Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Flow velocity measurement with ac gradients.

J H Walton, M S Conradi

    Magnetic Resonance in Medicine
    |March 1, 1987
    PubMed
    Summary

    Two novel Nuclear Magnetic Resonance (NMR) experiments measure fluid flow using alternating current (ac) field gradients. These methods convert flow velocity into frequency shifts, enabling velocity distribution analysis from a single Fourier transform.

    Related Concept Videos

    You might also read

    Related Articles

    Articles linked to this work by shared authors, journal, and citation graph.

    Sort by
    Same author

    Room temperature "optical nanodiamond hyperpolarizer": Physics, design, and operation.

    The Review of scientific instruments·2020
    Same author

    Effective-medium theory of elastic waves in random networks of rods.

    Physical review. E, Statistical, nonlinear, and soft matter physics·2012
    Same author

    Morphometric changes in the human pulmonary acinus during inflation.

    Journal of applied physiology (Bethesda, Md. : 1985)·2011
    Same author

    Amyloid oligomer formation probed by water proton magnetic resonance spectroscopy.

    Biophysical journal·2011
    Same author

    Imaging alveolar-duct geometry during expiration via ³He lung morphometry.

    Journal of applied physiology (Bethesda, Md. : 1985)·2011
    Same author

    ³He lung morphometry technique: accuracy analysis and pulse sequence optimization.

    Journal of magnetic resonance (San Diego, Calif. : 1997)·2010

    Area of Science:

    • Magnetic Resonance Imaging (MRI)
    • Fluid Dynamics
    • Biomedical Engineering

    Background:

    • Accurate measurement of fluid flow is crucial in various scientific and medical fields.
    • Traditional Nuclear Magnetic Resonance (NMR) techniques often require spatial localization for flow velocity assessment.
    • Field inhomogeneities and chemical shifts can complicate NMR-based flow measurements.

    Purpose of the Study:

    • To introduce two new NMR experiments for measuring fluid velocities.
    • To demonstrate a method that avoids spatial localization by converting flow velocity to a resonance frequency shift.
    • To present results applicable to time-resolved blood flow measurements.

    Main Methods:

    • Development of two distinct NMR experiments utilizing alternating current (ac) field gradients.
    • Method 1: Employs a single radiofrequency (rf) pulse, requiring a homogeneous static magnetic field.
    • Method 2: Utilizes the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence to mitigate field inhomogeneity and chemical shift artifacts.

    Main Results:

    • Both NMR experiments successfully convert fluid velocity into measurable resonance frequency shifts.
    • Velocity distribution can be obtained by Fourier transformation of a single Free Induction Decay (FID) or echo train.
    • Experimental validation was performed using a simple flowing phantom, demonstrating the efficacy of both techniques.

    Conclusions:

    • The presented NMR techniques offer a non-spatially localized approach to quantify fluid velocity distributions.
    • These methods are robust against field inhomogeneities and chemical shifts, particularly the CPMG-based approach.
    • The developed techniques hold significant potential for time-resolved blood flow measurements in clinical applications.

    Related Experiment Videos