Figure 2.

Least squares fit of hyperbola (Equation 5) to group-averaged AIF. The fit is shown in linear scale (left) as well as in double logarithmic scale (right). The specified uncertainty of the time exponent b is the standard deviation of this parameter when fitting the model separately to each of the 15 contributing AIFs which indicates the observed inter-individual variability. The data range indicated in red is used for the fit. The blue line extrapolates the fitted hyperbola to early times. Despite the obvious deviation of the hyperbola from the data in this time range, contribution to total AUC is small, and the residual difference negligible if AUC up to times t>20 min is considered.