Centric scan SPRITE for spin density imaging of short relaxation time porous materials

Q. Chen, M. Halse, B.J. Balcom

Research output: Contribution to journalArticlepeer-review


The single-point ramped imaging with T enhancement (SPRITE) imaging technique has proven to be a very robust and flexible method for the study of a wide range of systems with short signal lifetimes. As a pure phase encoding technique, SPRITE is largely immune to image distortions generated by susceptibility variations, chemical shift and paramagnetic impurities. In addition, it avoids the line width restrictions on resolution common to time-based sampling, frequency encoding methods. The standard SPRITE technique is however a longitudinal steady-state imaging method; the image intensity is related to the longitudinal steady state, which not only decreases the signal-to-noise ratio, but also introduces many parameters into the image signal equation. A centric scan strategy for SPRITE removes the longitudinal steady state from the image intensity equation and increases the inherent image intensity. Two centric scan SPRITE methods, that is, Spiral-SPRITE and Conical-SPRITE, with fast acquisition and greatly reduced gradient duty cycle, are outlined. Multiple free induction decay (FID) points may be acquired during SPRITE sampling for signal averaging to increase signal-to-noise ratio or for T* and spin density mapping without an increase in acquisition time. Experimental results show that most porous sedimentary rock and concrete samples have a single exponential T* decay due to susceptibility difference-induced field distortion. Inhomogeneous broadening thus dominates, which suggests that spin density imaging can be easily obtained by SPRITE.
Original languageEnglish
Pages (from-to)263-266
Number of pages4
JournalMagnetic Resonance Imaging
Issue number2 SPEC. ISS.
Publication statusPublished - 1 Feb 2005

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