Table 1. Performance comparison of the proposed UDAN with six mainstream deformable image registration methods.

Method	TRE (mm) ↓	SSIM (%) ↑	DICE (%) ↑	TIME (s) ↓	|Jϕ|≤ 0(%) ↓
Affine	4.27	68.17	64.38	–	–
ANTs	2.32	74.43	79.27	1123	0.16
ELASTIX	2.45	73.56	75.24	265	0.09
B-spline	3.27	69.49	70.49	943	0.06
VTN	2.12	85.48	88.61	16	0.12
VoxelMorph	2.17	85.34	87.94	14	0.34
CycleMorph	2.14	85.73	87.81	23	0.16
UDAN	2.07	86.34	89.74	18	0.28

The best results are shown bold font. The line of affine is the result of rigid registration before the application of deformable registration. UDAN, unsupervised dual attention network; TRE, target registration error; SSIM, structural similarity; DICE, dice similarity coefficient; |J_ϕ|≤ 0(%), areas with negative Jacobian determinant are considered folding, the folded area as a percentage of the total area.