SENSE Parallel MRI Development for Small Animal Imaging Studies at 9.4 T
Wargo, Christopher Joseph
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2007-08-03
Abstract
The development of ultra-high field systems has benefited magnetic resonance imaging experiments due to the signal enhancement such systems provide. However, improvement in signal strength comes at the cost of increased artifacts caused by T2*, ƒ´B0, and susceptability effects leading to image intensity loss, blurring, and geometrical distortion. As these effects are time and field dependent, techniques have been developed to speed up image acquisition. In particular, parallel imaging based methods have been developed that use the signal reception properties of a surface coil parallel array. Specifically, each coil has a distinct spatial sensitivity to the established image object intensity that provides additional acquired signal encoding. Techniques such as SENSE use knowledge of the coil sensitivities to remove aliasing artifacts that result when the image spatial frequencies are sparsely acquired. The reduction in data acquisition translates directly to a reduced scan time to diminish time-dependent artifacts or improve resolution, but at a loss in SNR due to data reduction and SENSE reconstruction errors. To date, parallel imaging approaches have been largely applied to human studies, with limited animal experiment application where they would also be of benefit. This thesis describes the development of a four channel parallel array and SENSE reconstruction program that enables parallel imaging studies to be performed on a Varian 9.4T small animal MR system.