Optical coherence tomography and autofluorescence imaging of human tonsil

Abstract

For the first time, we present co-registered autofluorescence imaging and optical coherence tomography (AF/OCT) of excised human palatine tonsils to evaluate the capabilities of OCT to visualize tonsil tissue components. Despite limited penetration depth, OCT can provide detailed structural information about tonsil tissue with much higher resolution than that of computed tomography, magnetic resonance imaging, and Ultrasound. Different tonsil tissue components such as epithelium, dense connective tissue, lymphoid nodules, and crypts can be visualized by OCT. The co-registered AF imaging can provide matching biochemical information. AF/OCT scans may provide a non-invasive tool for detecting tonsillar cancers and for studying the natural history of their development.

Figure 1. AF/OCT system.

AF/OCT system for imaging excised tonsils placed between glass slides, BDM: broadband dielectric mirror, DBS: dichroic beamsplitter, APD: avalanche photodiode.

Figure 2. OCT vs. histology.

Comparing OCT B-scans with histopathology results, DCT: dense connective tissue, Epi: epithelium, Cr: crypt, LN: lymphoid nodules, and GC: germinal center. White bar is 100 µm.

Figure 3. Visualizing crypts by OCT.

Middle row are enface OCT sections, top and bottom rows are OCT B-scans corresponding to the green and blue dashed lines, respectively; Cr: crypt.

Figure 4. AF/OCT scans of tonsils.

Imaging results obtained from AF/OCT scans of three tonsils samples, including representative enface OCT (a_1-3), green AF images (b_1-3); Cr: crypt, DCT: dense connective tissue, LN: lymphoid nodules.

Figure 5. AF/OCT scan of thin tonsil section.

(a) AF image and (b) representative enface OCT section from a thin section cut from a tonsil sample along with the histopathology result (c) obtained from a 4 µm thick section cut from the same sample Cr: crypt, LN: lymphoid nodules, and DCT: dense connective tissue.