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Keywords:

  • blood flow;
  • transit time;
  • pseudo-random modulation;
  • arterial spin labeling

Abstract

Purpose:

To investigate blood flow and transit time measurement, using the pseudo-random arterial modulation (PRAM).

Materials and Methods:

PRAM is based on a pseudo-random sequence of inversions and noninversions of the arterial blood at a labeling plane inferior to the imaging plane. To accomplish this, a pseudo-continuous tagging is used to create inversion or noninversion prepulses before a gradient echo sequence and tested on phantoms and human volunteers.

Results:

We have shown here that the PRAM technique can measure the velocity profile and the transit time accurately and efficiently both in a phantom and in vivo in a human brain.

Conclusion:

PRAM does not require separate control and label acquisition as is common in arterial spin labeling (ASL) but rather measures the distribution of transit times to a voxel within one integrated scan. The PRAM method is a model-free approach in measuring transit time distributions, and therefore ultimately should provide more accurate perfusion measurements. J. Magn. Reson. Imaging 2012;35:223-228. © 2011 Wiley Periodicals, Inc.