scholarly journals Optical Coherence Tomography for Examination of Parchment Degradation

2006 ◽  
Vol 2006 ◽  
pp. 1-6 ◽  
Author(s):  
Michalina Góra ◽  
Michael Pircher ◽  
Erich Götzinger ◽  
Tomasz Bajraszewski ◽  
Matija Strlic ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Axis ◽  
Incident Light ◽  
Infrared Light ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Central Wavelength ◽  
Non Invasive ◽  
Spectral Oct ◽  
Iron Gall

A novel application of Optical Coherence Tomography utilizing infrared light of 830 nm central wavelength for non invasive examination of the structure of parchment, some covered with iron gall ink, is presented. It is shown that both the parchment and the ink applied are sufficiently transparent to light of this wavelength. In the study, Spectral OCT (SOCT) as well as Polarisation Sensitive OCT (PS-OCT) techniques were used to obtain cross-sectional images of samples of parchment based on scattering properties. The second technique was additionally employed to recover the birefringence properties and the optical axis orientations of the sample. It was shown that freshly produced parchment exhibits a degree of birefringence. However, this property declines with ageing, and samples of old parchment completely depolarise the incident light.

scholarly journals Coherence tomography with broad bandwidth extreme ultraviolet and soft X-ray radiation

2021 ◽  
Vol 127 (4) ◽  
Author(s):  
S. Skruszewicz ◽  
S. Fuchs ◽  
J. J. Abel ◽  
J. Nathanael ◽  
J. Reinhard ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Near Infrared ◽  
Extreme Ultraviolet ◽  
Infrared Light ◽  
Imaging Method ◽  
Optical Coherence ◽  
Axial Resolution ◽  
Cross Sectional ◽  
X Ray ◽  
Broad Bandwidth

AbstractWe present an overview of recent results on optical coherence tomography with the use of extreme ultraviolet and soft X-ray radiation (XCT). XCT is a cross-sectional imaging method that has emerged as a derivative of optical coherence tomography (OCT). In contrast to OCT, which typically uses near-infrared light, XCT utilizes broad bandwidth extreme ultraviolet (XUV) and soft X-ray (SXR) radiation (Fuchs et al in Sci Rep 6:20658, 2016). As in OCT, XCT’s axial resolution only scales with the coherence length of the light source. Thus, an axial resolution down to the nanometer range can be achieved. This is an improvement of up to three orders of magnitude in comparison to OCT. XCT measures the reflected spectrum in a common-path interferometric setup to retrieve the axial structure of nanometer-sized samples. The technique has been demonstrated with broad bandwidth XUV/SXR radiation from synchrotron facilities and recently with compact laboratory-based laser-driven sources. Axial resolutions down to 2.2 nm have been achieved experimentally. XCT has potential applications in three-dimensional imaging of silicon-based semiconductors, lithography masks, and layered structures like XUV mirrors and solar cells.

A NEW AND MODERN DIGNOSTIC TECHNIQUE: SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY (SS-OCT)

2013 ◽  
Vol 5 (2) ◽  
pp. 31-33
Author(s):  
Prakash Lokhande
Keyword(s):  
Optical Coherence Tomography ◽  
High Resolution ◽  
Optical Imaging ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Swept Source ◽  
Non Invasive ◽  
Treatment Technologies ◽  
High Resolution Images ◽  
Swept Source Oct

ABSTRACT Innovative technique has been introduced in the field of dentistry for the purpose of diagnosis and treatment. Technologies like laser, composite curing techniques, optical imaging have been utilized in the field of dentistry. OCT(optical coherence tomography) is a recent. technique which creates cross-sectional high resolution images. SS-OCT(Swept -Source optical coherence tomography) is a variant of optical coherence tomography, which provides instant imaging with high resolution, non-invasive and ease of handling. This article provides a overview of Swept -Source OCT and its application in the field of dentistry.

scholarly journals Arthroscopic Optical Coherence Tomography in Diagnosis of Early Arthritis

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Michael J. O'Malley ◽  
Constance R. Chu
Keyword(s):  
Optical Coherence Tomography ◽  
Articular Cartilage ◽  
Articular Surface ◽  
Collagen Matrix ◽  
Quantitative Mri ◽  
Cartilage Injury ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Non Invasive ◽  
Surface Breakdown

Osteoarthritis (OA) is a progressive, debilitating disease that is increasing in prevalence. The pathogenesis of OA is likely multifactorial but ultimately leads to progressive breakdown of collagen matrix and loss of chondrocytes. Current clinical modalities employed to evaluate cartilage health and diagnose osteoarthritis in orthopaedic surgery include, radiography, MRI, and arthroscopy. While these assessment methods can show cartilage fissuring and loss, they are limited in ability to diagnose cartilage injury and degeneration prior breakdown of the articular surface. An improved clinical ability to detect subsurface cartilage pathology is important for development and testing of chondroprotective and chondrorestorative treatments because the pathological changes following surface breakdown are generally considered to be irreversible. Optical Coherence Tomography (OCT), is a novel, non-destructive imaging technology capable of near-real time cross-sectional images of articular cartilage at high resolutions comparable to low power histology. This review discusses a series of bench to bedside studies supporting the potential use of OCT for enhanced clinical diagnosis and staging of early cartilage injury and degeneration. OCT was also found to be useful as a translations research tool to assist in clinical evaluation of novel quantitative MRI technologies for non-invasive evaluation of articular cartilage.

Optical Biopsy of Lymph Node Morphology using Optical Coherence Tomography

2005 ◽  
Vol 4 (5) ◽  
pp. 539-547 ◽  
Author(s):  
Wei Luo ◽  
Freddy T. Nguyen ◽  
Adam M. Zysk ◽  
Tyler S. Ralston ◽  
John Brockenbrough ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Lymph Node ◽  
High Resolution ◽  
Breast Imaging ◽  
Optical Tomography ◽  
Screening Method ◽  
Optical Biopsy ◽  
Infrared Light ◽  
Optical Coherence ◽  
Cross Sectional

Optical diagnostic imaging techniques are increasingly being used in the clinical environment, allowing for improved screening and diagnosis while minimizing the number of invasive procedures. Diffuse optical tomography, for example, is capable of whole-breast imaging and is being developed as an alternative to traditional X-ray mammography. While this may eventually be a very effective screening method, other optical techniques are better suited for imaging on the cellular and molecular scale. Optical Coherence Tomography (OCT), for instance, is capable of high-resolution cross-sectional imaging of tissue morphology. In a manner analogous to ultrasound imaging except using optics, pulses of near-infrared light are sent into the tissue while coherence-gated reflections are measured interferometrically to form a cross-sectional image of tissue. In this paper we apply OCT techniques for the high-resolution three-dimensional visualization of lymph node morphology. We present the first reported OCT images showing detailed morphological structure and corresponding histological features of lymph nodes from a carcinogen-induced rat mammary tumor model, as well as from a human lymph node containing late stage metastatic disease. The results illustrate the potential for OCT to visualize detailed lymph node structures on the scale of micrometastases and the potential for the detection of metastatic nodal disease intraoperatively.

scholarly journals Evaluation of optical coherence tomography angiography parameters in patients treated with hydroxychloroquine

2021 ◽  
Author(s):  
Mohammad Reza Akhlaghi ◽  
Farzan Kianersi ◽  
Hamed Radmehr ◽  
Alireza Dehghani ◽  
Afsaneh Naderi Beni ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Cross Sectional Study ◽  
Normal Group ◽  
P Value ◽  
Optical Coherence ◽  
Flow Area ◽  
Cross Sectional ◽  
Non Invasive ◽  
The Mean

Abstract Background One of the major side effects of hydroxychloroquine is retinopathy. The aim of this study was to evaluate the Optical coherence tomography angiography (OCTA) parameters in a group of patients who have hydroxychloroquine-induced retinopathy based on Multifocal electroretinography (mfERG) with a group who do not have retinopathy.Method This is a Cross-Sectional Study. In this study, patients with RA or SLE who had been taking HCQ for at least 7 years were included. MfERG and OCTA imaging were performed for all patients. Patients were divided into Normal mfERG and Abnormal mfERG groups based on mfERG results. OCTA parameters were studied in these two groups.Result 61 patients (61 eyes) were included. 41 patients had SLE and 20 patients had RA. 40 patients (66.7%) had Abnormal mfERG. The mean VD in SCP layer was not significantly different between Normal mfERG and Abnormal mfERG groups (P-Value> 0.05). Mean VD in SCP layer was not significantly different between Normal mfERG and Abnormal mfERG groups (P-Value> 0.05). In RA subgroup, mean VD in SCP layer in PeriFovea region in Abnormal mfERG group was significantly lower than normal group (P-Value <0.05). Mean VD in DCP layer in Whole Image, Superior Hemi, Inferior Hemi, PeriFovea area in Abnormal mfERG group was significantly lower than normal group (P-Value <0.05). This discrepancy was also observed in the RA subgroup but not in the SLE subgroup. The mean of none of the parameters of FAZ (mm2), Flow Area of Outer Retina (mm2) and Flow Area of Choriocapillaris (mm2) were not statistically significant between the groups Abnormal mfERG and Normal mfERG. (p-value>0.05). Conclusion VD in the DCP layer decreased in abnormal mfERG patients compared to patients with normal mfERG. But it seems that VD in SCP layer, FAZ Area and Flow Area are similar in both groups. OCTA may be used as a non-invasive tool in the diagnosis of early stages of HCQ-induced retinopathy, especially in RA patients, but further studies are needed.

scholarly journals Non-invasive three-dimensional thickness analysis of oral epithelium based on optical coherence tomography—development and diagnostic performance

Heliyon ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. e06645
Author(s):  
Charlotte Theresa Trebing ◽  
Sinan Sen ◽  
Stefan Rues ◽  
Christopher Herpel ◽  
Maria Schöllhorn ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Diagnostic Performance ◽  
Three Dimensional ◽  
Oral Epithelium ◽  
Optical Coherence ◽  
Non Invasive

scholarly journals Comparison of swept-source versus spectral-domain optical coherence tomography angiography for detection of macular neovascularization

2021 ◽  
Author(s):  
Anna Lentzsch ◽  
Laura Schöllhorn ◽  
Christel Schnorr ◽  
Robert Siggel ◽  
Sandra Liakopoulos
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Spectral Domain ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Swept Source ◽  
En Face ◽  
Increased Sensitivity ◽  
Sensitivity Specificity ◽  
Subretinal Hyperreflective Material

Abstract Purpose To compare swept-source (SS) versus spectral-domain (SD) optical coherence tomography angiography (OCTA) for the detection of macular neovascularization (MNV). Methods In this prospective cohort study, 72 eyes of 54 patients with subretinal hyperreflective material (SHRM) and/or pigment epithelial detachment (PED) on OCT possibly corresponding to MNV in at least one eye were included. OCTA scans were acquired using two devices, the PLEX Elite 9000 SS-OCTA and the Spectralis SD-OCTA. Fluorescein angiography (FA) was used as reference. Two graders independently evaluated en face OCTA images using a preset slab as well as a manually modified slab, followed by a combination of en face and cross-sectional OCTA. Results Sensitivity (specificity) for the automated slabs was 51.7% (93.0%) for SS-OCTA versus 58.6% (95.3%) for SD-OCTA. Manual modification of segmentation increased sensitivity to 79.3% for SS-OCTA but not for SD-OCTA (58.6%). The combination of en face OCTA with cross-sectional OCTA reached highest sensitivity values (SS-OCTA: 82.8%, SD-OCTA: 86.2%), and lowest number of cases with discrepancies between SS-OCTA and SD-OCTA (4.2%). Fleiss kappa as measure of concordance between FA, SS-OCTA, and SD-OCTA was 0.56 for the automated slabs, 0.60 for the manual slabs, and 0.73 (good agreement) for the combination of en face OCTA with cross-sectional OCTA. Concordance to FA was moderate for the automated slabs and good for manual slabs and combination with cross-sectional OCTA of both devices. Conclusion Both devices reached comparable results regarding the detection of MNV on OCTA. Sensitivity for MNV detection and agreement between devices was best when evaluating a combination of en face and cross-sectional OCTA.

scholarly journals Utilization potential of intraluminal optical coherence tomography for the Eustachian tube

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hayoung Byun ◽  
Yeon Hoon Kim ◽  
Jingchao Xing ◽  
Su-Jin Shin ◽  
Seung Hwan Lee ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Eustachian Tube ◽  
Balloon Dilatation ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Anatomical Structures ◽  
Complex Anatomy ◽  
Before And After ◽  
Tubal Lumen ◽  
Oct Image

AbstractImaging the Eustachian tube is challenging because of its complex anatomy and limited accessibility. This study fabricated a fiber-based optical coherence tomography (OCT) catheter and investigated its potential for assessing the Eustachian tube anatomy. A customized OCT system and an imaging catheter, termed the Eustachian OCT, were developed for visualizing the Eustachian tube. Three male swine cadaver heads were used to study OCT image acquisition and for subsequent histologic correlation. The imaging catheter was introduced through the nasopharyngeal opening and reached toward the middle ear. The OCT images were acquired from the superior to the nasopharyngeal opening before and after Eustachian tube balloon dilatation. The histological anatomy of the Eustachian tube was compared with corresponding OCT images, The new, Eustachian OCT catheter was successfully inserted in the tubal lumen without damage. Cross-sectional images of the tube were successfully obtained, and the margins of the anatomical structures including cartilage, mucosa lining, and fat could be successfully delineated. After balloon dilatation, the expansion of the cross-sectional area could be identified from the OCT images. Using the OCT technique to assess the Eustachian tube anatomy was shown to be feasible, and the fabricated OCT image catheter was determined to be suitable for Eustachian tube assessment.

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