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.