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.

Multidomain Modeling of Spatial Distributions of Tissue Optical Properties During Indentation: Mechanical Tissue Optical Clearing Devices as Diagnostic Tools

2011 ◽  
Author(s):  
William C. Vogt ◽  
Alondra Izquierdo-Roman ◽  
Christopher G. Rylander
Keyword(s):  
Near Infrared ◽  
Soft Tissues ◽  
Light Transmission ◽  
Index Of Refraction ◽  
Diagnostic Tools ◽  
Infrared Range ◽  
Water Displacement ◽  
Optical Clearing ◽  
Tissue Optical Clearing ◽  
Mechanical Tissue

Soft tissues are highly heterogeneous materials comprised of water, proteins, and many types of cells. This composite configuration results in a large mismatch in index of refraction between tissue constituents, creating a high-scattering medium in the visible and near-infrared range. “Tissue optical clearing” can increase light transmission through these tissues, potentially improving both optical diagnostic and therapeutic procedures [1]. Dehydration has been shown to be a mechanism of optical clearing, and previous work has investigated mechanical loading as a method of creating reversible localized water displacement in skin using novel mechanical tissue optical clearing devices (TOCDs) [2]. In addition to potentially enhancing established light-based procedures, the principles of TOCD operation may provide a platform for a novel diagnostic tool capable of utilizing many different measurement types simultaneously.

Mechanical tissue optical clearing technique increases imaging resolution and contrast through Ex vivo porcine skin

2011 ◽  
Vol 43 (8) ◽  
pp. 814-823 ◽  
Author(s):  
Alondra Izquierdo-Román ◽  
William C. Vogt ◽  
Leeanna Hyacinth ◽  
Christopher G. Rylander
Keyword(s):  
Ex Vivo ◽  
Porcine Skin ◽  
Optical Clearing ◽  
Clearing Technique ◽  
Imaging Resolution ◽  
Tissue Optical Clearing ◽  
Mechanical Tissue

Increased Light Transport in Skin Using Mechanical Compression

2009 ◽  
Author(s):  
Chris W. Drew ◽  
Alondra Izquierdo-Roman ◽  
Yajing Liu ◽  
Christopher G. Rylander
Keyword(s):  
Light Scattering ◽  
Structural Modification ◽  
Near Infrared ◽  
Morphological Structure ◽  
Light Transport ◽  
Optical Clearing ◽  
Treatment Techniques ◽  
Infrared Wavelengths ◽  
Tissue Optical Clearing ◽  
Highly Scattering Medium

The complex morphological structure of skin with its variations in the indices of refraction of components therein provides a highly scattering medium for visible and near-infrared wavelengths of light. “Tissue optical clearing” increases transmission of near-collimated light in biological tissue, potentially enabling improved optical analysis and treatment techniques. Numerous methods of tissue optical clearing have been hypothesized using hyperosmostic agents [1]. These methods propose reduction in light scattering by means of dehydration of tissue constituents, replacement of interstitial or intracellular water with higher refractive agents, or structural modification or dissociation of collagen fibers [2]. It has been suggested that dehydration of tissue constituents alone can reduce light scattering by expulsing water between collagen fibrils, increasing protein and sugar concentrations, and decreasing refractive index mismatch [3].

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.

ALTERATIONS IN AUTOFLUORESCENCE SIGNAL FROM RAT SKIN EX VIVO UNDER OPTICAL IMMERSION CLEARING

2010 ◽  
Vol 03 (03) ◽  
pp. 147-152 ◽  
Author(s):  
E. V. MIGACHEVA ◽  
A. B. PRAVDIN ◽  
V. V. TUCHIN
Keyword(s):  
Fluorescence Spectroscopy ◽  
Ex Vivo ◽  
Rat Skin ◽  
Optical Clearing ◽  
Spectral Curves ◽  
The Common ◽  
First Time ◽  
Tissue Optical Clearing ◽  
Optical Immersion

For the first time, the changes in autofluorescence spectra of ex vivo rat skin have been experimentally investigated using the combination of fluorescence spectroscopy and optical immersion clearing. The glucose, glycerol and propylene glycol solutions were used as clearing agents. The optical clearing was performed from the dermal side of skin imitating the in vivo injection of clearing agent under the dermal layers. In this contribution, the common properties of autofluorescence variation during optical immersion clearing were determined. The tendency of autofluorescence signal to decrease with reduction of scattering in tissue was noticed and discussed in detail. However, the differences in the shape of spectral curves under application of different clearing agents showed that optical clearing affects the autofluorescence properties of tissue differently depending on the type of clearing liquid. The results obtained are useful for the understanding of tissue optical clearing mechanisms and for improving techniques such as fluorescence spectroscopy.

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.

scholarly journals Mechanical tissue optical clearing devices: Enhancement of light penetration in ex vivo porcine skin and adipose tissue

2008 ◽  
Vol 40 (10) ◽  
pp. 688-694 ◽  
Author(s):  
Christopher G. Rylander ◽  
Thomas E. Milner ◽  
Stepan A. Baranov ◽  
J. Stuart Nelson
Keyword(s):  
Adipose Tissue ◽  
Ex Vivo ◽  
Light Penetration ◽  
Porcine Skin ◽  
Optical Clearing ◽  
Tissue Optical Clearing ◽  
Mechanical Tissue

scholarly journals Erratum: Mechanical tissue optical clearing technique increases imaging resolution and contrast through Ex vivo porcine skin

2011 ◽  
Vol 43 (10) ◽  
pp. 998-1007 ◽  
Author(s):  
Alondra Izquierdo-Román ◽  
William C. Vogt ◽  
Leeanna Hyacinth ◽  
Christopher G. Rylander
Keyword(s):  
Ex Vivo ◽  
Porcine Skin ◽  
Optical Clearing ◽  
Clearing Technique ◽  
Imaging Resolution ◽  
Tissue Optical Clearing ◽  
Mechanical Tissue

Adenosine Diphosphate (ADP)-Induced ⍺-Granules Release from Platelets of Native Whole Blood Is Reduced by Ticlopidine but Not by Aspirin or Dipyridamole

1986 ◽  
Vol 56 (02) ◽  
pp. 147-150 ◽  
Author(s):  
V Pengo ◽  
M Boschello ◽  
A Marzari ◽  
M Baca ◽  
L Schivazappa ◽  
...  
Keyword(s):  
Whole Blood ◽  
Light Transmission ◽  
Ex Vivo ◽  
Early Stage ◽  
Shape Change ◽  
Adenosine Diphosphate ◽  
Dose Dependent ◽  
Plateletderived Growth Factor ◽  
Platelet Shape

SummaryA brief contact between native whole blood and ADP promotes a dose-dependent release of platelet a-granules without a fall in the platelet number. We assessed the “ex vivo” effect of three widely used antiplatelet drugs, aspirin dipyridamole and ticlopidine, on this system. Aspirin (a single 800 mg dose) and dipyridamole (300 mg/die for four days) had no effect, while ticlopidine (500 mg/die for four days) significantly reduced the a-granules release for an ADP stimulation of 0.4 (p <0.02), 1.2 (p <0.01) and 2 pM (p <0.01). No drug, however, completeley inhibits this early stage of platelet activation. The platelet release of α-granules may be related to platelet shape change of the light transmission aggregometer and may be important “in vivo” by enhancing platelet adhesiveness and by liberating the plateletderived growth factor.

Brain Tumor Detection via Asymmetry Quantification across Mid Sagittal Plane

2020 ◽  
Vol 13 ◽  
Author(s):  
Shoaib Amin Banday ◽  
Mohammad Khalid Pandit
Keyword(s):  
Brain Tumor ◽  
Brain Tumors ◽  
Sagittal Plane ◽  
Early Stage ◽  
Imaging Techniques ◽  
Complex Structure ◽  
Magnetic Resonance Images ◽  
Absolute Difference ◽  
Brain Hemispheres ◽  
The Brain

Introduction: Brain tumor is among the major causes of morbidity and mortality rates worldwide. According to National Brain Tumor Foundation (NBTS), the death rate has nearly increased by as much as 300% over last couple of decades. Tumors can be categorized as benign (non-cancerous) and malignant (cancerous). The type of the brain tumor significantly depends on various factors like the site of its occurrence, its shape, the age of the subject etc. On the other hand, Computer Aided Detection (CAD) has been improving significantly in recent times. The concept, design and implementation of these systems ascend from fairly simple ones to computationally intense ones. For efficient and effective diagnosis and treatment plans in brain tumor studies, it is imperative that an abnormality is detected at an early stage as it provides a little more time for medical professionals to respond. The early detection of diseases has predominantly been possible because of medical imaging techniques developed from past many decades like CT, MRI, PET, SPECT, FMRI etc. The detection of brain tumors however, has always been a challenging task because of the complex structure of the brain, diverse tumor sizes and locations in the brain. Method: This paper proposes an algorithm that can detect the brain tumors in the presence of the Radio-Frequency (RF) inhomoginiety. The algorithm utilizes the Mid Sagittal Plane as a landmark point across which the asymmetry between the two brain hemispheres is estimated using various intensity and texture based parameters. Result: The results show the efficacy of the proposed method for the detection of the brain tumors with an acceptable detection rate. Conclusion: In this paper, we have calculated three textural features from the two hemispheres of the brain viz: Contrast (CON), Entropy (ENT) and Homogeneity (HOM) and three parameters viz: Root Mean Square Error (RMSE), Correlation Co-efficient (CC), and Integral of Absolute Difference (IAD) from the intensity distribution profiles of the two brain hemispheres to predict any presence of the pathology. First a Mid Sagittal Plane (MSP) is obtained on the Magnetic Resonance Images that virtually divides brain into two bilaterally symmetric hemispheres. The block wise texture asymmetry is estimated for these hemispheres using the above 6 parameters.

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