In vivo 1H magnetic resonance imaging and spectroscopy of the rat spinal cord using an inductively-coupled chronically implanted RF coil.
An inductively coupled, chronically implanted short-solenoid coil was used to obtain in vivo localized 1H NMR spectra and diffusion-weighted images from a rat spinal cord. A 5 x 8 mm two-turn elliptically shaped solenoid coil was implanted in rats at the site of a T-12 vertebral-level laminectomy. Excitation was achieved solely by a 3 x 3 cm external surface coil, and signal detection was achieved by inductively coupling the external coil to the implanted coil. The image signal-to-noise ratio (SNR) obtained with the inductively-coupled implanted coil was compared with that obtained using a linear or a quadrature external surface coil. The implanted coil provided a gain by over a factor of 3 in SNR. The implanted coil was used to measure localized 1H spectra in vivo at the T13/L1 spinal-cord level within a 1.85 x 1.85 x 4.82 mm (16.5 microL) volume. With 256 averages, a approximately 3-s repetition delay and respiratory gating, a high-quality spectrum was acquired in 13 min. In addition, water translational diffusion was measured in three orthogonal directions using a stimulated-echo imaging sequence, with a short echo time (TE), to produce a quantitative map of diffusion in a rat spinal cord in vivo.
Silver
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Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610-0245, USA.
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Mercer
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Beck
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Bossart
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Inglis
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B
Mareci
T H
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D000818:Animals; D005260:Female; D008279:Magnetic Resonance Imaging / Q000295:instrumentation; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation; D019047:Phantoms, Imaging; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000033:anatomy & histology* / Q000378:metabolism*