Enhancing Capsule on Dynamic Liver CT: Association With Hepatocellular Carcinoma Diagnosis Using LI-RADS Version 2018

<b>Background:</b> The LI-RADS version 2018 (v2018) diagnostic algorithm prioritizes an enhancing capsule differently from other major features. An enhancing capsule's role in hepatocellular carcinoma (HCC) diagnosis remains uncertain, particularly for CT. <b>Objective:</b> To compare diagnostic performance for HCC diagnosis on CT between original LI-RADS v2018 criteria for LR-5 and modified LR-5 criteria that treat an enhancing capsule the same as other major features. <b>Methods:</b> This retrospective study included 546 patients (mean age, 59.8±9.6 years; 432 men, 114 female) at risk for HCC who underwent dynamic liver CT within 1 month before partial hepatectomy or liver transplant between January 2022 and December 2023. Two radiologists independently assessd hepatic observations (n=645) for LI-RADS major features, resolving discrepances with a third radiologist. LI-RADS categories were assigned using original LR-5 criteria and modified criteria giving an enhancing capsule the same priority as other major features (nonperipheral washout and threshold growth). The reference standard was pathologic assessment or ≥2 years of imaging follow-up. Criteria were compared using generalized estimating equations. <b>Results:</b> Sensitivity, specificity, PPV, NPV, and accuracy for reader 1 with original LR-5 criteria were 72.7%, 89.2%, 96.8%, 43.0%, and 75.2%; for reader 1 with modified criteria were 75.7%, 88.4%, 96.7%, 45.5%, and 77.5%; for reader 2 with original LR-5 criteria were 72.8%, 91.1%, 97.3%, 43.6%, and 75.6%; and for reader 2 with modified criteria were 75.0%, 90.3%, 97.1%, 45.4%, and 77.3%, respectively. For both readers, sensivitiy and accuracy were significantly higher for modified than for original criteria (p<.05); specificity, PPV, and NPV were not significantly different between criteria (p>.05). Among observations measuring 10-19 mm with nonrim arterial-phase hyperenhancement, using consensus assessments, sensitivity, specificity, PPV, NPV, and accuracy for original LR-5 criteria were 52.5%, 84.0%, 95.5%, 19.4%, and 56.3%; and for modified criteria were 64.9%, 78.3%, 95.1%, 23.2%, and 66.4%, respectively. <b>Conclusion:</b> When applying LI-RADS v2018 on CT, treating an enhancing capsule the same as other major features provided significantly increased sensitivity for HCC detection without significant change in specificity or PPV. <b>Clinical Impact:</b> Treating enhancing capsule the same as other major features for CT-based LI-RADS could improve noninvasive HCC diagnosis while simplifying interpretations.