MRI major and ancillary features of LI-RADS for diagnosis of pediatric malignant liver tumors.

OBJECTIVES

To evaluate LI-RADS major and ancillary features for MRI-based diagnosis of pediatric malignant liver tumors.

MATERIALS AND METHODS

This single-center retrospective study enrolled pediatric patients who underwent contrast-enhanced liver MRI for focal liver lesions from January 2010-February 2023. Three readers independently performed imaging analysis based on LI-RADS v2018. The reference standard was a pathological diagnosis or stability/regression for over one year on follow-up. Estimation of diagnostic accuracy and multivariable logistic regression were conducted to identify LI-RADS features associated with malignant hepatocellular tumors and hepatic malignancy in general.

RESULTS

Of the 102 patients (median age [interquartile range], 4.5 [0.6-14.0] years; boys:girls, 54:48), 58.8% (60/102) had malignant liver tumors and 49.0% (50/102) had malignant hepatocellular tumors. The sensitivity and specificity of major features for diagnosis of malignant hepatocellular tumors were as follows: nonrim arterial enhancement, 73.4% and 39.6%; enhancing capsule, 56.7% and 92.0%; nonperipheral washout, 70.1% and 94.2%. Nonperipheral washout (sensitivity, 70.1%; specificity, 94.2%; adjusted OR, 34.5; p < 0.001), restricted diffusion (sensitivity, 97.9%; specificity, 53.8%; adjusted OR, 72.3; p = 0.001), and fat-in-mass (sensitivity, 29.0%; specificity, 93.0%; adjusted OR, 4.3; p = 0.01) were associated with malignant hepatocellular tumors, while nonperipheral washout (sensitivity, 58.7%; specificity, 94.5%; adjusted OR, 12.5; p < 0.001), restricted diffusion (sensitivity, 97.1%; specificity, 65.8%; adjusted OR, 31.1; p < 0.001), and mosaic architecture (sensitivity, 79.5%; specificity, 90.0%; adjusted OR, 20.4; p < 0.001) were associated with hepatic malignancy in general.

CONCLUSION

Restricted diffusion was a sensitive MRI LI-RADS feature, while nonperipheral washout and mosaic architecture were specific features for diagnosing pediatric malignant liver tumors.

KEY POINTS

Questions MRI is the recommended modality for pediatric focal liver lesions, but only a few studies have examined the diagnostic accuracy of MRI LI-RADS features in children. Findings Restricted diffusion was sensitive for malignant liver tumors, while mosaic architectures were specific for malignant liver tumors. Nonperipheral washout was specific for diagnosing malignant hepatocellular tumors. Clinical relevance Nonperipheral washout, restricted diffusion, and mosaic architecture were reliable MRI LI-RADS features for diagnosing pediatric malignant liver tumors.