Access Type

Open Access Dissertation

Date of Award

January 2017

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Biomedical Engineering

First Advisor

Ewart M. Haacke

Second Advisor

Jaladhar Neelavalli

Abstract

Fetal magnetic resonance imaging (MRI) in recent times has become a well-established adjunct to ultrasound (US) in routine clinical prenatal care and diagnostics. The majority of fetal MRI is restricted to T2-weighted scans, where the diagnosis is based on the appearance of normal and abnormal tissue. Although there have been many advancements in MRI and a plethora of sequences, that probe different anatomical and different physiological process, the adaptation of these in fetal imaging has been rather slow. Many of these can extract quantitative parameters that can throw light on the underlying tissue’s normal/patho-physiology. But the use of such quantitative MRI methods has been extremely limited in fetal imaging due to its unique and dynamic physiological milieu that pose several technical challenges including low signal to noise and/or resolution, artifacts associated with abdominal imaging and most importantly fetal motion. These limitations are expected to be overcome by (a) optimizing and (b) developing novel MR imaging sequences, both of which constitute the primary aim of my work.

This work develops a framework that allows for vascular imaging in the fetus and placenta. This includes both qualitative vascular imaging and blood flow quantification. Towards this, three broad directions were explored (a) Moving to higher field imaging, while optimizing parameters for low energy deposition and (b) application of non-gated phase contrast MRI and (c) optimization of conventional time-of-flight angiography for fetal applications.

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