BOLD imaging in the mouse brain using a turboCRAZED sequence at high magnetic fields.

Area of Science:

• Magnetic Resonance Imaging
• Neuroimaging
• Biophysics

Background:

• Functional MRI (fMRI) using intermolecular double-quantum coherences (iDQC) offers strong activation signals.
• Conventional fMRI readout methods face challenges in small animals at very high magnetic fields.

Purpose of the Study:

• To develop and validate a rapid iDQC imaging technique for high-field fMRI in small animals.
• To improve signal-to-noise ratio (SNR) efficiency and imaging speed.

Main Methods:

• Implemented rapid iDQC imaging combining iDQC preparation with a Turbo spin echo-like readout.
• Utilized four-step phase cycling and intensity-ordered k-space encoding for optimized SNR.
• Achieved acceleration factors of 16 in phantoms and acquired mouse brain images in 30 seconds in vivo.

Main Results:

• Demonstrated successful in vivo mouse brain imaging with echo trains of up to 32 echoes.
• Observed blood oxygen level dependent (BOLD) effects with an average signal change of (6.3 +/- 1.1)% in iDQC images.
• Showcased comparable or superior signal changes to conventional multi-spin echo and gradient echo methods.

Conclusions:

• Fast iDQC imaging is a robust tool for high-field fMRI in small animals.
• The novel method enables rapid acquisition and efficient BOLD signal detection.
• Combining T(2)*-weighting with fast iDQC sequences may enhance signal changes for improved neuroimaging.