In vivo monitoring of blood-brain barrier leakage by using photoacoustic microscopy

Monitoring and evaluation of vascular leakage in brain is important in the research area of brain injuries and edema. A high-resolution photoacoustic microscopy (PAM) was developed to monitor the blood-brain barrier (BBB) permeability using Evans blue (EB) dye. We used a mouse traumatic brain injury (TBI) to validate the usefulness of our system. The uptake of EB in brain vessels was continuously studied for 2 hours after injection in a normal mouse. The TBI mice with and without injection of EB were both scanned by PAM for 2 hours, respectively. The PAM results showed that EB was a high contrast agent for PAM images and the degree of BBB leakage was accessed by EB leakage. Our studies demonstrate that PAM has potential in monitoring BBB leakage in vivo.