The adaptive bases algorithm for intensity-based nonrigid image registration

• Published in: IEEE transactions on medical imaging Vol. 22; no. 11; pp. 1470 - 1479
• Main Authors: Rohde, G.K., Aldroubi, A., Dawant, B.M.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.11.2003; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adaptation; Algorithms; Biological and medical sciences; Biomedical imaging; Brain - anatomy & histology; Computational complexity; Convergence; Deformable models; Feedback; Humans; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; Image registration; Image segmentation; Imaging, Three-Dimensional; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Mathematical analysis; Mathematical models; Medical; Medical sciences; Motion; Mutual information; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Registers; Reproducibility of Results; Segmentation; Sensitivity and Specificity; Spline; Studies; Subtraction Technique; Technology. Biomaterials. Equipments. Material. Instrumentation; Transformations; Biomedical engineering
• ISSN: 0278-0062; 1558-254X
• DOI: 10.1109/TMI.2003.819299

Nonrigid registration of medical images is important for a number of applications such as the creation of population averages, atlas-based segmentation, or geometric correction of functional magnetic resonance imaging (IMRI) images to name a few. In recent years, a number of methods have been proposed to solve this problem, one class of which involves maximizing a mutual information (Ml)-based objective function over a regular grid of splines. This approach has produced good results but its computational complexity is proportional to the compliance of the transformation required to register the smallest structures in the image. Here, we propose a method that permits the spatial adaptation of the transformation's compliance. This spatial adaptation allows us to reduce the number of degrees of freedom in the overall transformation, thus speeding up the process and improving its convergence properties. To develop this method, we introduce several novelties: 1) we rely on radially symmetric basis functions rather than B-splines traditionally used to model the deformation field; 2) we propose a metric to identify regions that are poorly registered and over which the transformation needs to be improved; 3) we partition the global registration problem into several smaller ones; and 4) we introduce a new constraint scheme that allows us to produce transformations that are topologically correct. We compare the approach we propose to more traditional ones and show that our new algorithm compares favorably to those in current use.