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Method for quantification of low flow velocities by magnetic resonance phase imaging
F Ståhlberg1, B Nordell, A Ericsson
1Department of Radiation Physics, University of Lund, Sweden.
Acta Radiologica. Supplementum
|January 1, 1986
Summary
This study shows magnetic resonance imaging (MRI) phase images can quantify low flow velocities. Phase image variations are monotone and flow direction-dependent, unlike modulus images.
Area of Science:
- Medical Imaging
- Biophysics
Background:
- Magnetic Resonance Imaging (MRI) is crucial for non-invasive physiological measurements.
- Quantifying fluid flow, such as blood or cerebrospinal fluid, remains a challenge in MRI.
Purpose of the Study:
- To compare the influence of flow (0-25 mm/s) on MRI image types (modulus, phase, real, imaginary).
- To develop a simple method for in vivo flow velocity determination using MRI data.
Main Methods:
- Utilized a flow phantom with non-doped water (CSF simulant) and Mn2+-doped water (blood simulant).
- Studied flow perpendicular to the image slice using a 0.5 T Siemens Magnetom scanner.
- Analyzed signal variations across modulus, phase, real, and imaginary images at different flow velocities.
Main Results:
- All studied MRI image types demonstrated significant flow dependence.
- Phase image variations were monotone and independent of relaxation times, unlike modulus images.
- Phase images showed clear flow direction dependence, enabling calibration for velocity quantification.
Conclusions:
- MRI phase information is a reliable indicator of fluid flow velocity.
- A simple calibration method using phase image signal versus velocity curves can quantify low flow velocities in vivo.