Very slow in-plane flow with gradient echo imaging

R. M. Henkelman, E. R. McVeigh, A. P. Crawley, W. Kucharczyk

Research output: Contribution to journalArticle

Abstract

It is well appreciated that gradient-echo imaging techniques with short recovery times are highly sensitive to flow. This article analyzes the effect of in-plane flow in gradient recalled acquisition in the steady state (GRASS). It is shown that there is loss of signal due to velocity-dependent dephasing effects at velo cities as slow as 0.2 mm per second. It is also shown that striations appear in GRASS images of flow phantoms. This effect, which has not been previously described, arises from a modulation of K-space in the phase-encoding direction during the transient approach to steady state. Although these bands can give the appearance of flow lines, they are completely artifactual and not readily interpretable. Thus, the appearance of in-plane fluid movement in clinical GRASS images is a complex combination of signal loss due to dephasing and artifactual banding. Therefore, the interpretation of flow in GRASS images should be attempted only with caution.

Original languageEnglish (US)
Pages (from-to)383-393
Number of pages11
JournalMagnetic Resonance Imaging
Volume7
Issue number4
DOIs
StatePublished - 1989
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics
  • Clinical Biochemistry
  • Structural Biology
  • Radiology Nuclear Medicine and imaging
  • Condensed Matter Physics

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    Henkelman, R. M., McVeigh, E. R., Crawley, A. P., & Kucharczyk, W. (1989). Very slow in-plane flow with gradient echo imaging. Magnetic Resonance Imaging, 7(4), 383-393. https://doi.org/10.1016/0730-725X(89)90487-6