Noninvasive Assessment of Liver Fibrosis in Patients With Iron Overload

Objective: We assessed the diagnostic performance of ultrasound two-dimensional shear wave elastography (US 2D-SWE) to predict clinically significant fibrosis (CSF) in patients with serologic iron overload (SIO) and the subgroup with histologic liver iron overload (LIO).

Methods: A single-center retrospective cross-sectional study of adults with SIO (serum ferritin ≥ 200 ng/mL in females and ≥ 300 ng/mL in males) and suspected chronic liver disease with nonfocal liver biopsy results and US 2D-SWE exams within 1 year was performed. Histopathological fibrosis stage ≥2 and liver iron ≥2+ was considered CSF and LIO, respectively. Univariate logistic regression to assess prediction of CSF by Young's modulus (YM) and serum ferritin was performed. Sensitivity and specificity were reported at optimal YM threshold determined by the Youden Index.

Results: 272 cases were included (211 (77.6%) females, 88 (32.4%) CSF cases) with mean (± standard deviation) age of 50.0 (13.6) years. Median YM predicted CSF in patients with SIO (AUC 0.73, 95% confidence intervals (CI) 0.66 -0.80, odds ratio (OR) 1.12), p < 0.001. Optimal YM threshold was 11 kPa (sensitivity 58%, specificity 79%). Subgroup analysis of 47 LIO cases (39 women, mean age 52.5 ± 11.6 years, 17 (36.2%) CSF) showed that median YM predicted CSF (AUC 0.85, 95% CI 0.73-0.97, OR 1.39), p < 0.001. Optimal YM threshold was 11 kPa (sensitivity 77%, specificity 87%).

Conclusion: 2D-SWE is a promising, widely available, and noninvasive tool for diagnosing liver fibrosis in iron overload, including when magnetic resonance elastography may be nondiagnostic due to iron-related artifact.