Positron emission tomography/computed tomography (PET/CT) as predictor of sarcoidosis activity: A case series

Abstract

Introduction: Sarcoidosis is a multisystemic granulomatous disease that can present different clinical and radiological manifestations, while nospecific exams exist to monitor its activity and spontaneous or drug-induced remission. Objective: This study aimed to evaluate the degree of consistency between patients’ symptoms and Positron emission tomography/computed tomography (PET/CT) results in patients with sarcoidosis. Methods: Patients with sarcoidosis underwent two PET/CT scans, which were performed at the nuclear medicine sector of the National Cancer Institute (INCA) at two different times during a four-year period, to assess disease activity. The SUVmax value was noted and its consistency with the clinical status of the disease was checked. The analysis was performed using the maximum standardized uptake value (SUVmax).  Results and Discussion: Twenty-seven patients were recruited, totaling 54 exams. The median SUVmax was 8.1 (range 3.5–16.1). Most examinations that showed hypermetabolism included both lung and extrapulmonary sarcoidosis sites in the same patient. The most affected sites with uptake by PET/CT were the lungs, followed by the intra-abdominal, pelvic, and peripheral lymph nodes. Other organs with glycolytic hypermetabolism included the spleen, subcutaneous tissue, bones, and heart. In 44% of the patients, the PET/CT scans and clinical status were not consistent. This result occurred mainly in: patients with cutaneous manifestations that exhibited no metabolic correspondence on PET/CT; patients with pulmonary fibrosis and dyspnea not attributable to disease activity; extrapulmonary sites such as the spleen, abdominal and peripheral lymph nodes, and bone without symptoms; and patients with pulmonary uptake on PET/CT despite being asymptomatic. Conclusions: The applicability of PET/CT should be discussed ineach case to ensure that the information will assist the patient’s diagnosis and management.