posters 5th Asia-Pacific NMR Symposium 2013

3-Dimensional fast spin echo MRI with planar phase encoding (#195)

Konstantin Romanenko 1 , Luke O'Dell 1 , Maria Forsyth
  1. Institute for Frontier Materials, Deakin Unversity, Geelong, VIC, Australia

Magnetic resonance imaging provides unique window on numerous phenomena in chemistry, biology and medicine. Great variety of MRI applications is based on non-invasive nature of magnetic resonance as well as on flexibility of approaches to MRI signal acquisition. The time efficiency of MRI is crucial both in clinical applications and material science. In the latter case the experimental techniques are also required to be quantitative to provide accurate estimation of dynamic physical parameters. A technique that is simultaneously fast, sensitive and quantitative would be advantageous for material science applications. An alternative version of three-dimensional (3-D) Fast Spin Echo (FSE) imaging method is proposed. FSE with planar phase encoding is a non-slice selective 3-D imaging method suitable for material science applications and medical research. Each echo is independently phase encoded with a combination of 1st and 2nd orthogonal gradients. The pairs of phase encoding gradients are chosen to form a planar k-space trajectory on a Cartesian grid. In the 3rd direction a line of k-space is sampled using conventional frequency encoding. The total number of echoes acquired is equal to the number of points in the phase encoding plane. A single trajectory covering the entire plane allows full 3-D imaging in a single shot. The use of multiple interleaved trajectories is favorable for image resolution. The resulting 3-D k-space does not require re-gridding. This imaging modality is particularly advantageous for 3-D mapping of spin density, diffusion, velocity, and relaxation time constants in dynamic systems. The benefits of conventional fast spin echo are retained. The time efficiency of the proposed approach is improved by a factor of ten compared to conventional 3-D FSE. The proposed method is well-suited for fast imaging of systems with background gradients. It will be used for the better understanding of  batteries and fuel cells.