Javier Gonzalez-Castillo1, Vinai
Roopchansingh2, Peter A. Bandettini1,2, Jerzy Bodurka3
1Section on Functional
Imaging Methods, National Institute of Mental Health, Bethesda, MD, United
States; 2Functional MRI Facility, National Institute of Mental
Health, Bethesda, MD, United States; 3Laureate Institute for Brain
Research, Tulsa, OK, United States
Flip angles near the Ernst angle are commonly used in fMRI to maximize image SNR. However, lower angles provide significant benefits such as better tissue contrast, less inflow effect, less through-plane motion artifacts, and reduced levels of radio-frequency energy deposition. Recent research has shown that TSNR, a better predictor of sensitivity than SNR, stays fairly constant and close to its maximum value for a wide range of angles when physiological noise dominates. Here we explore the hypothesis that low flip angles have no detrimental effects on our ability to detect BOLD neuronal activations; and might be advised for fMRI experiments