Diagnostic value of 18F-FDG-PET/CT in indeterminate infiltrative hepatic lesions in an endemic area of viral hepatitis

Abstract

Infiltrative hepatic lesions in conventional imaging modalities are a continuing diagnostic challenge in clinical practice, especially in an endemic area of viral hepatitis. The purpose of this study isto prospectively assess the role of F-fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography/computed tomography (PET/CT) in indeterminate infiltrative hepatic lesions seen in conventional CT or magnetic resonance imaging (MRI). Dual-phase FDG-PET/CT was performed on35consecutive patients with indeterminate infiltrative hepatic lesions in CT or MRI. The variables analyzed included visual score and maximum standardized uptakevalue. Final diagnosis was histopathology orclinicalfollow-up for at least 12 months. Malignancy was proven in 28 patients and there were benign strictures in seven patients. Sensitivity, specificity, and overall diagnostic accuracy of FDG-PET/CT using visual score were 85.7% (24/28), 71.4% (5/7), and 82.9% (29/35). Early and delayed maximum standardized uptake values were significantly higher in infiltrative hepatic malignancies than in benign lesions. Furthermore, PET/CT detected 13 unexpected distant metastatic foci notseen in other imaging studies. Thirteen patients (37.1%)had the plans of clinical treatment altered by FDG-PET/CT alone. FDG-PET/CT can help to clarify the diagnosis of indeterminate infiltrative hepatic lesions in CT or MRI. Inthis patient population, FDG-PET/CT may hold promisein the detection of unsuspected occult metastases, facilitating decision making and treatment planning.