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Evaluation of the RF field uniformity of a double‐tuned 31 P/ 1 H birdcage RF coil for spin‐echo MRI/MRS of the diabetic foot
Author(s) -
Greenman Robert L.,
RakowPenner Rebecca
Publication year - 2005
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.20372
Subject(s) - nuclear magnetic resonance , forefoot , radiofrequency coil , nuclear medicine , magnetic resonance imaging , flip angle , physics , electromagnetic coil , intensity (physics) , spin echo , medicine , optics , radiology , quantum mechanics , kinematics , classical mechanics
Purpose To evaluate the B1 field uniformity of a double‐tuned birdcage coil designed for 31 P/ 1 H MRI/MRS spin‐echo (SE) imaging of the metatarsal head region of the foot in neuropathic diabetic patients. Materials and Methods A low‐pass double‐tuned 31 P/ 1 H RF birdcage coil was constructed to fit over the adult forefoot. Flip angle (FA) maps were created from B1 data acquired at the 3T 31 P (four normal subjects) and 1 H (five normal subjects) frequencies. T2‐weighted (T2‐W) 1 H images, 31 P rapid acquisition with relaxation enhancement (RARE) images, and composite SE pulse CSI data were acquired to demonstrate the uniformity of the resulting images and data. Results The means and standard deviations (SDs) of the range of FAs across the feet of the volunteer subjects indicated good uniformity (the maximum coefficients of variation (CVs) for all of the 31 P and 1 H FA maps were 7.6% and 7.3%, respectively). The FA values across the metatarsal head region indicated a maximum signal intensity variation of ±3% in a RARE image acquired using an echo train length of 32. Conclusion A 31 P/ 1 H birdcage coil constructed for MRI/MRS studies of the human forefoot provided sufficient signal uniformity of SE data to facilitate accurate 31 P concentration measurements in muscle. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.