Dual-echo ASL contributes to decrypting the link between functional connectivity and cerebral blow flow

Area of Science:

• Neuroimaging
• Magnetic Resonance Imaging (MRI)
• Functional Connectivity

Background:

• Resting-state functional connectivity (FC) studies traditionally rely on blood oxygenation level dependent (BOLD) contrast, limiting research based on cerebral blood flow (CBF) fluctuations.
• Arterial spin labeling (ASL) MRI, particularly with a dual-echo readout module (DE-ASL), offers the potential for simultaneous CBF and BOLD signal acquisition.
• Assessing resting-state brain organization and network properties using ASL-derived CBF is an emerging area in neuroimaging.

Purpose of the Study:

• To evaluate the efficacy of the DE-ASL sequence for quantifying resting-state FC and brain organization.
• To compare DE-ASL derived FC and network measures against conventional BOLD (cvBOLD) imaging.
• To investigate the relationship between complex network measures and CBF information derived from DE-ASL.

Main Methods:

• Acquisition of pseudocontinuous multislice DE-ASL data from 13 volunteers on a 3T scanner.
• Simultaneous extraction of concomitant BOLD (ccBOLD) signals alongside ASL data.
• Application of graph-theoretical analysis to quantify FC strength and assess network properties across DE-ASL and cvBOLD sequences.

Main Results:

• The ccBOLD component of DE-ASL yielded highly comparable resting-state FC results to cvBOLD.
• ASL-based connectivity patterns and graph indices differed from BOLD sequences due to their distinct physiological underpinnings.
• DE-ASL demonstrated reliable detection of resting-state FC, enabling simultaneous CBF quantification.

Conclusions:

• DE-ASL is a viable technique for reliable resting-state FC detection and simultaneous CBF quantification.
• This method overcomes the limitations of single fMRI experiments that preclude quantitative BOLD signal change measurement.
• DE-ASL enhances neuroimaging capabilities by providing complementary CBF and BOLD information within a single scan.