T1 independent, T2* corrected MRI with accurate spectral modeling for quantification of fat: validation in a fat-water-SPIO phantom.
OBJECTIVE
To validate a T(1)-independent, T(2)*-corrected fat quantification technique that uses accurate spectral modeling of fat using a homogeneous fat-water-SPIO phantom over physiologically expected ranges of fat percentage and T(2)* decay in the presence of iron overload.


METHODS
A homogeneous gel phantom consisting of vials with known fat-fractions and iron concentrations is described. Fat-fraction imaging was performed using a multiecho chemical shift-based fat-water separation method (IDEAL), and various reconstructions were performed to determine the impact of T(2)* correction and accurate spectral modeling. Conventional two-point Dixon (in-phase/out-of-phase) imaging and MR spectroscopy were performed for comparison with known fat-fractions.


RESULTS
The best agreement with known fat-fractions over the full range of iron concentrations was found when T(2)* correction and accurate spectral modeling were used. Conventional two-point Dixon imaging grossly underestimated fat-fraction for all T(2)* values, but particularly at higher iron concentrations.


CONCLUSIONS
This work demonstrates the necessity of T(2)* correction and accurate spectral modeling of fat to accurately quantify fat using MRI.
Department of Radiology, University of Wisconsin, Madison, Wisconsin 53792-3252, USA.
Catherine D G
CD
Hines
Huanzhou
H
Yu
Ann
A
Shimakawa
Charles A
CA
McKenzie
Jean H
JH
Brittain
Scott B
SB
Reeder
D000273:Adipose Tissue / Q000378:metabolism*; D005290:Ferric Compounds / Q000494:pharmacology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007501:Iron / Q000737:chemistry; D008055:Lipids / Q000737:chemistry; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics; D019047:Phantoms, Imaging; D012044:Regression Analysis; D015203:Reproducibility of Results; D014867:Water / Q000737:chemistry*
D005290:Ferric Compounds; D008055:Lipids; D014867:Water; C000499:ferric oxide; D007501:Iron