10.1371/journal.pone.0025487.g001 Kenichi Odaka Kenichi Odaka Ichio Aoki Ichio Aoki Junji Moriya Junji Moriya Kaoru Tateno Kaoru Tateno Hiroyuki Tadokoro Hiroyuki Tadokoro Jeff Kershaw Jeff Kershaw Tohru Minamino Tohru Minamino Toshiaki Irie Toshiaki Irie Toshimitsu Fukumura Toshimitsu Fukumura Issei Komuro Issei Komuro Tsuneo Saga Tsuneo Saga Relaxation times and contrast of Mn-labeled MNCs. Public Library of Science 2013 times mn-labeled 2013-02-20 13:56:29 Figure https://plos.figshare.com/articles/figure/_Relaxation_times_and_contrast_of_Mn_labeled_MNCs_/396515 <p>(A) R<sub>1</sub> and R<sub>2</sub> calculated for the <i>in vitro</i> samples are presented. The pelleted 0.1 mM Mn-labeled MNCs showed larger R<sub>1</sub> and R<sub>2</sub> in comparison to the saline control. It was not possible to calculate the R<sub>1</sub> and R<sub>2</sub> values for the MNCs with 0.25 mM Mn-labeling and over (N/A) because the T<sub>2</sub> was too short due to the large susceptibility effect. The R<sub>1</sub>s of the MnCl<sub>2</sub> solutions were approximately linearly correlated with the Mn concentration. The R<sub>1</sub> and R<sub>2</sub> for the supernatant fluid were approximately independent of the initial Mn labeling concentration. (B) T<sub>1</sub>-weighted sagittal images of pelleted MNCs after suspension in 0, 0.1, 0.25, and 0.5 mM Mn solutions. The pelleted MNCs at 0.1 mM MnCl<sub>2</sub>-labeling showed partial signal enhancement in the T<sub>1</sub>-weighted 7 T MRI (arrow). The pelleted MNCs with MnCl<sub>2</sub>-labeling over 0.25 mM lost signal in comparison with the unlabeled (0 mM) control due to the very short T<sub>2</sub> and the T<sub>2</sub>* susceptibility effect at 7 T. In the 0.2 T MRI, the the 0.1, 0.25 and 0.5 mM MnCl<sub>2</sub>-labeled MNCs showed positive contrast, although there may have been some signal loss at the base of the 0.5 mM sample.</p>