Improvement on Coronary Artery Disease Diagnosis: MRA, Vessel Wall Imaging and Inflammation Detection

Coronary artery disease (CAD) is the leading cause of death in the industrialized world, which is the end result of accumulation of atherosclerotic plaque. Magnetic Resonance Imaging (MRI) is a very important imaging modality used in radiology and detecting this disease. It can visualize both internal structures and body function. It provides good contrast between the different tissues while emits no radiation to the patients. As a result, it's gaining more and more attention these days. And among various MRI techniques, the especially widely used ones are: Magnetic Resonance Angiography (MRA) to visualize the lumen; black-blood technique to visualized the vessel wall. However, there are several shortcomings related to cardiac MRI, including insufficient SNR, and long imaging time. This thesis tried to solve these limitations.;Another emerging hot application of MRI to diagnose CAD is to evaluate the vulnerability of coronary plaque. Recent advances in knowledge of the development of plaque from carotid suggest that the inflammation plays a major role in various stages of plaque. And the destructive enzymes and cytokines produced by the inflammation at the core of the plaque lead to the rupture of the fibrous cap of the plaque, which causes stroke or heart infarction. However, by traditional methods, plaque can only be diagnosed in sever e stages when the vessel lumen is significantly narrowed and blood flow to an organ is reduced. So this thesis also tries to solve this technique challenge.;In the 2nd chapter, a self-calibrated reconstruction method was developed to speed up acquisition and shorten the imaging time while suppress streaking artifacts for highly accelerated parallel radial acquisitions in cardiac magnetic resonance imaging. It was demonstrated that the proposed method can effectively remove undersampling streaking artifacts and significantly improve image quality.;In the 3rd chapter, steady-state free precession (SSFP) acquisition was combined with vastly undersampled isotropic projection reconstruction (VIPR) to provide higher SNR without banding artifacts. The non-selective RF pulse employed in the VIPR trajectory shortens TR, which in turn helps to reduce the banding artifacts which are really common in SSFP acquisition at 3.0T. And we found whole-heart coronary MRA at 3.0 Tesla using short-TR SSFP VIPR is feasible and it results in excellent coronary artery visualization.;In the 4th chapter, a novel three-dimensional flow-independent vessel wall imaging technique was proposed to address the limitation of blood suppression with slow and in-plane flow of flow-dependent vessel wall imaging techniques. This technique combined the T2-prepared Inversion-Recovery (T2IR) module with Phase-Sensitive reconstruction and utilized SSFP acquisition. And we proved that 3D T2PSIR SSFP is a promising vessel wall imaging technique that covers a 3D volume efficiently, improves vessel wall/blood contrast, and is flow and TI independent.;In the 5th chapter, a novel technique was developed for dynamic contrast-enhanced carotid vessel wall imaging for carotid inflammation detection. Previous related studies all used a black blood imaging technique, which is intrinsically difficult to measure accurate vessel wall information. This newly developed technique combined the Saturation Recovery pulse (SR) and Double Inversion Recovery module (SRDIR) to create a T1-independent blood suppression to consistently visualize the carotid vessel wall. It is proved in 9 volunteer studies that this technique improves on previous dynamic contrast-enhanced imaging on vessel wall visualization and measurement.;In the 6th chapter, the newly developed SRDIR technique described in the 5th chapter was further adapted to apply to coronary vessel wall case. This work is the first ever dynamic contrast-enhanced coronary vessel wall study. The feasibility of this technique was proved on 10 volunteers and proved to be a very promising way to detect coronary inflammation.