This PDF file contains the front matter associated with SPIE Proceedings Volume 12850, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

Necrotizing enterocolitis (NEC) is a gastrointestinal disease that affects 2% to 5% of premature infants and is responsible for almost 8% of all neonatal intensive care unit (NICU) admissions. NEC is caused by inflammation of the intestine, leading to an invasion of bacteria that can cause necrosis of the colon and intestine. Patients with NEC can suffer from a wide range of symptoms such as apnea, diarrhea and bloody stools, unstable body temperature, trouble feeding, discoloration of the abdominal region, and a swollen abdominal region. These symptoms of NEC often coincide with other gastrointestinal diseases, meaning that it can be difficult to definitively diagnose NEC without the use of radiographic imaging. Current diagnostic procedures utilize Bell’s staging system, which many believe is unreliable and inefficient practice. The progression of NEC occurs quickly and results in a mortality rate as high as 50%, yet the mortality rate can still increase when emergency surgical procedures are performed for more severe cases. Previous studies motivate our development of a noninvasive sensing and monitoring method that can be used in real-time. The proposed method utilizes both optical and thermal images to detect temperature differences in upper (thorax) and lower (abdomen) regions as an early indicator for NEC. We report on promising preliminary data from early studies at the Vanderbilt University Medical Center, Monroe Carell Jr. Children’s Hospital, under an approved IRB, investigating point-of-care NICU image-based thermographic trends of neonates at risk for NEC.

Impaired reperfusion of blood vessels is a fundamental cause of complications like tissue ischemia following reconstructive microsurgery or skin grafting. Clinicians have historically relied on visual and tactile assessment to evaluate perfusion intra- and postoperatively. Recently, indocyanine green angiography (ICGA) has been implemented during procedures to map the body’s vasculature in real time. However, ICGA requires the IV administration of a fluorescent dye that can be expensive and poorly tolerated by some patients. There is a need for a cheaper, more versatile tool that can image microvessels intraoperatively and help monitor healing at the bedside. Enhanced thermal imaging (ETI) is an infrared imaging technique that uses green LEDs to induce a natural thermal contrast between blood and surrounding water-rich tissue. ETI has proven capable of delineating millimeter-scale vessels ex vivo and the venous margins of cancerous tumors. Most recently, the potential of ETI to detect capillary growth as an indicator of early wound healing within skin flaps in a murine model was evaluated. In this study, MCmatlab—a MATLAB-interfaced, Monte Carlo light transport and heat diffusion solver—was used to simulate photon deposition and heat diffusion in a mouse-scale model of perfused skin tissue under ETI operating parameters. The relationship between capillary density and the thermal signal observed at the tissue surface suggests the response captured by ETI was related to fluctuations in blood flow intrinsic to the healing process. ETI offers a promising solution for intraoperative guidance and point-of-care diagnosis of tissue perfusion.

While the gold standard for infection diagnostics remains the PCR test, the pandemic has shown the importance of Point-of-Care devices that carry the test in the field and yield results in an hour or less. Lab-on-Chip systems have been a game changer in this respect, but PCR based devices are still rather expensive. Among the main cost drivers are the optical readout modules that excite and detect fluorescence signals in multiple spectral channels. Depending on the device concept, the bulk of this cost is either shifted towards component cost, precise alignment, or complex mechanics, but there is a lack of compact, simple irradiation and detection modules that scale well in mass production. In this contribution we focus on the excitation optics, which must provide visible radiation in well-defined spectral bands that illuminate the sample. While the state of the art teaches either a precise assembly of dichroic mirrors or a filter changing mechanism, we have devised and demonstrated a concept that involves a holographic optical element (HOE). This HOE does not only act as a beam combiner, directing light from the individual sources towards the sample, but also exploits the intrinsic spectral selectivity for bandpass filtering, rendering any dielectric multilayer components obsolete. We present a 4-channel excitation optics with a single HOE at its core that unites light from four different LEDs towards a sample, demonstrating quantitative fluorescence readouts from fluorophore concentrations in the sub-micromolar range.

Lab-on-chip analysis for molecular diagnostics use an analyzer unit and cartridges. Since the cartridges are disposables, their development cycle can be much shorter than the one of the analyzer unit. Hence, it is important to have a high degree of exibility in the analyzer unit to react to new cartridge developments. Our research tries to overcome limitations due to fixed interfaces by replacing a static illumination system for uorescence analysis by an adjustable module. The benefit of adjustability goes along with harder requirements. In the case of the illumination system, that means a decrease in etendue of the optical system. Purpose of the presented research is to define the spectral radiance requirements on the light source as a bottleneck in an etendue limited optical system. As light source a phosphor converted light source should be used due to the benefits of a broad spectrum. First, the concept of etendue is used to specify a theoretical spectral radiance requirement on the light source. In the second step, the best available light source is used in a prototype to measure the performance of the adjustable illumination system and to derive a practical spectral radiance requirement. With the currently used light source in the lab prototype, requirements are fulfilled for one out of four spectral wavelength bands. The comparison between theory and experiment shows that the theoretical requirement must be corrected by a factor of two to a practical spectral radiance requirement of about 14mW=(sr • mm² • nm). It can be concluded that especially in the blue and red wavelength range below 500nm and over 600nm bright phosphor converted light sources are required. Since the time the light source was selected, a new light source candidate with stronger emission for shorter wavelengths was found.

We aim to develop a benchtop imaging device to quantitatively measure stress biomarkers like HSP90 on a biochip. Measurement of HSP90 is based on the masking of fluorescence of Streptavidin conjugated Quantum dots (Sav-QDs) when HSP90 attaches to it. The higher the masking of fluorescence, the higher the HSP90 concentration. Measurement of fluorescence is done by a custom-built optical device. The goal in this work was to demonstrate a testing system which is handy to use in the field, cheaper and with a simplified readout system for the users. Sav-QDs are fixed on nitrocellulose coated glass slides (NC slides). A biotinylated antibody is attached to Sav-QD. When HSP90 interacts with the antibody it causes masking of fluorescence, which is dependent on the concentration of HSP90 in serum. The imaging device developed for measurement is based on a CMOS sensor. It uses narrow bandpass filters, optically eliminating fluorescence produced by the background. Analysis of the results shows that these agree well with those of standard laboratory equipment using a photomultiplier tube (PMT) scanner to detect HSP90 in the nanomolar range. Results from the work show that the used approach is promising for developing a multifunctional, robust, and point-of-care detection system for stress biomarkers.

The global rise of infectious diseases underscores the urgent need for rapid, accurate diagnostics. Our study introduces a novel polymerase chain reaction technique utilizing gold nanoshells for faster and more efficient DNA amplification. These nanoshells' unique properties enable rapid heating in the near-infrared spectrum, accelerating the PCR process by quickly reaching optimal temperatures. This approach streamlines DNA amplification and ensures detection of small DNA quantities. Integrating photothermal PCR with advanced real-time fluorometry and non-invasive temperature monitoring, we can amplify DNA in just 25 minutes and detect as little as 50 picograms. The use of gold nanoshells' heating capabilities leads to quicker, more sensitive DNA detection. This innovation is a significant advancement in PCR technology, especially for point-of-care diagnostics, promising quick identification of DNA markers vital for prompt infectious disease diagnosis. It's particularly valuable in urgent care or resource-limited settings, where rapid, reliable results are essential.

Viral infections such as HIV and SARS-CoV-2 have significantly increased morbidity in humans and resulted in a significant number of fatalities globally, hence early detection is crucial, particularly at a point-of-care (POC) setting to prevent the spread of these diseases. Localized surface plasmon resonance (LSPR) and green light-based Transmission spectroscopy techniques were used in this study to assess real-time molecular interactions between virus-spiked and nonspiked samples. The current study focuses on integrating selenium nanoparticles (SeNPs) with different optical photonic techniques for enhanced detection of HIV. Selenium nanoparticles were synthesized and functionalized with antibodies specific to HIV. Before and after bioconjugation with viral secondary antibodies, the SeNPs were characterized using Ultraviolet–visible (UV-Vis) spectroscopy, Dynamic light scattering (DLS), High-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy, to elucidate their properties and confirm the presence of functional groups. After that, the NPs were integrated with plasmonic systems and used for the enhanced detection of HIV in comparison to traditional LSPR and Transmission spectroscopy. Colloidal selenium nanoparticles were successfully synthesized, using ND: YAG laser. The orange-colored, spherically shaped nanoparticles were evenly distributed and easily resuspended. Anti-HIV antibodies conjugated to SeNPs were added after HIV-specific antibodies were successfully immobilized on a glass slide substrate to react with HIV pseudovirus. The pseudovirus was effectively identified by the use of Transmission Spectroscopy and LSPR techniques. The two optical techniques for HIV detection were more sensitive after integrating selenium nanoparticles, as compared to the conventional Transmission spectroscopy and LSPR methods. This improved and highly sensitive approach may be utilized to identify viral infections early, thus combating the spread of infectious diseases.

Cardiovascular diseases (CVD) are considered a major threat to global health. CVD biomarkers in blood are important indicators for CVD, being currently analyzed in specialized laboratories through expensive and time-consuming procedures (several hours). Therefore, for the rapid detection of biomarkers in undiluted plasma, we developed a new multiplexed and portable diagnostic system, CardioSense, based on a proprietary surface plasmon resonance (SPR) technology recently developed by us. For this, we also developed a biosensor for multiplexed SPR measurements, with increased sensitivity and robust to non-specific binding in undiluted plasma, as well as a portable and low-cost centrifugation system for rapid separation of plasma from blood. CVD biomarkers (B-natriuretic peptide, C-reactive protein, cardiac troponin I and myoglobin) are simultaneously detected by sensitive angle resolved SPR measurements in very low volumes of undiluted plasma (~10 μl). The novel system allows biomarker levels detection in minutes, and is cost effective, compatible with mass-production, and could be tailored to other biomarkers with minimal technology change. After testing and validation in clinical trials, the developed point-of-care device is envisaged to be used for rapid diagnosis (of CVD, and other diseases with known blood markers) in point of needs in hospitals (emergency departments).

Millions of people worldwide are affected by cardiovascular diseases (CVDs) resulting from blood clotting events, posing a significant health challenge. Warfarin is a common medicine that is used for thinning blood. However, the impact of a patient's daily diet on warfarin's effectiveness necessitates adjusting the dosage based on blood coagulation levels. Blood coagulation condition is commonly indicated by the international normalized ratio (INR). However, frequent hospital visits for coagulation tests conducted by trained personnel are inconvenient. Addressing this challenge, we have developed an innovative, cost-effective system that leverages smartphones for point-of-care INR testing. This device consists of two primary components—a 3D printed platform and customized microfluidic cartridges. Its foldable design enables easy transportation and enhanced durability, and the smartphone case on the platform is tilted at a 30- degree angle to accommodate both transparent samples (e.g., serum) and colored samples (e.g., whole blood). Illumination is ensured by LED backlight modules within the 3D-printed platform for uniform video recording conditions. The device utilizes a specially developed algorithm to process sample videos and obtain the INR level. Remarkably, the platform costs less than $8. We computed the flow stopping time of both commercial control samples and clinic human whole blood samples and evaluated the calculated INR values with the measured INR from a commercial blood analyzer. The results demonstrated an accuracy rate of over 90%. This platform presents an affordable and easily accessible solution for monitoring blood coagulation condition, offering significant benefits to patients and healthcare providers alike.

Perfusion of the flap is essential in Deep Inferior Epigastric Perforator (DIEP) flap breast reconstruction surgery for flap survival, yet perioperative assessment of flap perfusion to detect perfusion-related problems is challenging. Laser Speckle Contrast Imaging (LSCI) is an optical technique for quantitative microcirculation assessment. Mounted LSCI devices are bulky and impractical to use during surgery, or in other clinical settings where investigation of microcirculation is needed. Therefore, a handheld wireless perfusion imager (WIPI) was developed including a 660 nm laser and an RGB camera for image registration. With this device, flap perfusion during surgery (at baseline, after fully raising the flap, and during ischemia) was compared for different Hartrampf zones. The results indicate that poorly perfused DIEP flap zones may be detected in an early stage using a handheld LSCI device. More r

Continuous real-time monitoring of hemodynamic variables has become very relevant in modern medicine not only in clinical settings, but also for consumer wearables. Wearable technologies allow for vital sign monitoring (VSM) and help to promptly react in urgent situations. Photoplethysmography (PPG), an optical method based on absorption changes, is a well-known technique for non-invasive monitoring of cardiovascular biomarkers. However, PPG quality can be significantly compromised by skin melanin content, low perfusion, and ambient light changes. Unreliability under these conditions could potentially lead to severe consequences if threatening events remain undetected. Speckle Plethysmography (SPG) is based on the measurement of speckle variations and shows a robust signal quality independent of skin melanin content and ambient light, which indicates that SPG is a more reliable technology for continuous VSM. We present a compact, wearable device for simultaneous PPG and SPG VSM. The system consists of a laser diode illuminating the tissue, and a camera that captures the reflected light, forming a speckle pattern. Additionally, an acquisition platform (portable computer) is used to send the information wirelessly to a computer. The system allows for software-controlled tuning of parameters to optimize signal quality. SPG and PPG are calculated from the images, visualized in real-time and recorded to analyze cardiovascular biomarkers such as heart rate, heart rate variability and others. This compact wearable device is the first step towards full SPG/PPG sensor integration to enable robust, low-cost, wearable, non-invasive VSM.

Commercial and industry-standard pulse oximeters exhibit limitations in accurately measuring blood oxygen saturation (SpO2) across diverse skin tones, particularly in those with darker pigmentation. This discrepancy can lead to erroneous SpO2 readings due to the absorption of light by melanin, thereby placing those with darker skin tones at heightened risk. In this study, we designed, built, and tested a multimodal system capable of simultaneously measuring blood oxygen levels (SpO2) and contact pressure. Our primary objective was to evaluate the effects of contact pressure on mitigating inherent pulse oximetry inaccuracies across diverse skin tones. To achieve this, we calibrated and tested the device using five skin types in the range of 3–9 on the monk skin tone (MST) scale and seven contact pressure levels across the physiologic range of 10–70 mmHg. The research outcomes of this preliminary study showed that the most accurate results across a range of skin tones appear around the contact pressure range of 50 mmHg. This research has potential implications for healthcare providers, as accurate monitoring of blood oxygen levels is crucial for timely intervention and effective disease management. Moreover, addressing disparities in pulse oximetry readings that come from differences in skin tone across populations will help provide equitable healthcare outcomes for individuals from such diverse populations.

In this research, we examine the potential of measuring physiological variables, including heart rate (HR) and respiration rate (RR) on the upper arm using a wireless multimodal sensing system consisting of an accelerometer, a gyroscope, a three-wavelength photoplethysmography (PPG), single-sided electrocardiography (SS-ECG), and bioimpedance (BioZ). The study included collecting HR data when the subject was at rest and typing, and RR data when the subject was at rest. The data from three wavelengths of PPG and BioZ were collected and compared to the SS-ECG as the standard. The accelerometer and gyro signals were used to exclude data with excessive noise due to motion. The results showed that when the subject remained sedentary, the mean absolute error (MAE) for the HR calculation for all three wavelengths of the PPG modality was less than two bpm, while the BioZ was 3.5 bpm compared with SS-ECG HR. The MAE for typing increased for both modalities and was less than three bpm for all three wavelengths of the PPG but increased to 7.5 bpm for the BioZ. Regarding RR, both modalities resulted in RR within one breath per minute of the SS-ECG modality for the one breathing rate. Overall, all modalities on this upper arm wearable worked well when the subject was sedentary. Still, the SS-ECG and PPG showed less variability for the HR signal in the presence of motion during micro-motions such as typing.

This study proposes a new system that integrates pulse wave detection and personal authentication using compound eye optics. This system uses an individual's vein pattern for authentication and clearly identifies the individual based on the vein's running pattern. To measure pulse waves, the technique applies a wavelength filter to each segment of a compound eye image and analyzes the collected wavelength information. This approach provides a non-intrusive yet reliable method of personal identification that surpasses traditional methods such as fingerprinting. Vein patterns have the advantage of remaining constant throughout an individual's lifetime, unlike fingerprints, which can change due to a variety of factors. Our system is based on a TOMBO (Thin Observation of Bound Optics) camera, which consists of a lens array, a bulkhead to prevent light leakage, and a CMOS image sensor. We describe in detail the construction and validation of a vein authentication system that works effectively with filters at wavelengths of 940 nm, 850 nm, and 740 nm. By integrating these components, we propose a robust and efficient system for both pulse wave measurement and personal authentication.

We introduce a novel approach for measuring glucose concentration through mid-infrared transmission spectroscopy. This method utilizes a high-speed infrared spectroscopic technique employing a mid-infrared wavelength-swept (center wavelength 9.3 μm) pulse quantum cascade laser (QCL). Additionally, a special asynchronous signal control method is developed to reduce the measurement time to 20 ms. With the high power of the QCL and the proposed algorithm, the concentration of glucose solution samples can be accurately measured.

The skin’s interstitial fluid (ISF) represents a versatile platform for non-invasive in vivo biosensing of systemic biomarkers such as glucose. Biomedical applications of THz spectroscopy mostly leverage the strong interaction between THz light and water by mapping frequency-dependent changes in the sample’s dielectric response. We propose a novel THz spectroscopy-based approach for non-invasive detection of glucose in the skin’s ISF in conjunction with machine learning (ML). In this study, we explore advantages and limitations an ex vivo experiment on fresh porcine skin as a proof of concept of our approach. We investigate multiple sources of variation in such a dataset to understand how well our samples represent their in vivo counterpart. We characterize inter-sample and intra-sample variations to rule out undesired bias in our data that may complicate classification or regression tasks for glucose detection. Our results indicate that occlusion during THz contact measurements affects fresh ex vivo porcine skin similarly to what has previously been reported for in vivo human skin. Data processing strategies for ex vivo experiments for THz spectroscopy or imaging should therefore find ways to account for these effects.

Optical coherence tomography (OCT) is a non-invasive imaging method that provide high-resolution tomographic images. Attempts to incorporate OCT in dental practice have been ongoing, but the relatively bulky systems have limited their clinical utility. In this study, we utilized a microelectromechanical system (MEMS) to optimize the size of these OCT scanners to be similar to commercial intra-oral scanner (IOS) products. The optical axis of the internal scanner is designed in a Z shape to maximize the beam size reflected by the MEMS mirrors. To prove its usefulness in practical dentistry, we imaged the teeth in the oral cavity by position. Imaged teeth by position in the oral cavity demonstrated that the developed system can image deep into the oral cavity without difficulty. As a next step, we imaged teeth with cervical abrasion in three dimensions (3D) and high resolution. We classified the teeth into two types based on how the cervix was worn, and the degree of wear was quantitatively analyzed by performing A-scan profiling. This study demonstrates that the developed dental OCT system is effective in actual dental clinical practice and can be utilized for a variety of dental conditions.

In this study, features were extracted from PPG waveforms and used to train different classifier models, where cardiac output (CO) was classified into three ranges: low, healthy, and high. We used a curated dataset from the PhysioNet platform, Medical Information Mart for Intensive Care III (MIMIC-III) Matched database, which contains PPG waveforms and CO measurements. Specifically, there were 16 viable patients with over 184 hours of synchronous PPG and CO measurements. The data was then categorized into three distinct classes: Low CO (< 5 L/min), Healthy CO (5-6 L/min), and High CO (> 6 L/min). MATLAB’s Classification Learner application was used to implement and compare different classification techniques where thirty pre-configured models were compared, including SVMs, KNNs, Ensemble, Linear and Logistical Regression, and Neural Networks. From all the tested models, a Bagged Trees Ensemble model was determined to have the highest validation and testing accuracy (87.7% and 88.2%, respectively). It is noteworthy that, with our approach, there was no calibration needed and since the validation and testing accuracies were similar, this suggests that the selected model did not overfit the data.

Hematological analysis is based on assessing changes in the numbers of different blood cells and their morphological, molecular, and cytogenetic properties via a complete blood count. It is integral to diagnose and monitor a range of blood conditions and diseases, ranging from allergies and infections to different types of cancers. The conventional approach to hematology analysis requires time-consuming protocols, multiple expensive chemical reagents, complex equipment, and highly trained personnel for operation, and presents a significant burden to patients and healthcare systems. There is a need for simple, fast, low-cost alternatives such as label-free techniques that eliminate the need for staining or exogenous labels. We recently demonstrated label-free hematology analysis using deep-ultraviolet (UV) microscopy, a high-resolution imaging technique that yields quantitative molecular and structural information from biological samples. In this work, we present a fast, automated analysis pipeline to classify and count the different blood cell types in single-channel UV microscopy images using a low-cost, compact deep-UV microscope. Our previous work focused primarily on white blood cells; here, we further add platelets and red blood cells. We train a YOLOv7-style network to identify and count different blood cells in smear images acquired from a deep-UV microscopy system. Our deep-UV microscope in an LED-based, compact, and portable configuration and single-step analysis pipeline could be further combined with UV-transparent PDMS-based microfluidic devices to develop a fully automated, low-cost, label-free hematology analyzer.

Bone marrow aspiration procedures play an important role in the assessment of patients with blood and marrow diseases, including cancers. Evaluating the adequacy of aspirates, indicated by the presence of bony spicules, is crucial to ensure the procedural success and collection of relevant diagnostic material. Unfortunately, inadequate samples occur in approximately 50 % of cases, requiring patients to undergo repeat procedures. This is particularly problematic for pediatric patients who need to be anesthetized before each procedure. The current gold standard is hematopathologist examination of Giemsa-stained slides, which is time consuming and requires expensive biochemical reagents and trained technicians. Recently, Here we present a portable, LED-based UV microscope designed for real-time inspection of bone marrow aspirates. We discuss results from a clinical trial with pediatric oncology patients demonstrating excellent agreement between UV examination of unstained slides and ground truth pathologist examination of stained slides. Furthermore, we demonstrate whole slide imaging using a previously developed, compact UV microscopy system and automated spicule detection with deep neural networks to work towards point-of-care applications.

Glaucoma affects a significant portion of the global population, necessitating regular monitoring of intraocular pressure (IOP). Existing methods are limited by expensive equipment and infrequent measurements. This study proposes an implantable interferometric device for accurate, easy to use, handy and accessible IOP measurement. The device operates through reflection, receiving light from a near-infrared source. A retroreflector directs the light to a spectrometer for analysis. The device consists of a movable membrane and a fixed membrane, with pressure changes leading to spectral variations in the transmitted light. The system achieves a resolution of ~2nm, enabling precise IOP measurement. The design addresses the limitations of current approaches and offers a practical solution for accurate IOP monitoring.

Peripheral arterial disease (PAD) affects over 8.5 million people in the United States. Diagnostic tools to identify PAD continue to have low sensitivity for patients with diabetes and/or with poor vascular health in the small vessels of the lower extremities. A handheld device developed in our laboratory may address these limitations. The device combines dynamic vascular optical spectroscopy (DVOS) with pressure sensing to monitor the relationship between applied pressure and blood volume changes in tissues of interest, which is expected to differ between healthy and PAD subjects. Our probe is 20mm in diameter with the bottom face housing two infrared sources (wavelength λ = 780nm and 850nm) and one silicon photodetector located around 10mm from each source. The DVOS system continuously records the reflected light intensity from the local tissue at a frame rate of 10.24 frames per second. Simultaneously, the load applied by the probe to the tissue surface is measured continuously with a force sensor at the same frame rate. During data acquisition, the applied load is gradually increased, resulting in dynamic changes of the monitored DVOS signals. These recorded signals provide information on the response of the local tissue perfusion to changes in applied pressure. Here, we report on a preclinical study monitoring 3 vascular locations in the lower extremities of 3 healthy volunteers. Preliminary results suggest that on average there is a 0.03% change in total hemoglobin concentration per 10 mmHg change in applied pressure. We expect these changes to be significantly smaller in PAD patients.

Monitoring the carotid artery in patients who are at high-risk for stroke is crucial for early detection of abnormalities and may improve personalized, point-of-care diagnostics. We have developed a flexible 3-D printed patch for dynamic optical spectroscopy to evaluate the total blood oxygenation within the carotid artery. Each patch consists of a sensing module and detection module measuring 25 mm × 20 mm and 21 mm × 20 mm, respectively, placed a maximum distance of 32 mm apart. The sensing module contains four sources at wavelengths of 670 nm, 750 nm, 808 nm, and 850 nm placed in a square configuration, and the detection module contains two photodiodes in a parallel orientation. During data acquisition, two probes were applied proximally to both the left and right carotid arteries in the neck, and two probes were also placed proximally to the right and left radial arteries in the wrists. Six healthy participants were instructed to perform breathing exercises, such as a single deep breath, continuous deep breaths, and a timed breath hold, with intervals of routine breathing between each activity. Blood oxygenation was continuously measured during the data acquisition protocol. Our study demonstrated consistent blood oxygen content between the left and right carotid and radial arteries across all breathing exercises. Additionally, during a breath hold, we observed a 0.3% and a 0.1% decrease in oxygen saturation in the radial and carotid arteries, respectively. These findings underscore the system's potential to detect disease-related variations in individual carotid arteries, facilitating early detection.

We have developed an optical imaging system that allows monitoring arthritis in systemic lupus erythematosus (SLE) patients in multiple finger joints simultaneously. This system addresses the need for a low-cost accurate way to quickly assess SLE in a patient friendly manner. system comprises multiple flexible optical bands for each finger. Each band includes eight sets of three light-emitting-diodes (LEDs) (wavelength λ = 880 nm, 660 nm, and 530 nm) and a photodiode and can be wrapped around a proximal inter-phalangeal (PIP) joint allowing for the measurement of reflected and transmitted light from the LEDs by the photodetector. 24 LEDs and 8 detectors combine for a total of 192 measurements per finger per frame, which is acquired at a frame rate of 1 frame per second. We tested the performance of the system in a clinical pilot study comparing the results to an existing single-band system that makes measurements on one PIP joint at a time. During data acquisition, a partial venous inclusion is induced using a blood pressure cuff inflated to the subject’s diastolic blood pressure. Initial results show statistically significant differences between SLE patient and healthy volunteers, agreeing with our previous findings single-band technology.