Point shear wave elastography and vibration controlled transient elastography for estimating liver fibrosis in a cohort of liver transplant patients.

ABSTRACT

OBJECTIVE: Liver transplant (LT) patients need regular follow-up both by ultrasonography and elastography. Shear wave elastography is now available in high-end ultrasound systems that, however, may yield different values for any given liver, reflecting technological differences. The aim of this study was to establish whether the point shear wave elastography QElaXto® (QEpSWE), available on Esaote (Genoa, Italy) systems, is comparable to the standard Fibroscan® (vibration-controlled transient elastography, VCTE) in the real-life setting of liver transplant (LT) patients. PATIENTS AND METHODS: We prospectively examined with QEpSWE 196 consecutive LT patients referred for VCTE and ultrasound examination. The agreement between QEpSWE and VCTE was assessed with Lin concordance correlation coefficient (CCC) and Bland-Altman analysis. The performance of QEpSWE was assessed with the ROC curves using the VCTE cut-offs of 7 and 12 kPa for F2-F3 and F4, respectively. RESULTS: The two methods showed 100% of successful and reliable liver stiffness measurements (LSM), similar median LSM in the whole group and in the two subgroups F2-F3 and F4 of fibrosis, with a disagreement in categorization of liver fibrosis in only 2% of cases, and never more than 1 stage of fibrosis. Further, they presented the same degree of higher LSMs in clinically unstable LT patients and an excellent overall agreement (CCC=0.91, accuracy=0.95, precision=0.96), even if agreement was less satisfactory in the range of severe fibrosis. The optimal cutoffs of QEpSWE were 6.7 and 11.6 kPa for F2-F3 and F4, respectively. CONCLUSIONS: The values of VCTE and QEpSWE showed a very high correlation in the staging of liver fibrosis. QEpSWE seems a promising method for staging liver fibrosis in LT patients.