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Reproducible MRI measurement of adipose tissue volumes in genetic and dietary rodent obesity models
Author(s) -
Johnson David H.,
Flask Chris A.,
Ernsberger Paul R.,
Wong Wilbur C.K.,
Wilson David L.
Publication year - 2008
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.21481
Subject(s) - adipose tissue , obesity , medicine , endocrinology , partial volume , magnetic resonance imaging , reproducibility , lean tissue , nuclear medicine , chemistry , radiology , chromatography
Abstract Purpose To develop ratio MRI [lipid/(lipid+water)] methods for assessing lipid depots and compare measurement variability with biological differences among lean controls (spontaneously hypertensive rats [SHRs]), dietary obese rats (SHR‐DOs), and genetic/dietary obese rats (SHROBs). Materials and Methods Images with and without chemical shift‐selective (CHESS) water suppression were processed using a semiautomatic method that accounts for relaxometry, chemical shift, receive coil sensitivity, and partial volume. Results Partial volume correction improved results by 10% to 15%. Over six operators, volume variation was reduced to 1.9 mL from 30.6 mL for single‐image‐analysis with intensity inhomogeneity. For three acquisitions on the same animal, volume reproducibility was <1%. SHROBs had six times more visceral and eight times more subcutaneous adipose tissue than SHRs. SHR‐DOs had enlarged visceral depots (three times larger than those in SHRs). SHROBs had significantly more subcutaneous adipose tissue, indicating a strong genetic component to this fat depot. Liver ratios in SHR‐DO and SHROB were higher than in SHR, indicating elevated fat content. Among SHROBs, evidence suggested a phenotype SHROB* having elevated liver ratios and visceral adipose tissue volumes. Conclusion Effects of diet and genetics on obesity were significantly larger than variations due to image acquisition and analysis, indicating that these methods can be used to assess accumulation/depletion of lipid depots in animal models of obesity. J. Magn. Reson. Imaging 2008;28:915–927. © 2008 Wiley‐Liss, Inc.