Differences in cerebral blood vasculature and flow in awake and anesthetized mouse cortex revealed by quantitative optical coherence tomography angiography

Abstract

Background: Most of the in vivo neurovascular imaging studies are performed in anesthetized animals. However, anesthesia significantly affects cerebral hemodynamics.

New method: We applied optical coherence tomography (OCT) methods such as optical microangiography (OMAG) and Doppler optical microangiography (DOMAG) to quantitatively evaluate the effect of anesthesia in cerebral vasculature and blood flow in mouse brain.

Results: The OMAG results indicated the increase of large vessel diameter and capillary density induced by ketamine-xylazine and isoflurane, meaning that both anesthetics caused vasodilation. In addition, the preliminary results from DOMAG showed that isoflurane increased the baseline cerebral blood flow.

Comparison with existing methods: In comparison with other in vivo imaging modalities, OCT can provide label-free assessment of cortical tissue including tissue morphology, cerebral blood vessel network and flow information down to capillary level, with a large field of view and high imaging speed.

Conclusions: OCT angiography methods demonstrated the ability to measure the differences in the baseline morphological and flow parameters of both large and capillary cerebrovascular networks between awake and anesthetized mice.

Keywords: Anesthetized mouse; Awake mouse; Cerebral blood flow; Microvasculature; Optical coherence tomography; Optical microangiography.