Comparison of technical failure of MR elastography for measuring liver stiffness between gradient‐recalled echo and spin‐echo echo‐planar imaging: A systematic review and meta‐analysis

Background Magnetic resonance elastography (MRE) using a gradient‐recalled echo (GRE) or a recently available spin‐echo echo‐planar imaging (SE‐EPI) sequence is a promising noninvasive method for measuring liver stiffness. However, it sometimes fails to measure stiffness values, thereby resulting in technical failures. Purpose To assess and compare technical failures of MRE for measuring liver stiffness between GRE and SE‐EPI sequences. Study Type Systematic review and meta‐analysis. Population Eight studies with both GRE and SE‐EPI, 22 studies with only GRE, one study with only SE‐EPI. Field Strength/Sequence Either 1.5 or 3T MRE using GRE and/or SE‐EPI. Assessment Through an Ovid‐MEDLINE and EMBASE database search, original articles investigating the proportion of MRE technical failures in the measurement of liver stiffness published up until October 2018 were screened and selected. Statistical Analysis The pooled proportions of technical failures under GRE and SE‐EPI were calculated using random‐effects meta‐analysis of single proportions and inverse variance for calculating weights. Subgroup analyses were performed to explore the covariates affecting heterogeneity. Head‐to‐head comparisons of technical failure between the sequences were conducted with eight MRE studies using both GRE and SE‐EPI. Results The pooled proportion of technical failure under GRE MRE was 5.8% (95% confidence interval [CI], 4.6–7.4%), and a subgroup analysis showed higher technical failure rates at 3T than at 1.5T. The pooled proportion of technical failure under SE‐EPI MRE was 2.0% (95% CI, 1.3–3.4%), without significant differences (P = 0.38–0.89) being observed in the subgroup analyses. In the eight studies comparing the two sequences, failure was more frequently observed with GRE than with SE‐EPI (9.4% vs. 1.9%; P