Supplementary Methods
CT examination
CT scanning was performed with the following parameters: beam collimation,
24  1.2 mm; beam pitch, 1; gantry rotation time, 0.5 second; 120 kVp; tube current
determined by an automated dose reduction system (CARE Dose 4D; Siemens Medical
Solutions) with the maximum allowable tube current set at 200 mAs; section thickness,
5mm; and field of view to fit. Hepatic attenuation was measured by averaging
Hounsfield unit (HU) values of eight 1.5-cm2 circular ROIs: two ROIs were placed at
two different sites in each segment of the right hepatic lobe (hepatic segments V, VI, VII,
and VIII according to the Couinaud system). Splenic attenuation was obtained by
averaging three HU values of three 1.5-cm2 circular ROIs placed in the upper, middle,
and lower thirds of the spleen. For both hepatic and splenic attenuation measurement,
ROIs were placed with special care so as to exclude macroscopic vessels (Fig. S1A).
DGE-MRI examination
The first DGE-MRI scan was performed with a repetition time (TR)/echo time
(TE), 110.5 msec/1.15 msec (OP) and 2.3 msec (IP0); flip angle, 20˚; section thickness,
5mm; section gap 2mm; matrix, 256 x 175; number of sections, 30; and acquisition time,
21 seconds. The second DGE-MRI scan, which was used for correction of the T2* effect,
employed TR/TEs of 216.3 msec/2.3 msec (IP1) and 4.6 msec (IP2) and otherwise the
same parameters as those of the first DGE-MRI scan [10]. A low flip angle (20˚) was
chosen for both the first and the second DGE-MRI in order to minimize the bias from
the different T1 relaxation times of fat and water [10]. Using eight ROI measurements
of hepatic signal intensity (same as CT) on each of OP, IP0, IP1, and IP2 images (Figs.
S1B and S1C), a quantitative index of the degree of HS was calculated as (T2*corrected signal intensity on IP0 – signal intensity on OP)  (2  T2*-corrected signal
intensity on IP0), where T2*-corrected signal intensity on IP0 = signal intensity on IP0 
√ (signal intensity on IP1  signal intensity on IP2) [10].
1H-MRS
1
examination (Fig. S1D)
H-MRS was performed with a TR/TE of 3000 msec/135 msec, 128 acquisitions,
and 1024 data points over a 2000-Hz spectral bandwidth. 1H-MRS spectra were
processed using the MR User Interface software package (available at
http://www.mrui.uab.es/mrui/) [5, 20]. The water (4.7 ppm) and lipid (1.3 ppm) peaks
were measured and were corrected for T2 effect using the mean T2 relaxation times for
fat (78 msec) and water (60 msec) according to the previously described method [1, 14].
A quantitative index of the degree of HS was then calculated as the area of the lipid
peak  (the area of lipid peak + the area of water peak)  100%.
Supplementary Figure Legends
Fig.S1. Placement of regions-of-interest (ROIs) on CT and dual gradient echo magnetic
resonance imaging (DGE-MRI) and the voxel of interest for signal acquisition for
proton magnetic resonance spectroscopy (1H-MRS). (A) A transverse CT image of the
liver. White circles represent ROIs for measuring the hepatic and splenic attenuation.
(B-C) Opposed-phase (B) and in-phase (C) DGE-MR images of the liver. White circles
represent ROIs for measuring the hepatic signal intensity. (D) Left: Transverse T2weighted magnetic resonance image. White square shows the position of the voxel for
signal acquisition for 1H-MRS. Right: 1H-MRS spectra showing the water peak at 4.7
ppm and the lipid peak at 1.3 ppm.