The role of PET/CT in evaluating rheumatologic conditions in children with fever of unknown origin - a multicenter study

Neta Berlak¹, Lydia Christodoulou², Gil Amarilyo³, Oded Scheuerman⁴, Irit Tirosh⁵, Eyal Kristal⁶, Ester Forer⁷, Amit Carmi⁸, Alon Kalter⁹ and Yoel Levinsky¹⁰, ¹Schneider children's medical center of Israel, Tel Aviv, Israel, ²Tel Hashomer, Periatric rheumatology unit, Tel Aviv, Israel, ³Schneider Children's Medical Center of Israel, Kibbutz Maggal, Israel, ⁴schneider children's meidcal center of Israel, Petah tikva, Israel, ⁵Tel Aviv universty, Ramat Gan, Israel, ⁶Soroka medical center Beer Sheva, Beer Sheva, Israel, ⁷Soroka medical center, Beer Sheva, Israel, ⁸Schneider children's meidcal center of Israel, Tel Aviv, Israel, ⁹Schneider children's medical center of ISrael, Petah Tikva, Israel, ¹⁰Schneider Children's Medical Cenetr of Israel, Tel Aviv University, JERUSALEM, Israel

Meeting: ACR Convergence 2025

Keywords: Imaging, Infection, Inflammation, Juvenile idiopathic arthritis, Pediatric rheumatology

Session Information

Date: Monday, October 27, 2025

Title: (1272–1305) Pediatric Rheumatology – Clinical Poster II

Session Type: Poster Session B

Session Time: 10:30AM-12:30PM

Background/Purpose: Fever of Unknown Origin (FUO) is a relatively common clinical challenge that is frequently referred for evaluation by pediatric rheumatologists. In many cases, it is necessary to rule out other medical conditions before establishing a rheumatologic diagnosis. 18F-FDG PET/CT is a valuable diagnostic tool that may help identify the fever’s source. However, its use in children involves risks, including radiation exposure and the need for sedation. Our aims were To assess the contribution of PET/CT to FUO diagnosis in hospitalized children, and to identify rheumatologic conditions that are either detected through the evaluation or excluded by it. In addition, to identify predictive factors for its diagnostic utility.

Methods: A retrospective cohort study reviewing medical records of children (0-18 years) diagnosed with FUO who underwent PET/CT between 2010 and 2024 in three Israeli medical centers. Clinical and laboratory data were collected, and cases where PET/CT led to a diagnosis were compared to those where it did not.

Results: Among 113 cases, PET/CT contributed to diagnosis in 52 (46%). The majority of diagnoses identified by PET/CT were infectious (53.8%), whereas in cases where PET/CT did not aid in diagnosis, rheumatologic diseases were predominant (66.6%). Of all cases, 21% were ultimately diagnoses with a rheumatologic condition, the most frequent was systemic JIA. Immunodeficiency, low hemoglobin, and low albumin were more frequent in cases where PET/CT was diagnostic, while rash and arthritis were more common in cases where PET/CT did not contribute.

Conclusion: PET/CT is an effective diagnostic tool for FUO in children, aiding diagnosis in 46% of cases. Of all cases, 21% were ultimately diagnoses with a rheumatologic condition. However, most were diagnosed without direct findings on the PET/CT, which primarily served to rule out other conditions. Predictive factors for its utility are reported. In appropriate clinical scenarios, PET/CT should be considered as part of the FUO workup in pediatric patients.

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Disclosures: N. Berlak: None; L. Christodoulou: None; G. Amarilyo: None; O. Scheuerman: None; I. Tirosh: None; E. Kristal: None; E. Forer: None; A. Carmi: None; A. Kalter: None; Y. Levinsky: None.

To cite this abstract in AMA style:

Berlak N, Christodoulou L, Amarilyo G, Scheuerman O, Tirosh I, Kristal E, Forer E, Carmi A, Kalter A, Levinsky Y. The role of PET/CT in evaluating rheumatologic conditions in children with fever of unknown origin – a multicenter study [abstract]. Arthritis Rheumatol. 2025; 77 (suppl 9). https://acrabstracts.org/abstract/the-role-of-pet-ct-in-evaluating-rheumatologic-conditions-in-children-with-fever-of-unknown-origin-a-multicenter-study/. Accessed .

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