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Bilateral kidney sodium‐MRI: Enabling accurate quantification of renal sodium concentration through a two‐element phased array system
Author(s) -
Kalayciyan Raffi,
Wetterling Friedrich,
Neudecker Sabine,
Haneder Stefan,
Gretz Norbert,
Schad Lothar R.
Publication year - 2013
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.24024
Subject(s) - furosemide , diuresis , sodium , nuclear medicine , renal medulla , chemistry , biomedical engineering , materials science , nuclear magnetic resonance , kidney , medicine , physics , endocrinology , organic chemistry
Purpose: To develop a sodium‐MRI ( 23 Na‐MRI) method for bilateral renal sodium concentration (RSC) measurements in rat kidneys at 9.4 Tesla (T). Materials and Methods: To simultaneously achieve high B 1 ‐field homogeneity and high receive sensitivity a dual resonator system composed of a double‐tuned linearly polarized 1 H/ 23 Na volume resonator and a newly developed two‐element 23 Na receive array was used. In conjunction with three‐dimensional (3D) ultra‐short Time‐to‐Echo sequence a quantification accuracy of ± 10% was achieved for a nominal spatial resolution of (1 × 1 × 4) mm 3 in 10 min acquisition time. The technique was applied to study the RSC in six kidneys before and after furosemide‐induced diuresis. Results: The loop diuretic agent induced an increase of cortical RSC by 22% from 86 ± 16 mM to 105 ± 18 mM ( P = 0.02), whereas the RSC in the inner medulla decreased by 38% from 213 ± 24 mM to 132 ± 25 mM ( P = 0.8×10 −4 ). The RSC changes measured in this study agreed well with the qualitative sodium signal intensity variations reported elsewhere. Conclusion: Furosemide‐induced diuresis has been investigated accurately with herein presented quantitative 23 Na‐MRI technique. In the future, RSC quantification could allow for defining pathological and nonpathological RSC ranges to assess sodium concentration changes, e.g., induced by drugs. J. Magn. Reson. Imaging 2013;38:564–572. © 2013 Wiley Periodicals, Inc.