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Related Experiment Video

Updated: Jun 22, 2026

Blood Flow Imaging with Ultrafast Doppler
05:57

Blood Flow Imaging with Ultrafast Doppler

Published on: October 14, 2020

Self-gated Fourier velocity encoding.

Christopher K Macgowan1, Garry K C Liu, Joshua F P van Amerom

  • 1Department of Medical Biophysics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada. chris.macgowan@utoronto.ca

Magnetic Resonance Imaging
|June 26, 2009
PubMed
Summary
This summary is machine-generated.

Self-gating improves real-time flow MRI by combining interleaved k-space data for enhanced velocity resolution. This method provides high-resolution velocity spectra without a clear electrocardiogram signal, useful in fetal or arrhythmia cases.

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High-speed Particle Image Velocimetry Near Surfaces
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Published on: June 24, 2013

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Last Updated: Jun 22, 2026

Blood Flow Imaging with Ultrafast Doppler
05:57

Blood Flow Imaging with Ultrafast Doppler

Published on: October 14, 2020

High-speed Particle Image Velocimetry Near Surfaces
11:59

High-speed Particle Image Velocimetry Near Surfaces

Published on: June 24, 2013

Area of Science:

  • Magnetic Resonance Imaging (MRI)
  • Cardiovascular Flow Dynamics

Background:

  • Real-time Fourier velocity encoding (FVE) requires a reliable electrocardiogram (ECG) for accurate flow measurements.
  • Challenges arise in applications like fetal MRI or severe arrhythmias where ECG gating is unreliable.
  • Existing methods lack sufficient velocity resolution in these challenging scenarios.

Purpose of the Study:

  • To investigate a novel self-gating technique to enhance velocity resolution in real-time FVE.
  • To enable accurate flow quantification in the absence of a reliable ECG signal.
  • To improve the applicability of real-time FVE in challenging clinical and research settings.

Main Methods:

  • Acquisition of real-time flow data using interleaved k-space trajectories sharing common data near the k-space origin.
  • Utilizing these common data to generate a rapid self-gating signal for combining interleaved acquisitions.
  • Combining interleaved data to achieve a larger k-space coverage compared to single real-time acquisitions.

Main Results:

  • The self-gating approach significantly improved velocity resolution for a given aliasing velocity and temporal resolution.
  • Achieved velocity spectra with a temporal resolution of 19 ms and velocity resolution of 22 cm/s over an 818 cm/s field-of-view.
  • Experimental validation using a pulsatile flow apparatus and successful in vivo application to measure aortic-valve flow.

Conclusions:

  • Self-gating provides a robust method for improving velocity resolution in real-time FVE without ECG.
  • This technique enhances the utility of real-time flow MRI in applications with compromised ECG signals.
  • The validated method offers a promising solution for accurate cardiovascular flow assessment in diverse patient populations.