99mTc-MIBI Washout Rate to Evaluate the Effects of Steroid Therapy in Cardiac Sarcoidosis

Objective: We sought to determine the usefulness of the 99mTc-MIBI (MIBI) washout rate for the evaluation of steroid therapy in cardiac sarcoidosis (CS). Methods: Eleven CS patients underwent MIBI myocardial SPECT both before and 6 months after initiating steroid therapy. The washout rate (WOR) of MIBI was calculated using early and delayed polar map images. The washout score (WOS) of MIBI was derived from the difference between the early and delayed total defect scores (TDS). Results: Serum ACE and BNP exhibited significant improvement after the therapy (p = 0.004, p = 0.045). In the LV function, EDV and E/A ratio exhibited significant improvement after the therapy (p = 0.041, p = 0.007), while there were no significant differences between before and after therapy in EF or ESV. Early and delayed TDS showed no significant differences between before and after the therapy. In contrast, WOR differed significantly (p < .0001), while WOS did not differ significantly between before and after the therapy.Conclusion: The washout rate of MIBI is suitable for assessment of cardiac function in CS with steroid therapy, being especially better than the washout score of MIBI for assessment of disease activity of mild myocardial damage in CS with steroid therapy.