Outcome of hypovascular hepatic nodules revealing no gadoxetic acid uptake in patients with chronic liver disease.

PURPOSE

To elucidate the natural history of hypovascular nodules that appear hypointense on hepatocyte-phase gadoxetic acid-enhanced MR images by focusing on hypervascularization over time.

MATERIALS AND METHODS

In this study, 135 hypovascular nodules revealing no gadoxetic acid uptake in 53 patients were examined. All nodules were retrospectively examined using serial follow-up computed tomography (CT) and MRI examinations until hypervascularity was observed on arterial-phase dynamic CT or gadoxetic acid-enhanced MR images, or on CT during hepatic arteriography. Logistic regression analysis was used to investigate the association between hypervascularization and MR findings including a presence of fat assessed by a signal drop on opposed-phase T1-weighted images.

RESULTS

Of the 135 nodules, 16 underwent hypervascularization. The size of the nodules and the presence of fat in the nodules were independent indicators of hypervascularization. The 1-year cumulative risk of hypervascularization was 15.6%. This risk was significantly increased in the case of nodules >10 mm (37.6%, P < 0.01) and fat-containing nodules (26.5%, P < 0.01).

CONCLUSION

Hypovascular nodules that appear hypointense on hepatocyte-phase gadoxetic acid-enhanced MR images may progress to conventional hypervascular hepatocellular carcinoma. Nodules more than 10 mm in diameter and containing fat are at high risk for developing hypervascularization.