Table 2.

Comparison of elastic registration accuracy for MACMI and pairwise MI alignment of n=20 pairs of synthetic PD MRI with coregistered T1-w and T2-w MRI brain images. The measures illustrated below correspond to (i) error of recovered deformation field (in mm) in terms of F_MAD and F_RMS and (ii) distance (D_L2) between the undeformed and recovered PD MRI. MACMI results are significantly more accurate compared to either PW approach (p-values for both tests shown). The best values are indicated in bold.

	FMAD	FRMS	DL2
${\mathbf{T}}_{\text{PW}1}^{\text{co}}$ (T1-PD)	0.9117	2.1407	1.83×10+03
${\mathbf{T}}_{\text{PW}2}^{\text{co}}$ (T2-PD)	0.9506	2.0248	2.35×10+03
${\mathbf{T}}_{\text{MACMI}}^{\text{co}}$ [ε (T1T2)-PD]	0.8348	1.9307	1.71×10+03
p (${\mathbf{T}}_{\text{PW}1}^{\text{co}}$ vs ${\mathbf{T}}_{\text{MACMI}}^{\text{co}}$)	0.0817	0.0578	0.0174
p (${\mathbf{T}}_{\text{PW}2}^{\text{co}}$ vs ${\mathbf{T}}_{\text{MACMI}}^{\text{co}}$)	0.0013	0.2020	1.8×10−10