Malignant transformation of hypointense nodules seen only on hepatobiliary phase gadoxetic acid-enhanced MR imaging : a systematic review and meta-analysis

Abstract

Background: Hypointense nodules detected on the hepatobiliary phase (HBP) of gadoxetic acid–enhanced magnetic resonance imaging (MRI) are frequently seen in patients with chronic liver disease or cirrhosis. Such nodules may represent a spectrum from dysplasia to early hepatocellular carcinoma (HCC), and the development of arterialphase hyperenhancement and subsequent hypervascular transformation of these lesions is indicative of an increased malignant potential. Aim: Through a comprehensive systematic review and meta-analysis, this study seeks to evaluate the outcomes of hypointense nodules observed in the hepatobiliary phase on gadoxetic acid-enhanced MRI and to identify the risk factors associated with their hypervascular transformation. Methods: A computerised search of the Pubmed, Web of Science and Scopus databases was carried out to identify relevant literature reports on hypovascular hypointense nodules in the hepatobiliary phase of gadoxetic acid–enhanced MRI that will eventually undergo hypervascular transformation. Results: 18 studies were included in this meta-analysis, with 1563 patients and a total of 2136 hypointense hypovascular hepatic nodules. The pooled overall rate of hypervascular transformation was 34.4%, (95% CI: [28.7%, 40.2%]) and I2 was 87.4%. The pooled 1-, 2- and 3-year cumulative incidence rates were 19.7% (95% CI: [9.1%, 30.4%]), 27.9%, (95% CI: [16.3%, 39.5%]); and 27.2% (95% CI: [17.7%, 36.7%], respectively. A metaregression analysis revealed that the heterogeneity of malignant transformation was significantly affected by the initial mean nodule size, with a cutoff value of 9 mm. Conclusion: Hypovascular hypointense nodules observed during the hepatobiliary phase of Gadoxetic acid-enhanced MRI present a considerable risk of progressing to hypervascular hepatocellular carcinomas (HCCs). Initial nodule size is an important predictor of hypervascular transformation, with larger nodules being more likely to undergo this process. This highlights the importance of close monitoring, to enable timely intervention to improve patient outcomes.