Functional MRI of CO2 induced increase in cerebral perfusion

Abstract

The sensitivity of MR gradient echo imaging towards CO₂ induced changes in cerebral blood flow was investigated in 10 normal subjects. The subjects were inhaling 5% and 7% CO₂ and the experiments were carried out at 1.5T (n=6) and 2.0 T (n=5), allowing a comparison of field strengths. Additional experiments were carried out using a higher spatial resolution. The largest signal increases were noted in areas corresponding to larger vessels, but significant changes were also conspicuous in deeper cortical and central grey matter. The changes appeared linearly related to the arterial CO₂ tension, within the range of P_aCO₂ studied. In white matter, the changes were not statistically significant.