Blood flow imaging through detection of temporal variations in magnetization

Area of Science:

• Medical Imaging
• Biophysics
• Fluid Dynamics

Background:

• Magnetic resonance (MR) angiography is crucial for visualizing blood vessels.
• Signal intensity loss in poststenotic regions of MR angiograms is a known phenomenon.
• The underlying causes of signal loss and their relationship to blood flow dynamics are not fully understood.

Purpose of the Study:

• To test if view-to-view variations in magnetization indicate disordered blood flow.
• To determine if these magnetization changes cause signal intensity loss in MR angiograms.
• To develop a technique for visualizing disordered blood flow and improving MR angiography.

Main Methods:

• Developed a technique using view-to-view variations in transverse magnetization.
• Created angiographic projection images to map disordered flow (disordered flow maps).
• Validated the technique in vitro using phantoms and in vivo.

Main Results:

• The technique successfully identified disordered flow in vascular volume elements.
• Disordered flow maps recovered signal intensity downstream from simulated stenoses.
• Combining disordered flow maps with morphologic images enhanced visualization of stenotic regions and local flow characteristics.

Conclusions:

• View-to-view variations in transverse magnetization are indicative of disordered blood flow.
• These variations are a significant cause of signal intensity loss in MR angiography.
• The developed technique offers insights into dynamic blood flow and improves anatomical depiction in MR angiography.