MR velocity imaging by phase display

Area of Science:

• Medical Imaging
• Biophysics
• Cardiovascular Imaging

Background:

• Nuclear magnetic resonance (NMR) signal properties have long been known to encode macroscopic motion.
• Medical magnetic resonance imaging (MRI) has explored various flow imaging techniques for noninvasive assessment.
• X-ray angiography is a benchmark for sensitivity and specificity in vascular imaging.

Purpose of the Study:

• To demonstrate that conventional spin-echo Fourier transform MRI acquisitions inherently capture in-plane velocity information.
• To present a simple method for visualizing flow velocity distributions using existing MRI data.
• To highlight the potential of this technique for noninvasive cardiovascular assessment.

Main Methods:

• Utilized conventional spin-echo Fourier transform image acquisitions.
• Processed the real part of complex image data (phase display) to reveal velocity information.
• Employed a rotating disk phantom for velocity/phase-shift constant calibration.

Main Results:

• Conventional MRI acquisitions naturally encode in-plane flow velocity components.
• Phase display of image data effectively visualizes velocity distributions.
• Longitudinal views of flow channels provide extensive physiological information.
• Phantom and in vivo flow images were successfully generated.

Conclusions:

• Standard MRI techniques can be repurposed for noninvasive flow imaging without specialized sequences or software.
• Phase-based velocity mapping offers a simple and effective method for assessing in-plane flow.
• This approach has the potential to provide detailed physiological insights and complement existing angiography methods.