Estimation of the EEG power spectrum using MRI T-2 relaxation time in traumatic brain injury

Objectives: To study the relationship between magnetic resonance imaging (M RI) T-2 relaxation time and the power spectrum of the electroencephalogram (EEG) in long-term follow up of traumatic brain injury. Methods: Nineteen channel quantitative electroencephalograms or qEEG, tests of cognitive function and quantitative MRI T-2 relaxation times (qMRI) wer e measured in 18 mild to severe closed head injured outpatients 2 months to 4.6 years after injury and 11 normal controls. MRI T-2 and the Laplacian o f T-2 were then correlated with the power spectrum of the scalp electrical potentials and current source densities of the qEEG. Results: qEEG and qMRI T-2 were related by a frequency tuning with maxima i n the alpha (8-12 Hz) and the lower EEG frequencies (0.5-5 Hz), which varie d as a function of spatial location. The Laplacian of T2 acted like a spati al-temporal 'lens' by increasing the spatial-temporal resolution of correla tion between 3-dimensional T-2 and the ear referenced alert but resting spo ntaneous qEEG. Conclusions: The severity of traumatic brain injury can be modeled by a lin ear transfer function that relates the molecular qMRI to qEEG resonant freq uencies. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.