Fluorescence-based method for assessment of blood-brain barrier disruption

We report on a fluorescence-based optical method for assessment of blood-brain barrier in humans. The technique is based on monitoring of fluorescence light excited in the dye circulating in the brain. Measurements were carried out in healthy volunteers and in patients with disruption of the blood-brain barrier with the use of time-resolved method during inflow and washout of indocyanine green after its intravenous injection. We show large differences in the fluorescence signals - in healthy subjects a fast washout of the dye can be observed whereas in patients the washout is significantly prolonged. We conclude that the monitoring of the fluorescence signals during injection of exogenous optical contrast agent can be used for the assessment of the condition of blood-brain barrier at the bedside. The technique may be of benefit for diagnosis of the patients suffering from damage of the blood-brain barrier and in monitoring of therapies used in such patients.