Figure 1. (a) After contrast injection, DEA recorded contrast enhancement of IRF (ROI 1) and psoas muscle (ROI 2), which generates typical curves of the dynamic intensities by the “Mean-Curve” software package. (b) DEA shows a high DEQ in a patient before the start of medical treatment with prednisone. (c) After 3 months the retroperitoneal mass is significantly reduced, as is the DEQ. (d) At 6 months the mass shows no further reduction and the DEQ is changed only slightly.