Short- and midterm repeatability of magnetic resonance elastography in healthy volunteers at 3.0 T

The purpose of this study was to evaluate the short- and midterm repeatability of liver stiffness measurements with magnetic resonance elastography (MRE) in healthy subjects at 3.0T. Twenty-two healthy volunteers were enrolled in this prospective study. The stiffness measurements were obtained from three slices with three repeated acquisitions for each slice (session 1) by two independent raters. After a mean period of 7±2days (session 2) and 195±15days (session 3), each subject was scanned again using the same protocol and MR system. The liver stiffness differences were calculated between sessions or raters. The intraclass correlation coefficient (ICC) was calculated to assess interrater agreement and intersession agreement. The stiffness differences over the short- and midterm intervals was (-0.004±0.086) kPa for sessions 1-2, lower than (-0.055±0.150) kPa for sessions 1-3 and (-0.051±0.173) kPa for sessions 2-3. The liver stiffness was more repeatable for the short-term interval with the mean overall ICC of 0.96 (sessions 1-2) (95% confidence interval [CI]: 0.90-0.98) compared with 0.91 (sessions 1-3) (95% CI: 0.78-0.96) and 0.87 (sessions 2-3) (95% CI: 0.69-0.95) for the midterm intervals. The overall ICC of interrater agreement was excellent at 0.987 (95% CI: 0.983 to 0.990). These results confirm that MRE is a reproducible technique for liver stiffness quantification over short- and midterm intervals up to 6months in a healthy population at 3.0T.