Published online Dec 28, 2015. doi: 10.4254/wjh.v7.i30.2933
Peer-review started: May 25, 2015
First decision: August 16, 2015
Revised: October 7, 2015
Accepted: December 1, 2015
Article in press: December 2, 2015
Published online: December 28, 2015
Gadoxetic acid- or gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI) achieves excellent lesion detection and characterization for both hypervascular hepatocellular carcinoma (HCC) in arterial phase imaging and hypovascular early HCC (small well-differentiated HCC of the vaguely nodular type) in hepatobiliary phase imaging, and has become an indispensable imaging modality in the treatment of HCC. Early HCCs have been detected more frequently since the introduction of EOB-MRI into daily clinical practice. Early HCC is known to progress to conventional hypervascular HCC, and many risk factors have been identified for the hypervascularization of early HCC including the diameter of the tumor, presence of fat, and imaging findings of EOB-MRI. The rate of the development of hypervascular HCC was previously reported to be high in patients with chronic liver disease and early HCC. The presence of early HCC is regarded as a predictor for the recurrence of HCC following hepatic resection. On the other hand, although early HCC itself is currently not regarded as a target lesion for hepatic resection, early HCC at high risk of hypervascularity needs to be treated by local ablation therapy. If concomitant early HCC with progressed HCC is at high risk of hypervascularization and the functional liver reserve of a patient is sufficient, its simultaneous treatment at the time of hepatic resection for progressed HCC is recommended. Further studies on larger numbers of patients are needed before this strategy is adopted.
Core tip: Gadoxetic acid- or gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging has excellent lesion detection and characterization for both hypervascular hepatocellular carcinomas (HCC) in arterial phase imaging and hypovascular early HCC in hepatobiliary phase imaging, and has become an indispensable imaging modality in the treatment of HCC. Early HCC is known to progress to conventional hypervascular HCC. Although early HCC itself is currently not considered to be a target lesion for hepatic resection, if concomitant early HCC with progressed HCC is at high risk of hypervascularization, its simultaneous treatment at the time of hepatic resection is recommended.