Motion- and Field-Robust Mesoscopic Whole-Brain T 2 * $$ {T}_2^{\ast } $$ -Weighted Imaging at 7 and 11.7 T Using...

Area of Science:

• Neuroimaging
• Magnetic Resonance Imaging (MRI)

Background:

• High-resolution T2*-weighted imaging is crucial for visualizing brain vasculature.
• Motion and field changes introduce artifacts, degrading image quality, especially at ultra-high fields (UHF) like 7T and 11.7T.
• Prospective motion correction is essential for robust UHF neuroimaging.

Purpose of the Study:

• To mitigate motion and field change artifacts in high-resolution T2*-weighted human brain imaging.
• To evaluate the efficacy of MR-based servo navigators at ultra-high fields (up to 11.7T).
• To improve the quality of whole-brain imaging at 0.3mm isotropic resolution.

Main Methods:

• Integration of MR-based servo navigators into a segmented 3D-EPI sequence.
• Prospective correction for involuntary head motion and first-order shim changes.
• Acquisition of whole-brain data at 0.3mm isotropic resolution with and without correction at 7T and 11.7T.

Main Results:

• Servo navigation reduced blurring of small veins across all subjects and field strengths.
• Image quality was preserved during involuntary large motion with servo navigation, unlike uncorrected scans.
• Prospective field drift correction further reduced blurring and shading in the frontal lobe during microscopic motion.

Conclusions:

• Servo-navigated segmented 3D-EPI enhances 0.3mm isotropic whole-brain T2*-weighted imaging.
• The technique effectively handles realistic motion and field changes at 7T and 11.7T.
• Achieved scan times of 5.5-11 minutes for whole-brain imaging at UHF.