Rapid T2 estimation with phase-cycled variable nutation steady-state free precession

✍ Scribed by Sean C.L. Deoni; Heidi A. Ward; Terry M. Peters; Brian K. Rutt

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 187 KB
• Volume: 52
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.20159

✦ Synopsis

Abstract

Variable nutation SSFP (DESPOT2) permits rapid, high‐resolution determination of the transverse (T~2~) relaxation constant. A limitation of DESPOT2, however, is the presence of T~2~ voids due to off‐resonance banding artifacts associated with SSFP images. These artifacts typically occur in images acquired with long repetition times (TR) in the presence of B~0~ inhomogeneities, or near areas of magnetic susceptibility difference, such that the transverse magnetization experiences a net phase shift during the TR interval. This places constraints on the maximum spatial resolution that can be achieved without artifact. Here, a novel implementation of DESPOT2 is presented incorporating RF phase‐cycling which acts to shift the spatial location of the bands, allowing reconstruction of a single, reduced artifact‐image. The method is demonstrated in vivo with the acquisition of a 0.34 mm^3^ isotropic resolution T~2~ map of the brain with high precision and accuracy and significantly reduced artifact. Magn Reson Med 52:435–439, 2004. © 2004 Wiley‐Liss, Inc.