Appropriate Use Criteria Published for Nuclear Medicine in Fever of Unknown Origin

The Society of Nuclear Medicine and Molecular Imaging (SNMMI), Infectious Diseases Society of America and the American College of Nuclear Medicine, issued new appropriate use criteria (AUC) for the use of nuclear medicine in the diagnostic work-up of fever of unknown origin (FUO) in children and adults. Published in the November issue of The Journal of Nuclear Medicine, the AUC outlines six clinical scenarios for the diagnosis of FUO to assist physicians in their decision-making.

FUO in children and adults is among the more challenging clinical conditions for both patients and treating physicians. FUO is a manifestation of many different disease processes and does not present the same way in every patient. In up to 50 percent of cases, no definite diagnosis is established.

First-line evaluation of FUO includes basic laboratory and imaging tests, followed by more advanced imaging—including nuclear medicine studies—if the first-line evaluation is not conclusive. In recent years, ¹⁸F-FDG PET and PET/CT have rapidly assumed an increasingly important role in the diagnostic work-up of these patients.

SNMMI convened a multidisciplinary AUC work group of health care providers with substantive knowledge in the use of nuclear medicine procedures in FUO. The work group identified a list of relevant clinical scenarios in which nuclear medicine imaging can be used in the patient with FUO and conducted a systematic review of evidence related to these clinical scenarios. The group then developed AUC for each of the scenarios.

In adults with FUO, the work group recommended ¹⁸F-FDG PET and PET/CT as the nuclear medicine tests of choice. The group’s recommendations also included reserving ⁶⁷Ga scintigraphy for situations in which ¹⁸F-FDG PET and PET/CT are not available. In addition, labeled leukocyte scintigraphy was recommended to be reserved for situations in which ¹⁸F-FDG PET and PET/CT are not available and there is a high index of suspicion for infection as the cause of the fever.

For children with FUO, ¹⁸F-FDG PET and PET/CT are the nuclear medicine tests of choice, according to the work group. Based on the results that have been reported for both ⁶⁷Ga and labeled leukocyte scintigraphy, neither test is recommended for children with FUO.

“The intention of this AUC is to provide clinicians with scientifically based flexibility in their approach to clinical questions,” noted the authors. “The integration and complementary use of nuclear and morphologic techniques may indeed provide the most appropriate strategy for what are often complex questions of extent and severity of disease.”