Evaluation of Response to Steroid Therapy for Cardiac Sarcoidosis Using Volumetric Analysis of 18F-FDG PET/CT

Abstract

Background: The purpose of this study was to investigate the utility of total lesion glycolysis (TLG) in 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) to predict the response to steroid therapy for cardiac sarcoidosis (CS). Methods: Thirty-six patients with clinically suspected CS who had undergone 18F-FDG PET/CT were retrospectively analysed. Of the 36 patients, 21 were diagnosed as having CS according to Japanese Ministry of Health and Welfare guidelines and divided into 12 responders and 9 non-responders after steroid therapy by the mean follow-up period of 19 months. SUVmax and total lesion glycolysis (TLG) for the left ventricle (LV) on 18F-FDG PET/CT were compared between responders and non-responders using the Wilcoxon test. The predictability of response to steroid therapy was analysed using receiver operating characteristic curve analysis. Results: TLG for the LV wall was significantly higher in non-responders [1082 ± 715 g (mean ± SD)] than in responders (452 ± 385 g, p=0.02), while there was no difference in the SUVmax for the LV wall between the two groups (responders 8.6 ± 2.3 vs. non-responders 11.4 ± 3.8). Use of an optimal TLG cut-off of 1070 g differentiated responders from non-responders with a sensitivity of 100%, a specificity of 55.6%, an accuracy of 81.0% and area under the curve of 0.80. Conclusion: The non-responders to steroid therapy for CS showed a high level of TLG on 18F-FDG PET/CT. TLG of 18F-FDG PET/CT can be a predictor of response to steroid therapy in CS.