Estimation of the EEG power spectrum using MRI T2 relaxation time in traumatic brain injury

Objectives: To study the relationship between magnetic resonance imaging (MRI) T2 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 T2 relaxation times (qMRI) were measured in 18 mild to severe closed head injured outpatients 2 months to 4.6 years after injury and 11 normal controls. MRI T2 and the Laplacian of T2 were then correlated with the power spectrum of the scalp electrical potentials and current source densities of the qEEG. Results: qEEG and qMRI T2 were related by a frequency tuning with maxima in the alpha (8–12 Hz) and the lower EEG frequencies (0.5–5 Hz), which varied as a function of spatial location. The Laplacian of T2 acted like a spatial–temporal ‘lens’ by increasing the spatial–temporal resolution of correlation between 3-dimensional T2 and the ear referenced alert but resting spontaneous qEEG. Conclusions: The severity of traumatic brain injury can be modeled by a linear transfer function that relates the molecular qMRI to qEEG resonant frequencies.