real-time fMRI

real-time fMRI enhances BOLD sensitivity by integrating and comparing multi-echo fMRI data to optimize signal quality and functional contrast detection for both offline and real-time functional MRI applications.

Key Features:

• Multi-Echo Data Combination: Evaluates six approaches derived from multi-echo fMRI: single-echo time series (Echo 2), real-time T2*-mapped time series (T2*FIT), and four combined time series (T2*-weighted, tSNR-weighted, TE-weighted, and T2*FIT-weighted).
• BOLD Sensitivity Enhancement: Systematically compares these approaches to assess impacts on BOLD sensitivity and highlights the T2*FIT-weighted combination as producing the largest increase in temporal signal-to-noise ratio (tSNR) across task-based and resting-state runs.
• Offline and Real-Time Performance: Reports that the T2*FIT time series yields the largest offline effect size measures and provides strong real-time region-of-interest based functional contrasts in real-time paradigms.
• tSNR Trade-off: Notes a decrease in tSNR associated with the T2*FIT time series despite its advantages in effect size and ROI contrast, indicating a performance trade-off to consider.

Scientific Applications:

• Neural activity detection in task and resting-state fMRI: Enhances sensitivity of BOLD signals to improve detection of neural activity patterns during cognitive tasks and resting-state measurements.
• Real-time region-of-interest functional contrasts: Supports real-time fMRI paradigms by improving ROI-based functional contrast detection for dynamic brain mapping and online analyses.

Methodology:

Evaluates six multi-echo approaches (Echo 2, T2*FIT, T2*-weighted, tSNR-weighted, TE-weighted, T2*FIT-weighted) across four task-based fMRI runs and two resting-state runs from 28 healthy volunteers to assess BOLD sensitivity, tSNR, and effect sizes.