Sources of artifact and systematic error in quantitative snapshot FLASH imaging and methods for their elimination

C F M Williams, T W Redpath

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Snapshot FLASH preceded by a preparation sequence is used to measure NMR parameters. Some preparation information is lost during snapshot FLASH acquisition as the magnetization evolves towards the steady state. This problem is often addressed by assuming that image intensity is proportional to the central k-space line, which may be sampled immediately after preparation using a centric-reordered scheme, Although some limitations of this assumption have been discussed, they are often ignored in parameter measurement. In this study, magnetization evolution effects in snapshot FLASH were investigated by computer simulation and phantom experiments in the context of T-2 measurement, It was found that the standard analysis may lead to significant error in parameter measurement. Some improvement may be obtained using a more sophisticated analysis to take account of magnetization evolution. However, at the expense of a 50% reduction in signal intensity, accurate values may be obtained by a novel method that uses crusher gradients to eliminate evolved magnetization. Magn Reson Med 41:63-71, 1999, (C) 1999 Wiley-Liss, Inc.

Original languageEnglish
Pages (from-to)63-71
Number of pages9
JournalMagnetic Resonance in Medicine
Volume41
Publication statusPublished - 1999

Keywords

  • magnetic resonance imaging
  • snapshot FLASH
  • relaxation
  • artifacts
  • T1

Cite this

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title = "Sources of artifact and systematic error in quantitative snapshot FLASH imaging and methods for their elimination",
abstract = "Snapshot FLASH preceded by a preparation sequence is used to measure NMR parameters. Some preparation information is lost during snapshot FLASH acquisition as the magnetization evolves towards the steady state. This problem is often addressed by assuming that image intensity is proportional to the central k-space line, which may be sampled immediately after preparation using a centric-reordered scheme, Although some limitations of this assumption have been discussed, they are often ignored in parameter measurement. In this study, magnetization evolution effects in snapshot FLASH were investigated by computer simulation and phantom experiments in the context of T-2 measurement, It was found that the standard analysis may lead to significant error in parameter measurement. Some improvement may be obtained using a more sophisticated analysis to take account of magnetization evolution. However, at the expense of a 50{\%} reduction in signal intensity, accurate values may be obtained by a novel method that uses crusher gradients to eliminate evolved magnetization. Magn Reson Med 41:63-71, 1999, (C) 1999 Wiley-Liss, Inc.",
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T1 - Sources of artifact and systematic error in quantitative snapshot FLASH imaging and methods for their elimination

AU - Williams, C F M

AU - Redpath, T W

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N2 - Snapshot FLASH preceded by a preparation sequence is used to measure NMR parameters. Some preparation information is lost during snapshot FLASH acquisition as the magnetization evolves towards the steady state. This problem is often addressed by assuming that image intensity is proportional to the central k-space line, which may be sampled immediately after preparation using a centric-reordered scheme, Although some limitations of this assumption have been discussed, they are often ignored in parameter measurement. In this study, magnetization evolution effects in snapshot FLASH were investigated by computer simulation and phantom experiments in the context of T-2 measurement, It was found that the standard analysis may lead to significant error in parameter measurement. Some improvement may be obtained using a more sophisticated analysis to take account of magnetization evolution. However, at the expense of a 50% reduction in signal intensity, accurate values may be obtained by a novel method that uses crusher gradients to eliminate evolved magnetization. Magn Reson Med 41:63-71, 1999, (C) 1999 Wiley-Liss, Inc.

AB - Snapshot FLASH preceded by a preparation sequence is used to measure NMR parameters. Some preparation information is lost during snapshot FLASH acquisition as the magnetization evolves towards the steady state. This problem is often addressed by assuming that image intensity is proportional to the central k-space line, which may be sampled immediately after preparation using a centric-reordered scheme, Although some limitations of this assumption have been discussed, they are often ignored in parameter measurement. In this study, magnetization evolution effects in snapshot FLASH were investigated by computer simulation and phantom experiments in the context of T-2 measurement, It was found that the standard analysis may lead to significant error in parameter measurement. Some improvement may be obtained using a more sophisticated analysis to take account of magnetization evolution. However, at the expense of a 50% reduction in signal intensity, accurate values may be obtained by a novel method that uses crusher gradients to eliminate evolved magnetization. Magn Reson Med 41:63-71, 1999, (C) 1999 Wiley-Liss, Inc.

KW - magnetic resonance imaging

KW - snapshot FLASH

KW - relaxation

KW - artifacts

KW - T1

M3 - Article

VL - 41

SP - 63

EP - 71

JO - Magnetic Resonance in Medicine

JF - Magnetic Resonance in Medicine

SN - 0740-3194

ER -