title: Validation of nonrigid image registration using finite-element methods: application to breast MR images.
abstract: This paper presents a novel method for validation of nonrigid medical image registration. This method is based on the simulation of physically plausible, biomechanical tissue deformations using finite-element methods. Applying a range of displacements to finite-element models of different patient anatomies generates model solutions which simulate gold standard deformations. From these solutions, deformed images are generated with a range of deformations typical of those likely to occur in vivo. The registration accuracy with respect to the finite-element simulations is quantified by co-registering the deformed images with the original images and comparing the recovered voxel displacements with the biomechanically simulated ones. The functionality of the validation method is demonstrated for a previously described nonrigid image registration technique based on free-form deformations using B-splines and normalized mutual information as a voxel similarity measure, with an application to contrast-enhanced magnetic resonance mammography image pairs. The exemplar nonrigid registration technique is shown to be of subvoxel accuracy on average for this particular application. The validation method presented here is an important step toward more generic simulations of biomechanically plausible tissue deformations and quantification of tissue motion recovery using nonrigid image registration. It will provide a basis for improving and comparing different nonrigid registration techniques for a diversity of medical applications, such as intrasubject tissue deformation or motion correction in the brain, liver or heart.
authors.affiliation: Computational Imaging Sciences Group, Division of Imaging Sciences, Guy's, King's and St. Thomas' School of Medicine, King's College London, London SE1 9RT, UK. julia.schnabel@kcl.ac.uk
authors.forename: Julia A
authors.initials: JA
authors.lastname: Schnabel
authors.forename: Christine
authors.initials: C
authors.lastname: Tanner
authors.forename: Andy D
authors.initials: AD
authors.lastname: Castellano-Smith
authors.forename: Andreas
authors.initials: A
authors.lastname: Degenhard
authors.forename: Martin O
authors.initials: MO
authors.lastname: Leach
authors.forename: D Rodney
authors.initials: DR
authors.lastname: Hose
authors.forename: Derek L G
authors.initials: DL
authors.lastname: Hill
authors.forename: David J
authors.initials: DJ
authors.lastname: Hawkes
mesh_terms: D016477:Artifacts; D001940:Breast / Q000033:anatomy & histology; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology; D017352:Echo-Planar Imaging / Q000379:methods* / Q000592:standards; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D009038:Motion; D011786:Quality Control; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique