Importance of Blood Glucose Management Before 18F-FDG PET/CT in 322 Patients with Bacteremia of Unknown Origin

EANM consensus document on the use of [18F]FDG PET/CT in fever and inflammation of unknown origin

PURPOSE

Patients with fever and inflammation of unknown origin (FUO/IUO) are clinically challenging due to variable clinical presentations with nonspecific symptoms and many differential diagnoses. Positron emission tomography/computed tomography (PET/CT) with 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) is increasingly used in FUO and IUO, but the optimal diagnostic strategy remains controversial. This consensus document aims to assist clinicians and nuclear medicine specialists in the appropriate use of [18F]FDG-PET/CT in FUO and IUO based on current evidence.

METHODS

A working group created by the EANM infection and inflammation committee performed a systematic literature search based on PICOs with "patients with FUO/IUO" as population, "[18F]FDG-PET/CT" as intervention, and several outcomes including pre-scan characteristics, scan protocol, diagnostic yield, impact on management, prognosis, and cost-effectiveness.

RESULTS

We included 68 articles published from 2001 to 2023: 9 systematic reviews, 49 original papers on general adult populations, and 10 original papers on specific populations. All papers were analysed and included in the evidence-based recommendations.

CONCLUSION

FUO and IUO remains a clinical challenge and [18F]FDG PET/CT has a definite role in the diagnostic pathway with an overall diagnostic yield or helpfulness in 50-60% of patients. A positive scan is often contributory by directly guiding treatment or subsequent diagnostic procedure. However, a negative scan may be equally important by excluding focal disease and predicting a favorable prognosis. Similar results are obtained in specific populations such as ICU-patients, children and HIV-patients.

Gallium68-Labeled Fibroblast Activation Protein Inhibitor (68Ga-FAPI) PET/CT as an Alternative to Fluoro18-Fluorodeoxyglucose (18F-FDG) PET/CT: Discussion in a Case of Metastatic Adenocarcinoma of Pancreas

Positron emission tomography (PET) is an integral part of the imaging of solid tumors in today's oncology practice. The most commonly used PET radiotracer is 18F-Fluorodeoxyglucose (18F-FDG). FDG PET has imaging characteristics of a high tumor-to-background uptake ratio and is used in the detection of primary as well as metastatic sites. However, a significant pitfall is its inability to differentiate between neoplastic and infective lesions. To address this concern, many PET radiotracers have been developed and tried over time, a promising one being radiolabelled fibroblast activation protein inhibitor (FAPI). Fibroblast-activated protein (FAP) is a type II transmembrane glycoprotein expressed by cancer-associated fibroblasts (CAFs); it forms a significant component of the tumor stroma. Since there is over-expression of CAF in the majority of malignancies, it is a potential target for molecular imaging using PET. Several radiolabeled FAP inhibitors have been developed for PET imaging of malignancies and have also been used in theranostic applications.