Role of 18-F FDG-PET/CT in the Assessment of Extra Hepatic Metastatic Disease in Patients with Heptocellular Carcinoma (HCC) Post Hepatic Intervention

Background: Hepatocellular Carcinoma (HCC) is the cause of 250,000 deaths worldwide each year. Early HCC is typically clinically silent, and the disease is often well advanced at the first manifestation.Complete surgical resection and hepatic transplantation offer the best chance of a cure for HCC. However, surgery is often precluded by extensive disease or poor hepatic functional reserve.Positron Emission Tomography (PET) performed with 2- [Fluorine-18] Fluoro-2-Deoxy-D-Glucose (FDG) has proved valuable in providing important tumor-related qualitative and quantitative metabolic information that is critical to diagnosis and follow-up. PET-Computed Tomography (CT) is a unique combination of the cross-sectional anatomic information provided by CT and the metabolic information provided by PET, which are acquired during a single examination and fused.Several minimally invasive percutaneous techniques are now available to help manage localized HCC. The most used locoregional therapy consists of imaging-guided percutaneous ethanol or thermal ablation, such as Radiofrequency Ablation (RFA) and microwave ablation, TACE, and trans-arterial radioembolization.Many studies have indicated a greater accuracy of metastatic staging and detecting recurrent HCC by FDG-PET than by CT and other standard diagnostic modalities.Metastatic extra hepatic lesions show focal increased FDG uptake at regional and distant lymph nodes, pulmonary nodules and bones.Objective: The purpose of this study is to emphasis the role of combined PET/CT examination in detection of metastatic extra hepatic lesions in Heptocellular Carcinoma (HCC) post hepatic intervention.Patients and Methods: This is a retrospective study carried out in Alfa Scan Radiology Center from March 2013 to March 2015 for in patients pathologically proven to have HCC on top of liver cirhosis after session or more of local therapy. a total number of 40 patients: 33 (82.50%) male and 7 (17.50%) females with a median age 57.55±6.93(range, 42-47). The reference standard to determine the accuracy of the imaging findings is follow-up of the patient by PET/CT and other modalities and clinical data.Results: CECT had sensitivity and specificity of 76.7%, 100% respectively with Positive Predictive Value (PPV) of 100%, Negative Predictive Value (NPV) of 58.8% and accuracy of 82.5%. PET had sensitivity and specificity of 96.7%, 100% respectively with Positive Predictive Value (PPV) of 100%, Negative Predictive Value (NPV) of 90.9% and accuracy of 97.50%.Conclusion: FDG-PET/CT proved to be highly sensitive and specific in the assessment of hepatic bed after local therapy of HCC regardless the degree of tumor vascularity that could limit detecting residual disease based on contrast CT/MRI imaging.