fMRI performed intra-operatively has the potential to significantly improve the outcomes from neurosurgery. The question remains however as to whether the BOLD signal can be detected in anaesthetised patients and what effect anaesthesia has on the response. In 5 patients with brain tumours anaesthetised for surgery we performed a passive sensorimotor fMRI paradigm. Anaesthesia resulted in a reduction in the BOLD response relative to the awake state, but also reduced the variance in the statistical model resulting in significant, accurate activation in all patients.
We conclude that the fMRI BOLD signal can be accurately detected in anaesthetised neurosurgical patients.