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

Abstract

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 (0.9x2 microm, axialxlateral) is achieved in biological tissue by interfacing a state-of-the-art Ti:Al2O3 laser (lambda(c)=800 nm, delta lambda=260 nm, and P(out)=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 microm), enlarged nuclei of tumor cells (approximately 8 to 15 microm), small cysts, and blood vessels, which are characteristic of neuropathologies and normally absent in healthy brain tissue.

In vivo optical coherence tomography–based scoring of oral mucositis in human subjects: a pilot study

“…10,11 Conceptually, it has been compared to ultrasound scanning. 12 Both ultrasound and OCT provide real-time structural imaging, but unlike ultrasound, OCT is based on low-coherence interferometry, using broadband light to provide cross-sectional, high-resolution subsurface tissue images.…”

Review of the potential of optical technologies for cancer diagnosis in neurosurgery: a step toward intraoperative neurophotonics

“…Clinical applications of OCT have been mainly in ophthalmology, however, over the last 20 years it has been extended to cancer detection in a variety of tissues. 53,54 One of the first studies on ex vivo brain tissue by Bizheva et al 55 was reported in which the OCT signal was used to distinguish between healthy brain and multiple types of brain tumors. This study claims the source of OCT signal contrast comes from differences in cell nuclei, cysts, microvasculature, and microcalcifications in brain tissue.…”

High-Resolution, 2- and 3-Dimensional Imaging of Uncut, Unembedded Tissue Biopsy Samples

“…Previous attempts at creating large 3-D data sets from tissue have used methods producing poor contrast, poor depth penetration, or that successively remove tissue as the 3-D volume is imaged. [3][4][5][6] Thus, past 3-D reconstruction techniques fail to improve upon the most important limitations of traditional histology. But 3-D reconstructions of clarified tissue using MPM showed excellent cellular contrast; sufficient depth, such that entire biopsy specimens could be imaged; and compatibility with subsequent traditional processing, including preservation of immunostain capability with the few antibodies tested.…”

“…More recent ones include high-resolution x-ray computed tomography 1,2 and optical coherence tomography. 3,4 They have the advantages of being applicable to unprocessed fresh tissue and allowing complete 3-dimensional visual examination while leaving tissue unaltered and amenable to further characterization. While efforts in these fields continue, neither technique is able to produce images of sufficient resolution and contrast for adequate routine pathology evaluation.…”