scholarly journals Determining elastic properties of skin by measuring surface waves from an impulse mechanical stimulus using phase-sensitive optical coherence tomography

2011 ◽  
Vol 9 (70) ◽  
pp. 831-841 ◽  
Author(s):  
Chunhui Li ◽  
Guangying Guan ◽  
Roberto Reif ◽  
Zhihong Huang ◽  
Ruikang K. Wang
Keyword(s):  
Mechanical Properties ◽  
Optical Coherence Tomography ◽  
Surface Wave ◽  
Surface Waves ◽  
Disease Diagnosis ◽  
Optical Coherence ◽  
Measuring Surface ◽  
Phase Velocity Dispersion ◽  
Phase Sensitive

The mechanical properties of skin are important tissue parameters that are useful for understanding skin patho-physiology, which can aid disease diagnosis and treatment. This paper presents an innovative method that employs phase-sensitive spectral-domain optical coherence tomography (PhS-OCT) to characterize the biomechanical properties of skin by measuring surface waves induced by short impulses from a home-made shaker. Experiments are carried out on single and double-layer agar–agar phantoms, of different concentrations and thickness, and on in vivo human skin, at the forearm and the palm. For each experiment, the surface wave phase-velocity dispersion curves were calculated, from which the elasticity of each layer of the sample was determined. It is demonstrated that the experimental results agree well with previous work. This study provides a novel combination of PhS-OCT technology with a simple and an inexpensive mechanical impulse surface wave stimulation that can be used to non-invasively evaluate the mechanical properties of skin in vivo , and may offer potential use in clinical situations.

APPLICATION OF DOPPLER OPTICAL COHERENCE TOMOGRAPHY IN RHEOLOGICAL STUDIES: BLOOD FLOW AND VESSELS MECHANICAL PROPERTIES EVALUATION

2009 ◽  
Vol 02 (04) ◽  
pp. 431-440 ◽  
Author(s):  
MARCO BONESI ◽  
ANEURIN J. KENNERLEY ◽  
IGOR MEGLINSKI ◽  
STEPHEN MATCHER
Keyword(s):  
Mechanical Properties ◽  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Early Stage ◽  
Diagnostic Technique ◽  
Feasibility Studies ◽  
Optical Coherence ◽  
Blood Flow Dynamics ◽  
Doppler Optical Coherence Tomography

Doppler Optical Coherence Tomography (DOCT) is a noninvasive optical diagnostic technique, which is well suited for the quantitative mapping of microflow velocity profiles and the analysis of flow-vessel interactions. The noninvasive imaging and quantitative analysis of blood flow in the complex-structured vascular bed is required in many biomedical applications, including those where the determination of mechanical properties of vessels or the knowledge of the mechanic interactions between the flow and the housing medium plays a key role. The change of microvessel wall elasticity could be a potential indicator of cardiovascular disease at the very early stage, whilst monitoring the blood flow dynamics and associated temporal and spatial variations in vessel's wall shear stress could help predicting the possible rupture of atherosclerotic plaques. The results of feasibility studies of application of DOCT for the evaluation of mechanical properties of elastic vessel model are presented. The technique has also been applied for imaging of sub-cranial rat blood flow in vivo.

scholarly journals OCT2Hist: Non-Invasive Virtual Biopsy Using Optical Coherence Tomography

2021 ◽  
Author(s):  
Yonatan Winetraub ◽  
Edwin Yuan ◽  
Itamar Terem ◽  
Caroline Yu ◽  
Warren Chan ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Ground Truth ◽  
Disease Diagnosis ◽  
Optical Coherence ◽  
Label Free ◽  
Generative Adversarial Network ◽  
Non Invasive ◽  
Adversarial Network ◽  
Trained Neural Network

Histological haematoxylin and eosin–stained (H&E) tissue sections are used as the gold standard for pathologic detection of cancer, tumour margin detection, and disease diagnosis1. Producing H&E sections, however, is invasive and time-consuming. Non-invasive optical imaging modalities, such as optical coherence tomography (OCT), permit label-free, micron-scale 3D imaging of biological tissue microstructure with significant depth (up to 1mm) and large fields-of-view2, but are difficult to interpret and correlate with clinical ground truth without specialized training3. Here we introduce the concept of a virtual biopsy, using generative neural networks to synthesize virtual H&E sections from OCT images. To do so we have developed a novel technique, “optical barcoding”, which has allowed us to repeatedly extract the 2D OCT slice from a 3D OCT volume that corresponds to a given H&E tissue section, with very high alignment precision down to 25 microns. Using 1,005 prospectively collected human skin sections from Mohs surgery operations of 71 patients, we constructed the largest dataset of H&E images and their corresponding precisely aligned OCT images, and trained a conditional generative adversarial network4 on these image pairs. Our results demonstrate the ability to use OCT images to generate high-fidelity virtual H&E sections and entire 3D H&E volumes. Applying this trained neural network to in vivo OCT images should enable physicians to readily incorporate OCT imaging into their clinical practice, reducing the number of unnecessary biopsy procedures.

scholarly journals In vivo characterization of chick embryo mesoderm by optical coherence tomography assisted microindentation

2020 ◽  
Author(s):  
Marica Marrese ◽  
Nelda Antonovaité ◽  
Ben K.A. Nelemans ◽  
Ariana Ahmadzada ◽  
Davide Iannuzzi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Optical Coherence Tomography ◽  
Storage Modulus ◽  
Biological Tissues ◽  
Surrounding Tissue ◽  
Optical Coherence ◽  
Presomitic Mesoderm ◽  
New Instrument

AbstractEmbryos are growing organisms with highly heterogeneous properties in space and time. Understanding the mechanical properties is a crucial prerequisite for the investigation of morphogenesis. During the last ten years, new techniques have been developed to evaluate the mechanical properties of biological tissues in vivo. To address this need, we employed a new instrument that, via the combination of micro-indentation with Optical Coherence Tomography (OCT), allows us to determine both, the spatial distribution of mechanical properties of chick embryos and the structural changes in real-time provided by OCT. We report here the stiffness measurements on live chicken mesoderm during somite formation, from the mesenchymal tailbud to the epithelialized somites. The storage modulus of the mesoderm increases from (176±18) Pa in the tail up to (716±117) Pa in the somitic region. The midline has a storage modulus of (947±111) Pa in the caudal presomitic mesoderm, indicating a stiff rod along the body axis, which thereby mechanically supports the surrounding tissue. The difference in stiffness between midline and presomitic mesoderm decreases as the mesoderm forms somites. The viscoelastic response of the somites develops further until somite IV, which is commensurate with the slow process of epithelization of somites between S0 and SIV.Overall, this study provides an efficient method for the biomechanical characterization of soft biological tissues in vivo and shows that the mechanical properties strongly relate to different morphological features of the investigated regions.

258: Diagnosis and Intraoperative Staging of Bladder Disease by in-vivo Optical Coherence Tomography (OCT)

2004 ◽  
Vol 171 (4S) ◽  
pp. 68-68 ◽  
Author(s):  
Markus D. Sachs ◽  
Dmitry Daniltchenko ◽  
Eva Lankenau ◽  
Frank Koenig ◽  
Gerion Huettmann ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence ◽  
Bladder Disease

scholarly journals Evaluating Retinal and Choroidal Perfusion Changes after Isometric and Dynamic Activity Using Optical Coherence Tomography Angiography

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 808
Author(s):  
Max Philipp Brinkmann ◽  
Nikolas Xavier Kibele ◽  
Michelle Prasuhn ◽  
Vinodh Kakkassery ◽  
Mario Damiano Toro ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Isometric Exercise ◽  
Dynamic Exercise ◽  
Exercise Heart Rate ◽  
Optical Coherence ◽  
Dynamic Activity ◽  
Capillary Plexus ◽  
Choroidal Perfusion

Optical coherence tomography angiography (OCTA) is a non-invasive tool for imaging and quantifying the retinal and choroidal perfusion state in vivo. This study aimed to evaluate the acute effects of isometric and dynamic exercise on retinal and choroidal sublayer perfusion using OCTA. A pilot study was conducted on young, healthy participants, each of whom performed a specific isometric exercise on the first day and a dynamic exercise the day after. At baseline and immediately after the exercise, heart rate (HR), mean arterial pressure (MAP), superficial capillary plexus perfusion (SCPP), deep capillary plexus perfusion (DCPP), choriocapillaris perfusion (CCP), Sattlers’s layer perfusion (SLP), and Haller’s layer perfusion (HLP) were recorded. A total of 34 eyes of 34 subjects with a mean age of 32.35 ± 7.87 years were included. HR as well as MAP increased significantly after both types of exercise. Both SCPP and DCPP did not show any significant alteration due to isometric or dynamic exercise. After performing dynamic exercise, CCP, SLP, as well as HLP significantly increased. Changes in MAP correlated significantly with changes in HLP after the dynamic activity. OCTA-based analysis in healthy adults following physical activity demonstrated a constant retinal perfusion, supporting the theory of autoregulatory mechanisms. Dynamic exercise, as opposed to isometric activity, significantly changed choroidal perfusion. OCTA imaging may represent a novel and sensitive tool to expand the diagnostic spectrum in the field of sports medicine.

scholarly journals Quantitative Swept-Source Optical Coherence Tomography of Early Enamel Erosion in vivo

2017 ◽  
Vol 51 (4) ◽  
pp. 410-418 ◽  
Author(s):  
Rupert S. Austin ◽  
Maisalamah Haji Taha ◽  
Frederic Festy ◽  
Richard Cook ◽  
Manoharan Andiappan ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Healthy Volunteers ◽  
Orange Juice ◽  
Signal Intensity ◽  
Surface States ◽  
Enamel Surface ◽  
Optical Coherence ◽  
Swept Source ◽  
Water Rinsing

Swept-source optical coherence tomography (SS-OCT) shows potential for the in vivo quantitative evaluation of micro-structural enamel surface phenomena occurring during early erosive demineralization. This randomized controlled single-blind cross-over clinical study aimed to evaluate the use of SS-OCT for detecting optical changes in the enamel of 30 healthy volunteers subjected to orange juice rinsing (erosive challenge) in comparison to mineral water rinsing (control), according to wiped and non-wiped enamel surface states. Participants were randomly allocated to 60 min of orange juice rinsing (pH 3.8) followed by 60 min of water rinsing (pH 6.7) and vice versa, with a 2-week wash-out period. In addition, the labial surfaces of the right or left maxillary incisors were wiped prior to SS-OCT imaging. An automated ImageJ algorithm was designed to analyse the back-scattered OCT signal intensity (D) after orange juice rinsing compared to after water rinsing. D was quantified as the OCT signal scattering from the 33 µm sub-surface enamel, normalised by the total OCT signal intensity entering the enamel. The back-scattered OCT signal intensity increased by 3.1% (95% CI 1.1-5.1%) in the wiped incisors and by 3.5% (95% CI 1.5-5.5%) in the unwiped incisors (p < 0.0001). Wiping reduced the back-scattered OCT signal intensity by 1.7% (95% CI -3.2 to -0.3%; p = 0.02) in comparison to the unwiped enamel surfaces for both rinsing solutions (p = 0.2). SS-OCT detected OCT signal changes in the superficial sub-surface enamel of maxillary central incisor teeth of healthy volunteers after orange juice rinsing.

In vivo cellular optical coherence tomography imaging

1998 ◽  
Vol 4 (7) ◽  
pp. 861-865 ◽  
Author(s):  
Stephan A. Boppart ◽  
Brett E. Bouma ◽  
Costas Pitris ◽  
James F. Southern ◽  
Mark E. Brezinski ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence ◽  
Tomography Imaging ◽  
Optical Coherence Tomography Imaging

scholarly journals Optimization of X-ray Investigations in Dentistry Using Optical Coherence Tomography

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4554
Author(s):  
Ralph-Alexandru Erdelyi ◽  
Virgil-Florin Duma ◽  
Cosmin Sinescu ◽  
George Mihai Dobre ◽  
Adrian Bradu ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Radiation Dose ◽  
Imaging Techniques ◽  
Image Resolution ◽  
Optical Coherence ◽  
X Rays ◽  
High Quality ◽  
X Ray

The most common imaging technique for dental diagnoses and treatment monitoring is X-ray imaging, which evolved from the first intraoral radiographs to high-quality three-dimensional (3D) Cone Beam Computed Tomography (CBCT). Other imaging techniques have shown potential, such as Optical Coherence Tomography (OCT). We have recently reported on the boundaries of these two types of techniques, regarding. the dental fields where each one is more appropriate or where they should be both used. The aim of the present study is to explore the unique capabilities of the OCT technique to optimize X-ray units imaging (i.e., in terms of image resolution, radiation dose, or contrast). Two types of commercially available and widely used X-ray units are considered. To adjust their parameters, a protocol is developed to employ OCT images of dental conditions that are documented on high (i.e., less than 10 μm) resolution OCT images (both B-scans/cross sections and 3D reconstructions) but are hardly identified on the 200 to 75 μm resolution panoramic or CBCT radiographs. The optimized calibration of the X-ray unit includes choosing appropriate values for the anode voltage and current intensity of the X-ray tube, as well as the patient’s positioning, in order to reach the highest possible X-rays resolution at a radiation dose that is safe for the patient. The optimization protocol is developed in vitro on OCT images of extracted teeth and is further applied in vivo for each type of dental investigation. Optimized radiographic results are compared with un-optimized previously performed radiographs. Also, we show that OCT can permit a rigorous comparison between two (types of) X-ray units. In conclusion, high-quality dental images are possible using low radiation doses if an optimized protocol, developed using OCT, is applied for each type of dental investigation. Also, there are situations when the X-ray technology has drawbacks for dental diagnosis or treatment assessment. In such situations, OCT proves capable to provide qualitative images.

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