Small hepatocellular carcinoma treated with percutaneous ethanol injection: unenhanced and gadolinium-enhanced MR imaging follow-up.

Abstract

To determine the value of magnetic resonance (MR) imaging in follow-up of small (< 3 cm) hepatocellular carcinoma treated with percutaneous ethanol injection (PEI). Fifty-seven patients underwent MR imaging before and after PEI. At follow-up every 6 months, MR images were correlated with results of fine-needle aspiration biopsy (FNAB). In 12 patients, correlation with histologic findings in surgical specimens was possible. In 39 patients followed up for 24 months, the treated lesions showed hypointensity on unenhanced (T2-weighted) images and loss of enhancement on enhanced (T1-weighted) images. At 6-month follow-up in six patients, the lesions showed areas of hyperintensity on unenhanced images and enhancement on enhanced images. These lesions contained residual viable tumor at FNAB. Twelve patients underwent surgical resection after 6-month follow-up. Correct diagnosis of complete or partial tumor necrosis was made in nine of these 12 patients with enhanced images and in three with unenhanced images. Gadolinium-enhanced T1-weighted MR imaging is more accurate than unenhanced T2-weighted MR imaging in evaluation of PEI therapy.