Determination of pharmacokinetic tumor parameters using dynamic magnetic resonance imaging

Changes in the properties of tissue microvasculature are prerequisite to tumor growth. Identifying and assessing these changes by determining pharmacokinetic parameters might be beneficial for the diagnosis and therapy of tumors. This dissertation investigates the determination of pharmacokinetic parameters using dynamic contrast-enhanced magnetic resonance imaging in conjunction with pharmacokinetic modeling. Accurate determination of pharmacokinetic parameters requires the deconvolution of the arterial input function (AIF) and the contrast-agent uptake in the tumor. Various deconvolution techniques are evaluated and compared to the method of template fitting. Employing template fitting, the impulse response function of the capillary wall is described by a template. The parameters of the template -- the pharmacokinetic parameters - are determined by means of least-squares-minimization. To simultaneously monitor the AIF and the contrast agent uptake in a lesion, a newly developed dual- stack technique is introduced. By using a calibration technique the signals from the dynamic scan are converted to contrast agent concentrations, and these concentration-time-courses are used for the deconvolution.Computer simulations and patient studies show that template fitting is a robust and reliable technique to determine pharmacokinetic parameters of tumor microvasculature. (author)