Institut für Analysis und Scientific Computing, 2021; final examination: 2021-03-23.

English abstract:
At the moment, the treatment of thyroid disorders is based on published literature, clinical practice guidelines and best local practice, which is based on clinical experience and accepted normal ranges of thyroid function tests. This strategy might work out in most situations, but can also lead to misdiagnosis and suboptimal treatment outcomes.The main focus of this thesis lies on the modelling of the Hypothalamus-Pituitary-Thyroid axis. The purpose of such a model is to gain insight into the mechanism of the hormonal feedback loop and to improve the diagnostic process as well as the treatment of thyroid dysfunctions. Therefore, two different approaches of modelling were used to simulate the relationship between the pituitary hormone TSH and the thyroid hormone FT4, one analytical and the other with parameter estimation in Simulink. Other involved hormones have been neglected due to various reasons. Apart from a comparison of the different modelling approaches, the main part of this thesis is the validation of the model with medical data, which was collected during a study at the Medical University of Vienna. In addition, other attempts at modelling the HPT-axis are discussed.The resulting exponentially decreasing curve, which depicts relationship between the pituitary hormone TSH and the thyroid hormone FT4, can be used to calculate the homeostatic set point of the Hypothalamus-Pituitary-Thyroid axis. The set point theory states that a unique set point connected to the euthyroid state exists for every human being. The calculated set point can be used to improve therapy of thyroid dysfunctions and consequently the state of many patients, who would otherwise suffer from discomforts even though their hormone levels are located in the normal range. Although, it was not possible to validate the set point theory with the available data, the influence of the modelling approach on the set point was examined. The resulting model should be used to improve the therapy of thyroid disorders and consequently the quality of life of the patient as long as the hypothalamus and pituitary are not influenced by disorders and drugs.

Transfer Function / Minimal Mathematical Model / Model Validation; Set-Point Theory; Hypothalamus-Pituitary-Thyroid Axis; Thyroid Disease

Created from the Publication Database of the Vienna University of Technology.