Wide-field imaging of brain white matter fiber tracts with Mueller polarimetry in backscattering configuration

Abstract

The accurate detection of brain tumor border during neurosurgery is crucial for the safe and complete tumor resection, but it is often difficult to differentiate solid tumor tissue from infiltrated white matter. To address this problem we suggest detecting optical anisotropy of brain white matter which consists of bundles of axons (or fiber tracts). Tumor growth erases this optical anisotropy of healthy brain. We used a wide-field imaging Mueller polarimeter to measure thick fixed human and fresh animal brain sections in reflection. The maps of azimuth of fast optical axis of linear birefringent medium obtained from Lu-Chipman decomposition of the experimental Mueller matrices showed a compelling correlation with the fiber tracts directions on histology image of thin whole mount silver-stained brain tissue section.