Utility of [18F]FDG PET/CT in sarcoidosis management: A retrospective case series

Sarcoidosis is a granulomatosis of variable manifestation and evolution. It is crucial to assess the disease's extent, activity, and severity to effectively manage and monitor patients with sarcoidosis. Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) is a nuclear medicine technique that proved to be of great use in oncology. Its role in extra-oncological indications, including sarcoidosis, has been reported.

Twenty-five patients with sarcoidosis were retrospectively included. All patients underwent at least one [18F]FDG PET/CT scan. Five patients underwent a second [18F]FDG PET/CT to assess their response to corticosteroid treatment. Clinical data were gathered from medical records. Radiological and PET data were obtained from reports and digital imaging and communications in medicine (DICOM) archives.

[18F]FDG PET/CT revealed active inflammation in 76% of patients. All had intrathoracic activity, including 76% mediastinal and 44% pulmonary lesions. Additionally, 60% of patients displayed associated extrathoracic activity, mainly in peripheral lymph nodes, spleen, and bone. Cardiac activity was reported in two patients. [18F]FDG PET/CT prompted a diagnostic biopsy in 32% of patients. [18F]FDG PET/CT had an impact on therapeutic decision-making in 60% of patients. Follow-up [18F]FDG PET/CT showed a complete metabolic response in two cases and an incomplete metabolic response in one patient. Disease progression was noted in two patients.

Providing a complete functional map of the extent of inflammatory active disease, [18F]FDG PET/CT proves to be particularly useful in the management of sarcoidosis patients, by explaining persistent disabling symptoms, revealing suitable sites for biopsy, guiding therapeutic decisions and assessing treatment response.