18F-Fdg Pet Scans Demonstrate Strong Correlation Between Spleen Metabolism and Serum Il-2r Levels in Patients with Untreated Sarcoidosis under Surveillance

Introduction: F-18 fluorodeoxyglucose used in positron emission tomography and computed tomography (FDG PET/CT) has been shown to be a sensitive molecular imaging marker of inflammation. Aims: To use FDG PET/CT to assess splenic hypermetabolism in therapy-naive sarcoidosis patients and to examine possible correlation between splenic FDG uptake and biochemical markers. Methods: All patients diagnosed with sarcoidosis were identified from a local database in our hospital. Therapy-naive patients under routine surveillance were enrolled in this study and after informed consent they prospectively underwent whole-body FDG PET/CT and same-day biochemical lab tests, including interleukin-2 receptor (IL-2R), C-reactive protein (CRP), serum angiotensin-I converting enzyme (SACE), serum calcium and urine calcium levels. Results: Thirty patients (10 male, 48.2 ±11.7 years) were included. Spleen SUVmax was 4.6 ±2.4 (range: 2.5-15.7) and SUVmean was 2.5 ±1.4 (range: 1.5-9). Serum IL-2R was 1417 ±1164 (range: 417-4992). Significant correlation was found between serum IL-2R levels and splenic SUVmax (Pearson9s r=0.7, p Conclusions: There is strong correlation between serum IL-2R levels and spleen metabolism and size, while no correlation is identified between spleen metabolism and CRP, SACE, serum or urine calcium levels in patients with untreated sarcoidosis.