Diagnostic Value of 18F-FDG-PET/CT in Patients with FUO.

Stamata Georga,Stamata Georga,Vasilios Mpalaris,Paraskevi Exadaktylou,Paraskevi Exadaktylou,Christos Papastergiou,Efstratios-Iordanis Moralidis,Efstratios-Iordanis Moralidis,Georgios Arsos,Georgios Arsos,Kostoula Arvaniti,Ioannis Petrou,Ioannis Petrou,Dimitrios Katsampoukas,Dimitrios Katsampoukas

doi:10.3390/jcm9072112

Abstract

Conventional diagnostic imaging is often ineffective in revealing the underlying cause in a considerable proportion of patients with fever of unknown origin (FUO). The aim of this study was to assess the diagnostic value of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) in patients with FUO. We retrospectively reviewed 18F-FDG-PET/CT scans performed on 50 consecutive adult patients referred to our department for further investigation of classic FUO. Final diagnosis was based on histopathological and microbiological findings, clinical criteria, or clinical follow-up. Final diagnosis was established in 39/50 (78%) of the patients. The cause of FUO was infection in 20/50 (40%), noninfectious inflammatory diseases in 11/50 (22%), and malignancy in 8/50 (16%) patients. Fever remained unexplained in 11/50 (22%) patients. 18F-FDG-PET/CT scan substantially contributed to the diagnosis in 70% of the patients, either by identifying the underlying cause of FUO or by directing to the most appropriate site for biopsy. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of 18F-FDG-PET/CT for active disease detection in patients with FUO were 94.7%, 50.0%, 84.0%, 85.7%, and 75.0%, respectively. In conclusion, whole-body 18F-FDG-PET/CT is a highly sensitive method for detection of the underlining cause of FUO or for correctly targeting suspicious lesions for further evaluation.

Highlights

Despite the immense progress of laboratory and imaging modalities, fever of unknown origin (FUO) remains a diagnostic challenge
The differential diagnosis of FUO includes a wide spectrum of highly heterogeneous diseases, which is traditionally subdivided into four categories: infections, malignancies, non-infectious inflammatory diseases (NIID), and miscellaneous causes, with their incidence strongly affected by the local epidemiology [6,7]
From November 2016 to July 2019, fifty-four patients were referred to our PET/Computed tomography (CT) facility installed in a 700-bed academic general hospital, for classic FUO investigation

Summary

Introduction

Despite the immense progress of laboratory and imaging modalities, fever of unknown origin (FUO) remains a diagnostic challenge. FUO was originally defined by Petersdorf and Beeson in 1961 as body temperature higher than 38.3 ◦C, on at least three occasions over a period of at least three weeks, with no diagnosis made despite one week of inpatient investigation [1]. The initial definition of FUO was subsequently modified by Durack and Street in 1991 by removing the requirement of inpatient investigation and by excluding immunocompromised patients as they may require an entirely different diagnostic approach [2]. The quantitative criterion of uncertain diagnosis after a period of time was proposed to be replaced by a qualitative criterion of a number of obligatory investigations that should be performed to qualify the condition as FUO [3,4,5]. The proportion of undiagnosed cases of FUO ranged from 7% to 53% in various studies, indicating that the diagnostic investigation of FUO still remains a challenge [7,8]

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