studies

HEPATOLOGY, VOLUME 62, NUMBER 1 (SUPPL) AASLD ABSTRACTS 609A
802
Feasibility of three ultrasound shear wave elastographic
methods in overweight and obese patients
Ioan Sporea; University of Medicine and Pharmacy Timisoara,
Timisoara, Romania
In the last decade, different types of ultrasound based elastographic
methods that noninvasively quantify liver fibrosis
have been developed. Even though, Transient Elastography
is a validated method for liver fibrosis assessment in chronic
B and C hepatitis, reliable elasticity measurements are difficult
to obtain in obese (BMI>30kg/m 2 ) patients. The aim of this
study was to compare the feasibility of three elastrographic
methods used for liver fibrosis evaluation (Transient Elastography-TE,
point Shear Wave Elastography (pSWE) using ARFI
technique - VTQ and SuperSonic Shear Imaging-2D-SWE) in
overweight and obese patients. Material and methods: The
study included 183 consecutive subjects with or without chronic
hepatopathies, in which liver stiffness (LS) was evaluated in
the same session by means of 3 elastographic methods: TE
(Fibroscan, Echosens), VTQ (Siemens Acuson S200 TM ) and
2D-SWE (Aixplorer, SuperSonic Imagine S. A). Reliable LS
measurements were defined as follows: for TE and VTQ – the
median value of 10 LS measurements with a success rate≥60%
and an interquartile range 25kg/m 2 ), 32.2 % with
obesity grade 1 (BMI=30-34.9 kg/m 2 ), 4.3% with obesity
grade 2 (BMI=35-39.9 kg/m 2 ) and 1.1% with obesity grade
3 (BMI>40 kg/m 2 ). From the 114 overweight patients, reliable
LS measurements (LSM) were obtained in 83.3% (95%)
by means of TE, 85.1% (97) by means of VTQ and in 88.6%
(101) by 2D-SWE. TE, 2D-SWE and VTQ had similar rates
of reliable LSM in overweight patients: TE (83.3%) vs. VTQ
(85.1%) p=0.84; TE (83.3%) vs. 2D-SWE (88.6%) p=0.33;
2D-SWE (88.6%) vs. VTQ (85.1% ) p=0.55. The percentage of
reliable LSM in obese patients was similar: VTQ (79.7%) vs TE
(82.6%) (p=0.82), 2D SWE (85.5%) vs TE (82.6%) p=0.81,
VTQ (79.7%) vs 2D SWE (85.5%) p=0.5 Conclusion: Feasibility
of TE, VTQ and 2D-SWE in overweight and obese patients
was similar.
Disclosures:
The following authors have nothing to disclose: Ioan Sporea
803
Fast macromolecular proton fraction (MPF) mapping of
the human liver in vivo for quantitative assessment of
hepatic fibrosis
Vasily L. Yarnykh 1,2 , Erica Tartaglione 3 , George N. Ioannou 3,4 ;
1 Radiology, University of Washington, Seattle, WA; 2 Research
Institute of Biology and Biophysics, Tomsk State University, Tomsk,
Russian Federation; 3 Research and Development, Veterans Affairs
Puget Sound Health Care System, Seattle, WA; 4 Medicine, Division
of Gastroenterology, University of Washington, Seattle, WA
Background: MPF is a quantitative MRI parameter determining
the magnetization transfer (MT) effect and defined as a relative
amount of immobile macromolecular protons involved into
magnetization exchange with mobile water protons. MPF has
a potential for quantitative assessment of fibrous tissue due to
intrinsically high MPF in collagen. A recent fast single-point
MPF mapping method (Magn Reson Med 2012;68:166)
enables the capability of liver MPF assessment. The goal of this
study was to prospectively investigate a relationship between
MPF in the liver parenchyma and fibrosis stage. Methods:
16 patients with chronic HCV infection underwent MRI at 3T
using a three-dimensional MPF mapping protocol comprising
four breath-hold scans obtained with 2x3x6 mm 3 voxel size
and 10 sections:1) dynamic acquisition of MT-weighted (TR/
TE=18.5/2.3 ms, flip angle (FA)=80, saturation frequency 2
kHz and FA=2520) and reference (same parameters, no saturation)
images; 2) dynamic acquisition of three images for variable
FA T1 mapping (same TR/TE, FA=3,10,20°); 3) dual-TE
B0 map; and 4) dual-TR B1 map. MPF maps were reconstructed
using the single-point algorithm. 14 patients had liver
biopsy within one year prior to study entry, and two patients
had clinically diagnosed cirrhosis. Fibrosis was histologically
staged according to METAVIR. Score F4 was assigned to clinical
cirrhosis. The mode of liver MPF histograms was compared
between groups with (F2-F4, n=6) and without (F0-F1, n=10)
significant fibrosis by Mann-Whitney test. Association between
MPF and fibrosis score tested using Spearman correlation coefficient
(ρ). Results: MPF was increased in the significant fibrosis
group compared to the no or mild fibrosis group (6.49±0.36%
vs. 5.94±0.26%, P