title: Cardiac motion estimation by joint alignment of tagged MRI sequences.
abstract: Image registration has been proposed as an automatic method for recovering cardiac displacement fields from tagged Magnetic Resonance Imaging (tMRI) sequences. Initially performed as a set of pairwise registrations, these techniques have evolved to the use of 3D+t deformation models, requiring metrics of joint image alignment (JA). However, only linear combinations of cost functions defined with respect to the first frame have been used. In this paper, we have applied k-Nearest Neighbors Graphs (kNNG) estimators of the α-entropy (H(α)) to measure the joint similarity between frames, and to combine the information provided by different cardiac views in an unified metric. Experiments performed on six subjects showed a significantly higher accuracy (p<0.05) with respect to a standard pairwise alignment (PA) approach in terms of mean positional error and variance with respect to manually placed landmarks. The developed method was used to study strains in patients with myocardial infarction, showing a consistency between strain, infarction location, and coronary occlusion. This paper also presents an interesting clinical application of graph-based metric estimators, showing their value for solving practical problems found in medical imaging.
authors: Center for Computational Imaging & Simulation Technologies in Biomedicine (CISTIB), Information and Communication Technologies Department, Universitat Pompeu Fabra, Barcelona, Spain.
authors: E
authors: E
authors: Oubel
authors: M
authors: M
authors: De Craene
authors: A O
authors: AO
authors: Hero
authors: A
authors: A
authors: Pourmorteza
authors: M
authors: M
authors: Huguet
authors: G
authors: G
authors: Avegliano
authors: B H
authors: BH
authors: Bijnens
authors: A F
authors: AF
authors: Frangi
mesh_terms: D016477:Artifacts; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity