Fluorinated gases are a promising alternative to hyperpolarized gases to study ventilation in clinical and preclinical applications. 3D Ultra Short Echo Time (UTE) acquisitions can be employed to visualize inhaled SF6 and lung parenchyma. DC self-gating was applied to discriminate between inspiration and expiration in free-breathing acquisitions. Proton and gas density were estimated in inspiration, expiration and in ungated data. The information derived from tissue-density changes matched the changes observed in the gas density, thus indicating the ventilation information can be derived from tissue density mapping.