TY  - JOUR
AU  - Aganj, Iman
AU  - Iglesias, Juan Eugenio
AU  - Reuter, Martin
AU  - Sabuncu, Mert Rory
AU  - Fischl, Bruce
TI  - Mid-space-independent deformable image registration.
JO  - NeuroImage
VL  - 152
SN  - 1053-8119
CY  - Orlando, Fla.
PB  - Academic Press
M1  - DZNE-2020-05620
SP  - 158-170
PY  - 2017
AB  - Aligning images in a mid-space is a common approach to ensuring that deformable image registration is symmetric - that it does not depend on the arbitrary ordering of the input images. The results are, however, generally dependent on the mathematical definition of the mid-space. In particular, the set of possible solutions is typically restricted by the constraints that are enforced on the transformations to prevent the mid-space from drifting too far from the native image spaces. The use of an implicit atlas has been proposed as an approach to mid-space image registration. In this work, we show that when the atlas is aligned to each image in the native image space, the data term of implicit-atlas-based deformable registration is inherently independent of the mid-space. In addition, we show that the regularization term can be reformulated independently of the mid-space as well. We derive a new symmetric cost function that only depends on the transformation morphing the images to each other, rather than to the atlas. This eliminates the need for anti-drift constraints, thereby expanding the space of allowable deformations. We provide an implementation scheme for the proposed framework, and validate it through diffeomorphic registration experiments on brain magnetic resonance images.
KW  - Algorithms
KW  - Atlases as Topic
KW  - Brain: anatomy & histology
KW  - Brain Mapping: methods
KW  - Female
KW  - Humans
KW  - Imaging, Three-Dimensional
KW  - Magnetic Resonance Imaging
KW  - Male
KW  - Middle Aged
KW  - Signal Processing, Computer-Assisted
LB  - PUB:(DE-HGF)16
C6  - pmid:28242316
C2  - pmc:PMC5432428
DO  - DOI:10.1016/j.neuroimage.2017.02.055
UR  - https://pub.dzne.de/record/139298
ER  -