Oxygen-enhanced proton imaging of the human lung using T2.

Magnetic susceptibility gradients caused by tissue/air interfaces lead to very short T(2)* times in the human lung. These susceptibility gradients are dependent on the magnetic susceptibility of the respiratory gas and therefore should influence T(2)* relaxation. In this work, a technique for quantitative T(2)* mapping of the human lung during one breath hold is presented. Using this method, the lung T(2)* relaxation time was measured under normoxic (room air, 21% O(2)) and hyperoxic (100% O(2)) conditions to verify this assumption. The mean T(2)* difference between room air and 100% O(2) is about 10% and contains ventilation information, since only ventilated regions contribute to signal change due to different susceptibility gradients. Copyright 2005 Wiley-Liss, Inc.