Comparison of extracellular and hepatobiliary MR contrast agents for the diagnosis of small HCCs

Background & Aims: The aim of this study was to use a head-to-head nodule comparison to compare the performance of extracellular contrast agent MRI (ECA-MRI) with that of hepatobiliary contrast agent MRI (HBA-MRI) for the non-invasive diagnosis of small hepatocellular carcinomas (HCCs). Methods: Between August 2014 and October 2017, 171 patients with cirrhosis, each with 1 to 3 nodules measuring 1-3 cm, were enrolled across 8 centers. All patients underwent both an ECA-MRI and an HBA-MRI within a month. A non-invasive diagnosis of HCC was made when a nodule exhibited arterial phase hyper-enhancement (APHE) with washout at the portal venous phase (PVP) and/or delayed phase (DP) for ECA-MRI, or the PVP and/or HB phase (HBP) for HBA-MRI. The gold standard was defined by using a previously published composite algorithm. Results: A total of 225 nodules, of which 153 were HCCs and 72 were not, were included. The sensitivites of both MRI techniques were similar. Specificity was 83.3% (95% CI 72.7-91.1) for ECA- MRI and 68.1% (95% CI 56.0-78.6) for HBA-MRI. In terms of HCC diagnosis on ECA-MRI, 138 nodules had APHE, 84 had washout at PVP, and 104 at DP; on HBA-MRI, 128 nodules had APHE, 71 had washout at PVP, and 99 at HBP. For nodules 2-3 cm in size, sensitivity and specificity were similar between the 2 approaches. For nodules 1-2 cm in size, specificity dropped to 66.1% (95% CI 52.2-78.2) for HBA-MRI vs. 85.7% (95% CI 73.8-93.6) for ECA-MRI. Conclusions: HBA-MRI specificity is lower than that of ECA-MRI for diagnosing small HCCs in patients with cirrhosis. These results raise the question of the proper use of HBA-MRI in algorithms for the non-invasive diagnosis of small HCCs. Lay summary: There are 2 magnetic resonance imaging (MRI)-based approaches available for the non-invasive diagnosis of hepatocellular carcinoma (HCC), using either extracellular or hepatobiliary contrast agents. The current results showed that the sensitivity of MRI with hepatobiliary contrast agents was similar to that with extracellular contrast agents, but the specificity was lower. Thus, hepatobiliary contrast agent-based MRI, although detailed in international guidelines, should be used with caution for the non-invasive diagnosis of HCC. Clinical trial number: NCT00848952. (c) 2019 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.