Percutaneous ethanol injection therapy for hepatocellular carcinoma: validity of MR imaging in the evaluation of treatment effect.

To evaluate the validity of magnetic resonance imaging for the follow-up of percutaneous ethanol injection therapy, 14 patients with a single hepatocellular carcinoma lesion smaller than 2.5 cm in diameter underwent MR imaging at 0.5 Tesla before and after treatment. Posttreatment follow-up examination included ultrasonography, contrast-enhanced computed tomography, and fine-needle biopsy in all cases. Only one patient showed recurrence within the 12-month follow-up period. After treatment, HCC lesions showed hypointensity on T1-, and T2-weighted images that lasted 12 months after treatment. In three cases, wedge-shaped hyperintense regions peripheral to the HCC nodule were observed after treatment on T2-weighted images. Obstructive vasculitis of the portal vein was considered to occur as a result of the drainage of ethanol injected in the tumor. These MR imaging findings may be helpful in clinical practice.