18F-FDG-PET and Histopathology in 131I-Lipiodol Treatment for Primary Liver Cancer

Role of 18-FDG/PET in evaluation of hepatocellular carcinoma managed locally by transarterial chemoembolization compared to triphasic computed tomography

Background

This study was done to evaluate the role of FDG/PET compared to CECT in evaluating HCC after local interventional treatment. We evaluate forty-six patients with known history of TACE as a locoregional treatment of pathologically proved HCC. There were forty-three males and three females.

Results

The collected data were statistically analyzed, and we found that FDG-PET has a sensitivity of 94%, specificity of 84%, positive predictive value of 86.7%, negative predictive value of 86.4%, and accuracy of 93.4% in the detection of residual or recurrent at the managed tumor bed compared to CECT which shows a sensitivity of 94%, specificity of 84%, positive predictive value of 86.7%, negative predictive value of 86.4%, and accuracy of 93.4 %). Combined views ( FDG-PET/CT ) are better in evaluation.

Conclusion

FDG-PET is better in the detection of residual or recurrence in HCC which is locally managed by TACE.

Evaluation of metabolic characteristics and viability of lipiodolized hepatocellular carcinomas using 18F-FDG PET/CT

This study aimed to evaluate the metabolic characteristics of lipiodolized hepatocellular carcinomas (HCCs) and the diagnostic accuracy of (18)F-FDG PET/CT in assessing the viability of lipiodolized HCCs.

METHODS

Thirty-six patients (age range, 32-73 y) with 38 lipiodolized HCCs who had undergone transcatheter arterial chemoembolization (TACE) with lipiodol before (18)F-FDG PET/CT (2-434 d) and 55 patients (age range, 36-77 y) with 57 treatment-naïve HCCs who had not been treated with TACE were retrospectively studied. All patients underwent hepatic lobectomy or transplantation within 1 mo after PET/CT and multiphasic contrast-enhanced CT. (18)F-FDG uptake by lipiodolized and naïve HCCs was compared and correlated with tumor size, pathologic grade, serum α-fetoprotein (AFP) concentration, and time interval between TACE and PET/CT. The diagnostic accuracy of PET/CT and contrast-enhanced CT in evaluating the viability of lipiodolized HCC was compared.

RESULTS

Histologic examination showed 30 viable and 8 nonviable lipiodolized HCCs. Of the 30 viable tumors, 19 showed increased, 10 similar, and 1 decreased (18)F-FDG uptake. Of the 8 nonviable HCCs, 3 showed increased and 5 decreased (18)F-FDG uptake. Uptake by viable lipiodolized HCCs was correlated with tumor size (P < 0.05) but not correlated with pathologic grade, AFP concentration, or interval between TACE and PET/CT. In contrast, (18)F-FDG uptake by naïve HCCs was significantly correlated with tumor size and pathologic grade (P < 0.05 for each comparison). When lipiodolized HCCs with (18)F-FDG uptake that was greater than or similar to that in the surrounding normal liver were considered viable, the diagnostic sensitivity of PET/CT and contrast-enhanced CT in the early postembolic period (<3 mo) was 100% and 94%, respectively, and that in the late postembolic period was 93% and 79%, respectively. The specificity of (18)F-FDG PET/CT and contrast-enhanced CT was 63% and 100%, respectively, in the acute period. Three viable lipiodolized HCCs with high AFP concentration were true-positives on PET/CT but false-negatives on contrast-enhanced CT images.

CONCLUSION

After TACE, (18)F-FDG uptake in lipiodolized HCCs was not correlated with pathologic grade, in contrast to uptake in treatment-naïve HCCs. (18)F-FDG PET/CT showed a high diagnostic sensitivity in assessing the viability of lipiodolized HCCs, with moderate specificity. This method may be useful in determining the viability of lipiodolized HCCs in patients with increased serum AFP concentration or normal results on contrast-enhanced CT images.

Detection of hepatocellular carcinoma with PET/CT: a prospective comparison of 18F-fluorocholine and 18F-FDG in patients with cirrhosis or chronic liver disease

This prospective study aimed to compare the diagnostic performance of (18)F-fluorocholine and (18)F-FDG for detecting and staging hepatocellular carcinoma (HCC) in patients with chronic liver disease and suspected liver nodules.

METHODS

Whole-body PET/CT was performed in a random order at 10 min after injection of 4 MBq of (18)F-fluorocholine per kilogram and at 1 h after injection of 5 MBq of (18)F-FDG per kilogram. PET/CT results were read in a masked manner by 2 specialists, and diagnostic performance was assessed from the results of consensus masked reading. Those focal lesions appearing with increased or decreased activity, compared with background, on (18)F-fluorocholine PET/CT were considered positive for malignancy. The standard of truth was determined on a per-site basis using data from a histologic examination and a follow-up period of more than 6 mo; on a per-patient basis, the Barcelona criteria were also accepted as a proof of HCC in 5 patients.

RESULTS

Eighty-one patients were recruited; standard of truth was determined in 59 cases. HCC was diagnosed in 34 patients. Therefore, sensitivity was 88% for (18)F-fluorocholine and 68% for (18)F-FDG (P = 0.07), and in 70 sites, sensitivity was 84% for (18)F-fluorocholine, significantly better than the 67% for (18)F-FDG (P = 0.01). Of the 11 patients with well-differentiated HCC, 6 had a positive result with (18)F-fluorocholine alone, whereas (18)F-FDG was never positive alone; corresponding site-based sensitivity was 94% for (18)F-fluorocholine and 59% for (18)F-FDG (P = 0.001). The detection rate of 18 sites corresponding to other malignancies was 78% for (18)F-fluorocholine and 89% for (18)F-FDG. In nonmalignant sites, (18)F-fluorocholine appeared less specific than (18)F-FDG (62% vs. 91% P < 0.01) because of uptake by focal nodular hyperplasia.

CONCLUSION

(18)F-fluorocholine was significantly more sensitive than (18)F-FDG at detecting HCC, in particular in well-differentiated forms. In contrast, (18)F-FDG appeared somewhat more sensitive at detecting other malignancies and was negative in focal nodular hyperplasia. Thus (18)F-fluorocholine appears to be a useful PET/CT tracer for the detection and surveillance of HCC; however, performing PET/CT with both radiopharmaceuticals seems to be the best option.