Medical image registration

Radiological images are increasingly being used in healthcare and medical r esearch. There is, consequently, widespread interest in accurately relating information in the different images for diagnosis, treatment and basic sci ence. This article reviews registration techniques used to solve this probl em, and describes the wide variety of applications to which these technique s are applied. Applications of image registration include combining images of the same subject from different modalities, aligning temporal sequences of images to compensate for motion of the subject between scans, image guid ance during interventions and aligning images from multiple subjects in coh ort studies. Current registration algorithms can, in many cases, automatica lly register images that are related by a rigid body transformation (i.e. w here tissue deformation can be ignored). There has also been substantial pr ogress in non-rigid registration algorithms that can compensate for tissue deformation, or align images from different subjects. Nevertheless many reg istration problems remain unsolved, and this is likely to continue to be an active field of research in the future.