| Popis: |
Phase-contrast magnetic resonance imaging (PC-MRI) can provide a complement to echocardiography for the evaluation of the fetal heart. Cardiac imaging typically requires gating with peripheral hardware; however, a gating signal is not readily available in utero. In this thesis, I present a technique for reconstructing time-resolved fetal phase-contrast MRI in spite of this limitation. Metric Optimized Gating (MOG) involves acquiring data without gating and retrospectively determining the proper reconstruction by optimizing an image metric, and the research in this thesis describes the theory, implementation, and evaluation of this technique. In particular, results from an experiment with a pulsatile flow phantom, an adult volunteer study, in vivo application in the fetal population, and numerical simulations are presented for validation. MOG enables imaging with conventional PC-MRI sequences in the absence of a gating signal, permitting flow measurements in the great vessels in utero. |
