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Engineering › Biomedical Engineering

Optical Coherence Tomography Applications

Works Count: 30624

Description

This cluster of papers focuses on the advances in optical coherence tomography (OCT) imaging, particularly in the areas of high-resolution in vivo imaging, retinal blood flow measurement, and its applications in dermatological diseases. The papers cover various technological developments and biomedical applications of OCT, including the detection of microvasculature and tissue optical clearing.

Keywords

Optical Coherence Tomography; High-Resolution Imaging; Biomedical Applications; Spectral-Domain OCT; In Vivo Imaging; Retinal Blood Flow; Dermatological Diseases; Microvasculature Detection; OCT Technology; Tissue Optical Clearing

Handbook of Optical Coherence Tomography

2001-11-02
Brett E. Bouma , Guillermo J. Tearney
Introduction to optical coherence tomography. Technology: optical coherence tomography theory optical sources reference optical delay scanning scanning probe design system integration and signal/image processing speckle reduction techniques Doppler OCT polarization … Introduction to optical coherence tomography. Technology: optical coherence tomography theory optical sources reference optical delay scanning scanning probe design system integration and signal/image processing speckle reduction techniques Doppler OCT polarization sensitive OCT optical coherence microscopy full-field optical coherence microscopy spectral radar alternative OCT techniques. Applications: OCT for high-density data storage microstructure and damage characterization ofglass reinforced polymer composites using optical coherence tomography optical properties of biological tissue OCT in the diagnosis and management of posterior segment disorders OCT in the anterior segment developmental biology dermatology identification of neoplasias OCT in dentistry surgical guidance gynaecology cardiology otolaryngology urology.

Ultrahigh-resolution ophthalmic optical coherence tomography

2001-04-01
Wolfgang Drexler , Uwe Morgner , Ravi K. Ghanta +3 more

Theory, developments and applications of optical coherence tomography

2005-07-22
Peter H. Tomlins , Ruikang K. Wang
In this paper, we review the developments in optical coherence tomography (OCT) for three-dimensional non-invasive imaging. A number of different OCT techniques are discussed in some detail including time-domain, frequency-domain, … In this paper, we review the developments in optical coherence tomography (OCT) for three-dimensional non-invasive imaging. A number of different OCT techniques are discussed in some detail including time-domain, frequency-domain, full-field, quantum and Doppler OCT. A theoretical treatment is given and some relevant comparisons made between various implementations. The current and potential applications of OCT are discussed, with close attention paid to biomedical imaging and its metrological issues.

Micrometer-Scale Resolution Imaging of the Anterior Eye In Vivo With Optical Coherence Tomography

1994-12-01
Joseph A. Izatt , Michael R. Hee , Eric A. Swanson +5 more
To demonstrate a new diagnostic technique, optical coherence tomography, for high-resolution cross-sectional imaging of structures in the anterior segment of the human eye in vivo. Optical coherence tomography is a … To demonstrate a new diagnostic technique, optical coherence tomography, for high-resolution cross-sectional imaging of structures in the anterior segment of the human eye in vivo. Optical coherence tomography is a new, noninvasive, noncontact optical imaging modality that has spatial resolution superior to that of conventional clinical ultrasonography (< 20 microns) and high sensitivity (dynamic range, > 90 dB).Survey of intraocular structure and dimension measurements.Laboratory.Convenience sample.Correlation with range of accepted normal intraocular structure profiles and dimensions.Direct in vivo measurements with micrometer-scale resolution were performed of corneal thickness and surface profile (including visualization of the corneal epithelium), anterior chamber depth and angle, and iris thickness and surface profile. Dense nuclear cataracts were successfully imaged through their full thickness in a cold cataract model in calf eyes in vitro.Optical coherence tomography has potential as a diagnostic tool for applications in noncontact biometry, anterior chamber angle assessment, identification and monitoring of intraocular masses and tumors, and elucidation of abnormalities of the cornea, iris, and crystalline lens.

Optical Coherence Tomography: An Emerging Technology for Biomedical Imaging and Optical Biopsy

2000-01-01
James G. Fujimoto , Costas Pitris , Stephen A. Boppart +1 more
Optical coherence tomography (OCT) is an emerging technology for performing high-resolution cross-sectional imaging. OCT is analogous to ultrasound imaging, except that it uses light instead of sound. OCT can provide … Optical coherence tomography (OCT) is an emerging technology for performing high-resolution cross-sectional imaging. OCT is analogous to ultrasound imaging, except that it uses light instead of sound. OCT can provide cross-sectional images of tissue structure on the micron scale in situ and in real time. Using OCT in combination with catheters and endoscopes enables high-resolution intraluminal imaging of organ systems. OCT can function as a type of optical biopsy and is a powerful imaging technology for medical diagnostics because unlike conventional histopathology which requires removal of a tissue specimen and processing for microscopic examination, OCT can provide images of tissue in situ and in real time. OCT can be used where standard excisional biopsy is hazardous or impossible, to reduce sampling errors associated with excisional biopsy, and to guide interventional procedures. In this paper, we review OCT technology and describe its potential biomedical and clinical applications.
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Three dimensional optical angiography

2007-04-02
Ruikang K. Wang , Steven L. Jacques , Zhenhe Ma +3 more
With existing optical imaging techniques three-dimensional (3-D) mapping of microvascular perfusion within tissue beds is severely limited by the efficient scattering and absorption of light by tissue. To overcome these … With existing optical imaging techniques three-dimensional (3-D) mapping of microvascular perfusion within tissue beds is severely limited by the efficient scattering and absorption of light by tissue. To overcome these limitations we have developed a method of optical angiography (OAG) that can generate 3-D angiograms within millimeter tissue depths by analyzing the endogenous optical scattering signal from an illuminated sample. The technique effectively separates the moving and static scattering elements within tissue to achieve high resolution images of blood flow, mapped into the 3-D optically sectioned tissue beds, at speeds that allow for perfusion assessment in vivo. Its development has its origin in Fourier domain optical coherence tomography. We used OAG to visualize the cerebral microcirculation, of adult living mice through the intact cranium, measurements which would be difficult, if not impossible, with other optical imaging techniques.

OCT elastography: imaging microscopic deformation and strain of tissue

1998-09-14
Joseph M. Schmitt
Optical coherence tomography (OCT) has been applied to the study of the microscopic deformation of biological tissue under compressive stress. We describe the hardware and theory of operation of an … Optical coherence tomography (OCT) has been applied to the study of the microscopic deformation of biological tissue under compressive stress. We describe the hardware and theory of operation of an OCT elastography system that measures internal displacements as small as a few micrometers by using 2D cross-correlation speckle tracking. Results obtained from gelatin scattering models, pork meat, and intact skin suggest possible medical applications of the technique.

Ultrahigh-resolution, high-speed, Fourier domain optical coherence tomography and methods for dispersion compensation

2004-05-31
Maciej Wojtkowski , Vivek J. Srinivasan , Tony H. Ko +3 more
Ultrahigh-resolution optical coherence tomography uses broadband light sources to achieve axial image resolutions on the few micron scale. Fourier domain detection methods enable more than an order of magnitude increase … Ultrahigh-resolution optical coherence tomography uses broadband light sources to achieve axial image resolutions on the few micron scale. Fourier domain detection methods enable more than an order of magnitude increase in imaging speed and sensitivity, thus overcoming the sensitivity limitations inherent in ultrahigh-resolution OCT using standard time domain detection. Fourier domain methods also provide direct access to the spectrum of the optical signal. This enables automatic numerical dispersion compensation, a key factor in achieving ultrahigh image resolutions. We present ultrahigh-resolution, high-speed Fourier domain OCT imaging with an axial resolution of 2.1 ìm in tissue and 16,000 axial scans per second at 1024 pixels per axial scan. Ultrahigh-resolution spectral domain OCT is shown to provide a ~100x increase in imaging speed when compared to ultrahigh-resolution time domain OCT. In vivo imaging of the human retina is demonstrated. We also present a general technique for automatic numerical dispersion compensation, which is applicable to spectral domain as well as swept source embodiments of Fourier domain OCT.

Split-spectrum amplitude-decorrelation angiography with optical coherence tomography

2012-02-09
Yali Jia , Ou Tan , Jason Tokayer +7 more
Amplitude decorrelation measurement is sensitive to transverse flow and immune to phase noise in comparison to Doppler and other phase-based approaches. However, the high axial resolution of OCT makes it … Amplitude decorrelation measurement is sensitive to transverse flow and immune to phase noise in comparison to Doppler and other phase-based approaches. However, the high axial resolution of OCT makes it very sensitive to the pulsatile bulk motion noise in the axial direction. To overcome this limitation, we developed split-spectrum amplitude-decorrelation angiography (SSADA) to improve the signal-to-noise ratio (SNR) of flow detection. The full OCT spectrum was split into several narrower bands. Inter-B-scan decorrelation was computed using the spectral bands separately and then averaged. The SSADA algorithm was tested on in vivo images of the human macula and optic nerve head. It significantly improved both SNR for flow detection and connectivity of microvascular network when compared to other amplitude-decorrelation algorithms.
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State-of-the-art retinal optical coherence tomography

2007-08-14
Wolfgang Drexler , James G. Fujimoto

Optical coherence tomography in dermatology: a review

2001-02-01
Julia Welzel
Background/aims: Optical coherence tomography (OCT) is a non‐invasive technique for morphological investigation of tissue. Since its development in the late 1980s it is mainly used as a diagnostic tool in … Background/aims: Optical coherence tomography (OCT) is a non‐invasive technique for morphological investigation of tissue. Since its development in the late 1980s it is mainly used as a diagnostic tool in ophthalmology. For examination of a highly scattering tissue like the skin, it was necessary to modify the method. Early studies on the value of OCT for skin diagnosis gave promising results. Methods: The OCT technique is based on the principle of Michelson interferometry. The light sources used for OCT are low coherent superluminescent diodes operating at a wavelength of about 1300 nm. OCT provides two‐dimensional images with a scan length of a few millimeters (mm), a resolution of about 15 μm and a maximum detection depth of 1.5 mm. The image acquisition can be performed nearly in real time. The measurement is non‐invasive and with no side effects. Results: The in vivo OCT images of human skin show a strong scattering from tissue with a few layers and some optical inhomogeneities. The resolution enables the visualization of architectural changes, but not of single cells. In palmoplantar skin, the thick stratum corneum is visible as a low‐scattering superficial well defined layer with spiral sweat gland ducts inside. The epidermis can be distinguished from the dermis. Adnexal structures and blood vessels are low‐scattering regions in the upper dermis. Skin tumors show a homogenous signal distribution. In some cases, tumor borders to healthy skin are detectable. Inflammatory skin diseases lead to changes of the OCT image, such as thickening of the epidermis and reduction of the light attenuation in the dermis. A quantification of treatment effects, such as swelling of the horny layer due to application of a moisturizer, is possible. Repeated measurements allow a monitoring of the changes over time. Conclusion: OCT is a promising new bioengineering method for investigation of skin morphology. In some cases it may be useful for diagnosis of skin diseases. Because of its non‐invasive character, the technique allows monitoring of inflammatory diseases over time. An objective quantification of the efficacy and tolerance of topical treatment is also possible. Due to the high resolution and simple application, OCT is an interesting addition to other morphological techniques in dermatology.
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Performance of fourier domain vs time domain optical coherence tomography

2003-04-21
Rainer A. Leitgeb , Christoph K. Hitzenberger , Adolf F. Fercher
In this article we present a detailed discussion of noise sources in Fourier Domain Optical Coherence Tomography (FDOCT) setups. The performance of FDOCT with charge coupled device (CCD) cameras is … In this article we present a detailed discussion of noise sources in Fourier Domain Optical Coherence Tomography (FDOCT) setups. The performance of FDOCT with charge coupled device (CCD) cameras is compared to current standard time domain OCT systems. We describe how to measure sensitivity in the case of FDOCT and confirm the theoretically obtained values. It is shown that FDOCT systems have a large sensitivity advantage and allow for sensitivities well above 80dB, even in situations with low light levels and high speed detection.

Ultrahigh-resolution optical coherence tomography using continuum generation in an air–silica microstructure optical fiber

2001-05-01
Ingmar Hartl , X. D. Li , C. Chudoba +5 more
We demonstrate ultrahigh-resolution optical coherence tomography (OCT) using continuum generation in an air–silica microstructure fiber as a low-coherence light source. A broadband OCT system was developed and imaging was performed … We demonstrate ultrahigh-resolution optical coherence tomography (OCT) using continuum generation in an air–silica microstructure fiber as a low-coherence light source. A broadband OCT system was developed and imaging was performed with a bandwidth of 370 nm at a 1.3‐μm center wavelength. Longitudinal resolutions of 2.5 μm in air and ∼2 μm in tissue were achieved. Ultrahigh-resolution imaging in biological tissuein vivo was demonstrated.

Optical coherence angiography

2006-08-21
Shuichi Makita , Young-Joo Hong , Masahiro Yamanari +2 more
Noninvasive angiography is demonstrated for the in vivo human eye. Three-dimensional flow imaging has been performed with high-speed spectral-domain optical coherence tomography. Sample motion is compensated by two algorithms. Axial … Noninvasive angiography is demonstrated for the in vivo human eye. Three-dimensional flow imaging has been performed with high-speed spectral-domain optical coherence tomography. Sample motion is compensated by two algorithms. Axial motion between adjacent A-lines within one OCT image is compensated by the Doppler shift due to bulk sample motion. Axial displacements between neighboring images are compensated by a correlation-based algorithm. Three-dimensional vasculature of ocular vessels has been visualized. By integrating volume sets of flow images, two-dimensional images of blood vessels are obtained. Retinal and choroidal blood vessel images are simultaneously obtained by separating the volume set into retinal part and choroidal parts. These are corresponding to fluorescein angiogram and indocyanine angiogram.
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Speckle variance detection of microvasculature using swept-source optical coherence tomography

2008-06-26
Adrian Mariampillai , Beau A. Standish , Eduardo H. Moriyama +7 more
We report on imaging of microcirculation by calculating the speckle variance of optical coherence tomography (OCT) structural images acquired using a Fourier domain mode-locked swept-wavelength laser. The algorithm calculates interframe … We report on imaging of microcirculation by calculating the speckle variance of optical coherence tomography (OCT) structural images acquired using a Fourier domain mode-locked swept-wavelength laser. The algorithm calculates interframe speckle variance in two-dimensional and three-dimensional OCT data sets and shows little dependence to the Doppler angle ranging from 75 degrees to 90 degrees . We demonstrate in vivo detection of blood flow in vessels as small as 25 microm in diameter in a dorsal skinfold window chamber model with direct comparison with intravital fluorescence confocal microscopy. This technique can visualize vessel-size-dependent vascular shutdown and transient vascular occlusion during Visudyne photodynamic therapy and may provide opportunities for studying therapeutic effects of antivascular treatments without on exogenous contrast agent.

In Vivo Endoscopic Optical Biopsy with Optical Coherence Tomography

1997-06-27
Guillermo J. Tearney , Mark E. Brezinski , Brett E. Bouma +4 more
Current medical imaging technologies allow visualization of tissue anatomy in the human body at resolutions ranging from 100 micrometers to 1 millimeter. These technologies are generally not sensitive enough to … Current medical imaging technologies allow visualization of tissue anatomy in the human body at resolutions ranging from 100 micrometers to 1 millimeter. These technologies are generally not sensitive enough to detect early-stage tissue abnormalities associated with diseases such as cancer and atherosclerosis, which require micrometer-scale resolution. Here, optical coherence tomography was adapted to allow high-speed visualization of tissue in a living animal with a catheter-endoscope 1 millimeter in diameter. This method, referred to as “optical biopsy,” was used to obtain cross-sectional images of the rabbit gastrointestinal and respiratory tracts at 10-micrometer resolution.

Improved signal-to-noise ratio in spectral-domain compared with time-domain optical coherence tomography

2003-11-01
Johannes F. de Boer , Barry Cense , B. Hyle Park +3 more
A signal-to-noise ratio (SNR) analysis is presented for optical coherence tomography (OCT) signals in which time-domain performance is compared with that of the spectral domain. A significant SNR gain of … A signal-to-noise ratio (SNR) analysis is presented for optical coherence tomography (OCT) signals in which time-domain performance is compared with that of the spectral domain. A significant SNR gain of several hundredfold is found for acquisition in the spectral domain. The SNR benefit is demonstrated experimentally in a hybrid time-domain–spectral-domain OCT system.
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Optical coherence tomography for ultrahigh resolution in vivo imaging

2003-10-31
James G. Fujimoto

Enhanced Depth Imaging Spectral-Domain Optical Coherence Tomography

2008-07-18
Richard F. Spaide , Hideki Koizumi , Maria C. Pozonni

Fourier Domain Mode Locking (FDML): A new laser operating regime and applications for optical coherence tomography

2006-04-17
Robert Huber , Maciej Wojtkowski , James G. Fujimoto
We demonstrate a new technique for frequency-swept laser operation--Fourier domain mode locking (FDML)--and its application for swept-source optical coherence tomography (OCT) imaging. FDML is analogous to active laser mode locking … We demonstrate a new technique for frequency-swept laser operation--Fourier domain mode locking (FDML)--and its application for swept-source optical coherence tomography (OCT) imaging. FDML is analogous to active laser mode locking for short pulse generation, except that the spectrum rather than the amplitude of the light field is modulated. High-speed, narrowband optical frequency sweeps are generated with a repetition period equal to the fundamental or a harmonic of cavity round-trip time. An FDML laser is constructed using a long fiber ring cavity, a semiconductor optical amplifier, and a tunable fiber Fabry-Perot filter. Effective sweep rates of up to 290 kHz are demonstrated with a 105 nm tuning range at 1300 nm center wavelength. The average output power is 3mW directly from the laser and 20 mW after post-amplification. Using the FDML laser for swept-source OCT, sensitivities of 108 dB are achieved and dynamic linewidths are narrow enough to enable imaging over a 7 mm depth with only a 7.5 dB decrease in sensitivity. We demonstrate swept-source OCT imaging with acquisition rates of up to 232,000 axial scans per second. This corresponds to 906 frames/second with 256 transverse pixel images, and 3.5 volumes/second with a 256x128x256 voxel element 3-DOCT data set. The FDML laser is ideal for swept-source OCT imaging, thus enabling high imaging speeds and large imaging depths.

Speckle in Optical Coherence Tomography

1999-01-01
Joseph M. Schmitt , Shaohua Xiang , Ka-Wai Yung
The <i>Journal of Biomedical Optics</i> (JBO) is a Gold Open Access journal that publishes peer-reviewed papers on the use of novel optical systems and techniques for improved health care and … The <i>Journal of Biomedical Optics</i> (JBO) is a Gold Open Access journal that publishes peer-reviewed papers on the use of novel optical systems and techniques for improved health care and biomedical research.
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High-speed optical frequency-domain imaging

2003-11-03
Seok‐Hyun Yun , G. J. Tearney , Johannes F. de Boer +2 more
We demonstrate high-speed, high-sensitivity, high-resolution optical imaging based on optical frequency-domain interferometry using a rapidly-tuned wavelength-swept laser.We derive and show experimentally that frequency-domain ranging provides a superior signal-to-noise ratio compared … We demonstrate high-speed, high-sensitivity, high-resolution optical imaging based on optical frequency-domain interferometry using a rapidly-tuned wavelength-swept laser.We derive and show experimentally that frequency-domain ranging provides a superior signal-to-noise ratio compared with conventional time-domain ranging as used in optical coherence tomography.A high sensitivity of -110 dB was obtained with a 6 mW source at an axial resolution of 13.5 µm and an A-line rate of 15.7 kHz, representing more than an order-of-magnitude improvement compared with previous OCT and interferometric imaging methods.
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In vivo retinal imaging by optical coherence tomography

1993-11-01
Eric A. Swanson , J. A. Izatt , Charles P. Lin +5 more
We describe what are to our knowledge the first in vivo measurements of human retinal structure with optical coherence tomography. These images represent the highest depth resolution in vivo retinal … We describe what are to our knowledge the first in vivo measurements of human retinal structure with optical coherence tomography. These images represent the highest depth resolution in vivo retinal images to date. The tomographic system, image-processing techniques, and examples of high-resolution tomographs and their clinical relevance are discussed.

Extended depth of field through wave-front coding

1995-04-10
Edward R. Dowski , W. Thomas Cathey
We designed an optical-digital system that delivers near-diffraction-limited imaging performance with a large depth of field. This system is the standard incoherent optical system modified by a phase mask with … We designed an optical-digital system that delivers near-diffraction-limited imaging performance with a large depth of field. This system is the standard incoherent optical system modified by a phase mask with digital processing of the resulting intermediate image. The phase mask alters or codes the received incoherent wave front in such a way that the point-spread function and the optical transfer function do not change appreciably as a function of misfocus. Focus-independent digital filtering of the intermediate image is used to produce a combined optical-digital system that has a nearly diffraction limited point-spread function. This high-resolution extended depth of field is obtained through the expense of an increased dynamic range of the incoherent system. We use both the ambiguity function and the stationary-phase method to design these phase masks.

Three-dimensional Retinal Imaging with High-Speed Ultrahigh-Resolution Optical Coherence Tomography

2005-09-03
Maciej Wojtkowski , Vivek J. Srinivasan , James G. Fujimoto +4 more
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In Vivo Confocal Scanning Laser Microscopy of Human Skin II: Advances in Instrumentation and Comparison With Histology11The authors have declared conflict of interest.

1999-09-01
Milind Rajadhyaksha , Salvador González , James M. Zavislan +2 more

Fiber-optic fluorescence imaging

2005-11-18
Benjamin A. Flusberg , Eric D. Cocker , Wibool Piyawattanametha +3 more
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Optical coherence microscopy in scattering media

1994-04-15
Joseph A. Izatt , Eric A. Swanson , James G. Fujimoto +2 more
We describe a novel technique, based on optical coherence tomography, for enhanced optical sectioning in confocal microscopy. Confocal imaging deep into highly scattering media is demonstrated and compared with the … We describe a novel technique, based on optical coherence tomography, for enhanced optical sectioning in confocal microscopy. Confocal imaging deep into highly scattering media is demonstrated and compared with the predictions of a single-backscatter theory.

In vivo bidirectional color Doppler flow imaging of picoliter blood volumes using optical coherence tomography

1997-09-15
Joseph A. Izatt , Manish D. Kulkarni , Siavash Yazdanfar +2 more
We describe a novel optical system for bidirectional color Doppler imaging of flow in biological tissues with micrometer-scale resolution and demonstrate its use for in vivo imaging of blood flow … We describe a novel optical system for bidirectional color Doppler imaging of flow in biological tissues with micrometer-scale resolution and demonstrate its use for in vivo imaging of blood flow in an animal model. Our technique, color Doppler optical coherence tomography (CDOCT), performs spatially localized optical Doppler velocimetry by use of scanning low-coherence interferometry. CDOCT is an extension of optical coherence tomography (OCT), employing coherent signal-acquisition electronics and joint time-frequency analysis algorithms to perform flow imaging simultaneous with conventional OCT imaging. Cross-sectional maps of blood flow velocity with <50-µm spatial resolution and <0.6-mm/s velocity precision were obtained through intact skin in living hamster subdermal tissue. This technology has several potential medical applications.

Optical coherence tomography - principles and applications

2003-01-20
Adolf F. Fercher , Wolfgang Drexler , Christoph K. Hitzenberger +1 more
There have been three basic approaches to optical tomography since the early 1980s: diffraction tomography, diffuse optical tomography and optical coherence tomography (OCT). Optical techniques are of particular importance in … There have been three basic approaches to optical tomography since the early 1980s: diffraction tomography, diffuse optical tomography and optical coherence tomography (OCT). Optical techniques are of particular importance in the medical field, because these techniques promise to be safe and cheap and, in addition, offer a therapeutic potential. Advances in OCT technology have made it possible to apply OCT in a wide variety of applications but medical applications are still dominating. Specific advantages of OCT are its high depth and transversal resolution, the fact, that its depth resolution is decoupled from transverse resolution, high probing depth in scattering media, contact-free and non-invasive operation, and the possibility to create various function dependent image contrasting methods. This report presents the principles of OCT and the state of important OCT applications.

Imaging of Macular Diseases with Optical Coherence Tomography

1995-02-01
Carmen A. Puliafito , Michael R. Hee , Charles P. Lin +6 more

In vivo human retinal imaging by Fourier domain optical coherence tomography

2002-01-01
Maciej Wojtkowski , Rainer A. Leitgeb , Andrzej Kowalczyk +2 more
The <i>Journal of Biomedical Optics</i> (JBO) is a Gold Open Access journal that publishes peer-reviewed papers on the use of novel optical systems and techniques for improved health care and … The <i>Journal of Biomedical Optics</i> (JBO) is a Gold Open Access journal that publishes peer-reviewed papers on the use of novel optical systems and techniques for improved health care and biomedical research.
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Optical biopsy and imaging using optical coherence tomography

1995-09-01
James G. Fujimoto , Mark E. Brezinski , Guillermo J. Tearney +5 more

Sensitivity advantage of swept source and Fourier domain optical coherence tomography

2003-09-08
Michael A. Choma , Marinko V. Šarunic , Changhuei Yang +1 more
We present theoretical and experimental results which demonstrate the superior sensitivity of swept source (SS) and Fourier domain (FD) optical coherence tomography (OCT) techniques over the conventional time domain (TD) … We present theoretical and experimental results which demonstrate the superior sensitivity of swept source (SS) and Fourier domain (FD) optical coherence tomography (OCT) techniques over the conventional time domain (TD) approach. We show that SS- and FD-OCT have equivalent expressions for system signal-to-noise ratio which result in a typical sensitivity advantage of 20-30dB over TD-OCT. Experimental verification is provided using two novel spectral discrimination (SD) OCT systems: a differential fiber-based 800nm FD-OCT system which employs deep-well photodiode arrays, and a differential 1300nm SS-OCT system based on a swept laser with an 87nm tuning range.
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Optical coherence tomography (OCT): a review

1999-01-01
Joseph M. Schmitt
This paper reviews the state of the art of optical coherence tomography (OCT), an interferometric imaging technique that provides cross-sectional views of the subsurface microstructure of biological tissue. Following a … This paper reviews the state of the art of optical coherence tomography (OCT), an interferometric imaging technique that provides cross-sectional views of the subsurface microstructure of biological tissue. Following a discussion of the basic theory of OCT, an overview of the issues involved in the design of the main components of OCT systems is presented. The review concludes by introducing new imaging modes being developed to extract additional diagnostic information.

“Coherence Radar” and “Spectral Radar”—New Tools for Dermatological Diagnosis

1998-01-01
G Ha Usler , Michael Lindner
"Coherence radar," an optical 3-D sensor based on short coherence interferometry, is used to measure skin surface topology. This method is called optical coherence profilometry (OCP) and it may be … "Coherence radar," an optical 3-D sensor based on short coherence interferometry, is used to measure skin surface topology. This method is called optical coherence profilometry (OCP) and it may be a useful tool for medical diagnosis in dermatology because different medical conditions show distinct alterations of the skin surface. The measuring uncertainty is less than 2 μm. The measuring time is about 4 s. in vivo 3-D mapping of naked skin was performed without preparation. For clinical application, a fiber optical implementation was introduced. Spectral radar is an optical sensor for the acquisition of skin morphology based on OCT techniques. The scattering amplitude a(z) along one vertical axis from the surface into the bulk can be measured within one exposure. No reference arm scanning is necessary. The theory of the sensor, including the dynamic range, is discussed and in vivo measurements of human skin by a fiber optical implementation of the sensor are demonstrated. © 1998 Society of Photo-Optical Instrumentation Engineers.
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Quantification of Macrophage Content in Atherosclerotic Plaques by Optical Coherence Tomography

2003-01-07
Guillermo J. Tearney , Hiroshi Yabushita , Stuart L. Houser +7 more
Background— Macrophage degradation of fibrous cap matrix is an important contributor to atherosclerotic plaque instability. An imaging technology capable of identifying macrophages in patients could provide valuable information for assessing … Background— Macrophage degradation of fibrous cap matrix is an important contributor to atherosclerotic plaque instability. An imaging technology capable of identifying macrophages in patients could provide valuable information for assessing plaque vulnerability. Optical coherence tomography (OCT) is a new intravascular imaging modality that allows cross-sectional imaging of tissue with a resolution of ≈10 μm. The aim of this study was to investigate the use of OCT for identifying macrophages in fibrous caps. Methods and Results— OCT images of 26 lipid-rich atherosclerotic arterial segments obtained at autopsy were correlated with histology. Cap macrophage density was quantified morphometrically by immunoperoxidase staining with CD68 and smooth muscle actin and compared with the standard deviation of the OCT signal intensity at corresponding locations. There was a high degree of positive correlation between OCT and histological measurements of fibrous cap macrophage density ( r =0.84, P &lt;0.0001) and a negative correlation between OCT and histological measurements of smooth muscle actin density ( r =−0.56, P &lt;0.005). A range of OCT signal standard deviation thresholds (6.15% to 6.35%) yielded 100% sensitivity and specificity for identifying caps containing &gt;10% CD68 staining. Conclusions— The high contrast and resolution of OCT enables the quantification of macrophages within fibrous caps. The unique capabilities of OCT for fibrous cap characterization suggest that this technology may be well suited for identifying vulnerable plaques in patients.

Automated 3-D Intraretinal Layer Segmentation of Macular Spectral-Domain Optical Coherence Tomography Images

2009-03-12
Mona K. Garvin , Michael D. Abràmoff , Xiaodong Wu +3 more
With the introduction of spectral-domain optical coherence tomography (OCT), much larger image datasets are routinely acquired compared to what was possible using the previous generation of time-domain OCT. Thus, the … With the introduction of spectral-domain optical coherence tomography (OCT), much larger image datasets are routinely acquired compared to what was possible using the previous generation of time-domain OCT. Thus, the need for 3-D segmentation methods for processing such data is becoming increasingly important. We report a graph-theoretic segmentation method for the simultaneous segmentation of multiple 3-D surfaces that is guaranteed to be optimal with respect to the cost function and that is directly applicable to the segmentation of 3-D spectral OCT image data. We present two extensions to the general layered graph segmentation method: the ability to incorporate varying feasibility constraints and the ability to incorporate true regional information. Appropriate feasibility constraints and cost functions were learned from a training set of 13 spectral-domain OCT images from 13 subjects. After training, our approach was tested on a test set of 28 images from 14 subjects. An overall mean unsigned border positioning error of 5.69+/-2.41 microm was achieved when segmenting seven surfaces (six layers) and using the average of the manual tracings of two ophthalmologists as the reference standard. This result is very comparable to the measured interobserver variability of 5.71+/-1.98 microm.
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In vivo ultrahigh-resolution optical coherence tomography

1999-09-01
Wolfgang Drexler , Uwe Morgner , Franz X. Kärtner +5 more
Ultrahigh-resolution optical coherence tomography (OCT) by use of state of the art broad-bandwidth femtosecond laser technology is demonstrated and applied to in vivo subcellular imaging. Imaging is performed with a … Ultrahigh-resolution optical coherence tomography (OCT) by use of state of the art broad-bandwidth femtosecond laser technology is demonstrated and applied to in vivo subcellular imaging. Imaging is performed with a Kerr-lens mode-locked Ti:sapphire laser with double-chirped mirrors that emits sub-two-cycle pulses with bandwidths of up to 350 nm, centered at 800 nm. Longitudinal resolutions of ~1mum and transverse resolution of 3mum, with a 110-dB dynamic range, are achieved in biological tissue. To overcome depth-of-field limitations we perform zone focusing and image fusion to construct a tomogram with high transverse resolution throughout the image depth. To our knowledge this is the highest longitudinal resolution demonstrated to date for in vivo OCT imaging.

Characterization of Human Atherosclerosis by Optical Coherence Tomography

2002-09-23
Hiroshi Yabushita , Brett E. Bouma , Stuart L. Houser +7 more
Background— High-resolution visualization of atherosclerotic plaque morphology may be essential for identifying coronary plaques that cause acute coronary events. Optical coherence tomography (OCT) is an intravascular imaging modality capable of … Background— High-resolution visualization of atherosclerotic plaque morphology may be essential for identifying coronary plaques that cause acute coronary events. Optical coherence tomography (OCT) is an intravascular imaging modality capable of providing cross-sectional images of tissue with a resolution of 10 μm. To date, OCT imaging has not been investigated in sufficient detail to assess its accuracy for characterizing atherosclerotic plaques. The aim of this study was to establish objective OCT image criteria for atherosclerotic plaque characterization in vitro. Methods and Results— OCT images of 357 (diseased) atherosclerotic arterial segments obtained at autopsy were correlated with histology. OCT image criteria for 3 types of plaque were formulated by analysis of a subset (n=50) of arterial segments. OCT images of fibrous plaques were characterized by homogeneous, signal-rich regions; fibrocalcific plaques by well-delineated, signal-poor regions with sharp borders; and lipid-rich plaques by signal-poor regions with diffuse borders. Independent validation of these criteria by 2 OCT readers for the remaining segments (n=307) demonstrated a sensitivity and specificity ranging from 71% to 79% and 97% to 98% for fibrous plaques, 95% to 96% and 97% for fibrocalcific plaques, and 90% to 94% and 90% to 92% for lipid-rich plaques, respectively (overall agreement, κ=0.83 to 0.84). The interobserver and intraobserver reliabilities of OCT assessment were high (κ values of 0.88 and 0.91, respectively). Conclusions— Objective OCT criteria are highly sensitive and specific for characterizing different types of atherosclerotic plaques. These results represent an important step in validating this new intravascular imaging modality and will provide a basis for the interpretation of intracoronary OCT images obtained from patients.

Detection of Macular Ganglion Cell Loss in Glaucoma by Fourier-Domain Optical Coherence Tomography

2009-09-11
Ou Tan , Vikás Chopra , Ake Tzu-Hui Lu +5 more
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Microscopy with self-reconstructing beams

2010-09-12
Florian O. Fahrbach , P. Simon , Alexander Rohrbach
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Two-dimensional birefringence imaging in biological tissue by polarization-sensitive optical coherence tomography

1997-06-15
Johannes F. de Boer , Thomas E. Milner , Martin J. C. van Gemert +1 more
Using a low-coherence Michelson interferometer, we measure two-dimensional images of optical birefringence in bovine tendon as a function of depth. Polarization-sensitive detection of the signal formed by interference of backscattered … Using a low-coherence Michelson interferometer, we measure two-dimensional images of optical birefringence in bovine tendon as a function of depth. Polarization-sensitive detection of the signal formed by interference of backscattered light from the sample and a mirror in the reference arm give the optical phase delay between light that is propagating along the fast and slow axes of the birefringent tendon. Images showing the change in birefringence in response to laser irradiation are presented. The technique permits rapid noncontact investigation of tissue structural properties through two-dimensional imaging of birefringence.
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IMAGE ARTIFACTS IN OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

2015-10-02
Richard F. Spaide , James G. Fujimoto , Nadia K. Waheed
In Brief Purpose: To describe image artifacts of optical coherence tomography (OCT) angiography and their underlying causative mechanisms. To establish a common vocabulary for the artifacts observed. Methods: The methods … In Brief Purpose: To describe image artifacts of optical coherence tomography (OCT) angiography and their underlying causative mechanisms. To establish a common vocabulary for the artifacts observed. Methods: The methods by which OCT angiography images are acquired, generated, and displayed are reviewed as are the mechanisms by which each or all of these methods can produce extraneous image information. A common set of terminology is proposed and used. Results: Optical coherence tomography angiography uses motion contrast to image blood flow and thereby images the vasculature without the need for a contrast agent. Artifacts are very common and can arise from the OCT image acquisition, intrinsic characteristics of the eye, eye motion, image processing, and display strategies. Optical coherence tomography image acquisition for angiography takes more time than simple structural scans and necessitates trade-offs in flow resolution, scan quality, and speed. An important set of artifacts are projection artifacts in which images of blood vessels seem at erroneous locations. Image processing used for OCT angiography can alter vascular appearance through segmentation defects, and because of image display strategies can give false impressions of the density and location of vessels. Eye motion leads to discontinuities in displayed data. Optical coherence tomography angiography artifacts can be detected by interactive evaluation of the images. Conclusion: Image artifacts are common and can lead to incorrect interpretations of OCT angiography images. Because of the quantity of data available and the potential for artifacts, physician interaction in viewing the image data will be required, much like what happens in modern radiology practice. Optical coherence tomography angiography is a noninvasive technique that can provide images of retinal and choroidal vascularization. Artifacts are common and originate in relation to image acquisition, intrinsic ocular characteristics, eye motion, image processing, and display strategies. Recognizing these artifacts is important in avoiding misinterpretation of diagnostic images.
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ANATOMICAL CORRELATES TO THE BANDS SEEN IN THE OUTER RETINA BY OPTICAL COHERENCE TOMOGRAPHY

2011-07-29
Richard F. Spaide , Christine A. Curcio
In Brief Purpose: To evaluate the validity of commonly used anatomical designations for the four hyperreflective outer retinal bands seen in current-generation optical coherence tomography, a scale model of outer … In Brief Purpose: To evaluate the validity of commonly used anatomical designations for the four hyperreflective outer retinal bands seen in current-generation optical coherence tomography, a scale model of outer retinal morphology was created using published information for direct comparison with optical coherence tomography scans. Methods: Articles and books concerning histology of the outer retina from 1900 until 2009 were evaluated, and data were used to create a scale model drawing. Boundaries between outer retinal tissue compartments described by the model were compared with intensity variations of representative spectral-domain optical coherence tomography scans using longitudinal reflectance profiles to determine the region of origin of the hyperreflective outer retinal bands. Results: This analysis showed a high likelihood that the spectral-domain optical coherence tomography bands attributed to the external limiting membrane (the first, innermost band) and to the retinal pigment epithelium (the fourth, outermost band) are correctly attributed. Comparative analysis showed that the second band, often attributed to the boundary between inner and outer segments of the photoreceptors, actually aligns with the ellipsoid portion of the inner segments. The third band corresponded to an ensheathment of the cone outer segments by apical processes of the retinal pigment epithelium in a structure known as the contact cylinder. Conclusion: Anatomical attributions and subsequent pathophysiologic assessments pertaining to the second and third outer retinal hyperreflective bands may not be correct. This analysis has identified testable hypotheses for the actual correlates of the second and third bands. Nonretinal pigment epithelium contributions to the fourth band (e.g., Bruch membrane) remain to be determined. Analysis of published outer retinal anatomy, creation of a scale outer retinal model, and comparison of the model with optical coherence tomography images showed that the bands seen in the outer retina appear to correspond to the external limiting membrane, ellipsoid portion of the photoreceptor inner segments, contact cylinders of outer segments, and finally the retinal pigment epithelium.
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Distributed systems: Concepts and design

1995-07-01
A.L. Ananda , G.-S. Poo

Optical Coherence Tomography

2008-01-01
Arnaud Dubois , Claude Boccara

Optical coherence tomography angiography: A comprehensive review of current methods and clinical applications

2017-07-29
Amir H. Kashani , Chieh‐Li Chen , Jin Kyu Gahm +5 more
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Optische Kohärenztomographie

2015-03-25
Tanja von Braunmühl

Temperature-sensitive polymer-nanoshell composites for photothermally modulated drug delivery

2000-06-28
S.R. Sershen , Sarah L. Westcott , Naomi J. Halas +1 more
Composites of thermally sensitive hydrogels and optically active nanoparticles have been developed for the purpose of photothermally modulated drug delivery. Copolymers of N-isopropylacrylamide (NIPAAm) and acrylamide (AAm) exhibit a lower … Composites of thermally sensitive hydrogels and optically active nanoparticles have been developed for the purpose of photothermally modulated drug delivery. Copolymers of N-isopropylacrylamide (NIPAAm) and acrylamide (AAm) exhibit a lower critical solution temperature (LCST) that is slightly above body temperature. When the temperature of the copolymer exceeds the LCST, the hydrogel collapses, causing a burst release of any soluble material held within the hydrogel matrix. Gold-gold sulfide nanoshells, a new class of nanoparticles designed to strongly absorb near-infrared light, have been incorporated into poly(NIPAAm-co-AAm) hydrogels for the purpose of initiating a temperature change with light; light at wavelengths between 800 and 1200 nm is transmitted through tissue with relatively little attenuation, absorbed by the nanoparticles, and converted to heat. Significantly enhanced drug release from composite hydrogels has been achieved in response to irradiation by light at 1064 nm. We have investigated the release of methylene blue and proteins of varying molecular weight. Additionally, the nanoshell-composite hydrogels can release multiple bursts of protein in response to repeated near-IR irradiation.
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Leveraging Pretrained Vision Transformers for Automated Cancer Diagnosis in Optical Coherence Tomography Images

2025-06-25
Soumyajit Ray , Cheng-Yu Lee , Hyeon‐Cheol Park +4 more | Biomedical Optics Express

3D Quantum Ghost Imaging Microscope

2025-06-25
Audrey Eshun , Dominique Davenport , Brandon Demory +7 more | Optica

Analysis of pulsatile motion in the murine cornea using phase-sensitive visible-light optical coherence tomography

2025-06-25
Lucas May , Sybren Worm , Maria Varaka +7 more | Biomedical Optics Express

Polyetheretherketone (PEEK) Onlay Implants: A Case Series and Comparative Analysis

2025-06-24
S. Saydzai , C. Fowell , Vimala Santhanam +6 more | International Journal of Oral and Maxillofacial Surgery

Comprehensive Investigation of the Eye‐Cornea Structure Based on the Extended Techniques of Polarization‐Sensitive Optical Coherence Tomography

2025-06-24
Oleg V. Angelsky , A. Ya. Bekshaev , C. Yu. Zenkova +4 more | Journal of Biophotonics
ABSTRACT We present a universal technique for noninvasive investigation of thin multilayer optically transparent tissues based on polarization‐sensitive optical coherence tomography. To reach higher diagnostic accuracy, we revisit the model … ABSTRACT We present a universal technique for noninvasive investigation of thin multilayer optically transparent tissues based on polarization‐sensitive optical coherence tomography. To reach higher diagnostic accuracy, we revisit the model of the cornea structure and reconsider the physical features of the interaction of light with the tissue structural elements. In the scheme proposed, the probing beam is algorithmically adjustable such that the x ‐polarized radiation impinges each consecutive structural layer; the object beam is formed by the reflection and back‐scattering. Its characteristics are found analytically and numerically within the framework of the polarized Monte‐Carlo model and the Jones matrix formalism. A modified Mach–Zehnder interferometer with orthogonal polarization channels enables the elimination of the object‐signal depolarization caused by stochastic scattering and facilitates evaluation of the refractive indices and birefringence of tissue elements. The technique permits spatial scanning of the object, providing a complete 3D mapping with a submicrometer resolution in the longitudinal and transverse directions.

Quantitative comparison of a novel swept-source optical coherence tomography angiography device with three established systems

2025-06-20
Michael Hafner , Siegfried Priglinger , Bettina von Livonius +1 more | Scientific Reports
Abstract Optical Coherence Tomography Angiography (OCTA) has become an essential non-invasive imaging technique for high-resolution visualization of retinal microvasculature. This study evaluates the performance of a novel Swept-Source OCTA device, … Abstract Optical Coherence Tomography Angiography (OCTA) has become an essential non-invasive imaging technique for high-resolution visualization of retinal microvasculature. This study evaluates the performance of a novel Swept-Source OCTA device, Intalight DREAM, compared to established systems: Heidelberg Spectralis, Topcon Triton, and Zeiss Cirrus. We assessed acquisition time and microvascular parameters in the superficial (SCP) and deep (DCP) capillary plexuses using the OCTA Vascular Analyser algorithm for standardized image analysis across devices on 30 eyes from 15 healthy participants. In the SCP, DREAM demonstrated a higher median vessel length (47 μm) and greater fractal dimension (mean: 1.999) than the other devices, indicating enhanced continuity and network complexity. In the DCP, DREAM showed a smaller foveal avascular zone (median: 0.339 mm 2 ) compared to Spectralis (0.51 mm 2 ), Triton (0.5935 mm 2 ), and Cirrus (0.9145 mm 2 ), along with a smaller vessel diameter (median: 23 μm) compared to Triton and Cirrus. With a median imaging time of 9.1 s, DREAM was significantly faster than the Spectralis system (23.3 s) while providing largely comparable image quality, enhancing patient comfort, and potentially minimizing motion artifacts. These findings suggest that DREAM OCT is a promising tool for deep retinal imaging, with strong potential for clinical application and research.

Optical coherence elastography

2025-06-19
Manmohan Singh , Matt S. Hepburn , Brendan F. Kennedy +1 more | Nature Reviews Methods Primers

Magnetically Controlled Reversible Photomagnetic Nanoactuators for Dynamic Contrast Enhancement in Optical Coherence Tomography

2025-06-19
Myeongsoo Kim , Samuel Medeiros Araujo Morais , Anamik Jhunjhunwala +3 more | Advanced Materials
Abstract Optical coherence tomography (OCT) is a high‐resolution imaging modality that detects scattered optical signals from light–tissue interaction. However, the ability of OCT to visualize specific molecular and cellular events … Abstract Optical coherence tomography (OCT) is a high‐resolution imaging modality that detects scattered optical signals from light–tissue interaction. However, the ability of OCT to visualize specific molecular and cellular events is hindered by the lack of effective exogenous contrast agents capable of producing noticeable imaging contrast. Here, photomagnetic nanoactuators with ≈90% scattering efficiency in the second near‐infrared window, capable of reversible magnetic field‐mediated modulation of optical scattering and, therefore, OCT signal, are proposed. These nanoactuators consist of a magnetite core and gold shell, functioning as a reversible magnetic actuator and an optical scatterer, respectively. When exposed to the external magnetic field, photomagnetic nanoactuators are assembled into chain structures via magnetostatic interactions between nearby nanoactuators, reducing their optical scattering and, consequently, the OCT signal. Upon removal of the magnetic field, the nanoactuators are disassembled, restoring their scattering property and OCT signal. It is demonstrated that this magnetically controlled OCT response allows enhanced particle‐associated signal detection with suppressed background signal via image subtraction before and after magnetic field treatment, both in vitro and in vivo. The developed nanoactuator platform offers a strategy for dynamic enhancement of OCT contrast, potentially broadening the utility of OCT for noninvasive cell tracking and molecular diagnostic imaging.

Nonmechanical spectral domain optical coherence tomography using an electrowetting beam-scanner

2025-06-19
Samuel Gilinsky , Eduardo J. Miscles , Jan Bartoš +4 more | Optics Express

Long-term investigation of 3D tissue detailed structure and multiparametric vascular network properties using OCT/OCTA for guiding atopic dermatitis theranostics

2025-06-19
Fengxian Du , Huiling Wu , Junwei Xue +7 more | Journal of Translational Medicine

Method of segmentation of OCT images using a convulsive neural network

2025-06-18
A.V. Shcherbatyuk , S.E. Tuzhanskyi | Optoelectronic Information-Power Technologies
The article analyzes the methods of segmentation of optical coherence tomography images, creates a convolutional neural network model U-Net, processes a series of test images from an open database, and … The article analyzes the methods of segmentation of optical coherence tomography images, creates a convolutional neural network model U-Net, processes a series of test images from an open database, and compares the results of processing with other algorithms using the structural similarity index (SSIM). Pre-processing of test images to improve the quality of segmentation is also performed. Preprocessing of test images was also carried out to improve the quality of segmentation. In this work, the U-Net convolutional neural network was created, trained and applied. Existing methods of segmentation of optical coherence tomography images for the diagnosis and monitoring of ophthalmic diseases were considered. The advantages of using the U-Net deep convolutional neural network in comparison with classical methods, such as the Sobel operator and the Pruitt operator, were analyzed. Unlike classical algorithms, which have limited ability to adapt to noise, image heterogeneity and pathologies, U-Net provided higher accuracy of image segmentation.

Polarisation Sensitive Optical Coherence Tomography Image Characteristics for Gastrointestinal Tumours and Normal Tissues at Surgical Margins in Dogs

2025-06-18
Helen Weaver , Gabrielle S. Fontes , Yifan Shen +3 more | Veterinary and Comparative Oncology
ABSTRACT The treatment of choice for canine alimentary tract neoplasms is surgical excision, but it can sometimes be difficult to achieve wide margins due to neoplasm location, size, or distribution. … ABSTRACT The treatment of choice for canine alimentary tract neoplasms is surgical excision, but it can sometimes be difficult to achieve wide margins due to neoplasm location, size, or distribution. Optical coherence tomography (OCT) is a rapid, noninvasive imaging modality that uses light to characterise tissue microstructure to allow identification of different tissue types. Spectral domain (SD)‐OCT allows for differentiation based on the total light intensity reflected from the tissue. Polarisation sensitive (PS)‐OCT detects the polarisation state of light reflected by the tissues. The polarisation properties are phase retardation, degree of polarisation uniformity (DOPU), and optical axis. Our objective was to qualitatively characterise different tissues at the excision sites of alimentary tract neoplasms using OCT. Oral, liver, and other alimentary tumours including stomach, intestine, and pancreas were imaged. Samples were then fixed in formalin, paraffin embedded and stained with haematoxylin and eosin. OCT images and histology slides were compared, and the tissues were qualitatively described by a single investigator. We hypothesized that PS‐OCT imaging would provide distinguishing characteristics of tissue appearances that could be used in the future to train observers or artificial intelligence to identify incomplete margins. Our results showed that alimentary tract tumours have disorganised microstructures on SD‐OCT and PS‐OCT DOPU, and PS‐OCT phase retardation and optical axis values that differ from normal tissues. Thus, these characteristics can be used to differentiate neoplastic and normal tissues at surgical margins.

Ultra-Fast Line-field Swept Source Scanning Optical Coherence Elastography

2025-06-18
Xinlu Cheng , J. R. Ren , Xin Wei +5 more | Biomedical Optics Express

Three-dimensional dynamic optical coherence tomography for breast tumor margin assessment

2025-06-17
Joel Bellesini , Ken Y. Foo , Jiayue Li +7 more | Biomedical Optics Express

Diffractive deep neural network-based depth-of-field expansion without image restoration

2025-06-16
Runze Li , Guang Jin , Xuemin Zhang +1 more | Optics Express

Phase-sensitive dynamic micro-optical coherence tomography for high-speed intracellular motion imaging

2025-06-16
Hinnerk Schulz‐Hildebrandt , Joseph A. Gardecki , Tiffany Miller +3 more | Optics Letters

Advanced Characterization of Vitreous Hyperreflective Dots via OCT-Derived Metrics: A Cross-Sectional Study

2025-06-16
William Rojas‐Carabali , Jin Lin , Paola Saboya‐Galindo +4 more | Ophthalmology and Therapy
The use of optical coherence tomography (OCT) as a potential tool for the measurement of vitreous inflammation has been previously described as a more objective and reproducible method when compared … The use of optical coherence tomography (OCT) as a potential tool for the measurement of vitreous inflammation has been previously described as a more objective and reproducible method when compared to historically known subjective scales. In this study, our objective is to evaluate OCT's ability to characterize vitreous hyperreflective dots (VHDs) across eyes with varying conditions, including healthy controls, vitreous degenerations, intraocular inflammation, and others. We utilized a purpose built semiautomated software comprising an image binarization tool to segment OCT scans of 61 eyes, comprising 15 eyes with vitreous degenerations, 20 uveitic eyes, 17 healthy controls, and 9 with other eye conditions. The vitreous dot index (VDI) was computed by determining the number of dots (VDI-N) and the dot area (VDI-A). VHDs were identified as the hyperreflective shadows observed in OCT images within segmented areas of the vitreous, stratified as zones I, II, and III. We compared the difference between groups using analysis of variance (ANOVA). Intergrader reliability was evaluated by comparing results obtained by two trained independent graders, employing intraclass correlation coefficient (ICC) analysis. When the medians of VDI-N and VDI-A were compared in healthy controls, patients with uveitis, patients with vitreous degeneration, and others, patients with vitreous degeneration had the highest VDI-N median (2.61 ± 2.76 mm3 p < 0.001) followed by healthy controls (0.48 ± 0.87 mm3 p < 0.001) in zone l. As for VDI-A in the same zone, healthy controls had the greatest median (0.71 ± 0.96, p < 0.001) among the different groups. In zone II, uveitis and the healthy control group had similar medians for VDI-N (0.03 ± 0.36 and 0.03 ± 0.29, p < 0.001 respectably) and VDI-A was greater in the vitreous degeneration group (0.40 ± 0.50 p < 0.001). Zone III had lower VDI-N and VDI-A; patients with uveitis and patients with vitreous degeneration had equal VDI-N (0.00 ± 0.03 p < 0.001) and patients with uveitis had the higher VDI-A among the rest of the groups (0.00 ± 0.65 p < 0.001). For the total vitreous (TV), the highest VDI-N was found in patients with vitreous degeneration (2.92 ± 2.85 p < 0.001) while the highest VDI-A was in the uveitis group patients (0.66 ± 1.31) p < 0.001. The average vitreous dot density index and the average vitreous dot reflectivity index (VDRI) in the TV were greater in patients with vitreous degeneration (2.15 × 10-5 ± 1.52 × 10-5) and patients with uveitis (0.13 ± 0.08), respectively. When comparing VDI markers using a Kruskal-Wallis nonparametric one-way ANOVA test, we found that only the average vitreous dot reflectivity index in zone I and VDI-A in TV were statistically significant. However, only the reflectivity index was significant when comparing patients with vitreous degeneration and healthy controls in a pairwise analysis. While vitreous inflammation scales must evolve toward more objective metrics, our findings suggest that VHDs on OCT can act as confounders, as they may represent normal vitreous cells or even the presence of vitreous degeneration. The reflectivity index appears to have better reproducibility than simple count; however, when searching for a more objective parameter for measuring vitreous inflammation, vitreous degeneration must be considered.

Ultrafast Time-Stretch Optical Coherence Tomography Using Reservoir Computing for Fourier-Free Signal Processing

2025-06-15
W.H. Liao , Tian‐Xiang Luan , Yuanli Yue +1 more | Sensors
Swept-source optical coherence tomography (SS-OCT) is a widely used imaging technique, particularly in medical diagnostics, due to its ability to provide high-resolution cross-sectional images. However, one of the main challenges … Swept-source optical coherence tomography (SS-OCT) is a widely used imaging technique, particularly in medical diagnostics, due to its ability to provide high-resolution cross-sectional images. However, one of the main challenges in SS-OCT systems is the nonlinearity in wavelength sweeping, which leads to degraded depth resolution after Fourier transform. Correcting for this nonlinearity typically requires complex re-sampling and chirp compensation methods. In this paper, we introduce the first ultrafast time-stretch optical coherence tomography (TS-OCT) system that utilizes reservoir computing (RC) to perform direct temporal signal analysis without relying on Fourier transform techniques. By focusing solely on the temporal characteristics of the interference signal, regardless of frequency chirp, we demonstrate a more efficient solution to address the nonlinear wavelength sweeping issue. By leveraging the dynamic temporal processing capabilities of RC, the proposed system effectively bypasses the challenges faced by Fourier analysis, maintaining high-resolution depth measurement without being affected by chirp-introduced spectral broadening. The system operates by categorizing the interference signals generated by variations in sample position. This classification-based approach simplifies the data processing pipeline. We developed an RC-based model to interpret the temporal patterns in the interferometric signals, achieving high classification accuracy. A proof-of-the-concept experiment demonstrated that this method allows for precise depth resolution, independent of system chirp. With an A-scan rate of 50 MHz, the classification model yielded 100% accuracy with a root mean square error (RMSE) of 0.2416. This approach offers a robust alternative to Fourier-based analysis, particularly in systems prone to nonlinearities during signal acquisition.

Visualization of specular reflections with phase coherence imaging using sub-apertures

2025-06-14
Tony Rasolonirina , Guillaume Painchaud-April , Alain Le Duff +1 more | Ultrasonics

Integrated visible-light optical coherence tomography and fluorescence scanning laser ophthalmoscopy to image retinal ganglion cell axons

2025-06-13
Tianyi Xu , Weijia Fan , Roman V. Kuranov +5 more | Biomedical Optics Express

Balanced-detection visible optical coherence tomography with a low-noise supercontinuum laser

2025-06-13
L. F. Abbott , Gianni Nteroli , Rasmus D. Engelsholm +3 more | Biomedical Optics Express

OCT in Oncology and Precision Medicine: From Nanoparticles to Advanced Technologies and AI

2025-06-13
Sanam Daneshpour Moghadam , Bogdan Maris , Ali Mokhtari +2 more | Bioengineering
Optical Coherence Tomography (OCT) is a relatively new medical imaging device that provides high-resolution and real-time visualization of biological tissues. Initially designed for ophthalmology, OCT is now being applied in … Optical Coherence Tomography (OCT) is a relatively new medical imaging device that provides high-resolution and real-time visualization of biological tissues. Initially designed for ophthalmology, OCT is now being applied in other types of pathologies, like cancer diagnosis. This review highlights its impact on disease diagnosis, biopsy guidance, and treatment monitoring. Despite its advantages, OCT has limitations, particularly in tissue penetration and differentiating between malignant and benign lesions. To overcome these challenges, the integration of nanoparticles has emerged as a transformative approach, which significantly enhances contrast and tumor vascularization at the molecular level. Gold and superparamagnetic iron oxide nanoparticles, for instance, have demonstrated great potential in increasing OCT’s diagnostic accuracy through enhanced optical scattering and targeted biomarker detection. Beyond these innovations, integrating OCT with multimodal imaging methods, including magnetic resonance imaging (MRI), positron emission tomography (PET), and ultrasound, offers a more comprehensive approach to disease assessment, particularly in oncology. Additionally, advances in artificial intelligence (AI) and biosensors have further expanded OCT’s capabilities, enabling real-time tumor characterization and optimizing surgical precision. However, despite these advancements, clinical adoption still faces several hurdles. Issues related to nanoparticle biocompatibility, regulatory approvals, and standardization need to be addressed. Moving forward, research should focus on refining nanoparticle technology, improving AI-driven image analysis, and ensuring broader accessibility to OCT-guided diagnostics. By tackling these challenges, OCT could become an essential tool in precision medicine, facilitating early disease detection, real-time monitoring, and personalized treatment for improved patient outcomes.

Experimental and numerical investigation of wavelength and resolution dependency of dynamic optical coherence tomography signals

2025-06-13
Shumpei Fujimura , Ibrahim Abd El-Sadek , Rion Morishita +7 more | Biomedical Optics Express

Optical coherence tomography for assessing port‐wine stains: a systematic review

2025-06-04
Marina Burlá , Fernanda Regina da Silva , Beatriz Ximenes Mendes +3 more | JDDG Journal der Deutschen Dermatologischen Gesellschaft

Space-time multiplexing coherence reconstruction

2025-06-01
Xin Tong , Chenglin Xing , Pengfei Xu +2 more | Optics Communications

Adaptive Structured‐Light 3D Surface Imaging with Cross‐Domain Learning (Laser Photonics Rev. 19(12)/2025)

2025-06-01
Xinsheng Li , Shijie Feng , Wenwu Chen +3 more | Laser & Photonics Review

Widefield OCT Angiography

2025-06-01
Yali Jia , Tristan T. Hormel , Thomas S. Hwang +7 more | Progress in Retinal and Eye Research

Optical coherence tomography (OCT) as a robust technique for the non-invasive imaging in membrane-based water treatment

2025-06-01
Hongting Wan , Danting Shi , Chu Zhou +4 more | Separation and Purification Technology

Aqueous humor flow in an implantable collamer lens with drain channels

2025-06-01
Z P Wang , Feng Zhang , Tiancai Huang +4 more | Physics of Fluids
An implantable collamer lens (ICL) is a biocompatible artificial lens specifically designed to correct refractive errors in myopic patients with high precision and stability, but postoperative complications are observed after … An implantable collamer lens (ICL) is a biocompatible artificial lens specifically designed to correct refractive errors in myopic patients with high precision and stability, but postoperative complications are observed after ICL implantation surgery. A novel ICL with drain channels is designed to improve the beneficial aqueous humor (AH) flow postoperatively and reduce the risk of visual impairment. This study analyzes the effects of conventional ICL, ICL with a central hole (Hole-ICL), and ICL with a drain channel (scICL) on AH flow. The impact of the geometric parameters of the drain channel in scICL on AH velocity and pupil flow rate is investigated. Additionally, a double-channel ICL (dcICL) is designed to analyze the impact of drain channel symmetry on AH flow. The results indicate the maximum velocities on the posterior chamber (PC) circle line are 2.24×10−6, 2.46×10−6, and 1.23×10−5 m/s for conventional ICL, Hole-ICL, and scICL in an up-facing eye, respectively. In both up-facing and horizontally facing eyes, the pupil flow rate in the scICL increase by 21% and 5.5%, respectively. The AH flow velocity reaches its maximum when the drain channel width is approximately 38% of the total scICL width and a concomitant proximity to the scICL thickness. When the width ratio and depth ratio of the dcICL are equal to zero (analogous to the scICL), the AH flow velocity and pupil flow rate reach their maximum. The scICL presented in this study improves the AH flow, reducing postoperative complications associated with ICL implantation and providing guidance for the clinical myopia treatment.