SMALL HEPATOCELLULAR-CARCINOMA TREATED WITH PERCUTANEOUS ETHANOL INJECTION - UNENHANCED AND GADOLINIUM-ENHANCED MR-IMAGING FOLLOW-UP

PURPOSE: To determine the value of magnetic resonance (MR) imaging in follow-up of small (<3 cm) hepatocellular carcinoma treated with percu taneous ethanol injection (PEI). MATERIALS AND METHODS: Fifty-seven pa tients underwent MR imaging before and after PEI. At follow-up every 6 months, MR images were correlated with results of fine-needle aspirat ion biopsy (FNAB). In 12 patients, correlation with histologic finding s in surgical specimens was possible. RESULTS: In 39 patients followed up for 24 months, the treated lesions showed hypointensity on unenhan ced (T2-weighted) images and loss of enhancement on enhanced (T1-weigh ted) images. At 6-month follow-up in six patients, the lesions showed areas of hyperintensity on unenhanced images and enhancement on enhanc ed images. These lesions contained residual viable tumor at FNAB. Twel ve patients underwent surgical resection after 6-month follow-up. Corr ect diagnosis of complete or partial tumor necrosis was made in nine o f these 12 patients with enhanced images and in three with unenhanced images. CONCLUSION: Gadolinium-enhanced T1-weighted MR imaging is more accurate than unenhanced T2-weighted MR imaging in evaluation of PEl therapy.