The data was collected using simple FID and saturation recovery (SM, section S1). Total program by the Schlumberger-Doll Research Center was utilized to process the data to generate the T1-T2* time correlation maps. This program assumed the signal change to be purely exponential. For non-exponential data processing, a new T1-T2* analysis method was employed. A detailed explanation of the MR measurement is in the supplementary information (SM, section S1).