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Modulated-alignment dual-axis (MAD) confocal microscopy combines the benefits of dual-axis confocal (DAC) microscopy and focal-modulation microscopy (FMM) for rejecting out-of-focus and multiply scattered light in tissues. The DAC architecture, which utilizes off-axis and separated beam paths for illumination and detection, has previously been shown to be superior to single-axis confocal (SAC) microscopy for the spatial filtering (rejection) of unwanted background light. With the MAD approach, a modulation of the alignment between the illumination and collection beam paths tags ballistic photons emanating from the focal volume with a characteristic radio frequency that can be extracted and separated from background signal using lock-in detection. We report here an optimized form of MAD confocal microscopy where we have fully mitigated tradeoffs in performance in an initial proof-of-concept system in order to recover the imaging speed of DAC microscopy while retaining contrast enhancement of 6 dB (signal-to-background ratio) with a secondary improvement in optical-sectioning and in-plane resolution. Validation is demonstrated with light-scattering tissue phantoms and freshly excised tissues.

Multiplexed surface-enhanced Raman scattering (SERS) nanoparticles (NPs) offer the potential for rapid molecular phenotyping of tissues, thereby enabling accurate disease detection as well as patient stratification to guide personalized therapies or to monitor treatment outcomes. The clinical success of molecular diagnostics based on SERS NPs would be facilitated by the ability to accurately identify tissue biomarkers under time-constrained staining and detection conditions with a portable device. In vitro, ex vivo and in vivo experiments were performed to optimize the technology and protocols for the rapid detection (0.1-s integration time) of multiple cell-surface biomarkers with a miniature fiber-optic spectral-detection probe following a brief (5 min) topical application of SERS NPs on tissues. Furthermore, we demonstrate that the simultaneous detection and ratiometric quantification of targeted and nontargeted NPs allows for an unambiguous assessment of molecular expression that is insensitive to nonspecific variations in NP concentrations.

The prevalence and consequences of financial barriers to health care among patients with multiple chronic diseases are poorly understood.We sought to assess the prevalence of self-reported financial barriers to health care among individuals with diabetes and coronary heart disease (CHD) and to determine their association with access to care, quality of care and clinical outcomes.The 2007 Centers for Disease Control Behavioral Risk Factor Surveillance Survey.Diabetic patients with CHD.Financial barriers to health care were defined by a self-reported time in the past 12 months when the respondent needed to see a doctor but could not because of cost. The primary clinical outcome was vascular morbidity—a composite of stroke, retinopathy, nonhealing foot sores or bilateral foot amputations.Among the 11,274 diabetics with CHD, 1,541 (13.7 %) reported financial barriers to health care. Compared to individuals without financial barriers, those with financial barriers had significantly reduced rates of medical assessments within the past 2 years, hemoglobin (Hgb) A1C measurements in the past year, cholesterol measurements at any time, eye and foot examinations within the past year, diabetic education, antihypertensive treatment, aspirin use and a higher prevalence of vascular morbidity. In multivariable analyses, financial barriers to health care were independently associated with reduced odds of medical checkups (Odds Ratio [OR], 0.61; 95 % Confidence Intervals [CI], 0.55–0.67), Hgb A1C measurement (OR, 0.85; 95 % CI, 0.77–0.94), cholesterol measurement (OR, 0.76; 95 % CI, 0.67–0.86), eye (OR, 0.85; 95 % CI, 0.79–0.92) and foot (OR, 0.92; 95 % CI, 0.84–1.00) examinations, diabetic education (OR, 0.93; 95 % CI, 0.87–0.99), aspirin use (OR, 0.88; 95 % CI, 0.81–0.96) and increased odds of vascular morbidity (OR, 1.23; 95 % CI, 1.14–1.33).In diabetic adults with CHD, financial barriers to health care were associated with impaired access to medical care, inferior quality of care and greater vascular morbidity. Eliminating financial barriers and adherence to guideline-based recommendations may improve the health of individuals with multiple chronic diseases.

The unambiguous demarcation of tumor margins is critical at the final stages in the surgical treatment of brain tumors because patient outcomes have been shown to correlate with the extent of resection. Real-time high-resolution imaging with the aid of a tumor-targeting fluorescent contrast agent has the potential to enable intraoperative differentiation of tumor versus normal tissues with accuracy approaching the current gold standard of histopathology. In this study, a monoclonal antibody targeting the vascular endothelial growth factor receptor 1 (VEGFR-1) was conjugated to fluorophores and evaluated as a tumor contrast agent in a transgenic mouse model of medulloblastoma. The probe was administered topically, and its efficacy as an imaging agent was evaluated in vitro using flow cytometry, as well as ex vivo on fixed and fresh tissues through immunohistochemistry and dual-axis confocal microscopy, respectively. Results show a preferential binding to tumor versus normal tissue, suggesting that a topically applied VEGFR-1 probe can potentially be used with real-time intraoperative optical sectioning microscopy to guide brain tumor resections.

We present a maskless micropatterning system that utilizes a fluorescence microscope with programmable X-Y stage and dry film photoresist to realize feature sizes in the sub-millimeter range (40–700 μm). The method allows for flexible in-house maskless photolithography without a dedicated microfabrication facility and is well-suited for rapid prototyping of microfluidic channels, scaffold templates for protein/cell patterning or optically-guided cell encapsulation for biomedical applications.

There is a need to image excised tissues during tumor-resection procedures in order to identify residual tumors at the margins and to guide their complete removal. The imaging of dysregulated cell-surface receptors is a potential means of identifying the presence of diseases with high sensitivity and specificity. However, due to heterogeneities in the expression of protein biomarkers in tumors, molecular-imaging technologies should ideally be capable of visualizing a multiplexed panel of cancer biomarkers. Here, we demonstrate that the topical application and quantification of a multiplexed cocktail of receptor-targeted surface-enhanced Raman scattering (SERS) nanoparticles (NPs) enables rapid quantitative molecular phenotyping (QMP) of the surface of freshly excised tissues to determine the presence of disease. In order to mitigate the ambiguity due to nonspecific sources of contrast such as off-target binding or uneven delivery, a ratiometric method is employed to quantify the specific vs. nonspecific binding of the multiplexed NPs. Validation experiments with human tumor cell lines, fresh human tumor xenografts in mice and fresh human breast specimens demonstrate that QMP imaging of excised tissues agrees with flow cytometry and immunohistochemistry and that this technique may be achieved in less than 15 minutes for potential intraoperative use in guiding breast-conserving surgeries.

There is a need for miniature optical-sectioning microscopes to enable in vivo interrogation of tissues as a real-time and noninvasive alternative to gold-standard histopathology. Such devices could have a transformative impact for the early detection of cancer as well as for guiding tumor-resection procedures. Miniature confocal microscopes have been developed by various researchers and corporations to enable optical sectioning of highly scattering tissues, all of which have necessitated various trade-offs in size, speed, depth selectivity, field of view, resolution, image contrast, and sensitivity. In this study, a miniature line-scanned (LS) dual-axis confocal (DAC) microscope, with a 12-mm diameter distal tip, has been developed for clinical point-of-care pathology. The dual-axis architecture has demonstrated an advantage over the conventional single-axis confocal configuration for reducing background noise from out-of-focus and multiply scattered light. The use of line scanning enables fast frame rates (16 frames/sec is demonstrated here, but faster rates are possible), which mitigates motion artifacts of a hand-held device during clinical use. We have developed a method to actively align the illumination and collection beams in a DAC microscope through the use of a pair of rotatable alignment mirrors. Incorporation of a custom objective lens, with a small form factor for in vivo clinical use, enables our device to achieve an optical-sectioning thickness and lateral resolution of 2.0 and 1.1 microns respectively. Validation measurements with reflective targets, as well as in vivo and ex vivo images of tissues, demonstrate the clinical potential of this high-speed optical-sectioning microscopy device.

To quantitatively image a panel of disease biomarkers for guiding tumor resection, we have developed a wide-area raster-scanned imaging device to rapidly image molecularly targeted SERS nanoparticles topically applied on fresh excised tissues.

To monitor the molecular changes that are relevant to esophageal cancer, a miniature spectral endoscope is developed for rotational imaging of biomarker-targeted SERS NPs topically applied on the lumenal surface within a rat esophagus.

We present a strategy to enhance the contrast of dual-axis confocal microscopy. This new method improves imaging by adding a modulation signature to ballistic photons, in addition to the spatial filtering inherent to confocal microscopy.

Miniature dual-axis confocal (DAC) microscopes are being developed for the early detection of oral cancers and for guiding brain tumor resection. The design of MEMS-scanned DAC microscopes, and their analysis and optimization are described.

We present a strategy to preserve contrast over a deeper range of imaging depths in the context of confocal microscopy using low-power (0.5 mW) diode laser illumination. While the dual-axis confocal microscope architecture's intersecting illumination and collection beams significantly improves the spatial-filtering and optical-sectioning performance of confocal microscopy, we propose that modulating the spatial alignment of the dual-axis beams at a frequency f will generate a focal volume signal modulated at 2f, which further provides nearly an order-of-magnitude improvement in optical-sectioning contrast. Lock-in detection is used to remove the unmodulated background light, thereby enhancing our ability to image deeply within highly scattering tissues.

Our lab is developing miniature Raman imaging systems and topical-staining protocols to rapidly image cell-surface biomarkers in fresh tissues. In particular, this work employs targeted surface-enhanced Raman scattering (SERS) nanoparticles (NPs) to enable the sensitive and multiplexed detection of a large number of cell-surface biomarkers of cancer. The SERS NPs were functionalized with different targeting antibodies, and their biomarker detection capability was investigated via in vitro and ex vivo experiments with cells and tissues. Here, we design SERS NPs to specifically target the cancer biomarker EGFR upon topical application on cells and tissues. In vitro flow cytometry with fluorescent SERS NPs reveals a high ratio of specific versus nonspecific binding for the tumor cell lines A431 (skin cancer), U251 (glioma) and SkBr3 (breast cancer). For tissue imaging, we have developed a fiber-optic-based spectral detection probe, with 785-nm laser illumination, for rapid detection of SERS NPs with sub-millimeter spatial resolution. Based on the spectral detection probe, multiple imaging systems were customized for rapid tissue phenotyping such as a comprehensive rotational scanning endoscope for in vivo imaging of the rat esophagus and a raster-scanning device for intraoperative imaging of breast tissue margins. Ex vivo experiments were performed to develop a strategy for the rapid detection of multiple cell-surface biomarkers following a brief (5-10 min) topical application of SERS NPs on tissues. By developing high-affinity targeted SERS NPs, sensitive spectral-imaging devices, and an optimized topical-delivery protocol, we demonstrate a ratio metric method to rapidly quantify the specific binding of biomarker-targeted NPs on fresh tissues, thereby eliminating the ambiguities that often arise due to nonspecific sources of contrast. These tools will enable multiplexed molecular imaging for the early detection of epithelial cancers, rapid surgical guidance, and monitoring the molecular response to treatments.

A strategy is presented to enable optical-sectioning microscopy with improved contrast and imaging depth using low-power (0.5 - 1 mW) diode laser illumination. This technology combines the inherent strengths of focal-modulation microscopy and dual-axis confocal (DAC) microscopy for rejecting out-of-focus and multiply scattered background light in tissues. The DAC architecture is unique in that it utilizes an intersecting pair of illumination and collection beams to improve the spatial-filtering and optical-sectioning performance of confocal microscopy while focal modulation selectively ‘labels’ in-focus signals via amplitude modulation. Simulations indicate that modulating the spatial alignment of dual-axis beams at a frequency f generates signals from the focal volume of the microscope that are modulated at 2f with minimal modulation of background signals, thus providing nearly an order-of-magnitude improvement in optical-sectioning contrast compared to DAC microscopy alone. Experiments show that 2f lock-in detection enhances contrast and imaging depth within scattering phantoms and fresh tissues.

We are developing a miniature fiber-optic spectral-detection device and topical-staining protocol to rapidly detect multiplexed surface-enhanced Raman scattering (SERS) nanoparticles (NPs) targeted to cell-surface biomarkers in fresh tissues. Ex vivo and in vivo experiments were performed to optimize our strategy for the rapid detection of multiple cell-surface biomarkers following a brief (5 min) topical application of SERS NPs on tissues. The simultaneous detection and ratiometric quantification of targeted and nontargeted NPs allows for an unambiguous assessment of molecular expression that is insensitive to nonspecific variations in NP concentrations, potentially enabling point-of-care surgical guidance or early disease detection.

Miniature microscopes are being developed to examine tissue in situ for early anatomic and molecular indicators of disease, in real time, and at cellular resolution. These new devices will lead to a shift from the current diagnostic paradigm of biopsy followed by histopathology and recommended therapy, to one of non-invasive point-of-care diagnosis with the possibility of treatment in the same session. This potential revolution in disease management may have a major impact on the training of future physicians to include the use and interpretation of real-time in vivo microscopic data, and will also affect the emerging fields of telepathology and telemedicine. Implementation of new technologies into clinical practice is a complex process that requires multidisciplinary communication and collaboration among clinicians, engineers and scientists. As such, our aim is to provide a forward-looking view of the critical issues facing the development of new technologies and directing clinical education. Here, we focus on the use of in vivo microscopy for detection of malignant and pre-malignant lesions as well as for guiding therapy. We will highlight some of the areas in which in vivo microscopy could address unmet clinical needs, and then review the technological challenges that are being addressed, or need to be addressed, for in vivo microscopy to become an effective clinical tool.

Surface-enhanced Raman scattering (SERS) nanoparticles have been engineered to generate unique fingerprint spectra and are potentially useful as bright contrast agents for molecular diagnostics. One promising strategy for biomedical diagnostics and imaging is to functionalize various particle types (“flavors”), each emitting a unique spectral signature, to target a large multiplexed panel of molecular biomarkers. While SERS particles emit narrow spectral features that allow them to be easily separable under ideal conditions, the presence of competing noise sources and background signals such as detector noise, laser background, and autofluorescence confounds the reliability of demultiplexing algorithms. Results obtained during time-constrained in vivo imaging experiments may not be reproducible or accurate. Therefore, our goal is to provide experimentalists with a metric that may be monitored to enforce a desired bound on accuracy within a user-defined confidence level. We have defined a spectral reliability index (SRI), based on the output of a direct classical least-squares (DCLS) demultiplexing routine, which provides a measure of the reliability of the computed nanoparticle concentrations and ratios. We present simulations and experiments to demonstrate the feasibility of this strategy, which can potentially be utilized for a range of instruments and biomedical applications involving multiplexed SERS nanoparticles.

Category: 31. Quality of Care and Outcomes AssessmentPresentation Number: 1256-292Authors: Puja Parikh, Steven Leigh, Roopali Parikh, Hongdao Meng, Nicholas Sakellarios, David Brown, Stony Brook University Medical Center, Stony Brook, NY, USA Background: As the cost of health care in the United States increases, more patients experience difficulty paying their medical bills. We sought to describe the impact of financial barriers to health care on access to care, quality of care and vascular outcomes of diabetic patients with coronary artery disease (CAD).Methods: The 2007 Centers for Disease Control’s Behavioral Risk Factor Surveillance Survey was utilized to identify a cohort of 11,274 diabetics with CAD. Demographic data, clinical history, quality of care indices, and clinical outcomes were recorded in these patients. The primary outcome was a composite of major adverse vascular events (MAVE), defined by a history of stroke, retinopathy or diabetes-related ocular changes, bilateral foot amputations, and nonhealing foot sores.Results: Of 11,274 patients, 1,541 (14%) patients reported financial barriers to health care and 9,733 (86%) reported no such barriers. Patients with financial barriers were younger, more often female, less often with health insurance, and had higher rates of obesity, smoking, and hypercholesterolemia. They were also noted to have impaired access to care resulting in less frequent medical checkups, lower rates of annual cholesterol screening, HgbA1c screening, eye exams, foot exams, and diabetic education classes, and less aspirin and antihypertensive use. Patients with financial barriers experienced significantly higher MAVE rates (68% vs 55%, p

An achromatic version of a micro-mirror-scanned surgical dual-axis confocal microscope has been developed for ratiometric quantification of biomarker expression as revealed by the topical application of fluorescent contrast agents.

We present a maskless micropatterning system that utilizes a fluorescence microscope with programmable X-Y stage and dry film photoresist to realize feature sizes in the sub-millimeter range (40–700 μm). The method allows for flexible in-house maskless photolithography without a dedicated microfabrication facility and is well-suited for rapid prototyping of microfluidic channels, scaffold templates for protein/cell patterning or optically-guided cell encapsulation for biomedical applications.

The early detection and biological investigation of esophageal cancer would benefit from the development of advanced imaging techniques to screen for the molecular changes that precede and accompany the onset of cancer. Surface-enhanced Raman scattering (SERS) nanoparticles (NPs) have the potential to improve cancer detection and the investigation of cancer progression through the sensitive and multiplexed phenotyping of cell-surface biomarkers. Here, a miniature endoscope featuring rotational scanning and axial pull back has been developed for 2D spectral imaging of SERS NPs topically applied on the lumenal surface of the rat esophagus. Raman signals from low-pM concentrations of SERS NP mixtures are demultiplexed in real time to accurately calculate the concentration and ratio of the NPs. Ex vivo and in vivo experiments demonstrate the feasibility of topical application and imaging of multiplexed SERS NPs along the entire length of the rat esophagus.

A strategy is presented to enable optical-sectioning microscopy with improved contrast and imaging depth using low-power (0.5 - 1 mW) diode laser illumination. This technology combines the inherent strengths of focal-modulation microscopy and dual-axis confocal (DAC) microscopy for rejecting out-of-focus and multiply scattered background light in tissues. The DAC architecture is unique in that it utilizes an intersecting pair of illumination and collection beams to improve the spatial-filtering and optical-sectioning performance of confocal microscopy while focal modulation selectively ‘labels’ in-focus signals via amplitude modulation. Simulations indicate that modulating the spatial alignment of dual-axis beams at a frequency f generates signals from the focal volume of the microscope that are modulated at 2f with minimal modulation of background signals, thus providing nearly an order-of-magnitude improvement in optical-sectioning contrast compared to DAC microscopy alone. Experiments show that 2f lock-in detection enhances contrast and imaging depth within scattering phantoms and fresh tissues.

We present a miniature microelectromechanical systems-based dual-axis confocal microscope capable of spatially coregistered fluorescence and reflectance imaging at multiple wavelengths. This device has a 10 mm diameter scan head with a 2 mm diameter tip for convenient use during surgery to guide tumor resection. The microscope has an adjustable focal depth of 20-200 micrometers and is capable of imaging with an axial resolution of 9 micrometers and in-plane resolution of 4 micrometers over a field of view of 450×450 micrometers. Simultaneous two-color imaging of individual optical sections is achieved by using a pair of grating-prism assemblies to compensate for chromatic dispersion in the 2 mm diameter gradient index relay lens at the distal tip of the device. Experimental measurements of the axial response of the microscope, as well as two-color images of a reflective bar target and fresh mouse brain tissues, demonstrate the performance of our device and its potential for multicolor in vivo optical sectioning microscopy.