Magnetic Resonance Imaging (MRI) is a non-invasive medical imaging method that is used in the diagnosis of many common diseases. Compared to other medical imaging modalities, MRI has the ability to provide high-resolution 2D and 3D images in arbitrary orientations, without the use of potentially damaging ionizing radiation. Myocardial perfusion MRI is a promising non- invasive clinical way to detect cardiac disease. It can also provide quantitative analysis for blood flow within the heart. However, MRI requires longer scan times to acquire images at comparable resolutions to some other imaging modalities. Increasing image resolution, both spatially and temporally, is very important to myocardial perfusion MRI. The work presented in this dissertation focuses on the development of novel dynamic contrast-enhanced (DCE) MRI that is able to achieve both high spatial and temporal resolutions, as well as suitable spatial coverage of the heart. Three novel acquisition and reconstruction frame- works are proposed and analyzed in this dissertation. The first framework we propose uses a highly undersampled 3D Cartesian acquisition and total variation (TV) constrained reconstruction to accelerate the acquisition of myocardial perfu- sion images. This technique increases temporal resolution for contrast tracking without sacrificing spatial resolution. An analysis of the effect of different k-space trajectories using this technique is performed. The purpose of the second framework is to simplify cardiac perfusion studies. An ECG- gated saturation recovery sequence is regularly used for cardiac perfusion imaging. However, using an ungated acquisition has the potential benefit of reducing the acquisition time by eliminating the need for the ECG trigger signal. We present a novel non-Cartesian 2D multi-slice ungated acquisition, and demonstrate that it is a promising alternative to ECG-gated cardiac perfusion studies. An optimization analysis of our ungated acquisition is also presented. The third method in this dissertation combines the 2D ungated acquisition with multi-band excitation, which enables the excitation of multiple slices simultaneously. This method is able to reduce scan time not only through the ungated acquisition, but also from obtaining multiple slices at once. This allows us to achieve whole heart coverage without sacrificing temporal resolution. The contributions presented in this dissertation demonstrate the basic feasibility of car- diac perfusion MRI achieving whole-heart coverage in a clinical setting by overcoming the major existing limitations: speed of acquisition and spatial coverage.
| Identifer | oai:union.ndltd.org:BGMYU2/oai:scholarsarchive.byu.edu:etd-7435 |
| Date | 01 June 2016 |
| Creators | Wang, Haonan |
| Publisher | BYU ScholarsArchive |
| Source Sets | Brigham Young University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | http://lib.byu.edu/about/copyright/ |
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