Improved correlation to quantitative DCE-MRI pharmacokinetic parameters using a modified initial area under the uptake curve (mIAUC) approach.
OBJECTIVE
To propose a modified initial area under the uptake curve (mIAUC) dynamic contrast-enhanced (DCE)-MRI approach to achieve better distinction of underlying physiology.


METHODS
The mIAUC is formulated on common characteristics of tissue contrast uptake curves observed over a wide range of physiological conditions. The new metrics, IAUC(Ktrans) and IAUC(ve), are related to the transfer constant (K(trans)) and interstitial volume (v(e)), respectively. Tissue uptake curves were simulated over a range of physiological values and analyzed using the proposed mIAUC, conventional IAUC, and Tofts' pharmacokinetic model.


RESULTS
IAUC(Ktrans) and IAUC(ve) are highly correlated to the true K(trans) and v(e) (rho = 0.97 and 0.95, respectively), approaching the performance of Tofts' model based on a 1.5-s sampled arterial input function (AIF) (rho = 0.98 and 0.98) under noise conditions typical in DCE-MRI experiments. Lower correlations were obtained with conventional IAUC(60) and IAUC(120) (rho = 0.82 and 0.61) and Tofts' parameters fitted using a biexponential AIF (rho = 0.81 and 0.90).


CONCLUSIONS
The proposed mIAUC approach retains advantages associated with nonmodel based methods (robust to noise and model fit failure, obviates need for an AIF) while providing better distinction of underlying physiological parameters. It can be a valuable alternative to pharmacokinetic modelling in the analysis of DCE-MRI data.
The Research Institute & Diagnostic Imaging, The Hospital for Sick Children and Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada. hai-ling.cheng@sickkids.ca
Hai-Ling Margaret
HL
Cheng
D019540:Area Under Curve; D003287:Contrast Media / Q000493:pharmacokinetics*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015233:Models, Statistical; D015203:Reproducibility of Results
D003287:Contrast Media