Example of fitting of arterial and portal-venous curves and tissue enhancement curves with various models.

<p>Graphs illustrate examples of (A and B) fitting of the arterial and portal input enhancement curves, (C and D) fitting of the five different models to a voxel enhancement curve which was sampled from the HCC, and (E and F) their corresponding impulse response curves (i.e., <i>Q</i>_T(<i>t</i>) = (<i>F</i>/<i>V</i>_T) ⋅ <i>R</i>_T(<i>t</i>)) where two different cases are shown in the left and right columns. WX = water-exchange-modified, TK = Tofts-Kety, ETK = extended Tofts-Kety. 2CX = two compartment exchange, AATH = adiabatic approximation to tissue homogeneity, and DP = distributed parameter.