Figure 1.

Two 3D gas-phase image acquisitions (I₁ (a) and I₄ (b)) from a single breath hold in volunteer H3. I₁ (a) is acquired at the beginning of the breath hold and therefore depicts ventilation. No AP-gradient was observed in I₁, however image intensity was increased in the most posterior and the most anterior partitions due to the surface coil intensity profile of the receive-array RF coil. After XTC-contrast encoding the gas phase signal is reduced in I₄, with a relatively larger decrease in posterior partitions indicating an increase in the tissue- to alveolar-volume ratio.