Effects of Different Scan Duration on Brain Effective Connectivity among Default Mode Network Nodes

Area of Science:

• Neuroimaging
• Functional Connectivity Analysis
• Brain Networks

Background:

• Resting-state functional magnetic resonance imaging (rs-fMRI) assesses brain connectivity without tasks, beneficial for patients with cognitive decline.
• Longer rs-fMRI scan durations are typically recommended for reliable connectivity measurements.
• Clinical limitations exist for extended scan times in certain patient populations.

Purpose of the Study:

• To evaluate the sufficiency of shorter scan durations for rs-fMRI.
• To compare the reliability of 10-minute versus 15-minute rs-fMRI scan durations.
• To assess effective connectivity within the default mode network (DMN).

Main Methods:

• Twenty-one healthy participants (ages 21-60) underwent both 10-minute and 15-minute rs-fMRI scans.
• Default mode network (DMN) regions, including PCC, mPFC, LIPC, and RIPC, were analyzed.
• Spectral dynamic causal modeling (spDCM) and Bayesian Model Selection (BMS) were used to analyze effective connectivity.

Main Results:

• The fully connected model was selected as the best model for both 10 and 15-minute scan durations.
• No significant differences in effective connectivity were found between the two scan durations.
• Bayesian Model Selection confirmed model consistency across scan lengths.

Conclusions:

• Scan durations of 10 to 15 minutes are adequate for evaluating effective connectivity within the DMN.
• Shorter scan durations are advantageous for frail individuals or those with limited tolerance.
• The findings support the clinical feasibility of reduced rs-fMRI scan times.