Imaging ex vivo healthy and pathological human brain tissue with ultra-high-resolution optical coherence tomography

The ability of ultra-high-resolution optical coherence tomography (UHR OCT) to discriminate between healthy and pathological human brain tissue is examined by imaging ex vivo tissue morphology of various brain biopsies. Micrometer-scale OCT resolution (0.9×2 µm, axial×lateral) is achieved in biological tissue by interfacing a state-of-the-art Ti:Al2O3 laser (c=800 nm, =260 nm, and Pout=120 mW exfiber) to a free-space OCT system utilizing dynamic focusing. UHR OCT images are acquired from both healthy brain tissue and various types of brain tumors including fibrous, athypical, and transitional meningioma and ganglioglioma. A comparison of the tomograms with standard hematoxylin and eosin (H&E) stained histological sections of the imaged biopsies demonstrates the ability of UHR OCT to visualize and identify morphological features such as microcalcifications (>20 µm), enlarged nuclei of tumor cells (~8 to 15 µm), small cysts, and blood vessels, which are characteristic of neuropathologies and normally absent in healthy brain tissue.