Dual-energy CT Results. (a) CT image of the phantom at one of the four acquired energies (100 kVp). (b) Relationships between Hounsfield unit and iron content at different energy levels (80, 100, 120, 140 kVp). (c) Sequence of CT images of the tubes that resulted in T2* values of 21 ms (top) and 10 ms (bottom), respectively, at different energy levels. (d) Linear relationships between Hounsfield unit and energy level for the iron tubes that resulted in T2* between 10 ms (red) and 21 ms (blue). The figure can be used as a map to identify the severity of iron overload based on the resulting Hounsfield unit and implemented kVp. Three regions can be identified on this map representing tissues with normal iron content (region below the blue line), iron overload (region between the blue and red lines), and severe iron overload (region above the red line).