The availability of confocal endomicroscopy motivates the development of optical contrast agents that can delineate the morphologic and metabolic features of gastrointestinal neoplasia. This study evaluates 2-NBDG, a fluorescent deoxyglucose, the uptake of which is associated with increased metabolic activity, in the identification of Barrett's-associated neoplasia. Surveillance biopsies from patients with varying pathologic grades of Barrett's esophagus were incubated ex vivo at 37°C with 2-NBDG and imaged with a fluorescence confocal microscope. Images were categorized as neoplastic (high grade dysplasia, esophageal adenocarcinoma) or metaplastic (intestinal metaplasia, low grade dysplasia) based on the degree of glandular 2-NBDG uptake. Classification accuracy was assessed using histopathology as the gold standard. Forty-four biopsies were obtained from twenty-six patients; 206 sites were imaged. The glandular mean fluorescence intensity of neoplastic sites was significantly higher than that of metaplastic sites (p < 0.001). Chronic inflammation was associated with increased 2-NBDG uptake in the lamina propria but not in glandular epithelium. Sites could be classified as neoplastic or not with 96% sensitivity and 90% specificity based on glandular mean fluorescence intensity. Classification accuracy was not affected by the presence of inflammation. By delineating the metabolic and morphologic features of neoplasia, 2-NBDG shows promise as a topical contrast agent for confocal imaging. Further in vivo testing is needed to determine its performance in identifying neoplasia during confocal endomicroscopic imaging.

Medical imaging technologies have become increasingly important in the clinical management of cancer, and now play key roles in cancer screening, diagnosis, staging, and monitoring response to treatment. Standard imaging modalities such as MRI, PET, and CT require significant financial resources and infrastructure, which limits access to these modalities to those patients in high-resource settings. In contrast, optical imaging strategies, with the potential for reduced cost and enhanced portability, are emerging as additional tools to facilitate the early detection and diagnosis of cancer. This article presents a vision for an expanding role for optical imaging in global cancer management, including screening, early detection at the point-of-care, biopsy guidance, and real-time histology. Multi-modal optical imaging - the combination of widefield and high resolution imaging - has the potential to aid in the detection and management of precancer and early cancer for traditionally underserved populations. Several recent widefield and high-resolution optical imaging technologies are described, along with requirements for implementing such devices into lower-resource settings.

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text V. Leautaud, V. Mack, J. N. Wright, J. Lu, D. Yu, and R. Richards-Kortum, "Optical Imaging of Transformed Breast Epithelial Cells and Breast Tumor Microenvironment," in Biomedical Optics and 3-D Imaging, OSA Technical Digest (CD) (Optica Publishing Group, 2010), paper BSuD76. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

A ball lens coupled fiber optic probe provides the ability to conduct depth sensitive spectroscopic measurements of oral epithelial tissue. Fluorescence and reflectance measurements of normal and abnormal human oral sites in vivo are reported.

Quantum dots (QDs) have many appealing properties for biological fluorescence imaging, but exhibit photostabilities that are dependent upon surface passivation to minimize susceptibility to oxygen and light. Here, through spectroscopy and imaging techniques, we compare the photostability of micelle-encapsulated QDs with QDs passivated with either crosslinked amphiphilic polymers or crosslink-free amphiphilic polymers. Both crosslinked and crosslink-free amphiphilic polymer passivation strategies produced QDs with high photoluminescence stability for exposure to light under ambient conditions. In contrast, micelle encapsulation resulted in QDs with photoluminescence emission levels that were highly sensitive to both light exposure and oxygen, exhibiting a reduction of up to 70% in photoluminescence intensity within twenty minutes of exposure. With the addition of reducing agents, the photoluminescence level of the micelle-encapsulated QDs was significantly stabilized. We conclude that amphiphilic polymers provide coatings with considerably higher integrity and stability than micelle encapsulation, reducing the QDs' sensitivities to oxygen and light, both of which are relevant factors in biological imaging applications.

We present 500times700 mum metal-coated scanning micromirrors fabricated from bonded SOI-Si wafers with ~90% reflectivity at 633 nm. Confocal images with 1 mum resolution were generated using single axis actuation of plusmn2.5deg at 1.87 KHz

Aptamers that bind to prostate specific membrane antigen (PSMA) were conjugated to luminescent CdSe and CdTe nanocrystals for cell-labeling studies. The aptamer-nanocrystal conjugates showed specific targeting of both fixed and live cells that overexpressed PSMA. More importantly, aptamers were able to label cells dispersed in a collagen gel matrix simulating tissue. The specific binding abilities and synthetic accessibility of aptamers combined with the photostability and small size of semiconductor nanocrystals offers a powerful and general tool for cellular imaging.

This paper discusses the selection of parameters and the design of a CMOS detector for use in a structured illumination technique implemented with a 4M device (Miniaturized Multi-Modal Microscope) for precancer detection. To obtain real time sectioning the framing rate was set on the order of 500 frames/sec. 500 images allow us to obtain 8 to 16 sections/sec reconstructed from 16 to 64 images. The reconstruction technique is a sine approximation algorithm. To obtain a 1 mu m spatial resolution, the required pixel size is 4 girt with a magnification 4:1. The field of extent of 250 mu m required approximately 350 x 350 array size.

Introduction. A study was designed to assess variability between different fluorescence spectroscopy devices. Measurements were made with all combinations of three devices, four probes, and thee sets of standards trays. Additionally, we made three measurements on the same day over 2 days for the same combination of device, probe, and standards tray to assess reproducibility over a day and across days.Materials and methods. The devices consisted of light sources, fiberoptics, and cameras. We measured thirteen standards and present the data from the frosted cuvette, water, and rhodamine standards. A preliminary analysis was performed with the data that were wavelength calibrated and background subtracted; however, the system has not been corrected for systematic intensity variations caused by the devices. Two analyses were performed on the rhodamine, water, and frosted cuvette standards data. The first one is based on first clustering the measurements and then looking for association between the 5 factors (device, probe, standards tray, day, measurement number) using chi-squared tests on the cross-tabulation of cluster and factor level. This showed that only device and probe were significant. We then did an analysis of variance to assess the percent variance explained by each factor that was significant from the chi-squared analysis.Results. The data were remarkably similar across the different combinations of factors. The analysis based on the clusters showed that sometimes devices alone, probes alone, but most often combinations of device and probe caused significant differences in measurements. The analysis showed that time of day, location of device, and standards trays do not vary significantly; whereas the devices and probes account for differences in measurement. We expected this type of significance using unprocessed data since the processing corrects for differences in devices. However, this analysis on raw data is useful to explore what combination of device and probe measurements should be targeted for further investigation. This experiment affirms that online quality control is necessary to obtain the best excitation-emission matrices from optical spectroscopy devices.Conclusion. The fact that the device and probe are the primary sources of variability indicates that proper correction for the transfer function of the individual devices should make the measurements essentially equivalent. (C) 2005 Elsevier Inc. All rights reserved.

Objective. Structured illumination microscopy is an inexpensive alternative to confocal microscopy that allows optical sectioning at a sub-cellular resolution. However, its application in imaging biological tissue has been limited by inadequate contrast present in them especially in reflectance imaging. Novel, optically active contrast agents like gold nanoparticles and quantum dots targeted against biomarkers of cancer can be integrated with structured illumination to image both the morphological and biochemical changes associated with epithelial pre-cancers.Methods. We modified the optical path of a widefield microscope to implement structured illumination both in reflectance and fluorescence modes. For imaging, we used 25-nm-diameter gold nanoparticles and CdSe quantum dots for reflectance and fluorescence imaging, respectively, to label three-dimensional tissue constructs of SiHa cervical cancer cells. Contrast agents were targeted against the epidermal growth factor receptor (EGFR) using an anti-EGFR monoclonal antibody. Agents targeted with a non-specific IgG antibody served as a control to monitor non-specific labeling.Results. Our result shows that optically sectioned images taken with structured illumination are very comparable to those obtained using confocal microscopy. Moreover, images of three-dimensional cultures stained with the anti-EGFR agents show significantly more image intensity than those stained with the IgG targeted control.Conclusion. Our findings suggest that the combination of novel optical contrast agents and structured illumination can differentiate neoplastic cells which overexpress EGFR from non-nal cells in intact tissue. Combining structured illumination microscopy with novel contrast agents can potentially provide a powerful and inexpensive tool to aid in the detection of cervical pre-cancers. (C) 2005 Elsevier Inc. All rights reserved.

OBJECTIVE:Optical coherence tomography (OCT) is a novel noninvasive technique that can map subsurface tissue structure with a resolution of 10 to 20 mum. The objective of this study was to determine whether an OCT imaging system could be used clinically in vivo to image and distinguish features of normal and abnormal cervical tissue. STUDY DESIGN:Cervical OCT images and biopsy specimens were obtained from consenting volunteers. Images were analyzed quantitatively for intensity of backscattered light from the epithelia and for rates of signal decay of signal over the depth of epithelia (slope). Patients were stratified by menopausal status, and parameters were compared in normal and abnormal cervical samples, as diagnosed by routine histopathologic techniques. RESULTS:Average epithelial intensities were significantly stronger in the abnormal tissue than in the normal tissue of premenopausal women (P<.0024), but were stronger in the normal tissue of postmenopausal women (P<.062). No significant differences in signal decay rate were detected. CONCLUSION:OCT images, which contain information about epithelial and stromal structure, can be clinically obtained. Image features of normal and abnormal cervical epithelium differ significantly.

OBJECTIVES:We explore the clinical potential of reflectance and fluorescence confocal microscopy to image the morphologic and biochemical changes associated with precancer, in order to aid in the detection and diagnosis of cervical dysplasia. METHODS:Cervical epithelial tissue samples imaged ex vivo or in vivo were obtained from M. D. Anderson Cancer Center and Lyndon B. Johnson Hospital in Houston, Texas. Confocal reflectance microscopy was used to image ex vivo cervical biopsies and in vivo cervical tissue. Confocal fluorescence microscopy was used to image ex vivo cervical tissue slices. RESULTS:We present reflectance and fluorescence confocal images of cervical tissue demonstrating the ability to differentiate between normal and abnormal cervical tissue. CONCLUSIONS:We believe that there is significant clinical potential for confocal microscopy to provide a sensitive and specific method for cervical precancer detection.

A ball lens coupled fiber-optic probe design is described for depth-resolved measurements of the fluorescence and reflectance properties of epithelial tissue. A reflectance target, fluorescence targets, and a two-layer tissue phantom consisting of fluorescent microspheres suspended in collagen are used to characterize the performance of the probe. Localization of the signal to within 300 microm of the probe tip is observed by use of reflectance and fluorescence targets in air. Differential enhancement of the fluorescence signal from the top layer of the two-layer tissue phantom is observed.

Fluorescence spectroscopy is a promising technology for detection of epithelial precancers and cancers. In preparation for a multicenter phase II screening trial, a pilot trial was conducted to test data collection and patient examination procedures, use data forms, time procedures, and identify problems with preliminary data analysis. Women 18 years of age and older underwent a questionnaire, a complete history, and a physical examination, including a pan-colposcopy of the lower genital tract. A fiber-optic probe measured fluorescence excitation–emission matrices at 1–3 cervical sites for 58 women. The data collection procedures, data forms, and procedure times worked well, although collection times for all the clinical data take an average of 28 min. The clinical team followed procedures well, and the data could be retrieved from the database at all sites. The multivariate analysis algorithm correctly identified squamous normal tissue 99% of the time and columnar normal tissue only 7%. The assessment of ploidy from monolayer samples was not accurate in this small sample. The study was successful as a pilot trial. We learned who participated, who withdrew, how often abnormalities were present, and that algorithms that have worked extremely well in previous studies do not work as well when a few study parameters are changed. The current algorithm for diagnosis identified squamous normal tissue very accurately and did less well for columnar normal tissue. Inflammation may be an explanation for this phenomenon. Fluorescence spectroscopy is a promising technology for the detection of epithelial precancers and cancers. The screening trial of fluorescence and reflectance spectroscopy was successful.

The Journal of Biomedical Optics (JBO) is a Gold Open Access journal that publishes peer-reviewed papers on the use of novel optical systems and techniques for improved health care and biomedical research.

Fluorescence spectroscopy is a promising technology for detection of epithelial precancers and cancers. While age and menopausal status influence measurements in the cervix, other variables do not significantly affect the diagnosis. In this study we examine probe pressure as a variable. A fiber optic probe to measure fluorescence spectra at different calibrated levels of pressure was designed and tested. A pilot study was conducted measuring fluorescence excitation emission matrices in 20 patients at light, medium, and firm pressure. Spectroscopic data were pre-processed and analyzed to compare mean peak intensities as a function of pressure. Further statistical analyses tested for differences in intensities at each excitation/emission wavelength pair. Four providers made measurements from 41 sites; 33 yielded good quality spectroscopic data (22 squamous normal, 7 squamous abnormal, 3 columnar normal, 1 transformation zone) from 17 of 20 patients. At all pressure levels, abnormal tissue showed less fluorescence intensity than normal tissue, and post-menopausal patients showed higher fluorescence intensity than premenopausal patients, consistent with previous analyses. A permutation analysis suggests that pressure does not significantly affect fluorescence intensity or lineshape. While other studies are needed to confirm these findings, this study suggests that fluorescence spectroscopy is a robust technology likely not influenced by fiber optic probe pressure.

This chapter reviews the importance and biology of cervical cancer, discusses techniques of technology assessment as applied to emerging technologies such as optical spectroscopy, describes the biological basis of cervical tissue autofluorescence, reviews clinical measurements and data analysis of in vivo cervical tissue fluorescence, and discusses approaches to evaluate new diagnostic technologies from several perspectives. A number of new clinical management strategies and new technologies have been proposed and tested to address the need to improve screening and detection of cervical cancer. Design and analysis of randomized clinical trials for the evaluation of diagnostic technology have been the subject of several excellent reviews. Measurement of in vivo tissue fluorescence from the cervix with good signal-to-noise ratios has been demonstrated in a number of clinical trials. The chapter reviews research to understand the biological basis for changes in optical spectra as cervical precancer develops. It concludes by discussing limitations and future directions for optical assessment of cervical neoplasia.

The finite-difference time-domain (FDTD) method provides a flexible approach to studying the scattering that arises from arbitrarily inhomogeneous structures. We implemented a three-dimensional FDTD program code to model light scattering from biological cells. The perfectly matched layer (PML) boundary condition has been used to terminate the FDTD computational grid. We investigated differences in angle-dependent scattering properties of normal and dysplastic cervical cells. Specifically, the scattering patterns and phase functions have been computed for normal and dysplastic cervical cells at three different epithelial depths, namely, basal/parabasal, intermediate, and superficial. Construction of cervical cells within the FDTD computational grid is based on morphological and chromatin texture features obtained from quantitative histopathology. The results show that angle-dependent scattering characteristics are different not only for normal and dysplastic cells but also for cells at different epithelial depths. The calculated scattering cross-sections are significantly greater for dysplastic cells. The scattering cross-sections of cells at different depths indicate that scattering decreases in going from the superficial layer to the intermediate layer, but then increases in the basal/parabasal layer. This trend for epithelial cell scattering has also been observed in confocal images of ex vivo cervical tissue.