MRI Results. (a) Picture of the phantom with different iron contents (in grams) identified. (b) T2* map showing estimated T2* values for different tubes. (c) Linear relationship between iron content and R2* (= 1000/T2*). (d) Exponential fittings of the T2* relaxation curves versus echo time (TE) for the tubes that resulted in T2* of 21 ms (blue) and 10 ms (red), which represent the boundaries for iron overload and severe iron overload, respectively. Three regions can be identified on this figure for relaxation curves from tissues with normal iron content (T2* > 21 ms), iron overload (10 ms < T2* < 21 ms), and severe iron overload (T2* < 10 ms).