System identification theory in pharmacokinetic modeling of dynamic contrast-enhanced MRI: influence of contrast injection.
Optimization of experimental settings of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), like the contrast administration protocol, is of great importance for reliable quantification of the microcirculatory properties, such as the volume transfer-constant K(trans). Using system identification theory and computer simulations, the confounding effects of volume, rate and multiplicity of a contrast injection on the reliability of K(trans) estimation was assessed. A new tracer-distribution model (TDM), based on in vivo data from rectal cancer patients, served to describe the relationship between the contrast agent injection and the blood time-course. A pharmacokinetic model (PKM) was used to describe the relation between the blood and tumor tissue time-courses. By means of TDM and PKM in series, the tissue-transfer function of the PKM was analyzed. As both the TDM and PKM represented low-frequency-pass filters, the energy-density at low frequencies of the blood and tissue time-courses was larger than at high frequencies. The simulations, based on measurements in humans, predict that the K(trans) is most reliable with a high injection volume administered in a single injection, where high rates only modestly improve K(trans).
Aerts
H J W L
HJ
Control Systems Group, Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands.
van Riel
N A W
NA
Backes
W H
WH
D003198:Computer Simulation; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005263:Femoral Artery; D019786:Gadolinium DTPA / Q000008:administration & dosage / Q000493:pharmacokinetics*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007269:Injections, Intra-Arterial; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009010:Monte Carlo Method; D009369:Neoplasms / Q000175:diagnosis*
D003287:Contrast Media; D019786:Gadolinium DTPA