18F-FDG PET, genotype-corrected ACE and sIL-2R in newly diagnosed sarcoidosis

R. Keijsers, F. Verzijlbergen, W. Oyen, J. van den Bosch, H. Ruven, H. van Velzen-Blad and J. Grutters

Department of Nuclear Medicine, St. Antonius Hospital Nieuwegein, P.O. Box 2500, 3430 EM, Nieuwegein, The Netherlands. r.keijsers@antonius.net
Jul, 2009



Angiotensin-converting enzyme (ACE) and soluble interleukin-2 receptor (sIL-2R) are serological markers, widely used for determining sarcoidosis activity. (18)F-FDG PET has proven to be a sensitive technique in the imaging of sarcoidosis. The aim of this study was to determine sensitivity of (18)F-FDG PET, genotype-corrected ACE and sIL-2R in active sarcoidosis as well as their correlation.This retrospective study included 36 newly diagnosed, symptomatic sarcoidosis patients. ACE and sIL-2R levels were simultaneously obtained within 4 weeks of (18)F-FDG PET. ACE was corrected for genotype and expressed as Z-score. (18)F-FDG PET was visually evaluated and scored as positive or negative. Maximum and average standardized uptake values (SUV(max) and SUV(avg)) were compared with ACE and sIL-2R.(18)F-FDG PET was found positive in 34 of 36 patients (94\%). Thirteen patients (36\%) showed an increased ACE with the highest sensitivity found in patients with the I/I genotype (67\%). Seventeen patients (47\%) showed an increased sIL-2R. No correlation was found between SUV and ACE or sIL-2R. Increased ACE and sIL-2R correlated with a positive (18)F-FDG PET in 12 patients (92\%) and 16 patients (94\%), respectively.(18)F-FDG PET is a very sensitive technique to assess active sarcoidosis, in contrast with ACE and sIL-2R, suggesting a pivotal role for (18)F-FDG PET in future sarcoidosis assessment.