Three-dimensional magnetic resonance imaging of rigid polymeric materials using single-point ramped imaging with T-1 enhancement (SPRITE)

A new MRT method, recently employed in porous-media studies, is introduced for the imaging of rigid polymeric materials. The method, Single-Point Ramp ed Imaging with T-1, Enhancement (SPRITE), is designed to spatially encode short lifetime, T-2*, signals characteristic of rigid materials. We investi gate the advantages of the SPRITE technique over conventional imaging metho ds by comparing a 2D SPRITE image of four common polymers to a 2D spin-echo image of the same substances. We demonstrate the general applicability of SPRITE by imaging two commercial products, a stop-valve made of chlorinated polyvinyl chloride and a solid-core, multilayer golf ball, both containing synthetic materials with effective H-1 spin-spin relaxation times, T-2*, w ell under 300 mu s. Three-dimensional images of millimeter resolution revea l internal physical differentiation and chemical inhomogeneities that canno t be observed using conventional MRI methods. We also consider the incorpor ation of active spoiler gradients in SPRITE for visualization of samples wi th long spin-spin relaxation times,T-2.