A methodology, system and computer program product for designing and optimizing a rapid magnetic resonance imaging pulse sequence for creating images of a gas or gas-filled structure with substantially reduced diffusion-induced signal attenuation during the course of data acquisition compared to that for currently available magnetic resonance imaging techniques is disclosed. The methodology and system allows desirable combinations of image signal-to-noise ration, spatial resolution and temporal resolution to be achieved that were heretofore not possible. For example, magnetic resonance imaging of hyperpolarized noble gases, which recently has shown significant promise for several medical imaging applications, particularly imaging of the human lung, can be improved. Pulse sequences designed according to the subject methods permit signal levels to be achieved that are up to ten times higher than those possible with the gradient-echo methods now commonly used for hyperpolarized-gas imaging. This signal increase can be traded for substantially lower does, and hence much lower cost, of the hyperpolarized-gas agent. The methodology and system will also be useful for non-biological applications of hyperpolarized gases for example material science studies, as well as for magnetic resonance imaging of any other gas for biological or non-biological applications. Pulse sequences designed according to the subject methods can also serve as the foundation for a variety of specialized gas-imaging pulse sequences, such as those for apparent-diffusion-coefficient, dynamic or oxygen-concentration imaging.