Contrast-enhanced US in assessment of hepatocellular carcinoma following percutaneous ethanol injection

Background: This study was designed to evaluate the use of contrast- enhanced ultrasound (CEUS) in the assessment of hepatocellular carcinoma (HCC) following percutaneous ethanol injection (PEI). Materials and Methods: Over a six-month period, CEUS was performed in 21 cases of HCC. Thirty tumors were identified. There was a single tumor in 15 patients, two tumors in three patients and three tumors in the remaining three patients. The mean size of the tumors was 2.4 cm (range, 1.7-4.9 cm). Serial CEUS studies with power Doppler ultrasound (PDU) were carried out before and within one to two weeks following multi-session PEI therapy. These results were subsequently compared with those obtained by angiography and/or dynamic computerized tomography (CT). Results: All 30 lesions showed positive contrast enhancement on PDU (grade 1-2+). After the initial multi-session PEI course, 25 tumors showed no vascularity on contrast-enhanced PDU. The remaining five tumors demonstrated contrast-enhanced PDU evidence of residual tumor vascularity, confirmed by dynamic CT and/or angiography, and were subsequently treated with a second course of PEI. There was a successful outcome in three and the remaining two were treated additionally with transcatheter arterial embolization to ensure complete tumor necrosis. Conclusion: CEUS may be a useful imaging modality in US-guided PEI of HCC. It can be used to assess the response of PEI therapy and as a guide in targeting the residual tumor during a second course of PEI.