Erschienen in:
22.02.2019 | Hepatobiliary
MR elastography of liver at 3 Tesla: comparison of gradient-recalled echo (GRE) and spin-echo (SE) echo-planar imaging (EPI) sequences and agreement across stiffness measurements
verfasst von:
Chenyang Zhan, Stephan Kannengiesser, Hersh Chandarana, Matthias Fenchel, Justin Ream, Krishna Prasad Shanbhogue
Erschienen in:
Abdominal Radiology
|
Ausgabe 5/2019
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Abstract
Purpose
To compare 2D gradient-recalled echo (GRE) and 2D spin-echo (SE) echo-planar imaging (EPI) MR elastography (MRE) for measurement of hepatic stiffness in adult patients with known or suspected liver disease at 3 Tesla.
Materials and methods
Three hundred and eighty-seven consecutive patients underwent MRE of the liver at 3 Tesla with 2D-GRE and 2D-SE-EPI sequences. ‘Mean liver stiffness (LS)’ calculated by averaging 3 ROIs in the right lobe, ‘Maximum LS’ calculated by an ROI in the right lobe; and ‘Freehand LS’ calculated by an ROI in the entire liver were measured by two independent readers. Inter-observer and inter-class variability in stiffness measurements were assessed. Stiffness values were correlated with degree of liver fibrosis (METAVIR scores) in 97 patients who underwent biopsy. The diagnostic performance was compared by a receiver-operating characteristic analysis.
Results
The technical failure rate was 2.8% for 2D-SE-EPI (11/387) and 4.1% for 2D-GRE (16/387, 9 had R2* > 80 s−1 indicating iron overload). There is high reproducibility for both GRE and SE-EPI variants (ICC = 0.84–0.94 for both GRE and SE-EPI MRE). The highest sensitivity, specificity, and accuracy of differentiating mild fibrosis (F0–F2) from advanced fibrosis (F3–F4) are 0.84 (GRE Freehand measurement), 0.92 (GRE Maximum stiffness measurement), and 0.88 (GRE Freehand measurement), respectively.
Conclusions
High intra-class correlation and intra-reader correlation are seen on measured hepatic stiffness for both 2D-GRE and 2D-SE-EPI MRE. 2D-SE-EPI has lower failure rate. Diagnostic performance of both sequences is equivalent, with highest sensitivity for 2D-GRE Freehand stiffness measurement, and highest specificity 2D-GRE Maximum stiffness measurement.