title: Dense motion field estimation from myocardial boundary displacements.
abstract: Minimally invasive cardiovascular interventions guided by multiple imaging modalities are rapidly gaining clinical acceptance for the treatment of several cardiovascular diseases. These images are typically fused with richly detailed pre-operative scans through registration techniques, enhancing the intra-operative clinical data and easing the image-guided procedures. Nonetheless, rigid models have been used to align the different modalities, not taking into account the anatomical variations of the cardiac muscle throughout the cardiac cycle. In the current study, we present a novel strategy to compensate the beat-to-beat physiological adaptation of the myocardium. Hereto, we intend to prove that a complete myocardial motion field can be quickly recovered from the displacement field at the myocardial boundaries, therefore being an efficient strategy to locally deform the cardiac muscle. We address this hypothesis by comparing three different strategies to recover a dense myocardial motion field from a sparse one, namely, a diffusion-based approach, thin-plate splines, and multiquadric radial basis functions. Two experimental setups were used to validate the proposed strategy. First, an in silico validation was carried out on synthetic motion fields obtained from two realistic simulated ultrasound sequences. Then, 45 mid-ventricular 2D sequences of cine magnetic resonance imaging were processed to further evaluate the different approaches. The results showed that accurate boundary tracking combined with dense myocardial recovery via interpolation/diffusion is a potentially viable solution to speed up dense myocardial motion field estimation and, consequently, to deform/compensate the myocardial wall throughout the cardiac cycle. Copyright © 2015 John Wiley & Sons, Ltd.
authors.affiliation: ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.|Lab on Cardiovascular Imaging & Dynamics, Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium.|INEGI, Faculdade de Engenharia, Universidade do Porto, Porto, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Morais
authors.affiliation: ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.|Lab on Cardiovascular Imaging & Dynamics, Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium.|Algoritmi Center, School of Engineering, University of Minho, Guimarães, Portugal.
authors.forename: Sandro
authors.initials: S
authors.lastname: Queirós
authors.affiliation: ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: Adriano
authors.initials: A
authors.lastname: Ferreira
authors.affiliation: ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.|Algoritmi Center, School of Engineering, University of Minho, Guimarães, Portugal.|DIGARC - Polytechnic Institute of C'avado and Ave, Barcelos, Portugal.
authors.forename: Nuno F
authors.initials: NF
authors.lastname: Rodrigues
authors.affiliation: ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Baptista
authors.affiliation: Lab on Cardiovascular Imaging & Dynamics, Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: D'hooge
authors.affiliation: ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.|DIGARC - Polytechnic Institute of C'avado and Ave, Barcelos, Portugal.
authors.forename: João L
authors.initials: JL
authors.lastname: Vilaça
authors.affiliation: ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.|DIGARC - Polytechnic Institute of C'avado and Ave, Barcelos, Portugal.
authors.forename: Daniel
authors.initials: D
authors.lastname: Barbosa
mesh_terms: D000465:Algorithms; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D009200:Myocardial Contraction; D009206:Myocardium
keywords: dense myocardial motion field from contours' displacement; diffusion; image fusion; radial basis functions