Merv Hammer

Purpose: To assess noninvasive optical coherence tomography and optical Doppler tomography for early detection and evaluation of chemotherapy-induced oral mucositis. Experimental Design: Cheek pouches of 10 Syrian golden hamsters were imaged using OCT/ODT during development of chemotherapy-induced mucositis. I.p. injections of 5-fluorouracil and mechanical irritation induced oral lesions. At 2, 4, 7, and 11 days, one hamster was sacrificed and processed for histopathology. OCT images were visually examined; ODT results were semiquantified. Imaging data were compared with histologic findings. Results: During the development of mucositis, OCT/ODT identified the following events: change in epithelial thickness, loss of surface keratinized layer continuity, loss of epithelial and submucosal integrity, changes in axial blood flow velocity, and changes in blood vessel size. The semiquantitative imaging-based scoring system identified the severity of mucositis as defined by histopathology. The combination of imaging criteria used allowed for the detection of early, intermediate, and late mucositic changes. Imaging data gave higher scores compared with clinical scores early on, suggesting that the imaging-based diagnostic scoring was more sensitive to early mucositic change than the clinical scoring system. Once mucositis was established, imaging and clinical scores converged. Conclusion: OCT/ODT identified chemotherapy-induced oral changes before their clinical manifestation, and the proposed scoring system for oral mucositis was validated for the semiquantification of mucositic change. © 2007 American Association for Cancer Research.

The Mueller matrix describes all the polarizing properties of a sample and, therefore, the optical differences between noncancerous and precancerous tissue that may be present within the matrix elements. A high-speed polarimetry system that generates 16 full Mueller matrices to characterize tissues is presented. Feature extraction is done on the Mueller matrix elements resulting in depolarization and retardance images by polar decomposition. These are used to detect and classify early oral cancers and precancerous changes in epithelium such as dysplasia. These images are compared with orthogonal polarization images and analyzed in an attempt to identity useful factors for the differentiation between cancerous lesions and their benign counterparts. Our results indicate that polarimetry has potential as a method for the in vivo early detection and diagnosis of oral premalignancy. © 2007 Optical Society of America.

Objective: To assess the ability of nonlinear optical microscopy to image ex vivo healthy and degenerative bovine articular cartilage. Method: Fresh bovine femoral-tibial joints were obtained from an abattoir. Articular cartilage specimens were harvested from the tibial plateau. Normal and degenerative specimens were imaged by NLOM and subsequently fixed and processed for histological examination. Results: NLOM provided high resolution images of articular cartilage at varying depths with high sensitivity to tissue morphology and high specificity to tissue components without fixing, sectioning or staining. Spectroscopic segmentation of nonlinear optical signals isolated the collagen matrix from the chondron. Images from the superficial zone were consistent with the presence of a matrix composed of both elastin-like and collagen fibers distributed in a depth-dependent morphological arrangement, whereas only collagen was demonstrated in the middle and deep zones. Alterations of collagen matrix associated with advanced degenerative joint disease were observed with NLOM. Individual chondrocytes were imaged and demonstrated intracellular fluorescence consistent with the presence of products of intracellular biochemical processes. Conclusion: Thin images of living articular cartilage using NLOM may be obtained with cellular resolution at varying depths without fixing, sectioning or staining. Extracellular matrical collagen and chondron may be imaged separately in native tissue using spectrally distinct, endogenous, nonlinear optical signals. NLOM was sensitive to macromolecular composition and pathologic changes in articular cartilage matrix. Advances in instrumentation may lead to the application of NLOM to study articular cartilage in vivo. © 2005 OsteoArthritis Research Society International. Published by Elsevier Ltd. All rights reserved.