The purpose of the study is to confirm the applicability and usefulness of the novel method
of assessment of the permeability of the blood-brain barrier and in monitoring of the
treatment of patients with meningitis. The proposed technique is based on evaluation of the
kinetics of the indocyanine green (ICG) outflow from the brain with the use of near-infrared
spectroscopy (NIRS). Usefulness of the NIRS-based method will be analyzed in relation to the
reference method, which is contrast-enhanced magnetic resonance imaging (MRI).