k-space and q-space: combining ultra-high spatial and angular resolution in diffusion imaging using ZOOPPA at 7 T

Area of Science:

• Neuroimaging
• Magnetic Resonance Imaging
• Diffusion MRI

Background:

• Diffusion MRI (dMRI) tractography aims to improve results through higher spatial or angular resolution.
• Signal-to-noise ratio (SNR) is a limiting factor due to restricted acquisition time.
• Ultra-high field strength (7 Tesla) offers potential for increased spatial resolution but faces challenges with conventional echo-planar imaging (EPI) due to distortions and blurring.

Purpose of the Study:

• To introduce an adapted EPI sequence combined with ZOOmed imaging and Partially Parallel Acquisition (ZOOPPA) for high-quality dMRI at 7 Tesla.
• To demonstrate the feasibility of achieving high spatial and angular resolution in vivo human dMRI at 7 Tesla.
• To showcase the utility of these high-resolution datasets for resolving complex white matter microstructures.

Main Methods:

• Development and application of an adapted EPI sequence at 7 Tesla.
• Integration of ZOOmed imaging and Partially Parallel Acquisition (ZOOPPA).
• Acquisition of in vivo human dMRI datasets with isotropic resolutions of 1 mm and 800 μm.

Main Results:

• The adapted EPI sequence successfully produced high-quality diffusion-weighted images at 7 Tesla.
• High spatial and angular resolution was achieved, overcoming typical EPI limitations at high field strengths.
• Demonstrated capability to resolve intricate fiber architectures, including crossing fibers, cortical anisotropy, and fibers entering the cortex.

Conclusions:

• The presented ZOOPPA-adapted EPI method enables high-resolution dMRI at 7 Tesla.
• This advancement facilitates detailed investigation of human brain white matter microstructure in vivo.
• The technique holds promise for improving the understanding of complex neural pathways and pathologies.