Development and application of rotationally compensated RARE

Area of Science:

• Medical Physics
• Magnetic Resonance Imaging
• Fluid Dynamics

Background:

• Rapid acquisition techniques in Magnetic Resonance Imaging (MRI) are crucial for dynamic processes.
• Conventional MRI sequences struggle with motion artifacts, especially rotational motion.
• Compensating for sample rotation is essential for accurate imaging in various applications.

Purpose of the Study:

• Introduce and validate ROTACOR, an extension of the Rapid Acquisition with Relaxation Enhancement (RARE) technique.
• Demonstrate ROTACOR's ability to compensate for constant sample rotational motion.
• Apply ROTACOR to image dynamic fluid systems and determine interfacial tension.

Main Methods:

• Developed ROTACOR by rotating the gradient coordinate system between refocusing radiofrequency pulses.
• Acquired k-space data with an irregularly sampled raster in the laboratory frame, resulting in a rectilinear raster for a rotating sample.
• Applied the technique to image a rotating mixing paddle and sheared water droplets in silicone oil within a Couette cell.

Main Results:

• ROTACOR significantly improved image quality compared to conventional RARE for a rotating mixing paddle.
• Accurate imaging of water droplet deformation under shear was achieved using ROTACOR.
• Interfacial tension values derived from ROTACOR imaging compared favorably with established literature values.

Conclusions:

• ROTACOR effectively compensates for constant rotational motion in rapid MRI.
• The technique enables accurate visualization and quantification of dynamic fluid behavior.
• ROTACOR offers a valuable tool for studying interfacial phenomena in fluid systems.