On-Off Study of Manganese Administration to Adult Patients Undergoing Home Parenteral Nutrition: New Indices of In Vivo Manganese Level

Background: Recently, there have been reports that magnetic resonance imaging (MRI) reveals high-intensity T1-weighted images (HI) in the basal ganglia (especially in the globus pallidus) of patients receiving total parenteral nutrition (TPN). This finding is presumably due to excess administration of manganese. We investigated the reversibility and reproducibility of these changes by means of an on-off manganese administration study. We also investigated the temporal relationships between the intensity of T 1-weighted images (MRI intensity) and the whole-blood and plasma manganese concentrations to evaluate the potential for the MRI intensity to serve as an index of the in vivo manganese level. Methods: Eleven adult patients undergoing home parenteral nutrition received TPN solutions containing manganese (0 or 20 μmol/d) according to an on-off design. The whole-blood and plasma manganese concentrations were determined at the same time the brain MRI was performed. Results: Both the whole-blood manganese concentration and the MRI intensity in the globus pallidus changed in response to the administration and withdrawal of manganese. It took at least 5 months for HI to disappear when manganese was withdrawn, and this change was reversible and reproducible. The whole-blood manganese concentration showed strong correlations with both the MRI intensity and the T1 value (r = 0.7693, -0.7011). The MRI intensity and the T1 value showed a strong correlation (r = -0.9051). Conclusions: The whole-blood manganese concentration, the MRI intensity in the globus pallidus and the T1 value, an objective index of the MRI intensity, may be useful indices of the manganese level in the body. (journal of Parenteral and Enteral Nutrition 25:87-92, 2001)