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In vivo comparison of MRI‐based and MRS‐based quantification of adipose tissue fatty acid composition against gas chromatography
Author(s) -
Trinh Lena,
Peterson Pernilla,
Leander Peter,
Brorson Håkan,
Månsson Sven
Publication year - 2020
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.28300
Subject(s) - polyunsaturated fatty acid , adipose tissue , in vivo , liposuction , chemistry , nuclear medicine , fatty acid , medicine , surgery , biology , biochemistry , microbiology and biotechnology
Purpose To compare MR‐based fatty acid composition (FAC) quantification methods against the gold standard technique, gas chromatography (GC), with comparison of a free and a constrained signal model. The FAC was measured in the healthy and edematous legs of lymphedema patients. Methods In vivo MRS and MRI data were acquired from 19 patients at 3 T. Biopsies were collected from subcutaneous adipose tissue of both thighs during liposuction. The saturated, monounsaturated, and polyunsaturated fatty acid fractions ( f SFA , f MUFA and f PUFA , respectively) were estimated with the MR‐based methods using two signal models: free and constrained (number of methylene‐interrupted double bonds expressed in number of double bonds, based on GC data). Linear regression, Bland–Altman plots, and correlation coefficients were used to evaluate the MR methods against the GC of the biopsies. Paired t ‐test was used to compare the FAC difference between edematous and healthy legs. Results The estimated parameters correlated well with the GC data ( r SFA , r MUFA , and r PUFA = 0.82, 0.81 and 0.89, respectively) using the free model MRI‐based approach. In comparison, the MRS‐based method resulted in weaker correlations and larger biases compared with MRI. In both cases, correct estimation of f MUFA and f PUFA fractions were not possible using the constrained model. The difference in FAC of healthy and edematous legs were estimated to 0.008 ( P = .01), −0.009 ( P = .005), and 0.002 ( P = .03) for f SFA , f MUFA , and f PUFA . Conclusion In this study, MRI‐based FAC quantification was highly correlated, although slightly biased, compared with GC, whereas the MRS‐based approach resulted in weaker correlations. Small but significant differences could be found between the healthy and edematous legs of lymphedema patients using GC analysis.