Myocardial washout of 99mTc-tetrofosmin and response to steroid therapy in patients with cardiac sarcoidosis

Abstract

Early diagnosis and initiating treatment of cardiac sarcoidosis are essential because cardiac involvement is an important prognostic factor. Although there are many reports on the diagnosis of cardiac sarcoidosis, the literature on predicting the efficacy of steroid therapy is very limited. The purposes of this study were to investigate the myocardial washout of (99m)Tc-tetrofosmin (TF), and to evaluate the predictability of left ventricular (LV) functional recovery after steroid therapy in patients with cardiac sarcoidosis. We performed TF-gated SPECT and echocardiography for ten patients with cardiac sarcoidosis before and after initiating steroid therapy. SPECT images were acquired at 30 min (early images) and 3 h (delayed images) after injection. We calculated the total defect score (TDS) and left ventricular ejection fraction (LVEF). The washout score (WOS) was considered as the difference between the early and delayed TDS. In addition, we defined DeltaLVEF as the change in LVEF after initiating steroid therapy. Furthermore, we analyzed the regional TF myocardial uptake (%uptake) and the regional LV function (wall thickness, WT) by the 20-segment model on polar maps as regional indices. The regional washout (RWO) was defined as the change in %uptake between the early and delayed images in TF SPECT before the therapy. We calculated the improvement factor of the regional LV function as DeltaWT (WT after initiating therapy - WT before the therapy) and investigated the relationships among the indices. We observed WO in 6 of 10 patients (60%). Decreased WT on echocardiography was observed in only 2 of 6 patients (33.3%) in the WO(+) group and in all 4 patients (100%) in the WO(-) group (p < 0.05). WOS before initiating steroid therapy exhibited a good correlation with DeltaLVEF (r = 0.685, p < 0.05). In the regional analysis, %uptake in the early images and delayed images before therapy did not significantly correlate with DeltaWT. In contrast, RWO before therapy was well correlated with DeltaWT (r = 0.435, p < 0.05). Our preliminary study shows that there is a relationship between washout of (99m)Tc-tetrofosmin and the LV functional recovery after steroid therapy in patients with cardiac sarcoidosis.