Ablation of hepatocellular carcinoma by percutaneous ethanol injection: imaging findings

Usefulness of F-18 FDG PET/CT in the Evaluation of Early Treatment Response After Interventional Therapy for Hepatocellular Carcinoma

PURPOSE

This retrospective study investigated the usefulness of F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) after interventional therapy for hepatocellular carcinoma (HCC).

METHODS

Between March 2007 and November 2010, 31 patients (24 men, 7 women; mean age, 61.8 ± 11.0 years) with 45 lesions underwent PET/CT within 1 month after interventional therapy for HCC. Twenty-six patients with 40 lesions underwent transcatheter arterial chemoembolization (TACE), two patients with 2 lesions underwent radiofrequency ablation (RFA), and three patients with 3 lesions underwent percutaneous ethanol injection therapy (PEIT). Patients with a history of previous interventional therapy were excluded. Visual analysis was graded as positive when FDG was observed as an eccentric, nodular, or infiltrative pattern, and negative in case of isometabolic, hypometabolic, or rim-shaped uptake. For quantitative analysis, the standardized uptake value (SUV) was measured by region of interest technique. Maximum SUV (SUVmax) was assessed, and the ratio of SUVmax of tumor to mean SUV of normal liver (TNR) was calculated. The patients were divided into two groups, with and without residual tumor, based on 6-month clinical follow-up with serum alpha-fetoprotein and contrast-enhanced abdominal CT.

RESULTS

Of the 45 lesions, 24 were classified in the residual tumor group and the other 21 lesions in the no residual tumor group. No residual tumor was detected after RFA or PEIT. By visual analysis, the respective values for sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 87.5, 71.4, 77.8, 83.3, and 80.0 %. However, there were no significant differences in the SUVmax and TNR between the two groups.

CONCLUSIONS

It is suggested that FDG PET/CT may play a role in the evaluation of early treatment response after interventional therapy for HCC. The results indicate that FDG PET/CT visual analysis may be more useful than quantitative analysis. Further prospective studies with a large number of patients and established protocol are needed to substantiate our results.

MR‐guided percutaneous ethanol ablation of hepatocellular carcinomas before liver transplantation

It was the objective of this study to evaluate MR-guided, percutaneous ethanol injection of hepatocellular carcinoma in ten patients scheduled for liver transplantation. Using a 0.2 T open MR scanner (Magnetom Open, Siemens Medical Systems, Erlangen, Germany) and percutaneous instillation of ethanol, 12 liver tumors (median tumor volume, 6.3; range, 0.6-43.2 ccm) were treated. Coagulation necrosis, morbidity, and post-transplant histology were assessed. No major complications were observed. A mean of 16.4+/-11.4 ml ethanol was injected for each tumor. The median volume of the ablation necrosis was 12.3 (range, 0.3-48.3) ccm. Three tumors were retreated and complete radiological necrosis before liver transplantation was found in eight of 12 tumors (67%). One patient developed multifocal disease and was excluded from transplantation; thus nine of ten patients underwent liver transplantation within 3.9+/-3.1 months. In the explants, satellite nodules (n = 2), new liver tumors (n = 2) and a complete necrosis were found in five of 12 treated tumors (42%). During follow-up (median 41.3; range, 0.4-86.1 months), three patients died, but no tumor-seeding or post-transplantation recurrence occurred. MR-guided ethanol injection is feasible, and may delay tumor progression. However, the local recurrence rate is high, and the spatial resolution of a low-field MR scanner limits the detection of small tumors.

Elastographic evaluation of the temporal formation of ethanol-induced hepatic lesions: preliminary in vitro results

OBJECTIVE

The purpose of this study was to evaluate the temporal formation of ethanol-induced hepatic lesions using ultrasound elastography.

METHODS

An in vitro porcine liver was used as the specimen, and 4 lesions were created by injection of 2 mL of ethanol. After the ethanol injection, freehand elastography of the lesion from an identical scan plane was obtained during a time series (with an interval of approximately 30 seconds in the first 2 minutes and 1 minute afterward) using a real-time ultrasound scanner. The area of the lesion in the elastographic sequences was calculated to depict the temporal formation of the lesion.

RESULTS

The ethanol-induced lesion on elastography appeared as a low-strain region whose boundary was clear and irregular. The elastographic sequences obtained after the ethanol injection showed that the lesion formed quickly in the first 2 minutes and then changed little in shape. The area of the lesion grew notably in the first 2 minutes after ethanol injection, and then it reached a plateau of about 0.7 cm(2).

CONCLUSIONS

Ultrasound elastography is capable of monitoring the temporal formation of ethanol-induced lesions and is a potential imaging modality to evaluate the response of percutaneous ethanol injection therapy.

Hepatocellular carcinoma in elderly patients: beneficial therapeutic efficacy using percutaneous ethanol injection therapy

BACKGROUND

The age of patients with hepatocellular carcinoma (HCC) has been increasing worldwide. The objective of this study was to assess the efficacy and safety of percutaneous ethanol injection therapy (PEIT) in elderly patients with HCC.

METHODS

The authors retrospectively analyzed 653 patients who were treated with PEIT between 1985 and 1997. One hundred thirty-seven patients were age > or = 70 years, 90 of 137 patients (66%) were male, and 106 of 137 patients (77%) were positive for hepatitis C virus antibodies. Both survival rates and standardized mortality ratios (SMRs) related to the causes of death were compared between patients age > or = 70 years and patients age < 70 years.

RESULTS

With the exception of greater maximum tumor size in elderly patients age > or = 70 years, the clinical features of tumors and underlying liver disease were similar to those of patients age < 70 years The survival rates after PEIT in patients age > or = 70 years were 83%, 52%, and 27% at 1 year, 3 years, and 5 years, respectively. These results were comparable to the rates for patients age < 70 years (1 year, 90%; 3 years, 65%; and 5 years, 40%). In addition, there was no difference in mortality from extrahepatic disease between the two groups (9.8% for patients age > or = 70 years vs. 9.4% for patients age < 70 years; P > 0.999). The SMR of patients age > or = 70 years who died of causes related to extrahepatic disease (SMR, 0.56; 95% confidence interval [95%CI], 0.18-1.30) was lower compared with the SMR of patients age < 70 years (SMR, 1.75; 95%CI, 1.07-2.71). The SMR of patients age > or = 70 years who died of causes related to liver disease (SMR, 115; 95%CI, 84.1-153.0) was similar to that of patients age < 70 years (SMR, 120; 95%CI, 103.0-138.0).

CONCLUSIONS

These results provide support for the treatment of patients with HCC age > or = 70 years by tumor ablation using PEIT.

Percutaneous ablation of liver malignancies: imaging evaluation of treatment response

Interventional procedures for percutaneous tumor ablation have gained an increasingly important role in the treatment of liver malignancies. After interventional therapies, diagnostic imaging has the key role to determine if the treated lesion is completely ablated or contains areas of residual viable neoplastic tissue. This is particularly important since in cases of incomplete necrosis of the lesions, treatment can be repeated, and tumor ablation can be further pursued. The evaluation of the therapeutic effect of the procedure arises different problems according to the histotype of the malignancy. In the case of hepatocellular carcinoma (HCC), detection of residual viable tumor is facilitated by the typical hypervascular pattern of this neoplasm. Contrast-enhanced US can be used to monitor tumor response, and, in cases of partial necrosis, to target the areas of residual viable tumor. With spiral CT or dynamic MR imaging, residual viable HCC is reliably depicted as it stands out in the arterial phase images against the unenhanced areas of coagulation necrosis. In the case of hypovascular metastases, a confident diagnosis of successfull ablation can be made when an area of thermal necrosis exceeding that of the original lesion is depicted. Peripheral inflammatory reaction following ablation procedures, that shows itself as an enhancing halo along the necrotic area boundary on spiral CT or dynamic MR images, should not be misinterpreted as tumor progression.

Nonsurgical treatment of hepatocellular carcinoma

Given the poor prognosis of HCC and the therapeutic challenge posed by underlying liver cirrhosis, efforts and resources must be directed towards preventive strategies. Return on the investment in such research is likely to be greater than can be expected from treatment of advanced disease.

Contrast-enhanced ultrasound for guidance of local tumor ablation

The objective was to assess the efficacy of sonography with and without contrast medium enhancement in guiding and monitoring percutaneous ethanol ablation of tumors in an animal model. VX-2 carcinoma was implanted into the thighs of New Zealand white rabbits and examined by grey-scale ultrasound, color, power, and pulse Doppler, before and after injection of 95% ethanol into the tumors. Injections of ethanol were guided by ultrasound to sites of tumor vascularity, until all tumor vascularity had been obliterated. Microbubble contrast medium or saline was injected i.v. prior to each of the ultrasonic interrogations. Arteriography was performed before and after ablation. Selected tumor samples were submitted for histologic examination. Contrast enhanced tumor vascularity over saline controls in all cases. In some, incompletely ablated foci of tumor could only be identified with contrast medium enhancement. Arteriography showed complete ablation of all but 1 tumor. We conclude that ultrasound enhanced by contrast better shows the presence or absence of tumor vascularity. Ultrasound enhanced by contrast might offer an accurate means of guiding and monitoring percutaneous ethanol injection for tumor ablation.