Accelerating MR Neuroimaging of Stroke Using Sparse Acquisition Coupled with Nonlinear Reconstruction Techniques.

摘要

The guiding theme of my research is to accelerate and improve magnetic resonance (MR) imaging such that it becomes the clinical modality of choice in diagnosing, treating, and hopefully preventing stroke. Stroke, be it ischemic or haemorrhagic, is a leading cause of death and permanent disability worldwide: it is a medical emergency that requires rapid diagnosis to initiate early patient treatment and prevent irreversible brain injury. Computed tomography (CT) is currently the preferred imaging modality due to its high spatial and temporal resolution. MR imaging is a slower technique than CT, but it offers a significantly broader and more varied set of image contrasts and functional information than CT. Simply stated, the goal of my research is to accelerate the MR acquisition and/or increase resolution without sacrificing image quality in order to provide high quality diagnostic information.;The most obvious way to scan faster is to acquire fewer data points, although this can often yield undesired reductions in image quality such as blurring, aliasing, or ghosting artefacts. Fortunately, numerous recent developments using multiple channel receiver coils and advanced reconstruction techniques are overcoming these drawbacks. This doctoral thesis investigates many of these advanced signal acquisition and processing techniques as they apply to stroke. In terms of diagnosis, I compare several state-of-the-art paradigms to accelerate key sequences of an acute MR stroke protocol. For treatment, I describe an enhanced passive MR catheter tracking approach that enables continuous monitoring of the catheter during endovascular procedures. And finally, with regards to stroke prevention, I present a novel imaging technique for assessing atherosclerosis in carotid arteries. In all cases, numerical and experimental verifications provided diagnostic images of very high quality (and comparable to conventional MR scans), albeit acquired 2 to 6 times faster. This work and continued efforts worldwide are inching us closer to making MR imaging the modality of choice in the comprehensive management of acute stroke patients.