Diagnostic value of F-18 FDG PET/CT in fever or inflammation of unknown origin in a large single-center retrospective study

Friedrich Weitzer,Reingard Maria Aigner,Tina Nazerani Hooshmand,Erich Sorantin,Birgit Pernthaler

doi:10.1038/s41598-022-05911-7

Friedrich Weitzer, Reingard Maria Aigner + Show 3 more

Open Access

https://doi.org/10.1038/s41598-022-05911-7

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Journal: Scientific Reports	Publication Date: Feb 3, 2022
Citations: 14	License type: open-access

Affiliation: Medical University of Graz

Abstract

Cause determination is challenging in fever or inflammation of unknown origin (FUO/IUO) despite today’s diagnostic modalities. We evaluated the value of F-18 FDG PET/CT in an unselected patient collective. This retrospective nonrandomized single-center study enrolled 300 male and female patients with FUO/IUO. PET/CT findings were compared with final clinical outcomes to determine the sensitivity, specificity, clinical significance, etiological distribution of final diagnoses, impact on treatment, role of white-blood cell count (WBC), and C-reactive protein (CRP). In 54.0% (162/300) PET/CT was the decisive exanimation for establishing the final diagnosis, in 13.3% (40/300) the findings were equivocal and indecisive, in 3.3% (10/300) PET/CT findings were false positive, while in 29.3% (88/300) a normal F-18 FDG pattern was present. Statistical analysis showed a sensitivity of 80.2% and a specificity of 89.8% for the contribution of PET/CT to the final diagnosis. CRP levels and WBC were not associated with PET/CT outcome. PET/CT let to new treatment in 24.0% (72/300), treatment change in 18.0% (54/300), no treatment change in 49.6% (149/300), and in 8.3% (25/300) no data was available. Our study demonstrates the utility of F-18 FDG PET/CT for source finding in FUO/IUO if other diagnostic tools fail.

Highlights

Fever is one of the most common clinical symptoms among patients across all ages
Wholebody F-18 FDG PET/computed tomography (CT) from vertex to toe was performed in 228/300 cases (76.0%) while torso imaging from supraorbital crest to mid-thigh due to limited patient compliance was performed in 72/300 cases (24.0%). 200/300 patients (66.67%) met the FUO characterization and 100/300 patients (33.33%) met the inflammation of unknown origin (IUO) characterization
In 162/300 (54.0%) cases, F-18 FDG PET/CT findings derived from reports matched the final clinical diagnosis, whereas in 40/300 (13.33%) cases the findings were equivocal and not decisive for determining the final diagnosis

Summary

Introduction

Fever is one of the most common clinical symptoms among patients across all ages. Based on clinical signs and symptoms, imaging studies or other diagnostic approaches such as endoscopy or biopsy of suspected sites of infection will be p erformed[1,2]. Despite state of the art diagnostic tools the diagnostic work-up in FUO/IUO can be a challenge[2]. Invasive or semi-invasive diagnostic methods such as endoscopy and biopsy expose patients to inherent risks, are costly, and time consuming[3]. Due to the high sensitivity of detecting early metabolic changes, F-18 FDG PET/CT represents the modality of choice in clinical management especially when other imaging modalities deliver inconclusive results (4)

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