Echo-Planar-Based Time-of-Flight Imaging Using a Modified Interleaved Flyback Trajectory

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Physics

Background:

• Flow artifacts, such as ghosting and signal dropout, are common in Echo Planar Imaging (EPI) due to alternating readout polarities.
• These artifacts can degrade image quality and complicate the interpretation of MRI scans, particularly in applications like Time-of-Flight Magnetic Resonance Angiography (TOF-MRA).

Purpose of the Study:

• To introduce a modified interleaved flyback (miFB) approach to mitigate flow artifacts in EPI.
• To maintain high acquisition efficiency while reducing artifacts.
• To enable faster Magnetic Resonance Angiography (MRA) scans.

Main Methods:

• Reconstruction of odd and even echoes in 3D-EPI separately.
• Acquisition of missing lines using interleaved shots with inverted polarity and an additional gradient pre-lobe.
• Combination of the miFB approach with gradient moment smoothing.
• Comparison with the interleaved dual-echo with acceleration (IDEA) method in phantom and in vivo scans at 7 Tesla.

Main Results:

• Significant reduction in ghosting and signal dropout compared to conventional EPI.
• Image quality comparable to non-EPI acquisitions.
• Acquisition time reduced by approximately 50%.

Conclusions:

• The miFB approach effectively reduces flow artifacts in EPI.
• This method allows for decreased acquisition times in TOF-MRA.
• miFB offers a promising solution for efficient and high-quality EPI-based MRA.