Supplementary Material for: Detection and Characterization of Subcentimeter Hepatocellular Carcinoma: A Comparison of Gadoxetic Acid-Enhanced and Extracellular Contrast Agent-Enhanced MRI

Introduction The optimal imaging modality and diagnostic criteria for accurately detecting and characterizing subcentimeter hepatocellular carcinoma (HCC) remain uncertain, and this study aims to compare performance of gadoxetic acid-enhanced MRI (EOB-MRI) and extracellular contrast agent-enhanced MRI (ECA-MRI) in detecting and characterizing subcentimeter HCC.
Methods A total of 1022 patients at risk of HCC (mean age, 53.80 ± 11.24, 732 men) with 1210 subcentimeter hepatic lesions were retrospectively included. Lesion detection rate and HCC characterization performance were calculated and compared between EOB-MRI and ECA-MRI sets using generalized estimating equation method.
Results Consensually, EOB-MRI demonstrated significantly higher sensitivity for detecting subcentimeter hepatic lesions compared to ECA-MRI (0.995 vs. 0.953, p < 0.001). EOB-MRI and ECA-MRI showed comparable performance in characterizing subcentimeter HCC based on typical vascular pattern (sensitivity, 0.382 vs. 0.457, p = 0.064; specificity 0.941 vs. 0.933, p = 0.462). After applying modified criteria, the sensitivities (EOB-MRI: 0.382 vs. 0.812, p < 0.001; ECA-MRI: 0.457 vs. 0.574, p < 0.001) were significantly increased on both MRIs by consensus reading, while specificities did not differ a lot (EOB-MRI: 0.859 vs. 0.941, p = 0.012; ECA-MRI: 0.894 vs. 0.933, p = 0.084). And compared with ECA-MRI, EOB-MRI exhibited significantly higher sensitivity (0.812 vs. 0.574, p < 0.001) based on modified criteria, without a substantial loss of specificity (0.859 vs. 0894, p = 0.162).
Conclusion EOB-MRI with modified criteria exhibited superior detection and characterization performance of subcentimeter HCC when compared with ECA-MRI in patients at risk of HCC, thus offering clinicians more opportunities to accurately identify high-risk subcentimeter lesions.