Oxygen‐enhanced proton imaging of the human lung using T 2

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. Magn Reson Med 53:1193–1196, 2005. © 2005 Wiley‐Liss, Inc.