New indicies of manganese ; Magnetic resonance imaging(MRI) findings and T1 values on brain in relation to plasma and whole blood manganese levelsin patients receiving total parenteral nutrition

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Manganese (Mn) metabolism and kinetics in patients on total parenteral nutrition (TPN) still remain unclear. There is no establish standard for daily Mn requirement parenterally, nor are any indicies reflecting Mn concentration in tissue reliable. Although Mn accumulation in brain could be verified by magnetic resonance imaging (MRI) in TPN patients with Mn supplementation, no attempts have been made to investigate the relationship between the degree of high intensity (HI) and T1 relaxation time (I. E. T1 value) by brain MRI and blood Mn level. TPN patients with daily 20 μmol of Mn supply parenterally were participated in this on-off study of Mn. Before the discontinuation of Mn administration, plasma Mn level was within normal range, but whole blood level was higher than normal value and high intensity (HI) and shortened T1 value of basal ganglia by MRI, were noted in all patients. Discontinuation of Mn supply was followed in one month by lowering of plasma Mn below normal level. Whole blood Mn level also declined to return to normal in 2 months post discontinuation. The HI findings of the brain by MRI became less conspicuous to disappear completely by 11 months after discontinuation.After re-supply of Mn, plasma Mn level did not increase so much. Whole blood Mn level increased to above normal value after 2 months of re-supply. The HI findings of the brain were again observed by 3 months after re-supply. T1 value was correlated to the changes of whole blood Mn level and MRI findings during Mn on off study. Daily administration in the dose of one μmol of Mn should be recommended during TPN rather than the dose of 2 or 20 μmol judging from MRI findings and T1 value and whole blood Mn level.