Quantitative Phase Analysis Research Articles

Automated hyperspectral imaging for non-invasive characterization of human eye vasculature: A potential tool for ocular vascular evaluation

The vascular supply to the human eye plays a vital role in maintaining ocular health, making its non-invasive evaluation essential for diagnosing and managing various ocular disorders. This paper presents a novel approach utilizing hyperspectral imaging (HSI) to non-invasively characterize human eye vasculature. The proposed system aims to specifically identify the blood atrium and veins of the human eye at 470 nm and 750 nm, respectively, using quantitative phase analysis and k-means clustering. The study involved capturing diffused reflection spectra and hyperspectral images of the human eye at different wavelengths to reveal distinctive vascular features. The results of ten volunteers demonstrate promising capabilities in automated differentiation of atrium and veins, as well as the potential for mapping varicose veins in the lower limb. This non-invasive and non-contact imaging technique shows great promise in facilitating accurate and detailed evaluation of ocular blood flow, providing valuable information for clinical diagnosis and treatment in ophthalmology and vascular medicine fields.

The stone artifacts of the National Archaeological Museum of Adria (Rovigo, Italy): a noteworthy example of heterogeneity

This paper reports on the results of the analyses of 56 stone samples from Roman and pre-Roman artifacts from the ancient town of Atria, currently preserved at the National Archaeological Museum of Adria. The city is located in the eastern Veneto lowlands, close to the Po River delta, and far from the main rock outcrops of the region. The objective of this research is to determine the provenance of the stones used in ancient Atria and their trade networks. The analytical techniques adopted include polarized-light optical microscopy (PLM), X-ray fluorescence (XRF), and quantitative phase analysis by X-ray powder diffraction (QPA-XRPD). The results reveal a widespread use of imported stones from the central-western territories of Veneto, primarily comprising trachyte from the Euganean Hills and the soft limestone Vicenza Stone from the Berici Hills/eastern Lessini Mounts. Rosso Ammonitico, Maiolica (Biancone) and Scaglia Rossa limestones are also documented. From neighbouring regions, the imported stone types include Aurisina limestone from the Trieste Karst and Istrian Stone. Sandstone was uniquely recognized in G. Popillius’s milestone. Moreover, advanced geochemical and mineralogical analyses performed on the Euganean trachytes allow tracking accurately the quarry sites, revealing an extensive exploitation of the main historical quarries of M. Oliveto, Monselice and M. Merlo, although some provenances from outcrops less systematically exploited were also detected. Notably, the use of rhyolite for manufacturing a pre-Roman gravestone provides new insights regarding the exploitation of Euganean stone resources before the Roman era.

Quantitative phase analysis and molecular structure of human gallstones using synchrotron radiation X-ray diffraction and FTIR spectroscopy

Human gallstones are the most common disorder in the biliary system, affecting up to 20 % of the adult population. The formation of gallstones is primarily due to the supersaturating of cholesterol in bile. In order to comprehend gallstone disease in detail, it is necessary to have accurate information about phase identification and molecular structure. Different types of gallstone samples were collected from the Middle East area after surgical operations including; cholesterol, pigment, and mixed gallstones. To estimate the basic information about the stone formation and the pathophysiology of cholelithiasis as well as to classify the collected human gallstones, attenuated total reflection Fourier transform Infrared spectrometry (ATR-FTIR) was used to analyze the different gallstone structures in the wavenumber range from 400 to 4000 cm−1. Calcium bilirubinate was specified by the bands at 1662 cm−1, 1626 cm−1, and 1572 cm−1, while cholesterol rings were designated by the bands at 1464, 1438, 1055, and 1022 cm−1. It can be assumed that all samples consist of mixed gallstones based on the doublets at 1375 cm−1 and 1365 cm−1. The levels of calcium bilirubin and various minerals varied among the analyzed samples, indicating the heterogeneity in their composition and suggesting potential implications for gallstone formation. Based on the quantitative phase analysis using synchrotron radiation X-ray diffraction (SR-XRD), two phases of anhydrous cholesterol as a major content and one phase of monohydrate cholesterols as trace content represent the main components of most of the gallstones. Additional phases of calcium carbonate in the form of calcite, vaterite, aragonite, and bilirubinate were also quantified. According to the outcomes of the FTIR and the SR-XRD measurements, there exists a statistical correlation between the different types of chemical constituents of the gallstones.

Quantitative phase analysis method of palygorskite based on XRD orientational sample analysis and Rietveld full spectrum fitting

Palygorskite is a kind of water-rich magnesium aluminosilicate mineral with a chain-layered structure. Due to the difference in forming environment, the phase composition of palygorskite clay is various, and chemical compositions of palygorskite of different origins are also significantly different, which leads to a great difference in its application performance. Due to the coexistence of various types of layered and chain-layered minerals, conducting quantitative phase analysis of palygorskite raw ore becomes highly challenging. This significantly restricts the development and utilization of palygorskite. Herein, a new scheme is proposed to solve this problem by combining Rietveld full spectrum fitting based on the XRD patterns from internal standard method and orientational sample analysis. The new scheme was applied to the quantitative phase analysis of palygorskite raw ores from Mingguang, Xuyi, and Linze, three of the most representative places of origin in China. Not only the exact content of palygorskite and other crystalline phases in the raw ore, but also the content of mixed-layer minerals, and amorphous phase in the raw ore were obtained. The contents of palygorskite, quartz, illite-smectite mixed-layer minerals, and amorphous in the raw ore of Mingguang were 70.81%, 6.43%, 18.81%, and 3.98%, respectively; the contents of palygorskite, quartz, calcite, illite-smectite mixed-layer minerals in the raw ore of Xuyi were 36.08%, 16.18%, 27.06%, 18.04%, and 2.64%, respectively; the contents of palygorskite, quartz, illite-smectite mixed-layer minerals, calcite, illite, gypsum, feldspar, dolomite, microcline and amorphous in the raw ore of Linze were 10.11%, 34.82%, 5.77%, 1.07%, 5.57%, 8.06%, 12.38%, 17.05%, 2.21%, and 2.96%, respectively.

A Bogue approach applied to BOF slag

AbstractAn industrial by‐product of the steel industry called basic oxygen furnace (BOF) slag has recently undergone extensive research for high‐end applications outside of road load and landfill. In contrast to the Bogue methodology used with regular Portland cement, BOF slag lacks a quick and straightforward quantitative phase analysis procedure that would allow it to be employed as a high‐end raw material. The main phases of BOF slag (C2S, C2(A,F), Ff, RO‐Phase, and f‐C) can be calculated using the method presented in this paper based on chemical composition.

Evaluation of Kunkur Fines for Utilization in the Production of Ternary Blended Cements

Ternary blended cements, such as limestone calcined clay cement (LC3), represent a type of strategic binder for the mitigation of environmental impacts associated with cement production. These are estimated to reduce CO2 emissions by about 40% compared to ordinary Portland cement (OPC). In this paper, we explore the possibility of producing such ternary blends by utilizing secondary raw materials that may be locally available. Specifically, the primary limestone that is commonly used in LC3 is herein substituted with quarry dust obtained by sourcing “kunkur”, a carbonate-rich sedimentary rock (also known as caliche) that can be locally utilized for the production of ordinary OPC clinker. To optimize the blending proportions of ternary cement consisting of OPC, calcined clay, and kunkur fines, a “design of experiment” (DoE) approach was implemented with the goal of exploring the possibility of reducing the amount of the OPC fraction to values lower than 50%. The properties of the formulated blends were assessed by a combination of techniques that comprise mechanical strength testing, XRD time-dependent quantitative phase analysis, and SEM–EDS microstructural and microchemical analyses. The results suggest that ternary blended cement based on kunkur fines forms hydration products, such as hemicarboaluminates, which are also observed in LC3. This shows that such waste materials can potentially be used in sustainable cement blends; however, the presence of kaolinite in the kunkur fines seems to affect their strength development when compared to both OPC and conventional LC3.

Considerations for quantitative in situ X-ray powder diffraction studies of solid-state reactions

The importance of sample preparation in collecting high-fidelity powder diffraction data suitable for quantitative structure and phase analysis is well established. Such powder diffraction experiments are increasingly being applied in situ, during reactions, to explore solid-state reactivity. When applied in situ, X-ray diffraction is widely used to gain insight into the mechanism and kinetics, and to identify dynamic intermediate states. Here, using a model ion-exchange reaction (NaFeO2 + LiCl → LiFeO2 + NaCl), we show that sample preparation not only influences the fidelity of powder diffraction analysis but also impacts the observed reaction progress. Specifically, we found that the observed reaction progress can differ by ∼50% depending on the capillary sample preparation. Thus, for in situ diffraction studies of solid-state reactions, packing fraction is an important and previously unrecognized consideration that impacts reproducibility and fidelity of the reaction study.

Quantitative melanoma diagnosis using spectral phasor analysis of hyperspectral imaging from label-free slices.

Melanoma diagnosis traditionally relies on microscopic examination of hematoxylin and eosin (H&E) slides by dermatopathologists to search for specific architectural and cytological features. Unfortunately, no single molecular marker exists to reliably differentiate melanoma from benign lesions such as nevi. This study explored the potential of autofluorescent molecules within tissues to provide molecular fingerprints indicative of degenerated melanocytes in melanoma. Using hyperspectral imaging (HSI) and spectral phasor analysis, we investigated autofluorescence patterns in melanoma compared to intradermal nevi. Using UV excitation and a commercial spectral confocal microscope, we acquired label-free HSI data from the whole-slice samples. Our findings revealed distinct spectral phasor distributions between melanoma and intradermal nevi, with melanoma displaying a broader phasor phase distribution, signifying a more heterogeneous autofluorescence pattern. Notably, longer wavelengths associated with larger phases correlated with regions identified as melanoma by expert dermatopathologists using H&E staining. Quantitative analysis of phase and modulation histograms within the phasor clusters of five melanomas (with Breslow thicknesses ranging from 0.5mm to 6mm) and five intradermal nevi consistently highlighted differences between the two groups. We further demonstrated the potential for the discrimination of several melanocytic lesions using center-of-mass comparisons of phase and modulation variables. Remarkably, modulation versus phase center of mass comparisons revealed strong statistical significance among the groups. Additionally, we identified the molecular endogenous markers responsible for tissue autofluorescence, including collagen, elastin, NADH, FAD, and melanin. In melanoma, autofluorescence is characterized by a higher phase contribution, indicating an increase in FAD and melanin in melanocyte nests. In contrast, NADH, elastin, and collagen dominate the autofluorescence of the nevus. This work underscores the potential of autofluorescence and HSI-phasor analysis as valuable tools for quantifying tissue molecular fingerprints, thereby supporting more effective and quantitative melanoma diagnosis.

Semi-heuristic phase compensation in digital holographic microscopy for stable and accurate quantitative phase imaging of moving objects

Digital holographic microscopy (DHM) is a cutting-edge interferometric technique to recover the complex wavefield scattered by microscopic samples from digitally recorded intensity patterns. In off-axis DHM, the challenge is digitally generating the reference wavefront replica to compensate for the tilt between the interfering waves. Current methods to estimate the reference wavefront's parameters rely on brute-force grid searches or heuristics algorithms. Whereas brute-forced searches are time-consuming and impractical for video-rate quantitative phase imaging and analysis, applying heuristics methods in holographic videos is limited since the phase background level occasionally changes between frames. A semi-heuristic phase compensation (SHPC) algorithm is proposed to address these challenges to reconstruct phase images with minimum distortion in the full field-of-view (FOV) from holograms recorded by a telecentric off-axis digital holographic microscope. The method is tested with a USAF test target, smearing red blood cells and alive human sperm. The SHPC method provides accurate phase maps as the reference brute-force method but with a 92-fold reduction in processing time. Furthermore, this method was tested for reconstructing experimental holographic videos of dynamic specimens, obtaining stable phase values and minimal differences in the background between frames. This proposed method provides state-of-the-art phase reconstructions with high accuracy and stability in holographic videos, allowing the successful XYZ tracking of single-moving sperm cells.

A Bogue approach applied to basic oxygen furnace slag

Basic oxygen furnace (BOF) slag is an industrial by-product of the steel industry and has recently been investigated intensively for high-end applications other than road load and land fill. However, to be applied as a high-end raw material BOF slag lacks a quick and simple quantitative phase analysis method compared to the Bogue approach applied to ordinary Portland cement. This study presents a method to calculate the main phases of BOF slag (C2S, C2(A,F), magnetite (Ff), RO-Phase and f-C) based on chemical composition. A quantitative model assessment was performed in order to further improve the model and two approaches were used to validate the Bogue BOF slag model. One approach compared the calculated chemical composition of phases with real data the second one evaluated whether the Bogue BOF slag model gives comparable quantitative model assessment measures compared to the classical cement Bogue approach. Both approaches validated the proposed final model.

Mix and measure - Combining in situ X-ray powder diffraction and microtomography for accurate hydrating cement studies

It is reported an innovative methodology based on in situ MoKα1 laboratory X-ray powder diffraction (LXRPD) and microtomography (μCT) avoiding any sample conditioning. The pastes are injected in 2.0 mm capillaries and the extremes are just sealed. The measurements take place in the same region of the hydrating paste. Thick capillaries are key to avoiding self-desiccation, which dictates the need of high-energy X-ray radiation for the diffraction study. This approach has been tested with a PC 42.5 R paste having w/c = 0.50. μCT data were collected at 12 h and 1, 3, 7 and 79 days. LXRPD data were acquired at 1, 3, 7 and 77 days. In this proof-of-principle research, the same paste was also cured ex situ. Portlandite contents obtained by thermal analysis, ex situ powder diffraction, in situ mass balance calculation and in situ powder diffraction were 13.8, 13.1, 13.1 and 12.5 wt%, respectively. From the μCT study, the grey value histogram evolution with time showed a crossing point which allowed us to distinguish (appearing) hydrated products from (dissolving) unhydrated cement particles. Segmentations were carried out by global thresholding and the random forest approach (one type of supervised Machine Learning). The comparison of the segmented results for the unhydrated cement fraction and the Rietveld quantitative phase analysis outputs gave an agreement of 2 %. The potential of this methodology to deal with more complex binders is also presented.

Calculating the reference intensity ratio of crystalline phases with unknown atomic arrangements using the lattice parameters and chemical information

The reference intensity ratio (RIR) is the intensity ratio of a specified peak of the target crystalline phase to a certain peak of the reference phase in the powder X-ray diffraction pattern of a mixture of the target and reference phases in a weight ratio of 1:1. The RIR represents the diffraction power of the target phase compared with that of the reference phase. A quantitative phase analysis (QPA) can be readily made on the basis of only a powder pattern when the RIR values of all component phases in the mixture are available. The RIR of a target phase can be measured experimentally or calculated in accordance with its crystal structure. RIR values are given in most powder diffraction files (PDFs) published by the International Centre for Diffraction Data, but there are still more than 110 000 PDFs for which the RIR is absent. Newly discovered phases may be present in a mixture as components of unknown weight fractions, for which the RIR values can be neither measured nor calculated with the currently available method. Herein is presented a new method of calculating the RIR of a crystalline phase from its lattice parameters, the chemical content of the unit cell and a list of normalized intensities of reflections over a sufficiently large diffraction angle range. The new method can be used to calculate not only the absent RIRs in the PDFs but also the RIR of a component phase of a mixture of unknown weight fraction when the lattice parameters and chemical content of the unit cell of the corresponding phase are known.

In-situ laser metal deposition of nitinol and the effect of Ni4Ti3 phase concentration on its pseudoelasticity

Pseudoelasticity is one of the major properties of nitinol. It is highly altered by the presence of nickel-rich Ni4Ti3 phase in the nitinol matrix. Hence it is significant to make an attempt to study the connection between Ni4Ti3-concentration and the matrix-pseudoelasticity. In this work, the connection of pseudoelasticity of nitinol with the concentration of Ni4Ti3 in the matrix was investigated. A 0.5 mm thick preplaced layer of a powder mixture of nickel and titanium (55 % and 45 % by weight, respectively) on a 4 mm thick nitinol substrate was laser scanned with a laser power of 1000 W, scan speeds of 200, 400, 600, 800 and 1000 mm/min and a laser spot diameter of 3 mm under a shielding of argon gas stream. The various phases formed during the process at different scan speeds were quantified by Rietveld quantitative phase analysis. Further, load-displacement curves were obtained with nano-indentation to estimate the pseudoelastic recovery of the matrix and to show the pseudoelastic connection of the matrix with its constituent Ni4Ti3 concentration. The laser scanned tracks (with the scan speeds of 600, 800 and 1000 mm/min) having a higher concentration of Ni4Ti3 showed a higher amount of pseudoelastic recovery. On the other hand, the tracks (with the scan speeds of 200 and 400 mm/min) having a lower concentration of Ni4Ti3 showed a lower amount of pseudoelastic recovery.

Development of highly sensitive and selective trace acetone sensor using perovskite yttrium ferrite: Mechanism, kinetics and phase dependence study

Detection and monitoring of exhale breath acetone, bio-marker of diabetes is the need of the day to save millions human life. Trace acetone sensor having capability to detect breath acetone has been developed using perovskite YFeO3 powder (YFO) synthesized through a facile solution combustion technique. It is observed that YFO started to form hexagonal phase at 700 °C (YF-7) and ultimately converted to orthorhombic phase at 1000 °C (YF-10). Amongst others, YF-10 delivered best trace acetone sensing performance including a eight-fold response (S= Rg/Ra∼10.25 folds) to 1ppm acetone with ultrafast response-recovery time (∼0.6s-2s). Further, YF-10 sensor shows excellent selectivity, long-term stability more than 180 days, almost insensitive towards moisture and lower detection limit as low as 100 ppb. X-ray photoelectron spectroscopy (XPS) reveals that along with Fe3+ there exist Fe2+ ions which become maximum at 1000 °C. Formation of Fe2+ gives rise to oxygen vacancies which is maximum for YF-10 which is confirmed by PL and EPR studies. Enhanced acetone sensing performance of orthorhombic YFO is explained using quantitative phase analysis, honey-comb morphology, regulation of oxygen vacancies and bivalency of iron in different phases of yttrium ferrite. Eley−Rideal model has been invoked to explain the affinity towards acetone in comparison with other interfering gases. DFT calculation demonstrate that adsorption energy, a major parameter for gas sensing performance of any materials is lower for orthorhombic phase. In totality, it is observed that YFeO3 powder based sensor have huge potential for exhale breath analysis to monitor diabetes.

Regularities of Changes in the Structure of Different Phases of Deformed Zirconium Alloys as a Result of Raising the Annealing Temperature According to Texture Analysis Data

Based on the data of synchrotron and electron microscopic studies of deformed and annealed Russian zirconium alloys, the possibility of analyzing the structural-phase state and crystallographic texture of individual phases has been demonstrated. A qualitative and quantitative phase analysis of deformed and annealed tubes made of Zr-Nb-(Sn-Fe-O) alloys was carried out using diffraction patterns obtained with synchrotron radiation. The main α-Zr phase and the following additional phases: β-Nb, β-Zr, and the Laves phase (intermetallic compound Zr(Nb,Fe)2), were found in the alloys. According to the results of texture analysis of all phases present in the alloy, the mechanisms of plastic deformation, recrystallization, and phase transformations of the main and additional phases were established. It is shown that during plastic deformation of the Zr-1%Nb alloy, a dynamic phase transformation β-Nb→α-Zr→β-Zr is observed. It is established that during recrystallization, larger grains of α-Zr are misoriented relative to the deformed matrix by rotating the prismatic axes around the basal axes by 30°, while fine grains are improved by polygonization and maintain the orientation of the deformed matrix. Processes for changing the orientation of grains of additional phases as a result of high-temperature annealing are also considered.

Investigation into the impact of phase composition on the thermal expansion and mechanical properties of Al–Cu–Li alloys

The study employed high-temperature X-ray diffraction, quantitative phase analysis, and tensile mechanical property measurements to investigate the relationship between coefficient of thermal expansion (CTE) and phase composition, along with the average yield strengths and Young's moduli of Al–Cu–Li alloys in three different sheet orientations: 1441, V-1461, V-1469, V-1480, and V-1481. The copper content within the solid solution and the mass fractions of the T1(Al2CuLi) and δ′(Al3Li) phases were determined using an innovative technique based on measuring the lattice distance of the α solid solution, Vegard's law, and balance equations for the elemental and phase compositions of the alloys. It was observed that as the lithium-to-copper ratio in the alloys increased from 0.32 to 1.12, the proportion of the δ′(Al3Li) phase increases from 6.3–8.4 wt.% in V-1481, V-1480 and V-1469 alloys to 16.0–17.3 wt.% in 1441 and V-1461 alloys, accompanied by a decrease in the T1(Al2CuLi) phase from 5 to 1 wt.%. This led to an increase in the Young's modulus from 75 to 77 GPa due to higher overall proportion of intermetallic compounds and a reduction in yield strength from 509 to 367 MPa due to the decrease in the T1 phase. This decrease in yield strength resulted from the fact that the hardening effect of the T1 phase was 3–4 times greater than that of the δ′ phase, and this couldn't be offset by an increase in the total intermetallic compound proportion. The observed increase in Young's modulus indicated that the elastic properties of the intermetallic phases were similar, and the rise in the total fraction of intermetallic compounds compensated for the decrease in the T1 phase. Furthermore, it was demonstrated that СTE, as measured based on the thermal expansion of the solid solution, also depended on the characteristics of the intermetallic phases present in the alloy. This expanded the potential interpretations of СTE measurement results.

Gamification to Improve Medication Adherence: A Mixed-method Usability Study for MedScrab.

Medication non-adherence is a prevalent healthcare problem with poor health outcomes and added healthcare costs. MedScrab, a gamification-based mHealth app, is the first attempt to deliver crucial life-saving medication information to patients and increase their medication adherence. The paper presents the development of MedScrab and a two-phase mixed-method usability evaluation of MedScrab. Phase I qualitatively evaluated MedScrab using a think-aloud protocol for its usability. With 51 participants, qualitative data analysis of Phase I revealed two themes: positive functionality of the app and four areas of improvement. The improvement recommendations were incorporated into MedScrab's design. Phase I also validated a widely used mHealth App Usability Questionnaire (MAUQ). Quantitative data analysis of Phase I reduced the original 18-item MAUQ scale to a 15-item scale with two factors: ease of use (4 items) and usefulness and satisfaction (11 items). Phase II surveyed 83 participants from Amazon's Mechanical Turk using a modified MAUQ. The modified MAUQ scale showed strong internal consistency (Cronbach alpha = 0.959) and high factor loadings (between 0.623 and 0.987). The study design of the usability evaluation can serve as a methodological guide for designing, evaluating, and improving mHealth apps.The usability study showed that MedScrab was perceived as ease of use (6.24 out of 7) with high usefulness and satisfaction (5.72 out of 7). The quantitative data analysis results support the use of the modified MAUQ as a valid instrument to measure the usability of the MedScrab. However, the instrument should be used with adaptation based on the app's characteristics.

Crystal structure simulation of cationic cholesteric Liquid-Crystal polyesters. Non-Viral vectors

The crystal structure of six cationic cholesteric liquid crystal polyesters with choline, ammonium, and amide end groups are reported: PTOBEE-Choline [(C26H20O8)n-C5H13N]; PTOBDME-Choline [(C34H36O8)n-C5H13N]; PTOBEE-Ammonium [(C26H20O8)n-C5H13N]; PTOBDME-Ammonium [(C34H36O8)n-C5H13N]; PTOBEE-Amide (C26H19O9N)n and PTOBUME-Amide (C33H33O9N)n, have demonstrated non-viral vector properties in gene therapy by delivering DNA to the cell nucleus. They were synthesized by functionalization of precursor racemic polyesters via a condensation reaction between 4,4′-(terephthaloyl-di-oxydibenzoic chloride) (TOBC) and the racemic mixture of glycol (R-S-1,2-butanediol) or (R-S-1,2-dodecanediol), respectively. The resulting helical macromolecular structures exhibit unexpected optical activity and chiral morphology, previously attributed to the kinetic resolution of one preferable helical conformer of the possible four observed by NMR. Conformational analysis and energy minimization are performed on the four helical conformer monomeric models which are then polymerized to obtain helical chains. Three levels of chirality were observed in these polymer structures. Crystal models are built in triclinic primitive P1cells, with their molecular chains oriented parallel to the Z-axis (c lattice parameter equal to the helical pitch length), the cell parameters are obtained by performing geometry optimization tasks. A raw estimation of the relative weight of the four possible helical conformers on each synthetic cationic polymer has been performed on ideal mixtures considering their approximate known crystal structure with their experimental X-ray powder diffraction by Powder Quantitative Phase Analysis. The results would confirm the theory of the preferable recrystallization of a diastereoisomer, among the four possible, during the synthetic procedures. These findings shed light on the observed optical activity and provide insights into the crystal structure of these cationic polymers. The morphology of the cationic polymers is studied by ESEM in wet samples and crystals after drying the solvent.

A-144 Three-wavelength Polarization Imaging Method for the Analysis of Individual Human Blood Cells With Dye-Enhanced Dispersion of Dilution Buffer

Abstract Background Performing basic hematology analysis in a near-patient setting enables more rapid clinical decision making in the process of diagnosis. Traditional blood analyzers in central labs use a complex combination of sensing principles and chemical modification of the sample to derive the necessary parameters for a complete blood count (CBC). To reduce cost and maintenance, varying approaches have been employed to determine a CBC with a single-step measurement technique. One common option is the use of optical microscopy to deliver highly reliable results, examples are fluorescence microscopy, digital holographic microscopy, or spatial light interference microscopy. However, most of these technologies lack a proper determination of cellular-level RBC parameters. Therefore, a non-interferometric, quantitative-phase measurement technique was developed to derive relevant CBC parameters from a single measurement, comparable to a standard lab analyzer. Methods The optical setup employed by this method enables the parallel acquisition of brightfield and differential interference contrast (DIC) images by polarization-sensitive cameras. By using three cameras with individual optical filters, quantitative phase and absorption information can be calculated, which enables the determination of mean cellular volume (MCV), mean cellular hemoglobin (MCH), and mean cellular hemoglobin concentration (MCHC) for red blood cells (RBCs). The whole-blood sample is diluted in a buffer containing a non-cell-penetrating dye to enhance optical refraction contrast and therefore precision in the dependent calculated quantities. The sample is then introduced to a glass flow cell, and the cells are allowed to sediment to the bottom for imaging. Machine learning is applied to the derived images to classify unstained native white blood cells (WBCs) to yield a 5-part differential, which distinguishes between neutrophil, monocyte, lymphocyte, eosinophil and basophil. The algorithm is trained by imaging FACS-validated, purified WBC subgroups. All blood samples are measured on an ADVIA® 2120 Hematology System for control. Results A one-step, optical CBC hematology system based on quantitative phase and absorption image analysis was developed. The correlations for MCV and MCHC compared to a standard lab CBC analyzer were 0.77 and 0.84. The accuracy for the 5-part differential WBC classification was approximately 0.8. To enable a visual inspection of the classification results, a pseudo-colored image of each cell was generated and uploaded in a review tool. Conclusion With a more-refined, less-expensive optical setup, a high-quality CBC analyzer suitable for use at the point of care can be derived with the presented method. A possible simplification could be the use of low-cost but high-resolution Fourier ptychography microscopy (FPM) technology. Imaging of blood samples on a single-cell level offers the potential for the analysis of even more morphological parameters, for example, disease-related changes in the cell membrane. Also, the adhesion behavior of the WBCs in the glass flow cell could indicate cell activation status and therefore give information about infection processes. *Trademark disclaimer: “ADVIA, and all associated marks are trademarks of Siemens Healthcare Diagnostics, Inc. or its affiliates. All other trademarks and brands are the property of their respective owners.”

Development of a custom optical imaging system for non-invasive monitoring and delineation of lower limb varicose veins using hyperspectral imaging and quantitative phase analysis

BackgroundVaricose veins (VV) are a prevalent chronic venous disorder, particularly affecting women of childbearing age. This condition is associated with significant complications, including pain, discomfort, leg cramps, ulceration, reduced quality of life, absenteeism, and even mortality. This study aims to develop a custom non-invasive, non-contact optical imaging system combined with magnitude and phase image calculation to monitor and visualize varicose veins and their tributaries using hyperspectral imaging and quantitative phase analysis with a k-means clustering algorithm. ResultsTen volunteers participated in the optical imaging system study. They were exposed to a polychromatic light source spanning the wavelength range of 400 nm–950 nm. The diffuse reflection spectra for varicose veins exhibited a peak at 530 nm, while leg veins showed a peak at 780 nm. Hyperspectral images obtained at these specific wavelengths were normalized in order to homogenize the spectral signatures of each pixel (converting the hyperspectral image to 8 bit RGB image) and filtered using a moving average filter. Subsequently, the varicose veins and leg veins were delineated and detected using quantitative phase analysis and a k-means clustering algorithm. ConclusionIn conclusion, the custom optical imaging system, utilizing hyperspectral imaging and the associated clustering algorithm, provides detailed information regarding the spatial distribution of varicose veins. This information can assist vascular physicians in facilitating easier diagnosis and treatment planning.