Percutaneous alcohol injection (PAI) is reported as a safe, inexpensive and effective method of treatment of small HCC in severely ill patients. Nevertheless, residual cancer can persist after treatment and multiple bioptic manoeveurs are needed to ascertain the actual completeness of treatment. In two cases of HCC treated by ethanol injections, MRI on T2 weighted sequences showed a characteristic change from the previous hyperintense or isointense signal to a hypointense one. This MRI pattern, quite different from the usual HCC features, was correlated to the histologic findings of complete coagulative necrosis of the tumoural mass. Further observations are needed to assess reproducibility and specificity of this finding and the MRI pattern needs to be evaluated also in unsatisfactory percutaneous alcohol treatment of HCC in order to demonstrate that cases with persistent neoplastic tissue display a different pattern. If our report should be confirmed, MRI might be a not invasive tool in evaluating the effectiveness of PAI in patients at risk for multiple histologic samplings. Furthermore MRI could be very useful in assessing the degree and extent of tissutal changes in response to local therapy also after the tumour and its margin are masked by US guided ethanol injections.