Three-point phase-contrast velocity measurements with increased velocity-to-noise ratio

Magn Reson Med. 1995 Jan;33(1):122-6. doi: 10.1002/mrm.1910330119.


We describe a technique to increase the velocity-to-noise ratio (VNR) of phase-contrast magnetic-resonance velocity images based on making three measurements/flow encoding axis rather than the usual two. A phase-aliased high first moment data set and a nonaliased low first moment data set are acquired, and the high-moment data are phase unwrapped using the low-moment data. The VNR of the resulting measurement is given by that of the high-moment measurement and increases linearly with the first moment. A factor of 4 gain in VNR was observed with only a 50% increase in scan time. Thus, this method is a much more efficient way to increase VNR than simple averaging.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cerebrospinal Fluid / physiology
  • Cerebrovascular Circulation / physiology
  • Humans
  • Image Enhancement / methods
  • Magnetic Resonance Imaging / methods*
  • Models, Cardiovascular
  • Models, Structural
  • Rheology