1Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, Korea, Republic of, 2Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea, Republic of
It is important to
assess liver stiffness and monitor the progression of fibrosis in patients with
liver diseases using non-invasive imaging. Exploiting the fact that the motion
of the heart during cardiac cycle is an intrinsic driving source to deform the
liver, dynamic tagged MRI can be employed to measure the cardiac motion induced
displacements using harmonic phase images and thereby evaluate the corresponding
strain maps in the liver. In this work, we
propose a novel framework of compressed sensing (CS) for dynamic tagged liver
MRI, in which: 1) data is acquired using tag-constrained, incoherent
undersampling in k-t space, 2) a time series of morphologies is decomposed into
transient tag-only images and stationary tag-free liver images, 3) both
morphological components are then reconstructed directly from the
tag-constrained, undersampled k-t space, and 4) the transient tag-only images
are employed to estimate time-varying displacements and the corresponding
strain maps while the stationary tag-free liver images are used as a structural
roadmap.
