Clinical Use of Inpatient FDG-PET/CT in Internal Medicine.

Objective: FDG-PET/CT is useful in internal medicine for evaluation of patients with various inflammatory presentations. However, data regarding its diagnostic role in inpatients is limited. This study aims to assess the contribution of FDG-PET/CT in hospitalized patients.

Methods: An observational cohort study was conducted at a tertiary medical center in Israel from 2015 to 2020. We analyzed FDG-PET/CT scans of 260 adult inpatients from Internal Medicine, Cardiology, Medical Intensive Care, and Intensive Cardiac Care units. Scans done solely for malignancy follow-up were excluded. The primary outcome was a change in diagnosis and/or management, assessed by at least two physicians.

Results: Among the 260 patients, indications included infection (42%), inflammation (35%), suspected malignancy (17%), cardiac disease (5%), and other (1%). 80% of studies were clinically helpful. In 40% treatment was changed, either in type (27%) or duration (13%). 9% of studies contributed to diagnosis alone, and 7% contributed to localization. 23% were negative studies, eliminating additional testing. 1% showed incidental findings requiring treatment. In 43% of studies, there were new findings that were not visible by prior morphologic imaging. A significantly higher percentage of clinically helpful studies was observed in patients with foreign devices compared with those without devices (89% versus 74%, P = 0.003), while immunocompromised patients had a lower percentage of clinically helpful studies (74% versus 84%, P = 0.06).

Conclusion: FDG-PET/CT is a useful, noninvasive diagnostic tool in patients hospitalized in Internal Medicine, Cardiology, and Intensive Care. This modality may aid in treatment and prevent unnecessary invasive procedures in selected patients.