scholarly journals Toward Better Medical Diagnosis: Tissue Optical Clearing

2020 ◽  
Vol 2 (1) ◽  
pp. 13-21
Author(s):  
Omnia Hamdy ◽  
Rania M. Abdelazeem
Keyword(s):  
Refractive Index ◽  
Medical Diagnosis ◽  
Imaging Techniques ◽  
High Refractive Index ◽  
Biological Tissues ◽  
Optical Clearing ◽  
Research Areas ◽  
Body Tissues ◽  
Deep Imaging ◽  
Tissue Optical Clearing

Reaching efficient, safe and painless medical diagnosis procedure is a very valued goal for many research areas. Despite the great advantages of using optical imaging techniques in medical diagnosis including high safety and relative simplicity, it still suffers from relatively low resolution and penetration depth in the multiple scattering mediums such as biological tissues. Therefore, researchers began to devise ways to reduce the scattering properties of the tissue, hence increasing the imaging contrast. Optical clearing concept is introduced to do this job. This technique can reduce tissues scattering properties by using high refractive index chemicals, thus making the tissue transparent by equalizing the refractive index through that medium. In this paper, theory and techniques of optical clearing method are illustrated utilizing its benefits for deep imaging of different body tissues and organs.

Tissue Optical Clearing Devices: Effects of Water Content on the Hyperelastic Mechanical Properties of Ex Vivo Porcine Skin

2010 ◽  
Author(s):  
William Vogt ◽  
Alondra Izquierdo-Roman ◽  
Christopher G. Rylander
Keyword(s):  
Near Infrared ◽  
Light Transmission ◽  
Ex Vivo ◽  
Imaging Techniques ◽  
Complex Structure ◽  
Heterogeneous Material ◽  
Index Of Refraction ◽  
Water Displacement ◽  
Optical Clearing ◽  
Tissue Optical Clearing

Skin is a highly anisotropic and heterogeneous material composed of water, proteins, and various cells arranged in several different layers. Because of this complex structure, there is a large mismatch in index of refraction between the tissue constituents, creating a highly scattering medium for near-infrared and visible light. “Tissue optical clearing” methods can improve light transmission through tissues, potentially improving optical imaging techniques and photoirradiative treatments [1]. Dehydration has been suggested as a possible mechanism of optical clearing [2], and previous work has demonstrated mechanical loading as a method of creating reversible localized water displacement in skin using novel tissue optical clearing devices (TOCDs) [3–4]. These TOCDs were hypothesized to increase light transmission by displacing water locally in the tissue, causing local dehydration. A model of the mechanical behavior of skin will enable improvement of current TOCDs that utilize local mechanical compression.

QUANTITATIVE CONTROL OF OPTICAL CLEARING EFFECTS STUDIED WITH TISSUE-LIKE PHANTOM

2010 ◽  
Vol 03 (03) ◽  
pp. 195-202 ◽  
Author(s):  
JINGYING JIANG ◽  
WEI CHEN ◽  
QILIANG GONG ◽  
KEXIN XU
Keyword(s):  
Optical Properties ◽  
Biological Tissues ◽  
Porcine Skin ◽  
Tissue Samples ◽  
Optical Clearing ◽  
Tissue Optical Properties ◽  
Application Potential ◽  
The Difference ◽  
Tissue Optical Clearing

Tissue optical clearing by use of optical clearing agents (OCAs) has been proven to have potential to reduce the highly scattering effect of biological tissues in optical techniques. However, the difference in tissue samples could lead to unreliable results, making it difficult to quantitatively control the dose of OCAs during the course of tissue optical clearing. In this work, in order to study the effects of optical clearing, we customized tissue-like phantoms with optical properties of some biological tissue. Diffuse reflectance and total transmittance of tissue-like phantoms with different OCAs (DMSO or glycerol) and porcine skin tissues were measured. Then optical property parameters were calculated by inverse adding-doubling (IAD) algorithm. Results showed that OCAs could lead to a reduction in scattering of tissue-like phantoms as it did to porcine skin tissue in vitro. Furthermore, a series of relational expressions could be fit to quantitatively describe the relationship between the doses of OCAs and the reduction of scattering effects. Therefore, proper tissue-like phantom could facilitate optical clearing to be used in quantitative control of tissue optical properties, and further promote the application potential of optical clearing to light-based noninvasive diagnostic and therapeutic techniques.

scholarly journals PARAMETRIC STUDY OF TISSUE OPTICAL CLEARING BY LOCALIZED MECHANICAL COMPRESSION USING COMBINED FINITE ELEMENT AND MONTE CARLO SIMULATION

2010 ◽  
Vol 03 (03) ◽  
pp. 203-211 ◽  
Author(s):  
WILLIAM C. VOGT ◽  
HAIOU SHEN ◽  
GE WANG ◽  
CHRISTOPHER G. RYLANDER
Keyword(s):  
Finite Element ◽  
Monte Carlo ◽  
Optical Properties ◽  
Light Transmission ◽  
Compressive Strain ◽  
Monte Carlo Model ◽  
Biological Tissues ◽  
Optical Clearing ◽  
Tissue Optical Properties ◽  
Tissue Optical Clearing

Tissue Optical Clearing Devices (TOCDs) have been shown to increase light transmission through mechanically compressed regions of naturally turbid biological tissues. We hypothesize that zones of high compressive strain induced by TOCD pins produce localized water displacement and reversible changes in tissue optical properties. In this paper, we demonstrate a novel combined mechanical finite element model and optical Monte Carlo model which simulates TOCD pin compression of an ex vivo porcine skin sample and modified spatial photon fluence distributions within the tissue. Results of this simulation qualitatively suggest that light transmission through the skin can be significantly affected by changes in compressed tissue geometry as well as concurrent changes in tissue optical properties. The development of a comprehensive multi-domain model of TOCD application to tissues such as skin could ultimately be used as a framework for optimizing future design of TOCDs.

scholarly journals Improved clearing method contributes to deep imaging of plant organs

2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Yuki Sakamoto ◽  
Anna Ishimoto ◽  
Yuuki Sakai ◽  
Moeko Sato ◽  
Ryuichi Nishihama ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Refractive Index ◽  
Fluorescent Proteins ◽  
High Refractive Index ◽  
Marchantia Polymorpha ◽  
Plant Tissues ◽  
Fluorescent Signal ◽  
Deep Imaging ◽  
Gfp Fluorescence ◽  
Clearing Method

AbstractTissue clearing methods are increasingly essential for the microscopic observation of internal tissues of thick biological organs. We previously developed TOMEI, a clearing method for plant tissues; however, it could not entirely remove chlorophylls nor reduce the fluorescent signal of fluorescent proteins. Here, we developed an improved TOMEI method (iTOMEI) to overcome these limitations. First, a caprylyl sulfobetaine was determined to efficiently remove chlorophylls from Arabidopsis thaliana seedlings without GFP quenching. Next, a weak alkaline solution restored GFP fluorescence, which was mainly lost during fixation, and an iohexol solution with a high refractive index increased sample transparency. These procedures were integrated to form iTOMEI. iTOMEI enables the detection of much brighter fluorescence than previous methods in tissues of A. thaliana, Oryza sativa, and Marchantia polymorpha. Moreover, a mouse brain was also efficiently cleared by the iTOMEI-Brain method within 48 h, and strong fluorescent signals were detected in the cleared brain.

scholarly journals Tissue Optical Clearing in the Ultraviolet for Clinical Use in Dentistry to Optimize the Treatment of Chronic Recurrent Aphthous Stomatitis

2020 ◽  
pp. 040301
Author(s):  
Alexey A. Selifonov ◽  
Valery V. Tuchin
Keyword(s):  
Uv Spectroscopy ◽  
Biological Tissues ◽  
Recurrent Aphthous Stomatitis ◽  
Glycerol Solution ◽  
Strong Light ◽  
Optical Clearing ◽  
Index Matching ◽  
Refractive Index Matching ◽  
Tissue Optical Clearing ◽  
Uv Range

The immersion optical clearing (OC) treatment with a highly concentrated glycerol solution has induced three new tissue windows in the UV spectral range of gingival tissues – from 200 to 250 nm, from 250 to 300 nm and from 300 to 400 nm. By combining the immersion OC technique in human tissues with UV-spectroscopy, it was possible to verify and study the major OC mechanisms – tissue dehydration and refractive index matching, and that the OC efficiency is higher in the deep-UV than in the visible-NIR range. Since all biological tissues present high scattering in the UV range, the presented technology, which basically reduces the strong light scattering in the UV range, has a broad application area in medicine. The effectiveness of the developed technology combining UV phototherapy and OC in application to treatment of aphthous recurrent stomatitis in children was demonstrated.

scholarly journals Multiscale label-free volumetric holographic histopathology of thick-tissue slides with subcellular resolution

2020 ◽  
Author(s):  
Herve Hugonnet ◽  
Yeon Wook Kim ◽  
Moosung Lee ◽  
Seungwoo Shin ◽  
Ralph H. Hruban ◽  
...  
Keyword(s):  
Refractive Index ◽  
Present Method ◽  
Imaging Techniques ◽  
Numerical Algorithms ◽  
Biological Tissues ◽  
Phase Imaging ◽  
Label Free ◽  
Volumetric Imaging ◽  
Optical Modes ◽  
Volumetric Reconstruction

ABSTRACTHistopathology relies upon the staining and sectioning of biological tissues, which can be laborious and may cause artefacts and distort tissues. Here, we demonstrate label-free volumetric imaging of thick-tissue slides, exploiting refractive index distributions as intrinsic imaging contrast. The present method systematically exploits label-free quantitative phase imaging techniques, volumetric reconstruction of intrinsic refractive index distributions in tissues, and numerical algorithms for the seamless stitching of multiple 3D tomograms and for reducing scattering-induced image distortion. We demonstrate demonstrated label-free volumetric imaging of thick tissues with the field of view of 2 mm × 1.75 mm × 0.2 mm with a spatial resolution of 170 nm × 170 nm × 1200 nm. The number of optical modes, calculated as the reconstructed volume divided by the size of the point spread function, was approximately 20 Giga voxels. We have also demonstrated that different tumour types, and a variety of precursor lesions and pathologies can be visualized with the present method.Abstract Figure

Coupled Poroviscoelastic and Optical Monte Carlo Simulation of Dynamic Light Transport Through Indented Soft Tissue

2013 ◽  
Author(s):  
William C. Vogt ◽  
Christopher G. Rylander
Keyword(s):  
Refractive Index ◽  
Water Distribution ◽  
Biological Tissues ◽  
Light Transport ◽  
Mathematical Framework ◽  
Interstitial Fluid Flow ◽  
Tissue Water ◽  
Porous Flow ◽  
Optical Clearing ◽  
Tissue Optical Properties

Biological tissues are heterogeneous materials that may be considered mixtures of water, proteins, and cells. The large mismatch in refractive index between these constituents causes tissues to be highly turbid, diffusing light and limiting the efficacy of optical diagnostic and therapeutic techniques [1]. Mechanical optical clearing is a technique for reducing tissue scattering and absorption using controlled tissue deformation. Mechanical optical clearing is performed using indentation to locally modify tissue optical properties, including refractive index [2] and reduced scattering coefficient [3]. This effect is attributed to transient changes in tissue water distribution as a result of interstitial fluid flow due to tissue compression. In this study, we have developed a multi-domain mathematical framework for simulating mechanical optical clearing effects on tissue mechanical and optical behavior, including hyperelasticity, viscoelasticity, porous flow, and light transport. This model was then fitted to mechanical force data and used to predict experimentally measured optical transmission.

Multipath Artifact Corrections in Ultrasonic Transmission Tomography

1982 ◽  
Vol 4 (3) ◽  
pp. 234-266 ◽  
Author(s):  
C. R. Crawford ◽  
A. C. Kak
Keyword(s):  
Refractive Index ◽  
Attenuation Coefficient ◽  
Arrival Time ◽  
Imaging Techniques ◽  
Biological Tissues ◽  
Median Filtering ◽  
Transmission Tomography ◽  
Cross Sectional ◽  
Tissue Equivalent

This paper deals with computed imaging techniques for ultrasonic transmission tomography. Cross-sectional images of the refractive index in soft biological tissues can be obtained by measuring the arrival-time of signals that propagate between two transducers. An alternative method to obtain images is to measure the attenuation in the path between the pair of transducers. In practice, images of the refractive index exhibit a better quality than images of the attenuation coefficient. In this report we have shown through computer simulation that some of the degradations in images of the attenuation coefficient are due to the existence of multiple rays that link the transmitting and the receiving transducers. This condition is known as multipath. We have demonstrated two methods to reduce the influence of multipath on reconstructions of the attenuation coefficient. The first method employs homomorphic signal processing to estimate the attenuation coefficient for one of the linking rays. The second method applies median filtering in the projection space to remove the artifacts caused by multipath. The correction techniques were tested on data obtained by scanning tissue equivalent phantoms. Results obtained indicate that the correction methods significantly improve the quality of images of the attenuation coefficient.

Numerical Ray Tracing in Media Involving Continuous and Discrete Refractive Boundaries

1980 ◽  
Vol 2 (4) ◽  
pp. 291-301 ◽  
Author(s):  
A.M. Smith ◽  
M. Goldberg ◽  
E.S.K. Liu
Keyword(s):  
Refractive Index ◽  
Medical Imaging ◽  
Boundary Conditions ◽  
Ray Tracing ◽  
Imaging Techniques ◽  
Biological Tissues ◽  
Inhomogeneous Media ◽  
Simulation Program ◽  
Digital Methods

Attempts to improve the performance of ultrasonic medical imaging techniques have led to an interest in digital methods for tracing rays through inhomogeneous media. Biological tissues involve both continuously varying and discrete refractive index boundaries. A ray tracing technique applicable for both cases is described. The performance of a simulation program is illustrated and discussed for a variety of boundary conditions.

scholarly journals ASSESSMENT OF TISSUE OPTICAL CLEARING AS A FUNCTION OF GLUCOSE CONCENTRATION USING OPTICAL COHERENCE TOMOGRAPHY

2010 ◽  
Vol 03 (03) ◽  
pp. 169-176 ◽  
Author(s):  
NARENDRAN SUDHEENDRAN ◽  
MOHAMED MOHAMED ◽  
MOHAMAD G. GHOSN ◽  
VALERY V. TUCHIN ◽  
KIRILL V. LARIN
Keyword(s):  
Optical Coherence Tomography ◽  
Glucose Concentration ◽  
Glucose Solution ◽  
Tissue Sample ◽  
Biological Tissues ◽  
Optical Coherence ◽  
Porcine Skin ◽  
Optical Clearing ◽  
Reflected Light ◽  
Tissue Optical Clearing

One of the major challenges in imaging biological tissues using optical techniques, such as optical coherence tomography (OCT), is the lack of light penetration due to highly turbid structures within the tissue. Optical clearing techniques enable the biological samples to be more optically homogeneous, allowing for deeper penetration of light into the tissue. This study investigates the effect of optical clearing utilizing various concentrations of glucose solution (10%, 30%, and 50%) on porcine skin. A gold-plated mirror was imaged beneath the tissue and percentage clearing was determined by monitoring the change in reflected light intensity from the mirror over time. The ratio of percentage clearing per tissue thickness for 10%, 30% and 50% glucose was determined to be 4.7 ±1.6% mm-1 (n = 6), 10.6 ±2.0% mm-1 (n = 7) and 21.8 ±2.2% mm-1 (n = 5), respectively. It was concluded that while higher glucose concentration has the highest optical clearing effect, a suitable concentration should be chosen for the purpose of clearing, considering the osmotic stress on the tissue sample.

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