Article

A dual-tuned resonator for proton-decoupled phosphorus-31 chemical shift imaging of the brain.

Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
Magnetic Resonance in Medicine (impact factor: 2.96). 05/1999; 41(4):809-15. pp.809-15
Source: PubMed

ABSTRACT A fully quadrature dome-shaped resonator is presented that has been dual-tuned for proton and phosphorus operation at 1.5 T. The resonator is 16.5 cm in length and 23 cm in diameter. Phantom studies were performed to demonstrate the utility of the resonator for proton imaging, shimming, and proton-decoupled phosphorus spectroscopy. In human subjects, proton-decoupled phosphorus chemical shift imaging spectra of the brain were acquired at 27 cm3 resolution in 34 min. Volunteer studies demonstrated improved resolution of phosphomonoesters, phosphodiesters, and nucleoside triphosphates due to proton decoupling. Sensitive coverage of the brain extended from the most superior cerebral cortex to the cerebellum. Acquisition of good quality 31P spectra over this volume is due to the dome structure as well as quadrature operation at both proton and phosphorus frequencies.

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    Article: An inverse design of an open, head/neck RF coil for MRI
    B.G. Lawrence, S. Crozier, G. Cowin, D.D. Yau
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    ABSTRACT: Radio-frequency (RF) coils are a necessary component of magnetic resonance imaging (MRI) systems. When used in transmit operation, they act to generate a homogeneous RF magnetic field within a volume of interest and when in receive operation, they act to receive the nuclear magnetic resonance signal from the RF-excited specimen. This paper outlines a procedure for the design of open RF coils using the time-harmonic inverse method. This method entails the calculation of an ideal current density on a multipaned planar surface that would generate a specified magnetic field within the volume of interest. Because of the averaging effect of the regularization technique in the matrix solution, the specified magnetic field is shaped within an iterative procedure until the generated magnetic field matches the desired magnetic field. The stream-function technique is used to ascertain conductor positions and a method of moments package is then used to finalize the design. An open head/neck coil was designed to operate in a clinical 2T MRI system and the presented results prove the efficacy of this design methodology.
    IEEE Transactions on Biomedical Engineering 10/2002; · 2.28 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

dome structure
 
good quality 31P spectra
 
human subjects
 
nucleoside triphosphates
 
phosphomonoesters
 
phosphorus frequencies
 
phosphorus operation
 
proton
 
proton decoupling
 
proton imaging
 
proton-decoupled phosphorus chemical shift imaging spectra
 
proton-decoupled phosphorus spectroscopy
 
quadrature dome-shaped resonator
 
quadrature operation
 
shimming
 
superior cerebral cortex
 
Volunteer studies
 

K L Zakian