title: Multi-oriented windowed harmonic phase reconstruction for robust cardiac strain imaging.
abstract: The purpose of this paper is to develop a method for direct estimation of the cardiac strain tensor by extending the harmonic phase reconstruction on tagged magnetic resonance images to obtain more precise and robust measurements. The extension relies on the reconstruction of the local phase of the image by means of the windowed Fourier transform and the acquisition of an overdetermined set of stripe orientations in order to avoid the phase interferences from structures outside the myocardium and the instabilities arising from the application of a gradient operator. Results have shown that increasing the number of acquired orientations provides a significant improvement in the reproducibility of the strain measurements and that the acquisition of an extended set of orientations also improves the reproducibility when compared with acquiring repeated samples from a smaller set of orientations. Additionally, biases in local phase estimation when using the original harmonic phase formulation are greatly diminished by the one here proposed. The ideas here presented allow the design of new methods for motion sensitive magnetic resonance imaging, which could simultaneously improve the resolution, robustness and accuracy of motion estimates.
authors.affiliation: Laboratorio de Procesado de Imagen, Department of Teoría de la Señal y Comunicaciones e Ingeniería Telemática, ETSIT, Universidad de Valladolid, Campus Miguel Delibes s.n., 40011, Valladolid, Spain; Centre for the Developing Brain and Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, St Thomas' Hospital, SE1 7EH, London, UK. Electronic address: lucilio.cordero_grande@kcl.ac.uk.
authors.forename: Lucilio
authors.initials: L
authors.lastname: Cordero-Grande
authors.affiliation: Laboratorio de Procesado de Imagen, Department of Teoría de la Señal y Comunicaciones e Ingeniería Telemática, ETSIT, Universidad de Valladolid, Campus Miguel Delibes s.n., 40011, Valladolid, Spain. Electronic address: jroyval@lpi.tel.uva.es.
authors.forename: Javier
authors.initials: J
authors.lastname: Royuela-del-Val
authors.affiliation: Laboratorio de Procesado de Imagen, Department of Teoría de la Señal y Comunicaciones e Ingeniería Telemática, ETSIT, Universidad de Valladolid, Campus Miguel Delibes s.n., 40011, Valladolid, Spain. Electronic address: ssanest@lpi.tel.uva.es.
authors.forename: Santiago
authors.initials: S
authors.lastname: Sanz-Estébanez
authors.affiliation: Laboratorio de Procesado de Imagen, Department of Teoría de la Señal y Comunicaciones e Ingeniería Telemática, ETSIT, Universidad de Valladolid, Campus Miguel Delibes s.n., 40011, Valladolid, Spain. Electronic address: marcma@tel.uva.es.
authors.forename: Marcos
authors.initials: M
authors.lastname: Martín-Fernández
authors.affiliation: Laboratorio de Procesado de Imagen, Department of Teoría de la Señal y Comunicaciones e Ingeniería Telemática, ETSIT, Universidad de Valladolid, Campus Miguel Delibes s.n., 40011, Valladolid, Spain. Electronic address: caralb@tel.uva.es.
authors.forename: Carlos
authors.initials: C
authors.lastname: Alberola-López
mesh_terms: D000465:Algorithms; D055119:Elastic Modulus / Q000502:physiology; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006321:Heart / Q000033:anatomy & histology* / Q000502:physiology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013314:Stress, Mechanical; D013382:Subtraction Technique
keywords: Artifacts; Harmonic phase reconstruction; Strain tensor; Tagged magnetic resonance imaging; Windowed Fourier transform