Magnetic resonance elastography of the liver: preliminary results and estimation of inter-rater reliability.
OBJECTIVE
The aim of this study was to estimate inter-rater reliability and validate magnetic resonance elastography (MRE) as a tool to measure liver elasticity.


METHODS
The study protocol was approved by the institutional review board at our institution. In all, 10 normal volunteers and 110 patients, who provided written informed consent, were enrolled. The pathological fibrosis score was applied as a standard reference of liver fibrosis in 21 patients. MRE was performed with a 1.5-T magnetic resonance imaging scanner with a cylindrical passive longitudinal shear wave driver placed over the right chest wall to deliver vibrations. A gradient-echo MRE sequence was used to acquire axial wave images, which were automatically converted to elastograms representing elasticity (in kilopascals, or kPa). The region of interest was placed in the right lobe of the liver on elastograms by two raters independently. To evaluate interrater reliability, the intraclass correlation coefficient was calculated. The elasticity measurements correlated with the pathological fibrosis score (F1-F4) in 21 patients.


RESULTS
The intraclass correlation coefficient was almost perfect (0.993) between the elasticities measured by the two raters. The mean elasticity value for patients with F4 was 5.7 kPa; F3, 4.4 kPa; F2, 3.1 kPa; F1, 2.2 kPa; and F0, 2.1 kPa.


CONCLUSIONS
MRE is a reliable tool to measure liver elasticity.
Motosugi
Utaroh
U
Department of Radiology, University of Yamanashi, Shimokato, Chuo, Japan. utaroh-motosugi@nifty.com
Ichikawa
Tomoaki
T
Sano
Katsuhiro
K
Sou
Hironobu
H
Muhi
Ali
A
Koshiishi
Tsuyota
T
Ehman
Richard L
RL
Araki
Tsutomu
T
D000328:Adult; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008103:Liver Cirrhosis / Q000473:pathology*; D008297:Male; D015203:Reproducibility of Results