1. Miniaturized multi-coil arrays for functional planar imaging with a single-sided NMR sensor
- Author
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Jan Watzlaw, Manuel Vossel, Stefan Benders, Sören Lehmkuhl, Christian Rehorn, Dirk Oligschläger, Bernhard Blümich, Eva De Boever, and Uwe Schnakenberg
- Subjects
Coupling ,Minerals ,Nuclear and High Energy Physics ,Planar Imaging ,Materials science ,Echo-Planar Imaging ,business.industry ,Biophysics ,Equipment Design ,Sense (electronics) ,Condensed Matter Physics ,Biochemistry ,Signal ,Inductance ,Electromagnetic Fields ,Nuclear magnetic resonance ,Optics ,Electromagnetic coil ,Adhesives ,Paint ,Image Processing, Computer-Assisted ,Sensitivity (control systems) ,business ,Image resolution - Abstract
Nowadays most low-field NMR sensors, such as the single-sided Profile NMR-MOUSE®, still suffer from poor sensitivity, either resulting from low magnetic field strengths and correspondingly low NMR frequencies, or lack of sensitivity. Generally, micro-coils can improve sensitivity, but due to their small size, and thus small inductance, they are mainly used for high-field NMR. Their main application field is parallel imaging, where those coils are typically assembled to receive-only coil-arrays and increase the field-of-view. Prominent signal combination techniques such as GRAPPA and SENSE are used to combine the spatially independent NMR signals to images in order to increase acquisition speed. A decisive disadvantage of today's single-sided NMR probes is the limited accessibility for NMR imaging. Although it is possible to use flat gradient coils on top of the NMR-MOUSE® to apply imaging techniques, such images can only be recorded with very long acquisition times, excluding the NMR-MOUSE® for lateral imaging of time-dependent processes. In this study sensitivity improved micro-structured RF coils, optimized for low frequencies, and correspondingly arrays of these coils, were employed to improve sensitivity and gave access to lateral spatial resolution within the sensitive plane at several observation points at the same time. Recently developed three- and four-coil arrays were combined with a Profile NMR-MOUSE® and characterized in terms of coil coupling, noise correlation and signal combination. The three-coil array was used for lateral imaging of moisture transport in travertine rock samples and to study the one-dimensional drying of paint.
- Published
- 2015