A method for MR quantification of flow velocities in blood and CSF using interleaved gradient-echo pulse sequences

Area of Science:

• Medical Imaging
• Biophysics
• Cardiovascular Physiology

Background:

• Accurate in vivo quantification of physiological flow is crucial for diagnosing various medical conditions.
• Existing magnetic resonance imaging (MRI) techniques for flow quantification can be time-consuming or limited in their velocity range.

Purpose of the Study:

• To develop and validate a rapid MRI method for quantifying a wide range of flow velocities using phase information.
• To assess the feasibility of this method for in vivo applications in humans.

Main Methods:

• A modified gradient-echo sequence was implemented, encoding flow along the slice selection direction using bipolar gradients.
• Phase information from velocity-encoded and non-encoded images was utilized for flow determination.
• Calibration was performed using flow phantoms, and in vivo studies included cardiac gating in thoracic vessels, popliteal vessels, and the cerebral aqueduct for cerebrospinal fluid (CSF) flow.

Main Results:

• The method demonstrated good agreement with established flow quantification techniques.
• Calibration results showed good correlation with theoretical encoding efficiencies.
• Successful in vivo flow measurements were obtained in major blood vessels and for CSF flow.

Conclusions:

• The developed MRI technique is rapid and flexible for in vivo flow quantification.
• The method shows promise for routine clinical application in MRI examinations.
• This approach can accurately measure diverse flow velocities in various physiological contexts.