FDG-PET/CT imaging findings of hepatic tumors and tumor-like lesions based on molecular background

Abstract

The usefulness of whole-body 18-fluoro-2-deoxyglucose (FDG)-fluorodeoxyglucose positron emission (PET)/computed tomography (CT) is established for assessment of disease staging, detection of early disease recurrence, therapeutic evaluation, and predicting prognosis in various malignancies; and for evaluating the spread of inflammation. However, the role of FDG-PET/CT for the liver is limited because CT and magnetic resonance imaging (MRI) can provide an accurate diagnosis of most tumors. In addition, in other potentially useful roles there are several pitfalls in the interpretation of FDG uptake in PET/CT imaging. Accurate evaluation demands knowledge of the FDG uptake of each lesion, including potential negative and positive uptakes, and requires an understanding of the underlying background of the molecular mechanisms. The degree of FDG uptake is dependent on cellular metabolic rate and the expression of glucose transporter, hexokinase, and glucose-6-phosphatase, which in turn are closely affected by biological characteristics such as pathological category (e.g., adenocarcinoma, squamous cell carcinoma, small cell cancer, transitional cell cancer, neuroendocrine tumor, sarcoma, lymphoma), tumor differentiation, histological behavior (e.g., solid, cystic, mucinous), and intratumoral alterations (e.g., necrosis, degeneration, hemorrhage). Correlation with the CT and MRI findings, which also precisely depict the pathological findings, is important to avoid misdiagnosis.

Feasibility of Patlak parametric imaging in the diagnosis of liver cancer

“…Liver is usually the nidus where malignant tumours are more likely to metastasise and is a good site for metastatic cancer, cause malignant problems. Liver is also a target organ for many malignant diseases and is associated with a large number of benign lesions [13]. Early diagnosis is therefore very important.…”

An activated excretion-retarded tumor imaging strategy towards metabolic organs

“…Based on the metabolism difference between tumors and normal tissues, 18F-FDG was designed for tumor detection before operation, which has achieved encouraging accomplishments through the combined use of PET/CT [ 11 ]. However, a variety of tumor types exhibit a non-specific difference to normal tissue on metabolism in the initial stage, which results in a lower detectable rate (50–65% for 18F-FDG) [ 12 ].…”

Case report: Rare isolated cystic hepatic metastasis of a patient with squamous cell lung carcinoma history and the prognosis

“…Imaging examinations like contrast-enhanced computed tomography (CT), magnetic resonance (MR), and ultrasound (US) are indispensable methods to differentiate these diagnoses ( 5 , 6 ). 18F-Fluorodeoxyglucose ( 18 F-FDG) PET/CT has been applied as a useful tool for malignance staging due to its whole-body scan and glucose-metabolic assessment for metastases ( 7 ). However, it is still necessary to perform aspiration biopsy for definitive pathological diagnosis of hepatic cystic lesion ( 8 ).…”