ABSTRACT
Nonrigid Registration...............................................................296 13.4 Conclusions ..............................................................................................296 Acknowledgments ..............................................................................................298 References ............................................................................................. 298
The previous chapters in this book have focused on rigid transformations for image-to-image and image-to-physical space registration. In many applications a rigid transformation is sufficient to describe the spatial relationship between two images. For example, brain images of the same subject can be related by a rigid transformation since the motion of the brain is largely
constrained by the skull. However, there are many other applications where nonrigid transformations are required to describe the spatial relationship between images adequately. For example, in intrasubject registration nonrigid transformations are required to accommodate any tissue deformation due to interventions or changes over time. Similarly, in intersubject registration, nonrigid transformations are often required to accommodate the substantial anatomical variability across individuals.
