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While histopathology of excised tissue remains the gold standard for diagnosis, several new, non-invasive diagnostic techniques are being developed. They rely on physical and biochemical changes that precede and mirror malignant change within tissue. The basic principle involves simple optical techniques of tissue interrogation. Their accuracy, expressed as sensitivity and specificity, are reported in a number of studies suggests that they have a potential for cost effective, real-time, in situ diagnosis. We review the Third Scientific Meeting of the Head and Neck Optical Diagnostics Society held in Congress Innsbruck, Innsbruck, Austria on the 11th May 2011. For the first time the HNODS Annual Scientific Meeting was held in association with the International Photodynamic Association (IPA) and the European Platform for Photodynamic Medicine (EPPM). The aim was to enhance the interdisciplinary aspects of optical diagnostics and other photodynamic applications. The meeting included 2 sections: oral communication sessions running in parallel to the IPA programme and poster presentation sessions combined with the IPA and EPPM posters sessions. © 2011 Jerjes et al; licensee BioMed Central Ltd.

The complete surgical removal of disease is a desirable outcome particularly in oncology. Unfortunately much disease is microscopic and difficult to detect causing a liability to recurrence and worsened overall prognosis with attendant costs in terms of morbidity and mortality. It is hoped that by advances in optical diagnostic technology we could better define our surgical margin and so increase the rate of truly negative margins on the one hand and on the other hand to take out only the necessary amount of tissue and leave more unaffected non-diseased areas so preserving function of vital structures. The task has not been easy but progress is being made as exemplified by the presentations at the 2nd Scientific Meeting of the Head and Neck Optical Diagnostics Society (HNODS) in San Francisco in January 2010. We review the salient advances in the field and propose further directions of investigation. © 2011 Upile et al; licensee BioMed Central Ltd.

We describe a system capable of measuring spatially resolved reflectance spectra from 380 to 950 nm and fluorescence excitation emission matrices from 330 to 500 nm excitation and 380 to 700 nm emission in vivo. System performance was compared to that of a standard scanning spectrofluorimeter. This 'FastEEM' system was used to interrogate human normal and neoplastic oral cavity mucosa in vivo. Measurements were made through a fiber-optic probe and require 4 min total measurement time. We present a method based on autocorrelation vectors to identify excitation and emission wavelengths where the spectra of normal and pathologic tissues differ most. The FastEEM system provides a tool with which to study the relative diagnostic ability of changes in absorption, scattering, and fluorescence properties of tissue.

Background and objectiveThis paper compares the ability of three analytic techniques to predict chromophore concentration from fluorescence emission spectra of homogeneous, turbid samples with optical properties similar to human tissue.Study design, materials and methodsTwo models of light propagation were implemented (exponential attenuation, two flux Kubelka-Munk theory); a priori information about sample optical properties was used to analyze data with the two flux Kubelka-Munk model. The third data analysis technique utilizes the method of partial least squares (PLS) to develop an empirical, linear model of sample fluorescence from a training set with optical properties and known concentrations representative of those to be predicted. This model can be applied to predict chromophore concentrations in the unknown samples.ResultsOf the three methods, PLS achieved the most accurate results and was able to predict fluorophore concentration to within +/- 6% of true values.ConclusionWe investigated conditions under which PLS predictions were most accurate and find that best results are achieved when predictions are based on fluorescence emission spectra at more than one excitation wavelength with inclusion of the tail of Rayleigh scattering at the excitation wavelength.

We present a method to extend rank-annihilation-factor analysis (RAFA) for the analysis of fluorescence from homogeneous turbid samples. The method is based on a fundamental relationship between the fluorescence of a dilute solution and that of a turbid solution. We have derived this relationship, known as the transfer function, for turbid materials using the two-flux Kubelka-Munk theory. The method is tested with spectroscopic data from optically thin and turbid samples of the media of a human aorta. At 450-nm excitation, agreement between the measured and predicted dilute-solution fluorescence spectra is within 5% at all emission wavelengths; at 340-nm excitation, agreement is within 20% at all wavelengths, with some residual Soret-band absorption. The simulations presented indicate that the transfer function is markedly more sensitive to absorption than to scattering properties.

We describe a fiber-optic-based confocal fluorescence spectrometer for obtaining depth-resolved, attenuated fluorescence emission spectra with lateral resolution of several microns and depth resolution of tens of microns. The confocal optics of the spectrometer are small, inexpensive, and easy to construct and to interface to existing spectrometers. We compare the performance of this system to that of conventional fluorescence spectrometers for nonscattering homogeneous and inhomogeneous samples. We demonstrate that the confocal measurements readily provide information about the sample geometry and optical properties not available from nonconfocal measurements. Potential applications of the technique are discussed.

This paper presents a phantom which simulates the optical properties of tissue. The phantom absorption coefficient, scattering coefficient, anisotropy factor, and fluorescence quantum yield can be independently varied to investigate the effects of these parameters on fluorescence excitation and emission spectra from 300 to 650 nm. Phantom fluorophores include Flavin Adenine Dinucleotide (FAD) and Rhodamine B. Absorption is controlled by adjusting phantom hemoglobin concentration. On the basis of their smoothly varying scattering coefficient and the relatively low amount of fluorescence contributed to the mixture in comparison to other available scatterers, 1.05-ttm-diameter polystyrene microspheres were selected as a scatterer. Sample inhomogeneities are simulated by preparing the phantom in a gelatin substrate. The optical properties of turbid phantoms determined with the use of indirect techniques agree well with known values as long as μ(1 - g) > μ. Data are presented from dilute, absorbing, and turbid phantoms and inhomogeneous phantoms to qualitatively illustrate the effects of optical properties and sample geometry on fluorescence spectra. The phantom provides the framework for detailed quantitative investigations of the effects of optical properties, sample size, shape, and structure, boundary conditions, and collection geometry on fluorescence spectra. © 1993 Society for Applied Spectroscopy.

Background and study aims: It can be difficult to distinguish adenomas from benign polyps during routine colonoscopy. High resolution microendoscopy (HRME) is a novelmethod for imaging colorectal mucosa with subcellular detail. HRME criteria for the classification of colorectal neoplasia have not been previously described. Study goals were to develop criteria to characterize HRME images of colorectal mucosa (normal, hyperplastic polyps, adenomas, cancer) and to determine the accuracy and interobserver variability for the discrimination of neoplastic from non-neoplastic polyps when these criteria were applied by novice and expert microendoscopists. Methods: Two expert pathologists created consensus HRME image criteria using images from 68 patients with polyps who had undergone colonoscopy plus HRME. Using these criteria, HRME expert and novice microendoscopists were shown a set of training images and then tested to determine accuracy and interobserver variability. Results: Expert microendoscopists identified neoplasia with sensitivity, specificity, and accuracy of 67% (95% confidence interval [CI] 58%- 75%), 97% (94%-100%), and 87%, respectively. Nonexperts achieved sensitivity, specificity, and accuracy of 73% (66%-80%), 91% (80%-100%), and 85%, respectively. Overall, neoplasia were identified with sensitivity 70% (65%-76%), specificity 94% (87%-100%), and accuracy 85%. Kappa values were: experts 0.86; nonexperts 0.72; and overall 0.78. Conclusions: Using the new criteria, observers achieved high specificity and substantial interobserver agreement for distinguishing benign polyps from neoplasia. Increased expertise in HRME imaging improves accuracy. This low-cost microendoscopic platform may be an alternative to confocal microendoscopy in lower-resource or community-based settings. [ABSTRACT FROM AUTHOR]

Most models of light propagation through tissue assume the scattering properties of the various tissue layers are the same. The authors present evidence that the scattering coefficient of normal cervical epithelium is significantly lower than values previously reported for bulk epithelial tissue. They estimated the scattering coefficient of normal and precancerous cervical epithelium using measurements of the reflectance as a function of depth from confocal images. Reflectance measurements were taken from ex vivo cervical biopsies and fit to an exponential function based upon Beer's law attenuation. The mean scattering coefficients derived were 22 cm-1 for normal tissue and 69 cm-1 for precancerous tissue. These values are significantly lower than previously reported for bulk epithelial tissues and suggest that scattering of bulk tissue is dominated by the stroma. They also suggest that computational models to describe light propagation in epithelial tissue must incorporate different scattering coefficients for the epithelium and stroma. Further, the lower scattering of the epithelium suggests greater probing depths for fiber optic probes used by optical diagnostic devices which measure reflectance and fluorescence in epithelial tissue. The difference in scattering between normal and precancerous tissue is attributed to increased nuclear size, optical density, and chromatin texture. The scattering coefficients measured here are consistent with predictions of numerical solutions to Maxwell's equations for epithelial cell scattering. [ABSTRACT FROM PUBLISHER]

While colposcopy remains an essential diagnostic tool in the hands of an experienced clinician, the five new technologies outlined here may eventually replace or at least supplement this important procedure. [ABSTRACT FROM AUTHOR]

Objectives: The use of high-resolution in vivo confocal imaging may offer a clinically useful adjunct to standard methods for the diagnosis and screening of epithelial precancers. This study assesses the feasibility of real-time confocal reflectance imaging of cervical tissue and the use of acetic acid as a contrast agent to increase visualization of cell nuclei.Study Design: A confocal microscope was used to image cervical cells and colposcopically normal and abnormal cervical biopsy specimens. Images were obtained before and after the application of 6% acetic acid.Results: The confocal imaging system resolved subcellular detail throughout the entire epithelial thickness. Normal and abnormal tissues were clearly able to be differentiated. Addition of acetic acid enhanced nuclear signal in all acquired images.Conclusion: High-contrast reflected light images of cervical tissue are attainable in near real time. Acetic acid significantly increases light scattering from cell nuclei, which may partially explain why acetowhitening occurs. [ABSTRACT FROM AUTHOR]

Objectives: To determine what structures flouresce and to what extent in normal colon and colonic adenomas to fully exploit laser-induced fluorescence spectroscopy as a tool for the diagnosis of dysplasia at endoscopy. Methods: Unstained frozen sections of normal colon and colonic adenomas were studied by fluorescence microscopy under 351-364-nm argon ion laser excitation. Tissue fluorescence was observed and compared to morphology in serial sections stained with hematoxylin and eosin (H&E), Movat pentachrome, mucicarmine, and oil red O. Results: In normal colon, fluorescence correlated morphologically with connective tissue fibers (principally collagen) in all layers of the bowel wall and with cytoplasmic granules within eosinophils present between the crypts in the lamina propria of the mucosa. Fluorescence of absorptive cells in normal crypts was very faint, and Goblet cells did not liuoresce. However, marked fluorescence was observed in the cytoplasm of dysplastic epithelial cells in the crypts of colonic adenomas. Fewer fluorescent connective tissue fibers were present in the lamina propria of colonic adenomas resulting in decreased fluorescence intensity as compared to that of normal colon. Fluorescent eosinophil granules were present in larger numbers in adenomas as compared with normal colon. Conclusion: Laser-induced fluorescence in normal colon and colonic adenomas correlates with morphology. Previous reported differences in laser-induced fluorescence emission spectra of normal colon and colonic adenomas obtained in vitro and in vivo may be due to differences in the cytoplasmic fluorescence between the dysplastic epitbeliuni in colonic adenomas and normal colonic epithelium. Laser-induced fluorescence spectroscopy may he useful in... [ABSTRACT FROM AUTHOR]

Discusses information regarding cervical cancer and the significance of a cervical Pap smear in developing countries. Information on the findings from the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesions (ASCUS/LSIL, or ALTS) Trial; Number of cervical cancer diagnosed worldwide in 1990; Estimate on the cases of invasive cervical cancer and deaths from this cancer in 1999; Natural history of cervical cancer.

Abstract Background The highest rates of cervical cancer are found in developing countries. Frontline monitoring has reduced these rates in developed countries and present day screening programs primarily identify precancerous lesions termed cervical intraepithelial neoplasias (CIN). CIN lesions described as mild dysplasia (CIN I) are likely to spontaneously regress while CIN III lesions (severe dysplasia) are likely to progress if untreated. Thoughtful consideration of gene expression changes paralleling the progressive pre invasive neoplastic development will yield insight into the key casual events involved in cervical cancer development. Results In this study, we have identified gene expression changes across 16 cervical cases (CIN I, CIN II, CIN III and normal cervical epithelium) using the unbiased long serial analysis of gene expression (L-SAGE) method. The 16 L-SAGE libraries were sequenced to the level of 2,481,387 tags, creating the largest SAGE data collection for cervical tissue worldwide. We have identified 222 genes differentially expressed between normal cervical tissue and CIN III. Many of these genes influence biological functions characteristic of cancer, such as cell death, cell growth/proliferation and cellular movement. Evaluation of these genes through network interactions identified multiple candidates that influence regulation of cellular transcription through chromatin remodelling (SMARCC1, NCOR1, MRFAP1 and MORF4L2). Further, these expression events are focused at the critical junction in disease development of moderate dysplasia (CIN II) indicating a role for chromatin remodelling as part of cervical cancer development. Conclusion We have created a valuable publically available resource for the study of gene expression in precancerous cervical lesions. Our results indicate deregulation of the chromatin remodelling complex components and its influencing factors occur in the development of CIN lesions. The increase in SWI/SNF stabilizing molecule SMARCC1 and other novel genes has not been previously illustrated as events in the early stages of dysplasia development and thus not only provides novel candidate markers for screening but a biological function for targeting treatment.

Provides a corrected version of the article 'Near Real Time in Vivo Fibre Optic Confocal Microscopy: Subcellular Structure Resolved,' by K.B. Sung et al published in the 2002 issue of the periodical 'The Royal Microscopical Society.'

Objectives: As cervical cancer screening programs are implemented and expanded, an increasing number of women require loop electrosurgical excision procedure (LEEP) for treatment of pre-invasive cervical disease. Our objective was to describe the pathological results of LEEP specimens performed as part of the MULHER study and identify factors associated with positive LEEP margins., Methods: The MULHER study enrolled 9014 women who underwent HPV testing followed by visual assessment for treatment (VAT) using visual inspection with acetic acid (VIA) and thermal ablation for those with positive results. Participants with lesions ineligible for ablation underwent LEEP. Pathology reports were reviewed for specimen size/volume, number of fragments, pathological diagnosis and margin status. Multivariable regression analysis was performed to identify variables associated with positive LEEP margins., Results: 169 participants underwent LEEP. The median age was 38 years (range 30-49). 65.1% were women living with HIV. Pathological diagnosis was available for 154 patients and included cancer (n=6, 3.9%); cervical intraepithelial neoplasia (CIN) 2/3 (n=75, 48.7%); CIN 1 (n=67, 43.5%); and normal/benign findings (n=6,3.9%). 31.8% of LEEP specimens were removed in more than one fragment. The mean specimen volume was 2.9 cm 3 (range 0.2-15.0). LEEP margin status was available for 130 patients. Positive margins (ectocervical/endocervical only, or both) were noted in 76 (58.5%) patients and associated with HIV+status (p=0.0499) and a diagnosis of CIN 2 or worse (p=0.0197). There were no associations between margin status and age, number of fragments or specimen volume., Conclusion: Our results showed a high number of LEEP specimens with positive margins. Additional evaluation is needed to better understand the characteristics of precancerous cervical lesions in this high-risk population. As cervical cancer screening programs are scaled in Mozambique and other lower-resource countries, there is a need to train providers to perform high-quality LEEP and for accurate and timely pathological interpretation., Competing Interests: Competing interests: None declared., (© IGCS and ESGO 2024. No commercial re-use. See rights and permissions. Published by BMJ.)