High-resolution Imaging System Research Articles

Multimodal high-resolution embryonic imaging with light sheet fluorescence microscopy and optical coherence tomography.

A high-resolution imaging system combining optical coherence tomography (OCT) and light sheet fluorescence microscopy (LSFM) was developed. LSFM confined the excitation to only the focal plane, removing the out of plane fluorescence. This enabled imaging a murine embryo with higher speed and specificity than traditional fluorescence microscopy. OCT gives information about the structure of the embryo from the same plane illuminated by LSFM. The co-planar OCT and LSFM instrument was capable of performing co-registered functional and structural imaging of mouse embryos simultaneously.

A novel bandpass filter fed antipodal tapered slot antenna for millimeter wave imaging

In this paper, we propose antipodal tapered slot antenna with integrated bandpass filter over 23.5–40 GHz for high resolution imaging applications. The novel antenna feed comprises of half mode substrate integrated waveguide and rectangular slots with isosceles trapezoidal variation. The feed section gives a passband over 23.5–40 GHz with S 11 <−10 dB and S 21 ≃0 dB. We present the design evolution procedure for the integrated filter antenna. The proposed antenna exhibits S 11 <−10 dB over the controlled bandwidth from 23.5 GHz to 40 GHz. We incorporate rectangular corrugations in the form of a staircase at the outer edges of the antenna and ground plane slots to achieve a stable gain and stable radiation pattern over the controlled bandwidth. The proposed antenna occupies a volume of 30.3 × 16 × 0.254 mm3, and is fabricated and tested. The measured results show good agreement with simulations. As compared to the state-of-the-art approaches, the proposed antenna is compact in size and exhibits a constant gain and stable radiation pattern over the operating bandwidth. We describe case studies to illustrate the application of the proposed antenna in a wideband imaging system for the detection of concealed objects and material defects. The reconstructed images obtained with the proposed antenna demonstrate its potential for use in high-resolution millimeter wave imaging systems.

A two-step channel mismatch estimation and compensation method for distributed MC SAR

ABSTRACT A distributed multichannel synthetic aperture radar system refers to a multichannel synthetic aperture radar system with channels distributed and installed at different locations on the platform. It is a promising system for high-resolution wide-swath imaging. The channels of the distributed multichannel synthetic aperture radar are sparsely distributed and have long cross-track baselines. The range-variant envelope migration and phase mismatch in the echoes between different channels are introduced by the long cross-track baselines and affect the performance of azimuth signal reconstruction. The sparsity of channels results in the poor correlation of data between channels, so the time-domain cross-correlation method typically used in azimuth multichannel synthetic aperture radar cannot be used in distributed multichannel synthetic aperture radar to estimate channel phase error directly. In this paper, the gain-phase error, sampling time delay and slant range difference introduced by cross-track baselines are modelled uniformly as channel mismatches. Firstly, a two-step channel mismatch estimation and compensation method for distributed multichannel synthetic aperture radar is proposed. Secondly, a range-variant envelope migration compensation method based on the chirp scaling principle is given. Thirdly, this paper also presents the processing of data rearrangement based on the distribution of spatial sampling points to make the time-domain cross-correlation method suitable for distributed multichannel synthetic aperture radar. Point target simulation and scene simulation are provided to show the effectiveness of the proposed methods.

A stereoscopic optical system for objective quantification of the change in cumulative acne scar depth following various treatment interventions.

Current approaches for assessment of acne scars are subjective, including counting scar subtypes, subjective self-assessment, or scoring global acne scar severity. We aimed to validate accuracy and present initial data of a new, simple, non-contact, high-resolution 3D stereoscopic optical imaging system in the setting of acne scarring. Ten patients treated for acne scars in the dermo-esthetic outpatient clinics in our institution from July to December 2019 were recruited from medical files and completed by telephone interview. Each patient was assessed by the 3D imaging system, the Qualitative Scarring Grading Score (QSGS), and the patient's questionnaire for Self-assessment of Clinical Acne-Related Scars (SCARS) before and 4 weeks after a single intervention. Scar depth measured by the imaging system correlated significantly with the actual depth of printed surface depressions and the 3D optical imaging assessments. The changes in SCARS and 3D optical imaging assessments correlated significantly, but there were no correlations between changes in QSGS and 3D optical assessment measures, or between the QSGS and SCARS results. The new stereoscopic optical system is a reliable and practical objective method for assessing the cumulative depth of atrophic acne scars and monitoring treatment response. It is more sensitive, accurate, and informative than subjective scales.

Abstract 2595: Cancer cachexia is mediated by the suppression of PGC1-alpha expression in the skeletal muscle vasculature

Abstract Background: Cancer patients experience cachexia which is characterized by extensive skeletal muscle wasting that worsens the quality of life and increases mortality. However, there are no approved treatments that can effectively counteract cancer cachexia. Prior research has focused on the changes within the muscle tissue but little is known about the role of the muscle vasculature in mediating cancer cachexia. Vascular endothelial cells (ECs) are essential for maintaining tissue perfusion, nutrient supply and preventing inappropriate transmigration of immune cells into the tissue. We therefore hypothesized that endothelial dysfunction in the skeletal muscle results in the development of cachexia in cancer. The transcriptional co-activator PGC1α (peroxisome proliferation activator receptor-γ coactivator1-α) regulates endothelial health. Methods and Results: To evaluate whether skeletal muscle EC-PGC1α is modulated in the setting of malignancy, we isolated muscle ECs from control and melanoma bearing mice at 1, 2, and 3 weeks after melanoma implantation. PGC1α expression was significantly decreased in mECs of melanoma bearing mice from early stage (1 week) compared with control mice. Thus, we generated an EC-specific inducible PGC1α deletion mouse model (ECΔPGC1α) to investigate the mechanistic role of EC-PGC1α in cancer cachexia in vivo. Interestingly, vascular density and muscle area were significantly decreased in the gastrocnemius (GC) of ECΔPGC1α mice compared with ECWT mice using an innovative tissue clearing and high-resolution 3D-tissue imaging system. Tumor bearing ECWT mice had decreased GC mass and weight compared with no tumor mice by enhancing cachexia marker genes, MuRF1 and Atrogin1. The tumor bearing ECΔPGC1α mice had further decreased muscle mass and weight, and grip strength than tumor bearing ECWT mice. We assessed the role of EC-PGC1α in the regulation of capillary function in vivo, and observed that ECΔPGC1α mice demonstrated significantly greater vascular leak than ECWT mice. Conclusion: These data suggest that the presence of melanoma suppresses PGC1α expression in the skeletal muscle endothelium. Endothelial PGC1α, in turn, is essential for maintaining the integrity of the skeletal muscle vascular barrier. Our study suggests that restoring muscle endothelial dysfunction could be a novel therapeutic approach to prevent or reverse cancer cachexia. Citation Format: Young-Mee Kim, Georgina Mancinelli, Paul Grippo, Jalees Rehman. Cancer cachexia is mediated by the suppression of PGC1-alpha expression in the skeletal muscle vasculature [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2595.

PHOTOGRAMMETRIC MAPPING FROM HIGH-RESOLUTION STEREO IMAGERY AND COMPARATIVE ANALYSIS USING EXISTING DATA

The launch of the very high resolution (VHR) sensor satellites has paved the way for further exploitation of the capabilities of stereo satellite imagery for many applications and most importantly in the extraction of topographical details. Advances in digital technologies in the photogrammetric technique provide more accurate and up to date topographic representation, while traditional methods of topographic mapping are time-consuming and require large technical support. This paper explores the methods of production and an analysis of the capabilities of the high-resolution stereo imaging system for the extraction of features (topographic map) and generation of digital elevation model (DEM). This study uses high-resolution GeoEye-1 stereo pair images. For qualitative assessment, topographic features were extracted by digitizing the georeferenced stereo pair images and overlapped to form a DEM and orthophoto within the Summit Evolution software. Georeferencing was carried out using the existing Ground Control Points (GCPs) and Check Points (CPs) established using Real-Time Kinematic Global Navigation Satellite System (RTK-GNSS) technique. For quantitative assessment, a total of 7 existing GCPs were considered suitable for use and 5 CPs were established as a check for accuracy of the output. The accuracy of the CPs was evaluated by computing Root Mean Square Error (RMSE). The average horizontal RMSE for the left image and right image were 1.17150098m and 0.819334672m respectively and the average vertical RMSE was 1.605898565m. Additionally, the standard deviation for elevation data from generated DEM using photogrammetric technique and existing elevation data of RTK-GNSS technique were computed, which resulted in 15.91286667 and 16.59529228 respectively. The accuracy was evaluated by comparing the results of the data extracted using stereo satellite images and those extracted from ground measurement techniques (Total station and RTK-GNSS). The comparative analysis showed that stereo pair images provide a viable alternative to other ground mapping techniques providing results within the acceptable range. Based on error estimation and analysis, it concludes that, if strict photogrammetric processing model and ground control points are employed, high-resolution satellite imagery can be used for the accurate generation and update of the topographic maps, DEM and digital orthophotos, which can be further be used as a reference for comparative analysis applications.

High-Resolution Imaging of Cold Atoms through a Multimode Fiber

We developed an ultra-compact high-resolution imaging system for cold atoms. Its only in-vacuum element is a multimode optical fiber with a diameter of $230\,\mu$m, which simultaneously collects light and guides it out of the vacuum chamber. External adaptive optics allow us to image cold Rb atoms with a $\sim 1\,\mu$m resolution over a $100 \times 100\,\mu$m$^2$ field of view. These optics can be easily rearranged to switch between fast absorption imaging and high-sensitivity fluorescence imaging. This system is particularly suited for hybrid quantum engineering platforms where cold atoms are combined with optical cavities, superconducting circuits or optomechanical devices restricting the optical access.

Adaptive adversarial neural networks for the analysis of lossy and domain-shifted datasets of medical images.

In machine learning for image-based medical diagnostics, supervised convolutional neural networks are typically trained with large and expertly annotated datasets obtained using high-resolution imaging systems. Moreover, the network's performance can degrade substantially when applied to a dataset with a different distribution. Here, we show that adversarial learning can be used to develop high-performing networks trained on unannotated medical images of varying image quality. Specifically, we used low-quality images acquired using inexpensive portable optical systems to train networks for the evaluation of human embryos, the quantification of human sperm morphology and the diagnosis of malarial infections in the blood, and show that the networks performed well across different data distributions. We also show that adversarial learning can be used with unlabelled data from unseen domain-shifted datasets to adapt pretrained supervised networks to new distributions, even when data from the original distribution are not available. Adaptive adversarial networks may expand the use of validated neural-network models for the evaluation of data collected from multiple imaging systems of varying quality without compromising the knowledge stored in the network.

A High-Resolution Microfluidic LAPS Imaging System for 3D Cell Metabolism Monitoring

A High-Resolution Microfluidic LAPS Imaging System for 3D Cell Metabolism Monitoring

MO336RENAL CONTRAST-ENHANCED ULTRASOUND (CEUS) TO EVALUATE EARLY AND CHRONIC MODIFICATIONS OF RENAL PERFUSION AND TO PREDICT RENAL DYSFUNCTION AFTER RENAL ISCHEMIA-REPERFUSION IN MICE

Abstract Background and Aims Renal ischemia-reperfusion can lead to acute kidney injury (AKI), increasing the risk of developing chronic kidney disease (CKD) through inflammation and vascular lesions. Serum urea or creatinine level routinely used as diagnostic indices of renal function are always delayed from the onset of the disease. Therefore, we currently lack reliable markers to early detect AKI, especially in animals. We aimed to show that non-invasive renal contrast-enhanced ultrasound (CEUS) could be a reliable tool to assess early and chronic changes of renal perfusion after renal ischemia-reperfusion. Method Male C57BL6 mice underwent 15 minutes of unilateral renal ischemia by clamping of the left renal vascular pedicle (n = 7), or a sham procedure (n = 3), under inhaled general anesthesia by Sevoflurane. A renal ultrasound was performed on the left ischemic kidney at baseline 1 week before the surgery, then, 20 minutes after reperfusion to assess early modifications of renal perfusion, and 1 month after reperfusion to follow chronic modifications. CEUS was performed in supine position by using a high-resolution ultrasonic imaging system (VEVO 3100 Fujifilm Visualsonics, Toronto, Canada) with a MX550D probe fixed in place with an iron support, ensuring the constant imaging plane throughout acquisition. First, a continuous infusion of microbubbles (VS-11913, Fujifilm Visualsonics, Toronto, Canada) was done through the tail vein, then a high mechanical index burst was given to destroy microbubbles when the contrast enhancement had reached a steady state, and finally, low mechanical-index imaging mode was used until, and 30 sec after the contrast agent concentration reached the plateau. Images were recorded and were analyzed using the “destruction-replenishment” fitting model of the Vevo LAB software (Fujifilm Visualsonics, Toronto, Canada). Renal perfusion was estimated by the total renal Blood Volume (rBV) parameter and was expressed as percentage of the baseline value for each animal. Renal function was also assessed by serum urea concentration 1 month after reperfusion, and the long axis lengths of both the kidneys were measured ex vivo after the mice were euthanized. Results Renal perfusion of the ischemic kidney measured by CEUS was significantly decreased as soon as 20 minutes of reperfusion compared to baseline (median 28,8% of baseline value; interquartiles [20,1 – 69,8%]). 1 month after reperfusion, renal perfusion recovered partially but was still significantly decreased compared to baseline (median 79,9% of baseline value; interquartiles [52,8 – 99,9%]) (Figure A). In sham operated mice, renal perfusion did not differ from baseline at 20 minutes or 1 month (p &amp;gt; 0.05). The renal function, assessed by serum urea, was mildly but significantly impaired 1 month after ischemia-reperfusion compared with sham (median serum urea 9,8 vs. 7,6 mmol/L) (p = 0.02), and this was consistent with the observed kidney atrophy in the ischemic group when compared to the contralateral kidney (median long axis length 7,5 vs 10,8 mm) (p = 0.03). Moreover, the decrease of renal perfusion 20 minutes after reperfusion was significantly correlated with the impairment of renal perfusion 1 month after reperfusion (Pearson r = 0.836, p = 0.005) and with the serum urea level at 1 month (Pearson r = -0.710, p = 0.03) (Figure B-C). Conclusion Renal CEUS was able to detect early impairment of renal perfusion as soon as 20 minutes after 15 minutes of renal ischemia in mice, and perfusion was still decreased 1 month after reperfusion, compared to baseline. This early impairment of perfusion was correlated with the chronic decrease of renal perfusion and renal function 1 month after reperfusion. This was also associated with a significant kidney atrophy. CEUS is an interesting non-invasive tool to assess renal lesions dynamically after ischemia-reperfusion.

Oocyte-derived microvilli control female fertility by optimizing ovarian follicle selection in mice

Crosstalk between oocytes and surrounding somatic cells is crucial for mammalian oogenesis, but the structural mechanisms on oocytes to control female reproduction remain unknown. Here we combine endogenous-fluorescent tracing mouse models with a high-resolution live-cell imaging system to characterize oocyte-derived mushroom-like microvilli (Oo-Mvi), which mediate germ-somatic communication in mice. We perform 3D live-cell imaging to show that Oo-Mvi exhibit cellular characteristics that fit an exocrine function for signaling communication. We find that deletion of the microvilli-forming gene Radixin in oocytes leads to the loss of Oo-Mvi in ovaries, and causes a series of abnormalities in ovarian development, resulting in shortened reproductive lifespan in females. Mechanistically, we find that Oo-Mvi enrich oocyte-secreted factors and control their release, resulting in optimal selection of ovarian follicles. Taken together, our data show that the Oo-Mvi system controls the female reproductive lifespan by governing the fate of follicles.

Can chlorophyll fluorescence imaging make the invisible visible?

Chlorophyll fluorescence has developed into a well-established noninvasive technique to study photosynthesis and by extension, the physiology of plants and algae. The versatility of the fluorescence analysis has been improved significantly due to advancements in the technology of light sources, detectors, and data handling. This allowed the development of an instrumention that is effective, easy to handle, and affordable. Several of these techniques rely on point measurements. However, the response of plants to environmental stresses is heterogeneous, both spatially and temporally. Beside the nonimaging systems, low- and high-resolution imaging systems have been developed and are in use as real-time, multi-channel fluorometers to investigate heterogeneous patterns of photosynthetic performance of leaves and algae. This review will revise in several paragraphs the current status of chlorophyll fluorescence imaging, in exploring photosynthetic features to evaluate the physiological response of plant organisms in different domains. In the conclusion paragraph, an attempt will be made to answer the question posed in the title.

Preview the Products on Display at Display Week 2021

Preview the Products on Display at Display Week 2021

Optical control of the density and spin spatial profiles of a planar Bose gas

We demonstrate the arbitrary control of the density profile of a two-dimensional Bose gas by shaping the optical potential applied to the atoms. We use a digital micromirror device (DMD) directly imaged onto the atomic cloud through a high resolution imaging system. Our approach relies on averaging the response of many pixels of the DMD over the diffraction spot of the imaging system, which allows us to create an optical potential with an arbitrary intensity profile and with micron-scale resolution. The obtained density distribution is optimized with a feedback loop based on the measured absorption images of the cloud. Using the same device, we also engineer arbitrary spin distributions thanks to a two-photon Raman transfer between internal ground states.

Conformally Mapped Mikaelian Lens for Broadband Achromatic High Resolution Focusing

AbstractFocusing light into a tiny spot of high resolution is of significant importance in fields from imaging, photolithography to microwave engineering and sensing. However, most of the previous high resolution metalenses are constrained by their limited bandwidth and efficiency. In this paper, on the basis of Mikaelian lens derived from conformal transformation optics, a rectangular gradient refractive index lens with a relatively larger refractive index profile is put forward and manufactured by gradient isotropic dielectrics. Highly efficient (above 74%) broadband (7–14 GHz) achromatic high resolution focusing with full width at half maximum (FWHM) around 0.2λ as well as large numerical aperture (NA) of 2.04 has been accomplished. Measured results agree well with theoretical predictions, which makes the presented lens having a great potential to be employed in high resolution imaging systems.

Investigation of corneal topographic and densitometric properties of Wilson's disease patients with or without a Kayser-Fleischer ring

BackgroundTo investigate the topographic measurements and densitometry of corneas in Wilson’s disease (WD) patients with or without a Kayser-Fleischer ring (KF-r) compared to healthy individuals.MethodsThis cross-sectional study included 20 WD patients without a KF-r (group I), 18 WD patients with a KF-r (group II), and 20 age-matched controls (group III). The Pentacam high resolution imaging system is used to determine corneal topographic measurements and densitometry.ResultsMean age for groups I, II and III was 25.40 ± 6.43 years (14–36 years), 25.38 ± 6.96 years (16–39 years), 23.60 ± 6.56 years (17–35 years), respectively (P = 0.623). There was no significant difference between the groups in terms of the anterior corneal densitometry values (P > 0.05), while the 6–10 mm and 10–12 mm mid stroma and the 2–6 mm, 6–10 mm, and 10–12 mm posterior corneal densitometry values in group II were significantly higher than those in groups I and III (for all values, P < 0.05). However, the 10–12 mm posterior corneal densitometry values in group I were also significantly higher than those in group III (P = 0.038). The central corneal thickness (CCT), thinnest corneal thickness (tCT), and corneal volume (CV) values in groups I and II were significantly lower than those in group III (for CCT values, P = 0.011 and P = 0.009; for tCT values, P = 0.010 and P = 0.005; for CV values, P = 0.043 and P = 0.029).ConclusionIn WD patients with a KF-r, corneal transparency decreased in the peripheral posterior and mid stromal corneal layers; for these patients, corneal transparency may be impaired not only in the peripheral cornea but also in the paracentral cornea.

Three dimensional imaging of reinforcement corrosion using micro-computed tomography: Literature review

A deeper understanding of steel reinforcement corrosion and corrosion-induced cracking in concrete structures is crucial for taking preventive measures and performing effective and efficient repair. Recently, researchers started utilizing high-resolution and non-destructive micro-computed tomography (µCT) imaging systems to investigate the diffusion of corrosion products and the resulted cracks within structural elements throughout the corrosion process. Natural and accelerated reinforcement corrosion modes are induced using two techniques, namely: impressed current and wet-dry cyclic methods. The test specimens are scanned periodically using µCT during the corrosion process to accurately capture microstructural change. The reported findings demonstrated the potential of using µCT imaging to monitor the corrosion diffusion and crack propagation in addition to measuring the mass loss of reinforcement. This research area, however, is still relatively new with many uncovered areas that need to be investigated. Therefore, the main objective of this article is to provide a comprehensive review of the current research progress by reviewing the specifications of examined specimens, the applied corrosion-induction conditions, and the utilized imaging parameters to capture high-resolution µCT images. The reported corrosion diffusion and crack propagation mechanisms are presented. The effects of impressed current, type of steel reinforcement, structural defects, and physical confinement on the corrosion and cracking processes are discussed. Also, the accuracy of µCT measurements of reinforcement mass loss is described.

Simultaneous 4-phase-shifted full-field optical coherence microscopy.

A new method is presented for full-field optical coherence tomography imaging, which permits capturing single shot phase sensitive imaging through simultaneous acquisition of four phase-shifted images with a single camera using unpolarized light for object illumination. Our method retains the full dynamic range of the camera by using different areas of a single camera sensor to capture each image. We demonstrate the performance of our method by imaging phantoms and live cultures of fibroblast, cancer, and macrophage cells to achieve 59 dB sensitivity with isotropic resolution down to 1 μm, and displacement sensitivity down to 0.1 nm. Our method can serve as a platform for developing high resolution imaging systems because when used in conjunction with broadband spatially incoherent light sources, the resolution is not affected by optical aberrations or speckle noise.

Optical comparison between micro-CT and OCT in imaging of marginal composite adaptation: Observational study.

Dental composite is the most used aesthetic restorative biomaterial worldwide. However, it undergoes polymerisation shrinkage that could lead to loss of the interfacial seal between tooth and resin in some circumstances. This demands high-resolution imaging technologies to detect these defects. This study carried out a comparison between microcomputed tomography (micro-CT; Shimadzu, Japan) and swept-source optical coherence tomography (SS-OCT; Santec, Japan) in the detection of marginal adaptation defects at the tooth-resin interface. Unlike in micro-CT, it was possible to outline interfacial gaps along with tooth-resin interfaces with SS-OCT, which was attributed to the Fresnel diffraction of light. This in vitro comparison demonstrates SS-OCT has great potential in dental imaging to effectively assess dental composite adaptation and marginal defects when high resolution is desired in real time. LAY DESCRIPTION: Detection of tooth-colored restoration defects had been assessed by different radiographic methods. However, most of these methods are either invasive or suffer from low-resolution. In this study, a comparison has been carried out between two different high-resolution imaging systems; microcomputed tomography and optical coherence tomography, to explore their potentials in detecting restorations defects. The results showed optical coherence tomography has a great accuracy in locating the underlying defects when the obtained images were validated against confocal laser scanning microscopy images.

Calibration to Mitigate Near-Field Antennas Effects for a MIMO Radar Imaging System.

A calibration method for a high-resolution hybrid MIMO turntable radar imaging system is presented. A line of small metal spheres is employed as a test pattern in the calibration process to measure the position shift caused by undesired antenna effects. The unwanted effects in the antenna near-field responses are analysed, modelled and significantly mitigated based on the symmetry and differences in the responses of the MIMO configuration.