title: Mapping Cardiac Fiber Orientations from High-Resolution DTI to High-Frequency 3D Ultrasound.
abstract: The orientation of cardiac fibers affects the anatomical, mechanical, and electrophysiological properties of the heart. Although echocardiography is the most common imaging modality in clinical cardiac examination, it can only provide the cardiac geometry or motion information without cardiac fiber orientations. If the patient's cardiac fiber orientations can be mapped to his/her echocardiography images in clinical examinations, it may provide quantitative measures for diagnosis, personalized modeling, and image-guided cardiac therapies. Therefore, this project addresses the feasibility of mapping personalized cardiac fiber orientations to three-dimensional (3D) ultrasound image volumes. First, the geometry of the heart extracted from the MRI is translated to 3D ultrasound by rigid and deformable registration. Deformation fields between both geometries from MRI and ultrasound are obtained after registration. Three different deformable registration methods were utilized for the MRI-ultrasound registration. Finally, the cardiac fiber orientations imaged by DTI are mapped to ultrasound volumes based on the extracted deformation fields. Moreover, this study also demonstrated the ability to simulate electricity activations during the cardiac resynchronization therapy (CRT) process. The proposed method has been validated in two rat hearts and three canine hearts. After MRI/ultrasound image registration, the Dice similarity scores were more than 90% and the corresponding target errors were less than 0.25 mm. This proposed approach can provide cardiac fiber orientations to ultrasound images and can have a variety of potential applications in cardiac imaging.
authors.affiliation: Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA.
authors.forename: Xulei
authors.initials: X
authors.lastname: Qin
authors.affiliation: Yerkes National Primate Research Center, Emory University, Atlanta, GA.
authors.forename: Silun
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Pediatrics, Emory University, Atlanta, GA.
authors.forename: Ming
authors.initials: M
authors.lastname: Shen
authors.affiliation: Yerkes National Primate Research Center, Emory University, Atlanta, GA.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Pediatrics, Emory University, Atlanta, GA.
authors.forename: Mary B
authors.initials: MB
authors.lastname: Wagner
authors.affiliation: Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA ; Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA.
authors.forename: Baowei
authors.initials: B
authors.lastname: Fei
keywords: 3D ultrasound; Cardiac fiber orientations; Deformable image registration; Magnetic resonance imaging (MRI); diffusion tensor imaging (DTI); heart imaging