Article

In vivo characterization of the liver fat ¹H MR spectrum.

Department of Radiology, University of California, San Diego, CA 92103-8749, USA.
NMR in Biomedicine (impact factor: 3.21). 08/2011; 24(7):784-90. DOI:10.1002/nbm.1622 pp.784-90
Source: PubMed

ABSTRACT A theoretical triglyceride model was developed for in vivo human liver fat (1) H MRS characterization, using the number of double bonds (-CH=CH-), number of methylene-interrupted double bonds (-CH=CH-CH(2)-CH=CH-) and average fatty acid chain length. Five 3 T, single-voxel, stimulated echo acquisition mode spectra (STEAM) were acquired consecutively at progressively longer TEs in a fat-water emulsion phantom and in 121 human subjects with known or suspected nonalcoholic fatty liver disease. T(2)-corrected peak areas were calculated. Phantom data were used to validate the model. Human data were used in the model to determine the complete liver fat spectrum. In the fat-water emulsion phantom, the spectrum predicted by the model (based on known fatty acid chain distribution) agreed closely with spectroscopic measurement. In human subjects, areas of CH(2) peaks at 2.1 and 1.3 ppm were linearly correlated (slope, 0.172; r = 0.991), as were the 0.9 ppm CH(3) and 1.3 ppm CH(2) peaks (slope, 0.125; r = 0.989). The 2.75 ppm CH(2) peak represented 0.6% of the total fat signal in high-liver-fat subjects. These values predict that 8.6% of the total fat signal overlies the water peak. The triglyceride model can characterize human liver fat spectra. This allows more accurate determination of liver fat fraction from MRI and MRS.

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Keywords

121 human subjects
 
accurate determination
 
average fatty acid chain length
 
complete liver fat spectrum
 
echo acquisition mode spectra
 
fat-water emulsion phantom
 
fatty acid chain distribution
 
high-liver-fat subjects
 
Human data
 
human liver fat spectra
 
human subjects
 
liver fat fraction
 
nonalcoholic fatty liver disease
 
Phantom data
 
T(2)-corrected peak areas
 
theoretical triglyceride model
 
total fat signal
 
total fat signal overlies
 
triglyceride model
 
vivo human liver fat