Automated image analysis of digital colposcopy for the detection of cervical neoplasia.

Digital colposcopy is a promising technology for the detection of cervical intraepithelial neoplasia. Automated analysis of colposcopic images could provide an inexpensive alternative to existing screening tools. Our goal is to develop a diagnostic tool that can automatically identify neoplastic tissue from digital images.

Autofluorescence and diffuse reflectance spectroscopy of oral epithelial tissue using a depth-sensitive fiber-optic probe.

Optical spectroscopy can provide useful diagnostic information about the morphological and biochemical changes related to the progression of precancer in epithelial tissue. As precancerous lesions develop, the optical properties of both the superficial epithelium and underlying stroma are altered; measuring spectral data as a function of depth has the potential to improve diagnostic performance. We describe a clinical spectroscopy system with a depth-sensitive, ball lens coupled fiber-optic probe for noninvasive in vivo measurement of oral autofluorescence and diffuse reflectance spectra.

Penetration depth limits of in vivo confocal reflectance imaging.

We present experiments to predict the maximum penetration depth atwhich typical biological structures in amelanotic tissue can bedetected with confocal microscopy. The detected signal is examinedas the signal source strength (index of refraction mismatch), thesource depth, and the medium scattering coefficient are varied. Thedetected background produced by scattering outside the focal volume isexamined as the medium scattering coefficient, the depth in the medium, the dimensionless pinhole radius, nu(p), and theshape of the scattering phase function are varied.

Up regulation in gene expression of chromatin remodelling factors in cervical intraepithelial neoplasia.

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.

Photostability of quantum dots with amphiphilic polymer-based passivation strategies.

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.

Spatially resolved spectral interferometry for determination of subsurface structure.

We describe an instrument capable of obtaining two-dimensional images of subsurface structure in real time with no moving parts. The technique is based on spectral interferometry and uses an imaging spectrograph to obtain spatially resolved spectra. A test sample consisting of microscope coverslips and a Ronchi grating was measured, illustrating the system's depth resolution of 38 mum and transverse resolution of at least 12.

Fiber-optic confocal microscopy using a spatial light modulator.

We present a novel fiber-optic confocal microscope in which the scanning operation is achieved by use of a spatial light modulator (SLM) to sequentially illuminate individual fibers or patterns of multiple fibers. Experimental images are presented, and the optical-sectioning capability of the device is demonstrated. The novel SLM-based system is more optically efficient, achieves higher contrast, and has improved optical-sectioning capabilities compared with those of other proposed instruments for confocal microendoscopy.

Subcellular-resolution molecular imaging within living tissue by fiber microendoscopy.

Conventional histopathology involves sampling, sectioning and staining of tissue specimens prior to microscopic evaluation, and provides diagnostic information at a single location and point in time. In vivo microscopy and molecular-targeted optical labeling are two rapidly developing fields, which together have the potential to provide anatomical and functional indications of disease by staining and imaging tissue in situ. To address the need for high-resolution imaging instrumentation, we have developed a compact, robust, and inexpensive fiber-optic microendoscopy system based around wide-field LED illumination, a flexible 1 mm diameter fiber-optic bundle, and a color CCD camera.

The clinical effectiveness of optical spectroscopy for the in vivo diagnosis of cervical intraepithelial neoplasia: where are we?

Objective: In this review, we evaluate the diagnostic efficacy of optical spectroscopy technologies (fluorescence and reflectance spectroscopy) for the in vivo diagnosis of cervical neoplasia using both point probe and multispectral imaging approaches.

Methods: We searched electronic databases using the following terms: cervical cancer, cervical intraepithelial neoplasia, squamous intraepithelial lesion, and spectroscopy, fluorescence spectroscopy, or reflectance spectroscopy. We included studies that evaluated fluorescence and reflectance spectroscopy devices for in vivo diagnosis, compared those results with biopsy results, and reported on the sensitivity and specificity of the devices tested.

Widefield and high-resolution reflectance imaging of gold and silver nanospheres.

Metallic nanoparticles have unique optical properties that can be exploited for molecular imaging in tissue. Image contrast depends on the nature of the particles, properties of the target tissue, and the imaging system. Maximizing image contrast for a particular application requires an understanding of the interplay of these factors.

Oligonucleotide-coated metallic nanoparticles as a flexible platform for molecular imaging agents.

Targeted metallic nanoparticles have shown promise as contrast agents for molecular imaging. To obtain molecular specificity, the nanoparticle surface must be appropriately functionalized with probe molecules that will bind to biomarkers of interest. The aim of this study was to develop and characterize a flexible approach to generate molecular imaging agents based on gold nanoparticles conjugated to a diverse range of probe molecules.

Dual-mode reflectance and fluorescence near-video-rate confocal microscope for architectural, morphological and molecular imaging of tissue.

We have developed a near-video-rate dual-mode reflectance and fluorescence confocal microscope for the purpose of imaging ex vivo human specimens and in vivo animal models. The dual-mode confocal microscope (DCM) has light sources at 488, 664 and 784 nm, a frame rate of 15 frames per second, a maximum field of view of 300 x 250 mum and a resolution limit of 0.31 mum laterally and 1.

Confocal microscopy and molecular-specific optical contrast agents for the detection of oral neoplasia.

Using current clinical diagnostic techniques, it is difficult to visualize tumor morphology and architecture at the cellular level, which is necessary for diagnostic localization of pathologic lesions. Optical imaging techniques have the potential to address this clinical need by providing real-time, sub-cellular resolution images. This paper describes the use of dual mode confocal microscopy and optical molecular-specific contrast agents to image tissue architecture, cellular morphology, and sub-cellular molecular features of normal and neoplastic oral tissues.

Objective screening for cervical cancer in developing nations: lessons from Nigeria.

In developed countries, cervical cancer screening programs have been highly successful. In the United States a 70% decrease in the mortality of cervical cancer has occurred since the 1960's largely due to the Papanicolaou test. However, it is not clear how best to translate these advances to developing countries, where cervical cancer remains the leading cause of cancer death for woman.

Optical molecular imaging agents for cancer diagnostics and therapeutics.

The National Cancer Institute has set the goal of eliminating suffering and death due to cancer by 2015. A key strategy to achieve this goal is to improve early detection and prevention using novel molecularly targeted cancer diagnostics and therapeutics. As we begin to better understand the cellular and molecular pathways of carcinogenesis, it is possible to identify and treat precursors to cancer before changes are detected at anatomical levels.

Workshop on imaging science development for cancer prevention and preemption.

The concept of intraepithelial neoplasm (IEN) as a near-obligate precursor of cancers has generated opportunities to examine drug or device intervention strategies that may reverse or retard the sometimes lengthy process of carcinogenesis. Chemopreventive agents with high therapeutic indices, well-monitored for efficacy and safety, are greatly needed, as is development of less invasive or minimally disruptive visualization and assessment methods to safely screen nominally healthy but at-risk patients, often for extended periods of time and at repeated intervals. Imaging devices, alone or in combination with anticancer drugs, may also provide novel interventions to treat or prevent precancer.

Fiber-optic confocal microscope using a MEMS scanner and miniature objective lens.

We designed and constructed a single-fiber-optic confocal microscope (SFCM) with a microelectromechanical system (MEMS) scanner and a miniature objective lens. Axial and lateral resolution values for the system were experimentally measured to be 9.55 mum and 0.

Fluorescence and reflectance device variability throughout the progression of a phase II clinical trial to detect and screen for cervical neoplasia using a fiber optic probe.

Large phase II trials of fluorescence and reflectance spectroscopy using a fiber optic probe in the screening and diagnostic settings for detecting cervical neoplasia have been conducted. We present accrual and histopathology data, instrumentation, data processing, and the preliminary results of interdevice consistencies throughout the progression of a trial. Patients were recruited for either a screening trial (no history of abnormal Papanicolaou smears) or a diagnostic trial (a history of abnormal Papanicolaou smears).

Instrumentation as a source of variability in the application of fluorescence spectroscopic devices for detecting cervical neoplasia.

We report on a study designed to assess variability among three different fluorescence spectroscopy devices, four fiber optic probes, and three sets of optical calibration standards to better understand the reproducibility of measurements and interdevice comparisons of fluorescence spectroscopic data intended for clinical diagnostic use. Multiple measurements are acquired from all sets of standards using each combination of spectrometer, fiber optic probe, and optical standard. Data are processed using standard calibration methods to remove instrument-dependant responses.

Plasmon resonance coupling of metal nanoparticles for molecular imaging of carcinogenesis in vivo.

An effective cancer control strategy requires improved early detection methods, patient-specific drug selection, and the ability to assess response to targeted therapeutics. Recently, plasmon resonance coupling between closely spaced metal nanoparticles has been used to develop ultrasensitive bioanalytical assays in vitro. We demonstrate the first in vivo application of plasmon coupling for molecular imaging of carcinogenesis.

Real-time reflectance confocal microscopy: comparison of two-dimensional images and three-dimensional image stacks for detection of cervical precancer.

Confocal microscopy can provide real-time, 2-D and 3-D images of the cellular morphology and tissue architecture features that pathologists use to detect precancerous lesions without the need for tissue removal, sectioning, and staining. The utility of 3-D confocal image stacks of epithelial tissue for detecting dysplasia has not yet been explored. We aim to extract morphometry and tissue architecture information from 2-D confocal reflectance images and 3-D image stacks from fresh, unstained cervical biopsies and compare their potential for detecting dysplasia.

A translational bioengineering course provides substantial gains in civic scientific literacy.

A growing number of essential consumer choices and public policy issues require a basic level of scientific literacy. Recent studies suggest as many as three-quarters of adults are unable to read and understand news accounts of scientific advances and controversies. In response to this challenge, a new course for non-science majors, Bioengineering and World Health, was designed to improve biomedical literacy.

Plasmonic nanosensors for imaging intracellular biomarkers in live cells.

Here we present the first intracellular molecular imaging platform using multifunctional gold nanoparticles which incorporate both cytosolic delivery and targeting moieties on the same particle. The utility of these intracellular sensors was demonstrated by monitoring actin rearrangement in live fibroblasts. We observed a strong molecular specific optical signal associated with effective targeting of actin filaments.

High numerical aperture microendoscope objective for a fiber confocal reflectance microscope.

A disposable high numerical aperture microendoscope objective has been designed, fabricated, and tested for use with a fiber confocal reflectance microscope. The objective uses high precision LIGA fabricated components to integrate imaging components and hydraulic suction lines into a housing that measures only 3.85 mm in outer diameter and 14.