FIG. 3.

Validation step 1 (inner-DWI registration). (a) As an intensity-based measure for image alignment, the normalized cross correlation $\mathrm{NCC}(D_0,D_{750}^T)$ between the reference D₀ and the transformation of the image with the highest b-value $D_{750}^T$ within a ROI was considered. (b) As a quality measure of the exponential signal decay, the exponential fit error EFE(DWI) over all landmarks, i.e., the mean deviation of the image intensities of all $D_b\left(\overrightarrow{x_l}\right)$ at $\overrightarrow{x_l}$ (indicated as filled dots) to the exponential fit function $E(\overrightarrow{x_l},b)$, was considered. Note that according to Sec. 1, the image D₀ is excluded from the fitting process.