title: Spatio-temporal nonrigid registration for ultrasound cardiac motion estimation.
abstract: We propose a new spatio-temporal elastic registration algorithm for motion reconstruction from a series of images. The specific application is to estimate displacement fields from two-dimensional ultrasound sequences of the heart. The basic idea is to find a spatio-temporal deformation field that effectively compensates for the motion by minimizing a difference with respect to a reference frame. The key feature of our method is the use of a semi-local spatio-temporal parametric model for the deformation using splines, and the reformulation of the registration task as a global optimization problem. The scale of the spline model controls the smoothness of the displacement field. Our algorithm uses a multiresolution optimization strategy to obtain a higher speed and robustness. We evaluated the accuracy of our algorithm using a synthetic sequence generated with an ultrasound simulation package, together with a realistic cardiac motion model. We compared our new global multiframe approach with a previous method based on pairwise registration of consecutive frames to demonstrate the benefits of introducing temporal consistency. Finally, we applied the algorithm to the regional analysis of the left ventricle. Displacement and strain parameters were evaluated showing significant differences between the normal and pathological segments, thereby illustrating the clinical applicability of our method.
authors.affiliation: ETSI Telecomunicación, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, E-28040 Madrid, Spain. mledesma@die.upm.es
authors.forename: María J
authors.initials: MJ
authors.lastname: Ledesma-Carbayo
authors.forename: Jan
authors.initials: J
authors.lastname: Kybic
authors.forename: Manuel
authors.initials: M
authors.lastname: Desco
authors.forename: Andrés
authors.initials: A
authors.lastname: Santos
authors.forename: Michael
authors.initials: M
authors.lastname: Sühling
authors.forename: Patrick
authors.initials: P
authors.lastname: Hunziker
authors.forename: Michael
authors.initials: M
authors.lastname: Unser
mesh_terms: D001185:Artificial Intelligence; D004452:Echocardiography / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D009068:Movement; D009200:Myocardial Contraction; D010363:Pattern Recognition, Automated / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*