The accuracy of magnetic resonance phase velocity measurements in stenotic flow

John M. Siegel, John N. Oshinski, Roderic I. Pettigrew, David N. Ku

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

Nuclear magnetic resonance (MR) can be used to measure velocities in fluid flow using the technique of phase velocity mapping. Advantages of MR velocimetry include the simultaneous mapping of the entire flow field through a non-contacting, magnetic window. The phase velocity mapping technique assumes that velocity is constant over the measurement time (typically around 10 ms). For many fluid flows, this assumption is not valid. The current study showed that MR phase velocity measurements of velocity through stenotic flow can be in error by over 100% immediately upstream and downstream of the stenosis throat and by 20% far downstream of the throat in comparison with laser Doppler anemometer measurements taken at the same location. Highly turbulent how also led to significant errors in velocity measurement. These errors can be attributed to several sources including low signal-to-noise ratio, additional phase shifts due to non-constant velocities, and non-stationary transit-time effects. Velocity measurement errors could be reduced to under 30% at all measurement locations through the use of MR sequences with high signal-to-noise ratios, low echo times, and thick slices.

Original languageEnglish (US)
Pages (from-to)1665-1672
Number of pages8
JournalJournal of Biomechanics
Volume29
Issue number12
DOIs
StatePublished - Jan 1 1996

Keywords

  • Acceleration
  • LDA
  • MRI
  • Magnetic resonance
  • Phase velocity mapping
  • Stenosis

ASJC Scopus subject areas

  • Biophysics
  • Orthopedics and Sports Medicine
  • Biomedical Engineering
  • Rehabilitation

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