A preliminary study on using reverberant shear wave fields in optical coherence elastography to examine mice brain ex vivo

摘要

A number of approaches employ optical coherence tomography (OCT) to obtain the mechanical properties of biologicaltissue. These are generally referred to as optical coherence elastography (OCE), and have demonstrated promisingapplications with studies in cornea, breast, muscle, skin, and other soft tissues. A particular application of interest is thebrain, in which changes in local and global elastic properties may correlate with the onset and progression of degenerativebrain diseases. In this preliminary study, mice brains are studied ex vivo and in situ with preservation of the brain/skullanatomical architecture. A small 6 mm diameter portion of the skull is replaced with a glass cap to allow for OCT imaging.Various permutations of source placement for generating shear waves and modes of excitation are evaluated to optimizethe experimental setup. The use of reverberant shear wave fields, which takes advantage of inevitable reflections fromboundaries and tissue inhomogeneities, allow for estimation of the shear wave speed, which is directly related to the elasticmodulus of soft tissues. Preliminary estimates for the shear wave speed in brains of recently deceased mice are obtained.This study demonstrates potential applications in brain OCE ex vivo and in vivo.