scholarly journals Biophotonics Modalities for High-Resolution Imaging of Microcirculatory Tissue Beds Using Endogenous Contrast: A Review on Present Scenario and Prospects

2011 ◽  
Vol 2011 ◽  
pp. 1-20 ◽  
Author(s):  
Hrebesh M. Subhash
Keyword(s):  
High Resolution ◽  
Optical Imaging ◽  
Perfusion Imaging ◽  
Imaging Techniques ◽  
Laser Speckle ◽  
Contrast Imaging ◽  
Endogenous Contrast ◽  
Contrast Mechanism ◽  
Recent Developments ◽  
Resolution Imaging

The microcirculation is a complex system, and the visualization of microcirculation has great significance in improving our understanding of pathophysiological processes in various disease conditions, in both clinical and fundamental studies. A range of techniques are available or emerging for investigating different aspect of the microcirculation in animals and humans. This paper reviews the recent developments in the field of high-resolution and high-sensitive optical imaging of microcirculatory tissue beds, emphasizing technologies that utilize the endogenous contrast mechanism. Optical imaging techniques such as intravital microscopy, Capillaroscopy, laser Doppler perfusion imaging, laser speckle perfusion imaging, polarization spectroscopy, photo-acoustic tomography, and various implementations of optical coherence tomography based on Doppler and speckle contrast imaging are presented together with their prospectives and challenges.

scholarly journals High-Resolution Optical Imaging and Sensing Using Quantum Emitters in Hexagonal Boron-Nitride

2021 ◽  
Vol 9 ◽  
Author(s):  
Carlo Bradac
Keyword(s):  
High Resolution ◽  
Boron Nitride ◽  
Optical Imaging ◽  
Hexagonal Boron Nitride ◽  
Imaging Techniques ◽  
Super Resolution ◽  
Sensing Applications ◽  
Resolution Imaging ◽  
Super Resolution Microscopy ◽  
Quantum Emitters

Super-resolution microscopy has allowed optical imaging to reach resolutions well beyond the limit imposed by the diffraction of light. The advancement of super-resolution techniques is often an application-driven endeavor. However, progress in material science plays a central role too, as it allows for the synthesis and engineering of nanomaterials with the unique chemical and physical properties required to realize super-resolution imaging strategies. This aspect is the focus of this review. We show that quantum emitters in two-dimensional hexagonal boron nitride are proving to be excellent candidate systems for the realization of advanced high-resolution imaging techniques, and spin-based quantum sensing applications.

Recent applications of TEM to the study of interfaces

1990 ◽  
Vol 48 (4) ◽  
pp. 308-309
Author(s):  
C. Barry Carter
Keyword(s):  
High Resolution ◽  
Sample Preparation ◽  
Grain Boundaries ◽  
Diffuse Scattering ◽  
Imaging Techniques ◽  
Amorphous Material ◽  
Contrast Imaging ◽  
Current State ◽  
Actual Nature ◽  
High Resolution Images

This paper will review the current state of understanding of interface structure and highlight some of the future needs and problems which must be overcome. The study of this subject can be separated into three different topics: 1) the fundamental electron microscopy aspects, 2) material-specific features of the study and 3) the characteristics of the particular interfaces. The two topics which are relevant to most studies are the choice of imaging techniques and sample preparation. The techniques used to study interfaces in the TEM include high-resolution imaging, conventional diffraction-contrast imaging, and phase-contrast imaging (Fresnel fringe images, diffuse scattering). The material studied affects not only the characteristics of the interfaces (through changes in bonding, etc.) but also the method used for sample preparation which may in turn have a significant affect on the resulting image. Finally, the actual nature and geometry of the interface must be considered. For example, it has become increasingly clear that the plane of the interface is particularly important whenever at least one of the adjoining grains is crystalline.A particularly productive approach to the study of interfaces is to combine different imaging techniques as illustrated in the study of grain boundaries in alumina. In this case, the conventional imaging approach showed that most grain boundaries in ion-thinned samples are grooved at the grain boundary although the extent of this grooving clearly depends on the crystallography of the surface. The use of diffuse scattering (from amorphous regions) gives invaluable information here since it can be used to confirm directly that surface grooving does occur and that the grooves can fill with amorphous material during sample preparation (see Fig. 1). Extensive use of image simulation has shown that, although information concerning the interface can be obtained from Fresnel-fringe images, the introduction of artifacts through sample preparation cannot be lightly ignored. The Fresnel-fringe simulation has been carried out using a commercial multislice program (TEMPAS) which was intended for simulation of high-resolution images.

scholarly journals Handheld versus mounted laser speckle contrast perfusion imaging demonstrated in psoriasis lesions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ata Chizari ◽  
Mirjam J. Schaap ◽  
Tom Knop ◽  
Yoeri E. Boink ◽  
Marieke M. B. Seyger ◽  
...  
Keyword(s):  
Perfusion Imaging ◽  
Laser Speckle ◽  
Psoriatic Skin ◽  
Post Processing ◽  
Speed Of Light ◽  
Contrast Imaging ◽  
Speckle Contrast ◽  
Frame Alignment ◽  
Wide Range ◽  
Perfusion Maps

AbstractEnabling handheld perfusion imaging would drastically improve the feasibility of perfusion imaging in clinical practice. Therefore, we examine the performance of handheld laser speckle contrast imaging (LSCI) measurements compared to mounted measurements, demonstrated in psoriatic skin. A pipeline is introduced to process, analyze and compare data of 11 measurement pairs (mounted-handheld LSCI modes) operated on 5 patients and various skin locations. The on-surface speeds (i.e. speed of light beam movements on the surface) are quantified employing mean separation (MS) segmentation and enhanced correlation coefficient maximization (ECC). The average on-surface speeds are found to be 8.5 times greater in handheld mode compared to mounted mode. Frame alignment sharpens temporally averaged perfusion maps, especially in the handheld case. The results show that after proper post-processing, the handheld measurements are in agreement with the corresponding mounted measurements on a visual basis. The absolute movement-induced difference between mounted-handheld pairs after the background correction is $$16.4\pm 9.3~\%$$ 16.4 ± 9.3 % (mean ± std, $$n=11$$ n = 11 ), with an absolute median difference of $$23.8\%$$ 23.8 % . Realization of handheld LSCI facilitates measurements on a wide range of skin areas bringing more convenience for both patients and medical staff.

Use of ultrasound in psoriatic arthritis

2018 ◽  
Author(s):  
Gurjit S. Kaeley
Keyword(s):  
Psoriatic Arthritis ◽  
High Resolution ◽  
Imaging Techniques ◽  
Joint Disease ◽  
Joint Involvement ◽  
Close Link ◽  
Clinical Appearance ◽  
Axial Disease ◽  
Resolution Imaging ◽  
Outcome Tool

Psoriatic arthritis (PsA) is much more than just joint disease. Although previous clinical classifications have categorized by pattern of joint involvement and axial disease, imaging techniques such as MRI and ultrasound have demonstrated that not only are many more joints involved but also a wide variety of adjoining tissues. The concept of enthesitis is evolving and high resolution imaging studies are demonstrating involvement of tissues beyond just the enthesis. Many investigators have chosen to use sonographic entheseal systems designed for Spondyloarthritis in general which may not be appropriate and may lead to excess confounding by obesity. Inclusion of entheses that seem more relevant to PsA may improve the validity and specificity of the sonographic outcome tool. Nail affliction is associated with PsA, as well as enthesitis. Sonography is able to demonstrate the nail apparatus. More recent pathoanatomic findings may help explain the close link with enthesitis. Synovitis in PsA is often involved with inflammation and alteration of neighbouring structures such as the extensor tendons, palmar or plantar plates. Some investigators have proposed that inflammation in PsA may start at the entheseal sites and then spread to the joint. Dactylitis epitomizes the concept of multiple tissues involved in the digit giving rise to the clinical appearance of a uniformly swollen digit. Sonography can image many of these tissues in high resolution and offer insights into the pathophysiology of dactylitis.

scholarly journals Surface cleaning and sample carrier for complementary high-resolution imaging techniques

2020 ◽  
Vol 15 (2) ◽  
pp. 021005
Author(s):  
Pietro Benettoni ◽  
Jia-Yu Ye ◽  
Timothy R. Holbrook ◽  
Federica Calabrese ◽  
Stephan Wagner ◽  
...  
Keyword(s):  
High Resolution ◽  
Imaging Techniques ◽  
Surface Cleaning ◽  
High Resolution Imaging ◽  
Resolution Imaging ◽  
Sample Carrier

scholarly journals Ghost imaging with electron microscopy inspired, non-orthogonal phase masks

2021 ◽  
Author(s):  
Akhil Kallepalli ◽  
Daan Stellinga ◽  
Ming-Jie Sun ◽  
Richard Bowman ◽  
Enzo Rotunno ◽  
...  
Keyword(s):  
High Resolution ◽  
Imaging Techniques ◽  
High Energy ◽  
Reconstruction Method ◽  
Ghost Imaging ◽  
Light Modulator ◽  
Transmission Electron ◽  
Resolution Imaging ◽  
Electron Microscopes ◽  
Energy Processes

Abstract Transmission electron microscopes (TEM) achieve high resolution imaging by raster scanning a focused beam of electrons over the sample and measuring the transmission to form an image. While a TEM can achieve a much higher resolution than optical microscopes, they face challenges of damage to samples during the high energy processes involved. Here, we explore the possibility of applying computational ghost imaging techniques adapted from the optical regime to reduce the total, required illumination intensity. The technological lack of the equivalent high-resolution, optical spatial light modulator for electrons means that a different approach needs to be pursued. Using the optical equivalent, we show that a simple six-needle charged device to modulate the illuminating beam, alongside a novel reconstruction method to handle the resulting highly non-orthogonal patterns, is capable of producing images comparable in quality to a raster-scanned approach with much lower peak intensity.

scholarly journals Novel imaging techniques to study postmortem human fetal anatomy: a systematic review on microfocus-CT and ultra-high-field MRI

2019 ◽  
Vol 30 (4) ◽  
pp. 2280-2292 ◽  
Author(s):  
Y. Dawood ◽  
G. J. Strijkers ◽  
J. Limpens ◽  
R. J. Oostra ◽  
B. S. de Bakker
Keyword(s):  
High Resolution ◽  
Best Practices ◽  
High Field ◽  
Imaging Techniques ◽  
Specimen Preparation ◽  
High Resolution Imaging ◽  
Micro Ct ◽  
Ultra High Field ◽  
Scanning Time ◽  
Resolution Imaging

Abstract Background MRI and CT have been extensively used to study fetal anatomy for research and diagnostic purposes, enabling minimally invasive autopsy and giving insight in human fetal development. Novel (contrast-enhanced) microfocus CT (micro-CT) and ultra-high-field (≥ 7.0 T) MRI (UHF-MRI) techniques now enable micron-level resolution that combats the disadvantages of low-field MRI and conventional CT. Thereby, they might be suitable to study fetal anatomy in high detail and, in time, contribute to the postmortem diagnosis of fetal conditions. Objectives (1) To systematically examine the usability of micro-CT and UHF-MRI to study postmortem human fetal anatomy, and (2) to analyze factors that govern success at each step of the specimen preparation and imaging. Method MEDLINE and EMBASE were systematically searched to identify publications on fetal imaging by micro-CT or UHF-MRI. Scanning protocols were summarized and best practices concerning specimen preparation and imaging were enumerated. Results Thirty-two publications reporting on micro-CT and UHF-MRI were included. The majority of the publications focused on imaging organs separately and seven publications focused on whole body imaging, demonstrating the possibility of visualization of small anatomical structures with a resolution well below 100 μm. When imaging soft tissues by micro-CT, the fetus should be stained by immersion in Lugol’s staining solution. Conclusion Micro-CT and UHF-MRI are both excellent imaging techniques to provide detailed images of gross anatomy of human fetuses. The present study offers an overview of the current best practices when using micro-CT and/or UHF-MRI to study fetal anatomy for clinical and research purposes. Key Points • Micro-CT and UHF-MRI can both be used to study postmortem human fetal anatomy for clinical and research purposes. • Micro-CT enables high-resolution imaging of fetal specimens in relatively short scanning time. However, tissue staining using a contrast solution is necessary to enable soft-tissue visualization. • UHF-MRI enables high-resolution imaging of fetal specimens, without the necessity of prior staining, but with the drawback of long scanning time.

Sign in / Sign up

Export Citation Format

Share Document