Two-dimensional ultrasound shear wave elastography for identifying and staging liver fibrosis in pediatric patients with known or suspected liver disease: a clinical effectiveness study

Background: Ultrasound shear wave elastography (SWE) measures liver stiffness noninvasively, but few studies have defined cutoff values for detecting liver fibrosis in pediatric patients using 2-D ultrasound SWE. Objective: To evaluate the diagnostic performance of 2-D ultrasound SWE and define cutoff values for liver fibrosis in pediatric patients, using Canon (Toshiba) Aplio ultrasound systems. Materials and methods: This was an institutional review board-approved retrospective study of patients (≤18 years old) who had undergone both liver 2-D ultrasound SWE and percutaneous liver biopsy within 6 months. Liver biopsies were staged using the METAVIR (fibrosis) scoring system. Continuous data were compared using the Mann-Whitney U test. Receiver operating characteristic (ROC) curve analysis was used to evaluate diagnostic performance. Results: Forty-six patients, with a median age of 11.5 years (interquartile range: 8.0–14.3 years), were included. Twenty-three patients were male (50%). Twenty-seven patients had a METAVIR fibrosis score of F0–1, and 19 patients had a score of F2–4. For differentiating METAVIR F0–1 from F2-–4, the area under the ROC (AuROC) was 0.75 (95% confidence interval [CI]: 0.60–0.90). A cutoff of >1.89 m/s yielded sensitivity of 73.7% (95% CI: 51.2–88.2) and specificity of 77.8% (95% CI: 59.2–89.4). For the subset of patients without histological hepatic steatosis (n=35), the AuROC was 0.86 (95% CI: 0.71–1.0). The same cutoff of >1.89 m/s yielded a sensitivity of 80.0% (95% CI: 54.8–93.0) and specificity of 95.0% (95% CI 76.4–99.7). Conclusion: Two-dimensional ultrasound SWE distinguishes patients with no/mild fibrosis from those with moderate/severe fibrosis with good sensitivity and specificity. Diagnostic performance is comparable to that published for magnetic resonance elastography and is likely adversely impacted by steatosis.