Blood oxygen-level-dependent magnetic resonance imaging

Functional magnetic resonance imaging (fMRI) scanning to visualize brain activity relies primarily on the blood oxygen level dependent (BOLD) signal, an indirect measurement of cerebral blood flow associated with neuronal activity. In a prospective study of fMRI, 14 children were randomized to propofol 1 mg/kg by bolus injection followed either by propofol 4 mg/kg/hour or by midazolam 0.6 mg/kg/hour [80 ]. There were no differences in MRI time, and all studies were completed without movement or adverse events. The children in both groups required further boluses of sedation, and there were no differences in recovery time. Midazolam temporally affected neuronal activity and vascular response leading to a delay in functional response whereas propofol produced a similar activation pattern to non-sedated adults. 

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