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Conference 13305
Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXIX
27 - 29 January 2025 | Moscone Center, Room 203 (Level 2 South)
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POST-DEADLINE ABSTRACT SUBMISSIONS
This conference is not accepting post-deadline abstracts.
This conference is not accepting post-deadline abstracts.
BiOS Poster Session - Sunday
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
Conference attendees are invited to attend the BiOS poster session on Sunday evening. Come view the posters, enjoy light refreshments, ask questions, and network with colleagues in your field. Authors of poster papers will be present to answer questions concerning their papers. Attendees are required to wear their conference registration badges to the poster sessions.
Poster Setup: Sunday 10:00 AM - 5:00 PM
Poster authors, view poster presentation guidelines and set-up instructions at https://spie.org/PWPosterGuidelines.
Poster Setup: Sunday 10:00 AM - 5:00 PM
Poster authors, view poster presentation guidelines and set-up instructions at https://spie.org/PWPosterGuidelines.
13305-78
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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The broad application of deconvolution in OCT is hindered by (1) speckle-noise-induced deconvolution artifacts and (2) the time-consuming deconvolution process. To address these issues, we propose a deep-learning-based method for fast OCT deconvolution, which include a speckle noise reduction module and a deconvolution module. We also introduce a lightweight convolutional neural network (CNN) for accelerating the inference processes. With similar performance on artifact-free deconvolution, our method is 2,777 times faster than the state-of-the-art iterative deconvolution algorithm and achieves an average inference time of 1.41 ms for a single B-frame. The number of parameters of our proposed CNN architecture is 2.17 times less than that of U-Net, and the inference is 5 times faster. For the discrete objects in OCT images, our method achieves 50.58% and 60.36% improvements in axial and transverse resolutions, respectively. For the continuous objects, our method achieves an average 13.91 dB improvements in the contrast-to-noise ratio.
13305-79
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Robotics has been leveraged in OCT to extend the scale of imaging. It still has two technical issues that should be addressed before practical applications: (1) For the probe-to-surface control, the rule-based feature extraction is susceptible to imaging artifacts of OCT. (2) The use of ultra-fast swept-sources improves the speed of scanning, but leads to a significant increase in system cost. Here we attempt to address the above issues by introducing a trained U-shape segmentation network for robust surface detection despite OCT imaging artifacts and a cycle-consistent generative adversarial network for efficient, real-time reconstruction of high-resolution OCT images from sparse measurements. It should be noted that the end-to-end, fast inference of trained deep learning models would not degrade the acquisition speed of robotic OCT. We think the adoption of our methods may promote more medical and industrial applications for the robotic-assisted OCT.
13305-80
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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We have demonstrated a coherence-property evaluation of a tunable vertical-cavity surface-emitting laser for swept-source optical coherence tomography by using a 3×3 coupler interferometer, which tells us the time-resolved electric field of the source light. In this study, we improve the method considering time-variance of experimental elements including the 3×3 coupler and apply the method to accurately evaluate the coherence properties. The coherence lengths derived by this method agree well with those derived by the method, we have previously proposed, that relies on the depth variation of the noise floor.
13305-81
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Dynamic optical coherence tomography (DOCT) can contrast intracellular motilities, but it is hard to quantitatively
measure the intracellular motility from DOCT. We propose a method to estimate the intracellular activity type and
its motion parameters from DOCT. We used two DOCT algorithms with OCT images with two resolutions, where all
of them are generated from the same OCT dataset. The method was applied to tumor spheroids and determined the
motion type and the speed of intracellular scatterers.
13305-82
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Zebrafish are important models in biomedicine due to their genetic similarity to humans and cost-effectiveness. Traditional imaging methods often cannot visualize detailed internal structures.
This study utilized Jones-matrix optical coherence tomography (JM-OCT) with a 1,310 nm swept source laser to image a one-year-old zebrafish. Using a 4-frame-repeated scanning protocol, we captured primary contrasts including OCT angiography (OCTA), birefringence, and degree of polarization uniformity (DOPU). Principal component analysis (PCA) synthesized an additional contrast, improving tissue discrimination and revealing fine anatomical structures, such as the neural and hemal arches, with greater clarity which were difficult to interpret in the primary contrasts.
13305-83
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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We demonstrate a spatially coherent full-field OCM hardware, which is specifically designed to be incorporated with computational signal processing. The hardware provides the in-focus lateral resolution of 1.7 µm, but its theoretical depth of focus (DOF) is only 5.5 µm. However, the absence of the confocal effect and additional phase-only spatial frequency filtering can enable post-acquisition extension of the imaging depth up to a few millimeters with a high signal-to-noise ratio.
The cellular-level volumetric imaging of the cancer spheroid is demonstrated over the full depth of the spheroid (around 0.3 mm).
13305-84
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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The last few decades have seen the emergence of a huge number of optical imaging techniques. Among these, full-field optical coherence tomography (FF-OCT) has become valuable for many biomedical applications. Indeed, FF-OCT is a noninvasive and label-free imaging technique that produces high-resolution 3D microscopic images of ex-vivo scattering biological samples without the need for labels. We have developped a single-shot off-axis FF-OCT (SO-FF-OCT) approach that extends these capabilities to in-vivo imaging, enabling the observation of cellular-scale structures in living samples. This advancement is particularly significant for observing active vascularization and cellular activity within living tissues. In this work, we present the first results of Doppler and dynamic imaging using the SO-FF-OCT system, showcasing its potential for real-time, high-resolution imaging in living organisms.
13305-85
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Tumor spheroids, which closely replicate the tumor microenvironment in biological systems, can serve as a viable testing platform for assessing the effectiveness of immune cells in immunotherapy. However, evaluating the efficacy of the cell-based therapy in these models is challenging due to the lack of quantitative imaging tools that enable high-resolution, non-perturbative and real-time analysis for such three-dimensional structures.
Herein, we present an optical coherence tomography (OCT)-based analysis for the quantitative evaluation of the kinetics and cytotoxicity of chimeric antigen receptor (CAR) T cells against tumor spheroids. In addition to the various physical features of the spheroids that can be measured by OCT systems (e.g., diameter, height, and volume), we performed Fourier-based extraction of the attenuation coefficient (AC) in three-dimensional space. These optical and physical parameters were then examined to correlate with and evaluate the kinetics and cytotoxic effects of human epidermal growth factor receptor 2 (HER2) CAR T cells on HER2-positive breast tumor cell spheroids.
13305-86
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Optical coherence tomography (OCT) retinal imaging often faces challenges from subject movement and focus accommodation, disrupting consistent imaging of targeted layers. We present a method utilizing OCT B-scan images and a deep reinforcement learning (DRL) algorithm to correct focus changes and axial shifts. Trained in a simulated environment and refined with transfer learning, the DRL agent provides consistent retinal layer focus and stable imaging.
13305-87
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Speckle is inevitable granular pattern in optical coherence tomography (OCT) images due to its coherent imaging nature. Speckle can obscure fine details and effectively reduce the resolution of OCT images. To address this issue, we present a speckle reduction method based on a new formulation using a dispersed scatterer model. Our method is fully numerical: this method involves digitally generating multiple images with different speckle patterns, called speckle-modulated images (SMIs), and averaging these SMIs. This approach reduces speckle but not resolution because the speckle varies among the SMIs while the shape of the point-spread function for the meaningful OCT part in SMIs does not alter. We validated this method using high-resolution full-field swept-source OCT to image a cancer spheroid. The speckle-reduced images revealed previously obscured cellular structures and cystic formations in a necrotic region.
13305-88
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Colorectal cancer (CRC) is one of the top causes of malignancy. To reduce the burden of colonoscopy, a “leave-in-situ” strategy is being considered. Such a strategy requires accurate evaluation which can be provided by Optical Coherence Tomography. Multi-spectral analysis of en face OCT images, i.e., utilization of images created from narrow spectral bands, was used to classify human colon polyps as benign or malignant. Classification using a DenseNet resulted in accuracy, sensitivity, and specificity of 91%, 94%, and 88%. These preliminary results provide evidence that this method has the potential to improve the accuracy of OCT for applications in CRC.
13305-89
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Keratoconus (KC) is a progressive condition causing corneal thinning and bulging, which leads to visual distortion. Early diagnosis is essential to prevent severe complications like scarring or transplantation. This preliminary study evaluates a custom-built ultrahigh-resolution Polarization-Sensitive Optical Coherence Tomography (UHR-PS-OCT) for early KC detection. We developed a random forest (RF) model to classify eyes as healthy, subclinical keratoconus (SKC), or KC, using data from 255 eyes of 140 subjects—101 healthy, 105 KC, and 49 SKC. The model achieved an AUROC of 0.911, with classification accuracy and recall of 0.820 and precision of 0.804. It excelled in KC classification (98.1%) but showed lower accuracy for SKC. Future research with larger cohorts will aim to validate and refine the model for improved early detection of KC and SKC.
13305-90
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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The most prevalent cancer in Canadian men is prostate cancer. While cancer behavior has been studied extensively with 2D cell culture methods, in recent decades tumor spheroids and other 3D cell culture methods have been employed to better replicate the physiological environment of the body. We recently presented an ultrahigh resolution line-field OCT (LF-OCT) technology and a dynamic OCT (dOCT) method to image tumor spheroids and identify areas of necrosis following radiation treatment, for comparison with computer simulation. Individual cells can be resolved by the LF-OCT system and the dOCT algorithm can resolve sub-cellular dynamic motion. The study investigated the morphological and dynamic behavior of PC3 prostate tumor spheroids over two weeks of growth. These results will be used to inform a computational model of tumor growth.
13305-91
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Colorectal cancer is the second leading cause of cancer-related deaths, highlighting the need for effective screening methods like colonoscopy. Traditional histopathologic analysis of biopsy samples is effective but costly and time-consuming. To alleviate this burden, it is crucial to accurately evaluate polyps in vivo, distinguishing benign from malignant ones. This study proposes a novel methodology using deep learning algorithms to segment and classify polyps from en face ex vivo Optical Coherence Tomography (OCT) images. A DC-UNet-based model classifies samples as benign or with malignant potential, using a dataset of 143 OCT images annotated by a histologist. The model achieved a training accuracy of 98.08%, with preliminary results indicating OCT's potential to improve early detection of colon malignancies and support a leave-in situ approach, reducing colonoscopy-related burdens.
13305-92
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Accelerating chemoresistance testing for personalized cancer care seeks to decrease testing times from months to hours. Chemoresistance assays based on patient-derived xenograft (PDX) models can take months, and it alters the tumor microenvironment. Holographic Dynamic-Contrast Optical Coherence Tomography (OCT), or biodynamic imaging (BDI), offers a potentially faster alternative by providing chemotherapy assay results within 48 hours using patient tumor biopsies. This study tests BET inhibitors on osteosarcoma PDX samples using BDI, comparing the results to traditional PDX models. BDI may offer faster and more effective alternatives for chemotherapy testing and treatment customization.
13305-93
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Suprachoroidal injections (SCI) allow for precise delivery of therapeutic agents to the posterior segment of the eye, targeting specific retinal layers and structures affected by diseases such as macular edema and choroidal neovascularization. This study investigates real-time optical coherence tomography (OCT) monitoring of SCI using a cost-effective customized needle adapted from a commercial insulin needle, which reduces costs significantly compared to specialized suprachoroidal needles. Real-time OCT imaging revealed gradual detachment of the suprachoroidal layer with accumulation of the injected fluid. The injection bleb rapidly diminished and resolved within 20 minutes post-injection. This approach not only enhances the understanding of injection dynamics but also offers potential applications in optimizing therapies for retinal diseases with improved efficacy and reduced procedural costs.
13305-94
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Polarization-Sensitive Optical Coherence Tomography (PS-OCT) is an extension of OCT that provides image contrast based on the polarization state of backscattered light. PS-OCT is a promising tool for non-invasive imaging due to its capability to offer depth-resolved polarization-sensitive contrasts. Among these contrasts, the Degree of Polarization Uniformity (DOPU) is a commonly used metric to represent variations in the polarization state. Depolarization refers to the random change in the polarization state of incident light at spatially adjacent sample locations. However, acquiring DOPU contrasts faces challenges that can impact image resolution. DOPU contrast depends on several factors, such as the incident polarization state, the size and shape of the averaging kernel. In this paper, we demonstrate a novel application of the Complex Inner Product (CIP) of two orthogonal linearly polarized virtual inputs as an alternative way to represent depolarization. CIP is analyzed on different OCT images, and the results show a strong correlation between CIP and DOPU. We compare these two parameters and investigate the advantages and drawbacks of the CIP parameter compared to DOPU.
13305-95
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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An optimized all-fiber Jones matrix optical coherence tomography (JMOCT) system for sensitivity, resolution, and stable phase-retardance is developed for clinical applications. The use of all-fiber components, a simplified balance detection scheme, and the use of only proper hardware dispersion compensation make presented JMOCT simple and easy to adapt to the clinical environment. The importance of hardware dispersion compensation and the verification results for waveplate retardance measurement with different fast axis orientation angles and with different sample arm fiber bendings are presented to demonstrate the clinical suitability of the JMOCT. Together with intensity images, depth-resolved retardance images for different locations of human skin are presented from JMOCT.
13305-96
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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An OCT-A phantom simulating retinal vessels is needed for calibrating OCT systems without flowing scatterers. This method uses Brownian motion of particles in microchannels to create dynamic OCT signal changes, extracting scattering changes through OCT-A operations. In experiments, scatterers were water, ethylene glycol, and glycerol (4.8-51 mPa·s viscosity) with iron(II) phthalocyanine (100-400 nm particles). The channels were sealed with 60 µm and 40 µm widths (100 µm depth). Results showed that OCT-A signal intensity varied with the suspension's viscosity, similar to signals from human retinal arterioles and capillaries. This method could be used for a model eye in OCT-A calibration.
13305-97
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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In this presentation, we demonstrate the generalized representation of optical coherence tomography (OCT) signal and its application to de-speckling and spatial-differential imaging. Here we introduce “shifted-complex-conjugate-product
(SCCP)”, where the complex OCT signal and its complex conjugate are mutually shifted and defocused. Several types of OCT images can be derived from SCCP by taking real part, imaginary part, or phase of SCCP. The imaginary-part
imaging enables volumetric differential contrast (VDC), and the real-part imaging enables OCT speckle modulation. The
phase part provides the Doppler phase of phase-sensitive Doppler OCT. In addition, we also showed that the
conventional OCT intensity image is a specialization of the real part imaging
13305-98
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Dynamic optical coherence tomography (DOCT) is a label-free modality that images intracellular and intratissue motilities of tissue. This study introduces a DOCT simulator using mathematical models to represent seven types of intratissue dynamics, generating dynamic OCT speckle patterns by considering two image formation models and accounting for measurement noise. Our simulation results show that logarithmic intensity variance (LIV), OCT correlation decay speed (OCDS) and amplitude power spectrum (APS) are sensitive to scatterer velocity. The fidelity of DOCT signals is preserved when the signal-to-noise ratio exceeds 30 dB, but they lose responsiveness when it drops below 10 dB.
13305-99
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Polarization Sensitive Optical Coherence Tomography (PS-OCT) provides tissue specific contrast by assessing tissue birefringence and optic axis (OA) orientation. Fiber-based PS-OCT systems suffer from polarization mode dispersion (PMD) due to birefringence induced by the optical fibers. We present a novel numerical method for correcting for PMD. By combining Jones eigenvector analysis with rotational Stokes analysis we construct a wavelength dependent correction matrix. We validate this novel method by simulating PS-OCT measurements. The newly found correction method is able to remove wavelength dependent effects and corect for an overal remaining OA rotation out of the Q-U plane.
13305-100
Switchable lateral resolution real-time MHz-OCT rectoscopy for enhanced colorectal disease diagnosis
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Optical coherence tomography (OCT) provides high-resolution, non-invasive imaging of the rectum. Extending the imaging range would allow a thorough examination, including detecting surface polyps, tumors, and their infiltration depth. This study combines a gradient index (GRIN) fiber for extended-range imaging and a single-mode fiber for standard-resolution imaging within a rigid rectoscope, using a 3.2 MHz-OCT system. A fiber optic MEMS switch enables easy transitions between both modes in real-time. The extended imaging range enables deeper structure visualizations, while the standard resolution offers improved image quality for direct contact assessments, highlighting the system's adaptability and enhanced diagnostic capabilities.
13305-101
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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A framework presented in this study demonstrates an adaptive contour-tracking and scanning strategy significantly improves the wide FoV imaging quality of samples with an uneven surface contour. By employing a high-speed adjustable optical delay line and a pre-scanning scheme, this strategy requires minimal additional time consumption while alleviating spectral sampling rate pressure, thereby enhancing the overall performance of OCT. This advancement holds promise for enhancing OCT imaging in clinical settings, particularly in applications requiring rapid, wide-field imaging of tissue structures and blood flow.
13305-102
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Conventional IV-OCT using a 1300 nm wavelength band does not provide sufficient imaging depth, and it is difficult to distinguish normal tissue from lipid due to low lipid absorption coefficient. To solve this problem, we used a 1700 nm wavelength band that has a low scattering coefficient and high lipid absorption. For spectroscopic analysis, the light source band was separated into two. The lipid absorption of the two bands was compared to analyze the presence and concentration of lipids. The performance of the OCT system was confirmed by imaging phantom samples and ex vivo samples.
13305-103
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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An ultra-high resolution visible light (VIS-)OCT system has been assembled and was used to examine human oral mucosa. With an illumination band of 540 to 930 nm, the system is characterised with maximal measurement depth of zmax = 1.34 mm, while the axial resolution was determined to Δz = (1.4 ± 0.2) µm. The extension of the VIS-OCT system to a polarisation sensitive setup with two single linear input states is discussed, whereat for each input state co- and cross-polarisation are measured. Three possibilities are presented.
13305-104
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Few-mode optical coherence tomography (FM-OCT) is an extension of OCT that exploits higher-order propagation modes to provide new contrast imaging through a mode-selective photonic lantern (MSPL). MSPLS allows efficient multiplexing and demultiplexing mode generation that is lossless (0.5dB}) and has high modal isolation (30dB). A novel four-mode photonic lantern at 1300nm highlights structural differences depending on the scatter size and a different speckle contrast depending on the illumination and detection. To our knowledge, this is the first FM-OCT that implements higher-order modes for illumination and detection, which paves the way for scattering analysis, efficient photon collection, or even speckle reduction.
13305-105
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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We present the development of a prototype for 3D dental imaging using optical coherence tomography (OCT) from multiple angles for the assessment of caries lesions. Therefore, OCT scans were acquired from four different scan directions on an extracted tooth sample and compared with micro computed tomography (µCT). A preliminary validation of the multi-angle data fusion and the advantages thereof in OCT-based caries diagnostics are demonstrated.
13305-106
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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The quality of optical coherence tomography (OCT) images is often compromised by multiple scattering and absorption, leading to reduced contrast, resolution, and limited probing depth. Additionally, unrectified aberrations and a short depth of focus (DOF) from OCT optical components can further degrade spatial resolution and imaging depth. To address these challenges and enable high-resolution imaging of deep tissues, an endoscopic OCT system has been developed using end-to-end learning-based optimization. The design pipeline includes optimizing the free-form mirror for the monolithic endoscope to correct aberrations such as astigmatism, and generating a needle-shaped beam to extend the DOF. A neural network (NN) is jointly trained to retrieve high-resolution images of deep tissue. The proposed method will facilitate OCT to be used for high-resolution deep tissue imaging.
13305-107
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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A deep learning algorithm based on the SVC-Net model to construct optical coherence tomography angiography (OCT-A) images from adjacent OCT images of the dorsal fingernail region in vivo has been explored. Using a spectral domain OCT (SD-OCT) system at a wavelength of 930 nm, we trained a 3N model with three adjacent images and a 5N model with five adjacent OCT B-Scans. Both models follow an encoder-decoder architecture, utilizing EfficientNetB0 as the encoder. Preliminary results show structural similarity index SSIM losses of 0.741 for the 3N model and 0.785 for the 5N model, indicating better generalization in the latter.
13305-108
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Depolarization imaging by polarization-sensitive optical coherence tomography (PS-OCT) is promising in dentistry to detect early carious lesions non-invasively and depth-resolved. The aim of this study is to evaluate the suitability of PS-OCT with examined degree of polarization (DOP) to monitor the progression of de- and remineralization processes using a standardized cyclic in vitro model with bovine enamel slabs. The evaluation of en face and B-scan polarization images show a significant increase in depolarization of the demineralized enamel slabs evident by decreasing DOP values. In summary PS-OCT based depolarization imaging proofed viable for the caries treatment control based on in-vitro studies.
13305-109
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Visible light optical coherence tomography (vis-OCT) is a non-invasive three-dimensional imaging technology that produces cross-sectional images of in vivo biological tissue with micrometer-scale resolution. With a center wavelength of 560 nm, the dispersion coefficient changes more rapidly with depth than near-infrared optical coherence tomography (NIR-OCT) systems. However, most vis-OCT processing workflows do not account for depth-related dispersion compensation. This dispersion mismatch at different depths can significantly degrade axial resolution when imaging the human retina and other biological or nonbiological samples with thicknesses greater than 300 micrometers. To address this issue, we report an automatic depth-dependent dispersion compensation workflow, ensuring consistent axial resolution throughout the entire imaging depth.
13305-110
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Balloon catheters are crucial for procedures such as angioplasty and transcatheter aortic valve replacement. However, they carry a rupture risk, causing complications such as vessel injury and embolization. This study employs visible-light optical coherence tomography (vis-OCT) for high-resolution imaging of balloon folding patterns and, in particular, stress points that often lead to ruptures. By examining commercially available balloons, we aim to understand their mechanical structure and identify design improvements. Using vis-OCT reveals critical details about pleating and microstructural characteristics, offering insights to enhance the safety and reliability of balloon catheters.
13305-111
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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While partially polarized light sources have been commonly used in OCT, the contribution of different states of polarization of the light source to the system's point spread function (PSF) has not been fully studied. This effect can have major implications in imaging, leading to data misinterpretation. This study evaluated the impact of polarization and phase distribution of the source on the PSF of OCT. Three partially polarized light sources with different degrees of polarization were considered for this evaluation. The simulations and experimental evaluations were in good agreement. The study highlighted different PSF patterns associated with the statistics of the phase distribution between two orthogonal x and y axes. This effect was evaluated in ex vivo imaging of the cornea of porcine eyeballs.
13305-112
26 January 2025 • 5:30 PM - 7:00 PM PST | Moscone Center, Room 2003 (Level 2 West)
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Dental imaging is a promising OCT application but has not yet been translated into clinical practice. Current limitations include the visibility of deeper structures, multiple-scattered light and shadowed regions. Here, we show the development of a setup and software for the 3D measurement of teeth from multiple angles and a reconstruction of refraction and optical path delay in the OCT volumes based on a surface segmentation and an estimated refractive index. The reconstruction using Snell’s law is validate by a comparison with X-ray micro-computed tomography (µCT) and the spatial registration of both volumes.
Biophotonics Focus: Nanophotonics and Imaging
26 January 2025 • 7:00 PM - 9:00 PM PST | Moscone Center, Room 305 (Level 3 South)
Hear experts working with nanotechnology and various imaging modalities describe how these tools can work together to advance diagnostics and therapeutics. All technical registration attendees are invited to attend.
Session 1:
Memorial Session for Professor Joe Izatt
27 January 2025 • 8:30 AM - 9:45 AM PST | Moscone Center, Room 203 (Level 2 South)
Session Chairs:
Rainer A. Leitgeb, Medizinische Univ. Wien (Austria), Yoshiaki Yasuno, Univ. of Tsukuba (Japan)
With the passing of Professor Joseph Izatt, our community has lost a visionary pioneer, a dedicated mentor, and spirit of our OCT conference from its inception. This session, held in his honor, celebrates his prolific and exemplary career through invited talks by close collaborators and friends, who will share reflections on their work with him at various stages of his remarkable academic journey.
https://spie.org/news/joseph-izatt-obit
Break
Coffee Break 9:45 AM - 10:15 AM
Session 2:
Dynamic Contrast OCT
27 January 2025 • 10:15 AM - 11:45 AM PST | Moscone Center, Room 203 (Level 2 South)
Session Chair:
Kostadinka Bizheva, Univ. of Waterloo (Canada)
13305-1
27 January 2025 • 10:15 AM - 10:30 AM PST | Moscone Center, Room 203 (Level 2 South)
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We demonstrate a 3.2 MHz-OCT system for inter-volume dynamic optical coherence tomography of ex vivo porcine tissue. Employing a home-built Fourier Domain mode-locked (FDML) laser with a 1310 nm wavelength, the system achieved a lateral resolution of 1.74 µm and a frame rate of 610 Hz. A motorized XYZ positioning stage allowed for precise acquisition of multiple volumes, which were then stitched together to create a dataset with a total scan area of 2.6 x 2.6 mm². Validations against histological sections confirmed the system’s ability to represent dynamic tissue processes accurately.
13305-2
27 January 2025 • 10:30 AM - 10:45 AM PST | Moscone Center, Room 203 (Level 2 South)
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We demonstrate a meta-contrast of dynamic optical coherence tomography (DOCT), so-called “multi-dynamics OCT,” which is generated by fusing multiple types of DOCT contrasts. The multi-dynamics OCT reveals complicated dynamics domains of anti-cancer-drug-treated tumor spheroids and an ex vivo mouse organ, that are obscured in conventional single-contrast DOCT images. In addition, a numerical simulation based on a mathematical model of biological sample dynamics clarifies the relationships between each DOCT contrast and the intra-tissue and intra-cellular dynamics. The combination of the multi-dynamics OCT and the DOCT interpretation enhances the subjective observation and objective interpretation ability of DOCT.
13305-3
27 January 2025 • 10:45 AM - 11:00 AM PST | Moscone Center, Room 203 (Level 2 South)
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Dynamic optical coherence tomography (DOCT) methods have been developed for tissue dynamics imaging. The amplitude-spectral (AS-) DOCT method, which evaluates intracellular motility utilizing the time-order information of many OCT frames for frequency analysis, suffers from slow imaging speed. To address this, a neural network (NN), which can extract time-order information and generate AS-DOCT images from only 16 OCT frames, is proposed. In validations using breast and colon cancer spheroids and zebrafish, the generated AS_OCT images showed high structural similarity to conventional AS-OCT images. The NN-based method significantly reduces the number of required OCT frames (96.9% reduction), enabling volumetric imaging in 26 s.
13305-4
27 January 2025 • 11:00 AM - 11:15 AM PST | Moscone Center, Room 203 (Level 2 South)
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Dynamic contrast optical coherence tomography (DyC-OCT) is a novel imaging technology for enhancing the contrast of OCT by generating the fluctuation feature maps of repeated OCT signal at the same positions. However, the features that DyC-OCT currently uses are limited to single type, and the choice of features is empirical. Here we propose a novel unsupervised machine learning pipeline, to generate DyC-OCT images by extracting representative features from large feature set and differentiate structures in tissues by clustering based on those extracted features. This pipeline can allow employing any feature sets to generate DyC-OCT images and provide a criterion to evaluate the ability of each feature to differentiate structures in tissue, thus provide insight into robust choice of features. This unsupervised machine learning pipeline can provide generalized methodology for generating DyC-OCT images in various type of tissues.
13305-5
27 January 2025 • 11:15 AM - 11:30 AM PST | Moscone Center, Room 203 (Level 2 South)
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Speckle variance optical coherence tomography (SV-OCT) is a non-invasive imaging technique that captures variations in speckle patterns caused by the motion of red blood cells to map blood flow in tissue. However, a common challenge with these algorithms is distinguishing between signal intensity variance due to blood flow and that caused by non-motion signals, such as shot noise, which reduces image contrast. Here, we use a quantified SV (qSV) algorithm for OCT imaging that effectively mitigates the influence of system noise, thereby quantifying intensity fluctuations arising due to motion. We validate the qSV algorithm by testing it on a phantom system with intralipid flowing through a thick tube embedded in gel, where it successfully normalizes the depth-dependent variation in SV intensity and preserves image contrast at greater depths. Additionally, our qSV measurements of human blood flow demonstrate high contrast, even for deeper vascular structures.
13305-6
27 January 2025 • 11:30 AM - 11:45 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
OCT is transitioning from a diagnostic tool to one that also aids in treatment. However, structural imaging is difficult to visualize the therapeutic field of minimally invasive thermal treatment, such as laser or radiofrequency ablation, due to the fact that the optical properties of the tissue are less altered during the temperature increase prior to denaturation of the tissue (~50 ℃). We propose a new contrast mechanism—speckle decorrelation rate—which provides a robust indicator for visualizing therapeutic thermal field with higher signal-to-noise ratios and less sensitivity to time interval selection, compared with the speckle decorrelation employed in existing works. Our method, validated on various biological tissues, is label-free and compatible with various OCT setups, potentially enhancing the precision and safety of thermal treatments.
Break
Lunch Break 11:45 AM - 1:15 PM
Session 3:
Ophthalmic OCT: Instrumentation and Methods
27 January 2025 • 1:15 PM - 3:15 PM PST | Moscone Center, Room 203 (Level 2 South)
Session Chair:
James G. Fujimoto, Massachusetts Institute of Technology (United States)
13305-7
27 January 2025 • 1:15 PM - 1:30 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Handheld OCT enables point-of-care retinal diagnostic imaging in bedridden and pediatric patients. These point-of-care imaging devices are commonly prototyped with methods that preclude sustained system alignment or result in heavy form factors that limit clinical translatability. Here, we present a multimodal handheld spectrally encoded coherence tomography and reflectometry (HH-SECTR) probe designed with finite element analysis and topology optimization to achieve an ergonomic and lightweight aluminum design with micron-scale mechanical stability for sustained alignment during clinical deployment. These methods can be broadly applied to optimize weight and mechanical stability in handheld imaging system designs.
13305-8
27 January 2025 • 1:30 PM - 1:45 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Anterior segment OCT aids in clinical assessment of anterior eye diseases and corneal structure in the clinic, but it is affected by speckle and angularly dependent backscattering intensity. Multi-angle optical coherence tomography (OCT) of the anterior segment can counteract these two angularly dependent phenomena to produce clearer visualizations with reduced speckle. We present a robotic multi-angle OCT system equipped with robotic pupil alignment capabilities and in-line high-resolution monochrome photography. The OCT sample arm, high-resolution camera, and three pupil-tracking cameras sit within a robot-mounted scan head at a 70 mm working distance. We rotate the system incrementally around the cornea to capture varying views of the eye, imaging the entire anterior segment with the 250 kHz swept-source OCT (~23 µm resolution) and the monochrome camera (>25 lp/mm). We acquire multi-angle B-scans of an anterior eye phantom (-20°–20°), perform dual-surface refraction correction, register the images, and merge them to yield clearer visualization of the cornea.
13305-9
27 January 2025 • 1:45 PM - 2:00 PM PST | Moscone Center, Room 203 (Level 2 South)
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We introduced an advanced panoramic retinal (panretinal) handheld swept-source OCT angiography (OCTA) system with an 800 kHz VCSEL light source, achieving a remarkable 140° field of view. Enhanced with a customized relay lens and a widefield eyepiece, the system’s optical design improved overall performance. The panretinal handheld OCT/OCTA system showcased detailed en face OCT and OCTA images of the posterior pole and retinal periphery, facilitating differentiation of the vascular-avascular border in retinopathy of prematurity cases. This technology provided valuable insights into retinal periphery pathologies, promising early detection and improved management of ocular disorders, aiming to enhance patient outcomes and care quality.
13305-10
27 January 2025 • 2:00 PM - 2:15 PM PST | Moscone Center, Room 203 (Level 2 South)
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Handheld optical coherence tomography (OCT) is a useful imaging modality for assessing and monitoring retinal disease in pediatric patients. However, acquiring consistent and repeatable data in this population remains difficult, even with trained operators. Here we propose a novel handheld device capable of optical auto-alignment with the pupil to account for subject and operator motion and mitigate resulting artifacts. We evaluate our device for use in ongoing clinical studies in pediatric subjects. We believe our device has the potential to increase accessibility and improve repeatability and reproducibility of OCT imaging in children and neonates.
13305-11
27 January 2025 • 2:15 PM - 2:30 PM PST | Moscone Center, Room 203 (Level 2 South)
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The biomechanical properties of the cornea can provide important information for assessing ocular health. Optical coherence elastography (OCE) is a pre-clinical technique for imaging the biomechanical properties of tissues. Typically, OCE involves inducing a force upon a tissue using an active excitation source and imaging the tissue response to that force using optical coherence tomography (OCT). In this study, we demonstrate the first use of in vivo, noncontact, heartbeat OCE (Hb-OCE), a passive imaging technique for assessing the biomechanical properties of the cornea in a rabbit and in a human subject. Future work will focus on live biomechanical mapping of the cornea.
13305-12
27 January 2025 • 2:30 PM - 2:45 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Deep-learning-based OCT segmentation methods are accurate but less flexible (need re-labeling and re-training) for unseen and varying Regions Of Interest (ROIs), which hinders their applications in many scenarios, such as surgical and navigation. Inspired by the recent emerging large vision models and their zero-shot capabilities (directly applicable to unseen ROIs), we propose a zero-shot OCT segmentation method. For volumetric and live-streaming data, it only requires the box or point prompts of ROIs at the first frame, then subsequent frames could be segmented automatically. Its superiority has been verified on publicly-available OCT datasets and the datasets collected via our home-built OCT systems. Along with the excellent generalization capability, our method also combines the high accuracy and real-time advantages of deep learning, which makes it promising to become a general-purpose analysis tool in the graphical user interface of OCT devices.
13305-13
27 January 2025 • 2:45 PM - 3:00 PM PST | Moscone Center, Room 203 (Level 2 South)
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We present a 4-channel multi-beam space division multiplexing optical coherence tomography (SDM-OCT) system for high-speed, wide-field angiographic imaging of the human retina. This system employs a swept-source laser at 1060 nm with a 200 kHz sweep rate, achieving an effective 800,000 A-scans per second. Our SDM-OCT setup, built with commercial optical components, integrates a customized stitching and flattening algorithm to enhance image quality. Preliminary tests on healthy volunteers demonstrate the system’s ability to produce high-resolution structural and angiographic OCT images, suggesting potential clinical application in ophthalmology.
13305-14
27 January 2025 • 3:00 PM - 3:15 PM PST | Moscone Center, Room 203 (Level 2 South)
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We present an ultra-thin 125 µm fiber distance sensor probe which is interrogated by a 1060 nm swept source OCT based common-path interferometer, developed for vitreoretinal microsurgery integration. The long proximal section is a single mode fiber; the sub-millimeter distal assembly integrates a beam expanding no-core fiber section, followed by multimode graded index fiber as a focusing lens, gold sputtered to prevent index matching. The focused spot size is approximately 10 µm at a working distance of approximately 630 µm, a range of 2 mm, both in air and water, with an axial resolution better than 20 µm.
Break
Coffee Break 3:15 PM - 3:45 PM
Session 4:
Functional and Advanced Retinal Imaging
27 January 2025 • 3:45 PM - 5:45 PM PST | Moscone Center, Room 203 (Level 2 South)
Session Chair:
Ruikang K. Wang, Univ. of Washington (United States)
13305-15
27 January 2025 • 3:45 PM - 4:00 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
The differential diagnosis of uveitis is broad and challenging. A key indicator of ocular inflammation is the presence of cells in the aqueous or vitreous humor. We developed a lightweight convolutional neural network (CNN) model to classify inflammatory cell types with ultrahigh-resolution optical coherence tomography (OCT). OCT images of known cell types (mononuclear cells and granulocytes) were used to train and optimize the model. The CNN model achieved an accuracy of 88.4 ± 0.7% with an area under the receiver operating characteristic curve (AUC) of 94.3 ± 0.4%. This method is valuable for uveitis diagnosis and monitoring of intraocular inflammation.
13305-16
27 January 2025 • 4:00 PM - 4:15 PM PST | Moscone Center, Room 203 (Level 2 South)
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This work presents the adaptation of an in-vivo signal processing technique for in-vitro applications, allowing for non-invasive assessment of photoreceptor function in retinal samples using dynamic full-field optical coherence tomography (D-FF-OCT). By analyzing the response of macaque retinal explants to visible light stimulation, we demonstrate the effectiveness of this method in evaluating cellular behavior and photoreceptor function. This innovative approach holds significant potential for disease modeling and therapy testing on retinal samples, including applications in stem cell-derived organoids and patient-derived cells. Our findings show feasability of optophysiology using D-FF-OCT.
13305-17
Combined OCT+ERG system for imaging neurovascular coupling in the healthy and diseased rodent retina
27 January 2025 • 4:15 PM - 4:30 PM PST | Moscone Center, Room 203 (Level 2 South)
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Neurodegenerative retinal diseases such as Retinitis Pigmentosa, Diabetic retinopathy, AMD and Glaucoma cause progressive loss of retinal neuronal function and eventually apoptosis of retinal neurons. We have developed a combined OCT+ERG system capable of simultaneous imaging of retinal morphology, probing of retinal function (ORG – optoretinography and ERG – electroretinography) and visually evoked transient changes of the retinal blood flow. This technology allows for non-invasive probing of retinal neurovascular coupling with high spatial and temporal resolution. The performance of the novel OCT+ERG system was tested in-vivo in healthy and diseased rat retinas.
13305-18
27 January 2025 • 4:30 PM - 4:45 PM PST | Moscone Center, Room 203 (Level 2 South)
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We present our progress on optoretinography (ORG) using optical coherence tomography (OCT) for human retinal imaging. The image data was acquired with a bespoke instrument providing visual stimulus and synchronized acquisition of the OCT data.
13305-19
27 January 2025 • 4:45 PM - 5:00 PM PST | Moscone Center, Room 203 (Level 2 South)
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Neurovascular coupling in the human retina refers to the transient increase in the retinal blood flow (RBF) caused by an increased metabolic demand of the retinal neurons associated with the visual simulation of the retina. Retinal neurodegenerative diseases such as Glaucoma have been linked with decreased RBF, in addition to abnormalities in the elasticity of the blood vessels’ walls. In this study, a research-grade, high-resolution Functional OCT system is used to investigate flicker-stimulus-induced color dependence of neurovascular coupling in retinal blood vessels around the Optic Nerve Head (ONH).
13305-20
27 January 2025 • 5:00 PM - 5:15 PM PST | Moscone Center, Room 203 (Level 2 South)
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Adaptive-optics optical coherence tomography (AO-OCT) can resolve cellular-scale structures in the retina and their dynamics. However, the hardware and software complexity have restricted its spreading at research level and clinical translation. Wavefront sensorless (WS) AO-OCT profiles as an alternative with simplified hardware but software control is still complex as current paradigm require motion-free volume reconstruction at real-time achieved using GPU. We propose to drive the WSAO optimization with the spectral fringes modulation, eliminating the need for tomogram reconstruction and increasing the robustness against axial motion, and demonstrate the performance in human retina imaging with 11 Zernike modes correction in 1.4 s.
13305-21
27 January 2025 • 5:15 PM - 5:30 PM PST | Moscone Center, Room 203 (Level 2 South)
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In this study, a micro-optical coherence tomography (µOCT) system is employed for label-free microscopic imaging of ex vivo ocular tissue samples. The implementation of a defocus correction algorithm that corrects bulk phase error and applies numerically calculated 2D phase-based spatial refocus filters enabled the acquisition of high-resolution in-focus microscopic ocular tissue images throughout the imaging depths in a single shot.
13305-22
27 January 2025 • 5:30 PM - 5:45 PM PST | Moscone Center, Room 203 (Level 2 South)
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This study aims to establish an optimal scanning protocol for effective visualization of the choriocapillaris (CC) using a 1.6 MHz FDML OCT system. A step-bidirectional scanning method is employed along with a buffer averaging approach. We investigate three different interscan times (1-ms, 2-ms, & 3-ms) on repeated B-scans and find that shorter interscan times provide clear CC vasculature. Additionally, we examine CC imaging across three different repeated B-scan sets (4, 5 & 6), observing similar vascular patterns in all. We conclude that a combination of shorter interscan time with the four BM scan protocol and step-bidirectional scanning with buffer averaging is the optimum scanning protocol for effectively visualizing the CC.
Session 5:
Polarization-Sensitive OCT: Clinical Translation
28 January 2025 • 8:15 AM - 10:55 AM PST | Moscone Center, Room 203 (Level 2 South)
Session Chair:
Johannes F. de Boer, Vrije Univ. Amsterdam (Netherlands)
13305-23
28 January 2025 • 8:15 AM - 8:35 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Atrial fibrillation has reached a global prevalence of over 60 million, and as the population ages, this number is expected to grow rapidly. A common treatment option is catheter ablation. The main goal of the treatment is to cause thermal damage that electrically isolates ectopic beats from the rest of the atrium. Unfortunately, insufficient intraoperative feedback means clinicians lack the tools necessary to predict treatment durability. Around 30% of treatments fail over time due to remodeling during healing or incomplete lesions that allow electrical reconnection of the arrhythmic region to the rest of the tissue. We have designed and fabricated a multi-modal catheter to collect polarization sensitive optical coherence tomography simultaneously with near infrared spectroscopy to enable clinicians to visualize atrial tissue at the tip of the catheter. This catheter will enable new in vivo experiments that could help determine how these two optical measurements can be used to predict lesion durability.
13305-24
28 January 2025 • 8:35 AM - 8:55 AM PST | Moscone Center, Room 203 (Level 2 South)
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PS-OCT imaging of retinal blood vessels in patients with various stages of hypertension, diabetes, and CAD from Fiona Stanley Hospital suggests a link between arterial health and CAD. This study aims to determine if arterial condition is a predictor of Coronary artery health. The analysis focuses on the retinal vessel wall thickness and birefringence. Previous research demonstrated that combining vessel wall structure and thickness measurements accurately identifies hypertension and diabetes. Current findings show retinal blood vessels can indicate CAD severity and aid patient stratification. PS-OCT detects minute cardiovascular changes before clinical manifestation, offering an inexpensive, non-invasive, and easily applicable screening method, particularly beneficial for underserved communities.
13305-25
28 January 2025 • 8:55 AM - 9:15 AM PST | Moscone Center, Room 203 (Level 2 South)
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Idiopathic pulmonary fibrosis (IPF), characterized by excessive collagen deposition in the lung, has widely variable prognosis that is difficult to predict but is important in therapeutic decision-making for individual patients. Polarization-sensitive endobronchial optical coherence tomography (PS-EB-OCT) is a bronchoscope-compatible volumetric imaging modality that detects in-vivo microscopic disease features of IPF and simultaneously visualizes collagen orientation. Here, we demonstrate the utility of in-vivo collagen orientation assessment using PS-EB-OCT as a novel, patient-specific optical biomarker to predict prognosis in subjects with early IPF.
13305-26
28 January 2025 • 9:15 AM - 9:35 AM PST | Moscone Center, Room 203 (Level 2 South)
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This study investigated the use of polarization-sensitive optical coherence tomography (PS-OCT) to assess the damage in the retina nerve fiber layer (RNFL) in glaucoma. Parameters such as retinal retardance (RR), measured by PS-OCT, and RNFL thickness (RNFLT), measured by OCT, were correlated with visual field (VF) tests in a clinical cohort (49 healthy individuals and 68 patients with various stages of glaucoma). We found that RR showed better association with VF-MD than RNFLT in glaucomatous eyes, especially in advanced cases. PS-OCT has the potential in evaluating the RNFL damage in eyes with severe glaucoma, addressing a current challenge in clinics.
13305-27
28 January 2025 • 9:35 AM - 9:55 AM PST | Moscone Center, Room 203 (Level 2 South)
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The study investigated the correlation between conventional caries detection methods and polarization-sensitive optical coherence tomography (PS-OCT), a non-invasive, radiation-free optical technique. Twenty Human extracted carious teeth were examined visually and radiographically by dentists, and PS-OCT images were acquired. Early detection of proximal lesions was achieved through intensity-based OCT cross-sectional images. The degree of polarization effectively distinguished proximal caries from healthy tooth structure. These results suggest potential for reducing invasive filling therapy by enabling early intervention opportunities. PS-OCT holds promise as a valuable tool for improved caries diagnosis and preventive dental care.
13305-28
28 January 2025 • 9:55 AM - 10:15 AM PST | Moscone Center, Room 203 (Level 2 South)
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We employed a 1700nm swept-source PS-OCT to image fibrous collagen in fibrotic lung tissue through phase retardation images. To confirm the fibrous collagen, we utilized SHG signal imaging from two-photon microscope. The SHG signal was generated specifically in fibrous collagen tissue. In conclusion, the comparison between the phase retardation images and SHG images demonstrated that the PS-OCT system can be useful in detecting pulmonary fibrosis.
13305-29
28 January 2025 • 10:15 AM - 10:35 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Cardiovascular diseases are a leading cause of death. About fifty percent of patients who have a heart attack did not know they had a cardiovascular disease. Screening with a low-cost and non-invasive tool can help to save lives.
A low degree of polarization uniformity (DOPU) and high double pass phase retardation (DPPR) values below the retinal-pigment epithelium – Bruch membrane’s (RPE-BM) complex in the human retina have been associated with hypertension. At Photonics West 2023, we showed measurements which demonstrated a strong correlation between high DPPR values induced by the RPE-BM complex and hypertension, suggesting that the induced retardance is the result of physiological changes associated with hypertension. This year, we analyzed data from patients diagnosed with coronary artery disease (CAD) through computed tomography coronary angiography (CTCA). Patients were categorized as either mild, moderate or severe, based on the amount of stenosis in their CTCA scans.
13305-30
28 January 2025 • 10:35 AM - 10:55 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Liver transplantation for severe hepatic diseases faces a critical shortage of donor livers globally. Utilizing marginal donor livers could alleviate this issue, yet current biopsy-based assessments are limited in evaluating their viability comprehensively. We propose employing polarization-sensitive optical coherence tomography (PS-OCT) to noninvasively scan multiple regions of donor livers, providing detailed microstructural and tissue property evaluations. Our approach integrates texture feature extraction and machine learning to correlate PS-OCT findings with pathological assessments, demonstrating its potential to enhance pre-transplantation viability evaluations. PS-OCT offers a promising tool for transplant clinics, offering precise, noninvasive insights into liver tissue quality across entire donor organs.
Session 6:
Preclinical Imaging
28 January 2025 • 10:45 AM - 12:15 PM PST | Moscone Center, Room 203 (Level 2 South)
Session Chair:
Xingde Li, Johns Hopkins Univ. (United States)
13305-31
28 January 2025 • 10:45 AM - 11:00 AM PST | Moscone Center, Room 203 (Level 2 South)
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During early embryonic development, critical biomechanical processes occur in embryo growth. In this work, reverberant optical coherence elastography (RevOCE) using multifocal acoustic radiation force was used to map the stiffness of cultured mouse embryos while still inside the yolk sac. Embryos at gestational days 8.5 were dissected and placed on a 1% (w/w) agarose to be imaged with a phase-sensitive OCT system. The ARF multifocal beam at a frequency of 1 kHz was focused on the embryos for RevOCE. This elastography technique enabled high-resolution stiffness mapping of whole embryos in 3D without external contrast agents or potentially damaging mechanical excitation.
13305-32
28 January 2025 • 11:00 AM - 11:15 AM PST | Moscone Center, Room 203 (Level 2 South)
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Ischemic stroke is associated with significant morbidity and mortality due to severe microvascular flow disruptions. We developed a high-resolution, volumetric assessment framework employing Bessel beam optical coherence microscopy to analyze flow alterations in cerebral microvasculature across the pial, penetrating and capillary blood vessels. The method combines angiographic and Doppler data with advanced segmentation techniques for detailed blood flow analysis. Experiments in living mice show significant reduction of blood flow velocity and capillary density following middle cerebral artery occlusion, underscoring the stroke's impact. Our framework advances stroke research by enabling detailed, multiscale comparisons across large datasets.
13305-33
28 January 2025 • 11:15 AM - 11:30 AM PST | Moscone Center, Room 203 (Level 2 South)
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Optical brain imaging has several advantages over other imaging techniques and was used to visualize both the structural and functional aspects of the brain, providing a more complete picture of brain activity. One of the promising techniques is optical coherence tomography (OCT), which uses low-coherence interferometry to obtain three-dimensional depth-resolved imaging of structures. In this research, we present a miniaturized head-mount Doppler OCT system tailored for high-resolution brain imaging in freely moving mice, providing an advanced non-invasive imaging tool in neuroscience research. With a maximum 4×4 mm field of view, 7.4µm axial resolution, the system offers reliable imaging capabilities. Its compact design and comprehensive imaging capabilities make it well-suited for studying various brain regions and dynamic processes, contributing significantly to our understanding of brain function and pathology.
13305-34
28 January 2025 • 11:30 AM - 11:45 AM PST | Moscone Center, Room 203 (Level 2 South)
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The selection of high-quality embryos is essential to enhance the implantation rate for in vitro fertilization (IVF). Optical coherence microscopy (OCM) can provide 3D label-free high-resolution imaging of embryos. The microstructures can assist in embryo evaluation and understanding embryo development. Here, we acquired time-lapse 3D OCM images with co-registered bright-field imaging on mouse embryos from the one-cell stage to blastocysts inside an incubator, demonstrating the structural features of the embryos. The second and third embryo’s cell cycle suggested a relationship between blastocyst formation and the hatching capability. OCM-based time-lapse technology is promising to enrich insights and help embryo selection for IVF.
13305-35
28 January 2025 • 11:45 AM - 12:00 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Non-human primates have been considered an excellent model for gene-related retinal disease research. Marmosets, one of the non-human primates with visual optics like humans, have the advantage of transgenic modification with rapid generation changes. It is well known that optical coherence tomography (OCT) and OCT-angiography (OCTA) are powerful tools for diagnosing and managing retina diseases. However, commercialized OCT designed for humans was unsuitable for 3-D retinal morphological and vascular (angiography) images of a marmoset. In this study, we developed a real-time wide field of view spectral-domain OCT (SD-OCT) to obtain retinal cross-sectional and angiographic images of the marmoset. We could obtain high-resolution cross-section images of both the optic nerve and fovea of the marmoset in a single image and visualize the retinal blood vessel networks clearly. In addition, our SD-OCT could obtain the retinal image of not only animals (mouse and marmoset) but also humans as a single system.
13305-36
28 January 2025 • 12:00 PM - 12:15 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Optical coherence tomography (OCT) is a powerful non-invasive imaging technique for biomedical research, providing high-resolution three-dimensional images of biological tissues. However, accurately segmenting regions-of-interest from large 3D images is challenging and often relies on manual processes that are labor-intensive, subjective, and prone to inter-operator variability. This is particularly true in dynamic processes like wound healing, where tissue structures continuously evolve. This study introduces a U-Net neural network model for automatic segmentation of 3D OCT images from mouse wound models treated with dextran-based hydrogels. The network achieves 85.5% per-pixel validation accuracy in identifying eight structural subtypes, with the same model operating across the entire 14-day healing period. This approach enabled longitudinal in vivo monitoring of hydrogel volume and degradation, providing valuable insights into wound healing dynamics and treatment efficiency without the need for invasive biopsies.
Session 7:
Polarization Sensitive OCT: Technologies
28 January 2025 • 1:45 PM - 3:15 PM PST | Moscone Center, Room 203 (Level 2 South)
Session Chair:
Bernhard Baumann, Medizinische Univ. Wien (Austria)
13305-37
28 January 2025 • 1:45 PM - 2:00 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Polarization-sensitive optical coherence tomography (PS-OCT) is a high-resolution imaging technique that provides additional contrast for many biological tissues by measuring polarization properties such as retardance and diattenuation. Dual alternating input-state PS-OCT sequentially alters the polarization state incident on the sample, offering a simplified optical design, but until now has relied on the assumption that the sample acts as a pure retarder, precluding measurements of diattenuation. In this study, a maximum likelihood based signal processing framework is employed that capitalizes on the round-trip geometry of OCT to enable diattenuation measurements in these systems.
13305-38
28 January 2025 • 2:00 PM - 2:15 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Speckle noise is inevitable in polarization-sensitive optical coherence tomography and complicates the retrieval of accurate retardance and optic axis orientation values. Here, we propose a novel unsupervised machine learning method, termed Stokes2Stokes (S2S), which learns how to convert speckle-corrupted Stokes vectors from the measured tomograms into clean, denoised Stokes vectors. Leveraging recent advances in machine learning and Noise2Noise algorithms, it is possible to train a deep neural network to infer denoised Stokes vectors without having a clean target and instead using an independent speckle realization as target. We accomplish this by utilizing the independent speckle realizations across spectral bins to generate suitable training pairs for the S2S model. We furthermore account for possible polarization mode dispersion by aligning the Stokes vectors across spectral bins. We reconstruct depth-resolved tissue birefringence from the denoised Stokes vectors, which avoids blurring artifacts encountered in the conventional approach of spatially filtering Stokes vectors.
13305-39
28 January 2025 • 2:15 PM - 2:30 PM PST | Moscone Center, Room 203 (Level 2 South)
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The framework presented in this study demonstrates that Eigen decomposition significantly minimizes flow-induced uncertainty in polarization-sensitive optical coherence tomography imaging. By extracting the static components through Eigen decomposition, the impact of dynamic blood flow on the polarization measurements of the underlying sample is suppressed. Our phantom study shows that this method significantly reduces the effect of overlying blood flow on measuring the birefringent properties of the underlying sample. We further validate this approach through in vivo imaging of the human nail fold.
13305-40
28 January 2025 • 2:30 PM - 2:45 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
PS-OCT visualizes microstructure by measuring the pathlength difference, amplitude, and polarization states of backscattered light. Speckle causes noise-like effects in PS-OCT scans due to small scattering structures. We modeled the effect of speckle on PS-OCT scans and analyzed changes in the degree of polarization (DOP) and depth-resolved retardance throughout a birefringent medium. We also characterized the reduction of noise in PS-OCT data with Stokes vector filtering. Determining the underlying properties of PS-OCT data is an important step to developing future noise compensation and reduction methods for characterizing ground-truth data and improving scan interpretability.
13305-41
28 January 2025 • 2:45 PM - 3:00 PM PST | Moscone Center, Room 203 (Level 2 South)
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The OCT system requires an optimal wavelength for imaging, considering the scattering and absorption of light that vary depending on the wavelength. Depolarization, which is influenced by scattering, scrambles polarization information, leading to noisy polarization imaging. In this study, we developed a swept-source PS-OCT using a wavelength of 1700 nm, chosen for its lower scattering coefficient compared to the 1300 nm, to achieve high-contrast brain myeline imaging. To quantitatively evaluate the polarization image, we defined the phase noise ratio(PNR). In conclusion, using a 1700 nm enables the acquisition of polarzied images with less noise compared to 1300 nm for brain myelin imaging.
13305-42
28 January 2025 • 3:00 PM - 3:15 PM PST | Moscone Center, Room 203 (Level 2 South)
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No diagnostic method is currently available to visualize and measure the airway smooth muscle (ASM) within a living patient. Endoscopic Polarization Sensitive Optical Coherence Tomography (PS-OCT) has the potential to detect and quantify ASM mass in vivo, by assessing tissue birefringence. An in-house built 1.35 mm diameter distal scanning catheter was used to perform in-vivo PS-OCT in patients with asthma (n=1), interstitial lung diseases (n=14) and healthy volunteers (n=2). We demonstrated PS-OCT to be a minimally invasive technique to detect airway remodeling and an increased ASM percentage in asthma and ILD relative to healthy subjects.
Session 8:
Imaging Cancer and Tissue Pathology
28 January 2025 • 3:45 PM - 5:30 PM PST | Moscone Center, Room 203 (Level 2 South)
Session Chair:
Christine P. Hendon, Columbia Univ. (United States)
13305-43
28 January 2025 • 3:45 PM - 4:00 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Immuno-OCT is a dual-modality imaging technique combining OCT and molecular sensitive imaging, with the use of fluorescently labelled monoclonal antibodies, to provide both morphological information and co-localised molecular contrast. We present the use of a novel capsule endoscope with a double clad fiber. Immuno-OCT was applied to imaging the esophagus in vivo of Barrett’s esophagus patients, where monitoring Barrett’s esophagus is crucial to early-stage detection of esophageal adenocarcinoma. To date, two patients have been imaged in vivo, after prior intravenous administration of bevacizumab-800CW. Initial data demonstrates good in vivo imaging stability and sensitivity to fluorescent tracer.
13305-44
28 January 2025 • 4:00 PM - 4:15 PM PST | Moscone Center, Room 203 (Level 2 South)
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Detecting the specificity of cancer cells is an important step in cancer diagnosis. Needle biopsy obtains samples of cells from e.g. a tumor to extract tissue or fluid samples from suspected organs. Analyzing these cells could reveal e.g.a cyst, an infection, a benign tumor or cancer. Recent research has hypothesized that extrachromosomal circular DNA (eccDNA) could be considered a new hallmark of cancer. In the present research using Full Field Optical Transmission Tomography with high NA microscope objective on 3 different living cancer cells nuclei we have observed circular ring structures in the micrometer range that could be assigned to eccDNA.
13305-45
28 January 2025 • 4:15 PM - 4:30 PM PST | Moscone Center, Room 203 (Level 2 South)
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We present an integrated system of DOCT and a portable cell-cultivation chamber. It enabled longitudinal imaging of a single or multiple spheroids over several days. The system was utilized for longitudinal (over 100 hours) tracking of several human breast cancer (MCF-7) spheroids treated with different concentrations of doxorubicin. In addition, high time-resolution longitudinal imaging of a single sample was performed. The proposed system is capable of fine time-lapse drug response analysis through its high-time resolution. In addition, it is less affected by inter-sample variation and the disruption of the time-course results caused by the sample transfer during the pseudo-longitudinal studies.
13305-46
28 January 2025 • 4:30 PM - 4:45 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
By mapping tissue elasticity on the micro-scale, optical coherence elastography (OCE) can improve the identification of breast cancer. Whilst OCE shows promise in intraoperative margin assessment, the mechanical models used assume uniaxial stress throughout the sample. Tissue is heterogeneous and exhibits compressible and anisotropic features. This invalidates the underlying assumption and reduces the accuracy of OCE. Here, we enhance the OCE contrast by utilizing tissue heterogeneity, termed the Euler angle of principal compression, removing the assumption of uniaxial deformation. We demonstrate multi-parametric OCE by mapping this new mechanical contrast, in addition to optical coherence tomography and elasticity, on ex vivo human breast tissue.
13305-47
28 January 2025 • 4:45 PM - 5:00 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
We developed an integrated intravaginal OCT/OCTA/OCE probe to quantitatively assess vaginal tissue. This multifunctional probe combines optical coherence tomography, angiography, and elastography, enabling detailed analysis of blood vessel density, vaginal epithelium thickness, and tissue stiffness. Using an ex vivo vaginal sample, we demonstrated the probe's ability to provide comprehensive imaging and mechanical property measurements, offering valuable insights for optimizing laser-based treatments for genitourinary syndrome of menopause. This innovative approach could significantly enhance long-term treatment evaluation and improve the quality of life for affected women.
13305-48
28 January 2025 • 5:00 PM - 5:15 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Colorectal cancer (CRC) is a leading cause of cancer deaths, developing from dysplastic polyps that become malignant. Population-based colonoscopy screening is crucial, potentially reducing CRC mortality by up to 57%. Efforts to improve efficiency by leaving diminutive polyps (<5 mm) in place introduce risks, as 80% of resected polyps remain untreated. Technological advancements are needed to decrease this risk. OCT aids in detecting and classifying polyps but lacks biochemical information for early cancer detection. This study uses ex vivo OCT images to extract features indicating biochemical changes, for colon polyps classification, achieving 88.3% accuracy with a novel deep learning method.
13305-49
28 January 2025 • 5:15 PM - 5:30 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Endobronchial optical coherence tomography (EB-OCT) is a high-resolution, bronchoscope compatible imaging technique with the potential to serve as a microscopic complement to HRCT in interstitial lung disease (ILD) for early microscopic diagnosis and therapeutic response assessment. However, integration of EB-OCT into clinical settings remains challenging due to the time- and labor-intensive qualitative evaluation and/or manual segmentation of large datasets consisting of tens of thousands of images acquired from individual patients. Here, we demonstrate the feasibility of a robust, computationally-efficient EB-OCT image analysis framework using artificial intelligence (AI) with deep learning architecture for rapid, automated ILD feature segmentation and volumetric quantification.
Session 9:
Award Ceremony: Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine
28 January 2025 • 5:30 PM - 6:00 PM PST | Moscone Center, Room 203 (Level 2 South)
Session Chairs:
Rainer A. Leitgeb, Medizinische Univ. Wien (Austria), Yoshiaki Yasuno, Univ. of Tsukuba (Japan)
Join the Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXIX conference for their award ceremony.
Session 10:
Full-Field OCT Technology
29 January 2025 • 8:30 AM - 10:00 AM PST | Moscone Center, Room 203 (Level 2 South)
Session Chair:
Maciej Wojtkowski, Institute of Physical Chemistry PAS (Poland)
13305-50
29 January 2025 • 8:30 AM - 8:45 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Full-field Fourier-domain optical coherence tomography (FF-FD-OCT) is an emerging OCT variant characterized by its high acquisition speed and phase stability. Like all OCT techniques, it suffers from speckle noise and aberrations and shows lower lateral resolution compared to confocal OCT. Here, we demonstrate an oblique illumination FF-FD-OCT that overcomes these limitations. The effective resolution is increased and the oblique illumination helps to reduce speckle noise. Compared to standard adaptive optics OCT, it uniquely allows for an objective determination of aberrations that can be corrected computationally. We demonstrate the enhanced image quality of the technique and show its potential for future in vivo applications.
13305-51
29 January 2025 • 8:45 AM - 9:00 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Neural networks (NNs) are capable of generalizing beyond training data, yet the required level of similarity between the training data and inference data remains unclear. This research investigates the potential of training NNs with purely synthetic data to achieve effective generalization in biomedical applications. Specifically, Perlin noise, a procedurally generated noise, was used to simulate pseudo-random signals with local spatial correlations resembling that of biomedical data. The study trained a U-net autoencoder on purely synthetic data to denoise time-domain full-field optical coherence tomography (TD-FF-OCT) images of human corneas. Remarkably, the NN successfully denoised real TD-FF-OCT images, suppressing not only the Gaussian noise but also the correlated interference fringes. We explore this method for denoising, dehazing and contrast enhancement across various imaging modalities and in particular in cases when clean data is fundamentally unavailable. Finally, we compare this method to other state-of-the-art synthetic data tools such as diffusion models.
13305-52
29 January 2025 • 9:00 AM - 9:15 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
We present an enhanced experimental STOC-T system featuring a high-speed phase modulator for optimized illumination. The combination of this rapid phase modulator with numerical magnitude averaging significantly improves the signal-to-noise ratio. The benefits of this enhancement are demonstrated through volumetric imaging of both reflecting and scattering objects.
13305-53
29 January 2025 • 9:15 AM - 9:30 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
We developed a novel method to provide rapid spectral shaping for full field OCT (FF-OCT) imaging. Combining a supercontinuum laser with a fast controllable acousto-optic tunable filter (AOTF) and a multimode fiber with passive and active mode mixing, we obtained an extremely flexible light source compatible with FF-OCT. By tuning the AOTF frequency every few microseconds, it becomes possible to build any spectrum of interest in the 575-1000 nm range integrated on the camera over one exposure time to achieve time domain OCT. Alternatively, the designed source module enables to perform swept source FF-OCT at up to 50 KHz at unprecedented axial resolution.
13305-54
29 January 2025 • 9:30 AM - 9:45 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
We propose a theoretical wave-optics model to simultaneously study the influence of aberrations and spatial coherence of the illumination on the lateral resolution and the signal level of a full-field optical coherence tomography (FFOCT) imaging system. We show that in a system under aberrations, the lower the spatial coherence, the better the resolution but the poorer the signal level: there is a tradeoff between lateral resolution and signal level. Our model makes it possible to find the right partial coherence regime to achieve high resolution in thick tissue with high signal, depending on the adaptive optics (AO) and computational tools at our disposal.
13305-55
29 January 2025 • 9:45 AM - 10:00 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Adaptive optics OCT (AO-OCT) offers superior spatial resolution for cellular imaging but faces challenges such as limited field of view. Digital adaptive optics (DAO) addresses these issues by utilising the phase content from OCT volumes, but requires high stability. Full field swept source OCT (FF-SS-OCT) improves acquisition speed but suffers from crosstalk. Spatiotemporal optical coherence tomography (STOC-T) mitigates crosstalk through spatial phase randomisation, achieving ~5μm resolution across the retina's thickness without mechanical scanning. This presentation will report images acquired with a STOC-T instrument (InCellVu) and combined with DAO for high-resolution retinal visualization and post-processing aberration correction in healthy human subjects.
Break
Coffee Break 10:00 AM - 10:30 AM
Session 11:
OCT Signal Understanding and Manipulation
29 January 2025 • 10:30 AM - 12:00 PM PST | Moscone Center, Room 203 (Level 2 South)
Session Chair:
Peter Eskil Andersen, Technical Univ. of Denmark (Denmark)
13305-56
29 January 2025 • 10:30 AM - 10:45 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
This study introduces a novel super-resolution (SR) and noise suppression method in optical coherence tomography (OCT) images using diffusion models (DM). To that end, a physics-informed DM is developed to learn an inverse function for reversing the degradations in OCT images due to defocus and digital sampling. The proposed method resulted in resolution enhancement and speckle noise removal in OCT images of various sample types including the human cornea, acquired using a Line-Field OCT (LF-OCT) system. By delivering noise-free and sharpened images at high digital resolutions, the proposed method can potentially facilitate tasks such as retrieving complex point spread functions (PSFs), thereby enabling more precise aberration correction in OCT images.
13305-57
29 January 2025 • 10:45 AM - 11:00 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Open Chrono-Morph Viewer (OCMV) is a new open-source bioimage informatics platform that enables advanced visualization of high-dimensionality OCT images. Built in Python, OCMV is a standalone software with a graphical user interface for real-time interactive visualization and an application programming interface for animation. OCMV efficiently handles large sequences of volumes with two timescales to accommodate longitudinal studies. Due to high levels of speckle noise, seeing inside an OCT volume requires cutting away part of the volume, yet the traditional clipping plane cannot reveal convoluted structures within the volume. OCMV features novel algorithms and methods, including a clipping spline that provides interactive, dynamic, smooth non-planar cutaway views inside a volume.
13305-58
29 January 2025 • 11:00 AM - 11:15 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
OCT speckle hinders image interpretation. Hardware-based suppression is impractical and slow for in vivo imaging. Software-based methods, including deep learning, offer alternatives. However, deep learning models often lack generalization across different OCT systems. This study investigates adaptive normalization as a data augmentation technique to enhance the generalizability of deep learning-based speckle suppression for data from OCT systems not included in the training dataset.
13305-59
29 January 2025 • 11:15 AM - 11:30 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
We present a new single-shot method to extract the combined confocal and fall-off functions and remove system-generated depth-dependent effects from OCT images. This method requires no prior knowledge of the OCT system parameters or assumed form for the confocal and fall-off functions. Basis functions allow for greater degrees of freedom to model the combined function. Only two or more vertically shifted A-scans (or B-scans) of a sample are required for this method, which is validated with simulation and experimental data (three-layer PDMS/TiO2 phantom and human fingertip OCT images). Improvement over the standard ratio fit method is demonstrated.
13305-60
29 January 2025 • 11:30 AM - 11:45 AM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
We present a hybrid particle-wave Monte Carlo method for Optical Coherence Tomography (OCT) simulations that, for identical conditions and number of launched photons, yields a signal increase of 3 orders of magnitude and a simulation efficiency increase of nearly 3 orders of magnitude compared to conventional Monte Carlo OCT simulations. Monte Carlo simulations are useful to investigate models for OCT attenuation coefficient extraction. We show that both a conventional MC OCT method and a hybrid particle-wave MC OCT method accurately describe OCT signals for weakly scattering media.
13305-61
29 January 2025 • 11:45 AM - 12:00 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
A theoretical model and experiments demonstrate that contours of B-scans are deviated from correct axial
position when a specular target is tilted or curved in a flying spot swept source OCT system. Paper shows
that such deviations are more evident when the tunable laser sweeps in both directions. The smaller the
number of sweeps per lateral scanning interval, the larger these errors and deviations. Two swept sources
at 850 nm were evaluated, one unidirectional at 2 kHz (CSU-SS), the other bidirectional at 32 kHz (RSB-SS), in
two configurations, as used for imaging skin and the other for imaging the retina.
Break
Lunch Break 12:00 PM - 1:30 PM
Session 12:
New OCT technology
29 January 2025 • 1:30 PM - 3:30 PM PST | Moscone Center, Room 203 (Level 2 South)
Session Chair:
Wolfgang Drexler, Medizinische Univ. Wien (Austria)
13305-62
29 January 2025 • 1:30 PM - 1:45 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
We introduce shearing interferometric fluorescence tomography (SIFT), which utilizes self-interference of fluorescence emission wavefronts to axially localize fluorophores in depth. Our proposed method uses shearing interferometer to encode wavefront curvature as spatial frequencies, decoupling axial resolution from lateral. A depth-multiplexed approach is described that includes simultaneous acquisition of entire depth fluorescence profile at each excitation location. We present theory and experimental validation displaying axial sectioning and verifying potential application of SIFT for volumetric spectroscopic fluorescence imaging. Depth-multiplexing can enable high-speed z-stack imaging and provides broad potential applications in in vitro and in vivo imaging in basic science and clinical diagnostics.
13305-63
29 January 2025 • 1:45 PM - 2:00 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Two Spontaneous Parametric Down-Conversion sources are prepared, one producing twin photons with negative frequency correlations and one where the frequency correlations are positive. They are used for Quantum Optical Coherence Tomography (Q-OCT) and compared for their impact on Q-OCT key parameters: axial resolution and artefact removal.
13305-64
29 January 2025 • 2:00 PM - 2:15 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
We use Machine Learning to remove image-scrambling artefacts from the quantum-mimic Optical Coherence Tomography B-scans, a data-processing method enabling the features known from quantum OCT: enhanced resolution and even order dispersion cancelation. Tested on computer-generated and experimental data, the network successfully suppressed the artefacts while maintaining the quantum-like benefits, outputting results superior to the state-of-the-art algorithm.
13305-65
29 January 2025 • 2:15 PM - 2:30 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Imaging deep in scattering samples with high resolution is potentially useful in a wide range of biomedical applications. In order to accomplish this, we utilize two off-the-shelf spectrometers centered at ~1300 nm and ~1550 nm along with a simple fiber-based interferometer and a supercontinuum source to synthesize an effective bandwidth of ~400 nm centered at ~1450 nm. A portion of the spectrum was missing and was filled-in using the gapped-data amplitude and phase estimation method. The axial resolution when using only the 1300 nm or 1550 nm spectrometer was 10.3 μm or 14.8 μm respectively, while the combined spectra yielded a 5.4 μm resolution in air while still maintaining a ~3.5 mm imaging range.
13305-66
29 January 2025 • 2:30 PM - 2:45 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Meter-scale working distance swept-source OCT has great potential for impact on a wide variety of fields, but -- with a finite aperture and fixed working distance -- this technique also necessitates optimization of the low-NA focused sample beam. We have previously shown that reflectance and spot size at a fixed working distance are optimized when the objective lens focal length equals the working distance, even though the smallest beam waist will no longer be located at the sample due to the focal shift effect. Here, we assess this theory in practice, comparing SS-OCT images in representative sample arm configurations.
13305-67
29 January 2025 • 2:45 PM - 3:00 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Morphological imaging with optical coherence tomography (OCT) has made major strides in the past few decades, however, there are major drawbacks in terms of its depth penetration. Recently, we have demonstrated that we can generate an OCT image by prioritizing the multiple scattering signal using a new collection geometry we call spatially offset OCT (SO-OCT). This leads to substantially enhanced imaging depth and contrast through a decrease in the effective attenuation in scattering samples and the preservation of the signal within the dynamic range of the detectors. Here, we explore methods for further optimizing the sensitivity and maximum probing depth in SO-OCT. We extend our modeling framework to consider Bessel-Gaussian illumination beam and explore the benefits of optimizing the detector for weak signals acquired at large spatial offsets. Our results show the high potential of SO-OCT as a new tool in biomedical imaging for deep tissue imaging.
13305-68
29 January 2025 • 3:00 PM - 3:15 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Deep tissue imaging is achieved with a long-wavelength conjugate SD-OCT (Spectral-Domain Optical Coherence Tomography) combined with balanced detection. The use of long wavelength and conjugate configuration serves to reduce scattering and counteract spectrometer roll off, respectively, in SD-OCT, thereby enhancing imaging depth. A 1550nm OCT system is designed with the use of supercontinuum source (SuperK FIANIUM FIU-6 OCT) and Cobra 1600 spectrometer with bandwidth 1450-1690 nm. Balanced detection is employed to mitigate the excess noise associated with the supercontinuum source and to minimize the autocorrelation noise artefacts. This advanced technique leveraging long wavelength and BD in conjugate SD-OCT has allowed us to achieve optical imaging depths exceeding 4 mm in chicken breast tissue and scotch tape.
13305-69
29 January 2025 • 3:15 PM - 3:30 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
This paper presents a novel approach for forward viewing endoscopy based on off-axis swept source full-field optical coherence tomography. In contrast to common OCT endoscope probes, based on side-viewing, we propose a design without electro-optical components, while still able to produce forward-view images. Here, through an analogous setup, we study the effect of the different free parameters of the design, such as input polarization state, off-axis angle, and beam divergence. As a result, we present B-Scans showing the OPD variation while changing the off-axis angle. Overall, we study the impact of the free parameters for optimal working conditions of the proposed endoscope.
Break
Coffee Break 3:30 PM - 4:00 PM
Session 13:
Novel Light Sources and Components
29 January 2025 • 4:00 PM - 6:00 PM PST | Moscone Center, Room 203 (Level 2 South)
Session Chair:
Robert A. Huber, Univ. zu Lübeck (Germany)
13305-70
29 January 2025 • 4:00 PM - 4:15 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
The cost, size, and weight associated with most optical coherence tomography (OCT) systems limit their widespread adoption for applications outside of in-clinic ophthalmology, especially in low-resource environments. Despite advances in optoelectronic integration technology, chip-scale OCT implementations to date have failed to simultaneously show high sensitivity, high imaging rate, and module-level integration. We report integrated chip-scale SS-OCT optical engines at 1310 nm and 1060 nm with a record high sensitivity of 100 dB at 100 kHz A-scan rate. These miniaturized yet powerful OCT engines can be readily integrated with commercial lasers and scan lenses for 2D and 3D imaging. This advancement represents a significant step towards widespread OCT adoption in non-traditional settings, potentially revolutionizing point-of-care diagnostics and telemedicine.
13305-71
29 January 2025 • 4:15 PM - 4:30 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Visible optical coherence tomography (vis-OCT) enables retinal oximetry in the 500-600nm wavelength range. Current research in vis-OCT uses spectral domain OCT (SD-OCT) with broadband supercontinuum sources. Although these systems afford high axial resolution, they have significant limitations in terms of sensitivity, imaging range, axial scan rate, and commercial scalability. Swept source OCT (SS-OCT) using micro-electromechanical systems tunable vertical cavity lasers (MEMS-VCSELs) has demonstrated MHz A-scan rates and meter scale imaging ranges at near infrared (NIR) wavelengths. No MEMS-VCSELs, however, exist in the 500-600nm range, due to fundamental material limitations. In this paper, we demonstrate visible SS-OCT using broadband frequency doubling of an amplified 1050nm MEMS-VCSEL in a thin-film periodically poled lithium niobate (PPLN) film. We show measurements of axial resolution, imaging range, frequency doubling conversion efficiency, and source stability.
13305-72
29 January 2025 • 4:30 PM - 4:45 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
High-resolution Optical Coherence Tomography (OCT) requires broadband, spatially coherent light sources. Now, the source of choice for ultrahigh-resolution visible light OCT is the supercontinuum, which is bulky, expensive, and optically noisy. Here we demonstrate an ultrahigh-resolution visible light OCT system with a combined superluminescent diode (SLD) source that achieves an axial resolution of ~3 micrometers in tissue after digital spectral shaping. The combined SLD source is situated above the blue light hazard range but below the high photopic efficiency range. The unique source wavelength range enables independent quantification of lutein and zeaxanthin and visualizes human Bruch’s membrane without requiring micrometer-scale resolution.
13305-73
29 January 2025 • 4:45 PM - 5:00 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Visible-light optical coherence tomography (vis-OCT) offers superior axial resolution and a unique biological tissue absorption spectrum but suffers from limited scanning rates and high signal attenuation. To address this, we designed a visible-light swept source using a fan-out periodically poled lithium niobate (PPLN) crystal to convert an amplified near-infrared swept source into visible-light range via second harmonic generation. The developed 100-kHz A-line scanning rate visible-light swept source features a 17 nm bandwidth with 0.5 mW power output and provides a vis-OCT roll-off of 0.68 dB/mm, a 30-50% improvement over traditional vis-OCT. This advancement could enhance vis-OCT performance in clinical settings.
13305-74
29 January 2025 • 5:00 PM - 5:15 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
A turnkey phase-sensitive swept-source OCT system requires stabilization of both the swept source and main
signal interferometer. We have provided stable clocking and triggering of a 1050 nm swept MEMS VCSEL by
mounting a solid clock etalon and volume Bragg grating optical trigger inside a temperature-stabilized butterfly
package. A photonic integrated circuit (PIC) provides a phase-stable main interferometer near the sample. This
system is only sensitive to the motion of sample, not to the fibers leading to and from the PIC.
13305-75
29 January 2025 • 5:15 PM - 5:30 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
The SPML swept source is a notable innovation, offering ultra-high-speed imaging with high-phase stability in SS-OCT field. However, there are two challenges when using SPML swept sources for OCT systems: data acquisition bandwidth and spectral holes in PMF-based cFBG. The PMF-based cFBG is used for polarization-stable dispersion components, enabling pulse compression and stretching repeatedly in the cavity. A comb-swept laser solution has been proposed to overcome data acquisition, reducing the burden on electronic acquisition devices during high-speed OCT processing. However, previous comb-swept source using Fabry-Perot etalons presented drawbacks such as optical loss, the need for free-space optics. This study presents all-PMF SPML comb-swept source using a specially designed dispersion component with a stable spectrum for subsampled OCT, overcoming the weaknesses associated with Fabry-Perot etalons and PMF-based cFBGs. The proposed all-PMF SPML comb-swept laser with high spectrum stability offers less than 400 comb lines within a 120 nm optical bandwidth. Consequently, we achieve deep depth range measurements multiple times of the subsampling period with quadrature detection.
13305-76
29 January 2025 • 5:30 PM - 5:45 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Swept-source OCT based on FDML lasers achieves imaging speeds well beyond 1MHz. However, compared to the highest resolving ophthalmic SD-OCT systems, the axial resolution of FDML-OCT is inferior due to the moderate sweep. We investigate various laser cavity designs with multiplexed SOA gain media for the future ultra-broadband operation of FDML lasers at 1050nm for retinal imaging. The performance and problems related to the optical isolators necessary for the fiber ring cavity are evaluated. In an experimental cavity, we achieved 187nm tuning bandwidth, which theoretically supports better than 3µm axial resolution in optical coherence tomography application.
13305-77
29 January 2025 • 5:45 PM - 6:00 PM PST | Moscone Center, Room 203 (Level 2 South)
Show Abstract +
Optical coherence tomography (OCT) systems are traditionally decomposed into engine and scanner components with an expensive and noise-prone analog interface to communicate the scan pattern between the two. To overcome these limitations, we implement a digital interface for our OCT system using low-cost embedded microprocessor and custom PC software. We demonstrate quantitative and qualitative equivalence of the interfaces to the theoretical optical resolution limits of our scanner through signal and image quality metrics, despite an order of magnitude reduction in cost. These results demonstrate the potential for reducing costs without sacrificing image quality through digital interfacing.
Program Committee
Beckman Institute for Advanced Science and Technology (United States)
Program Committee
Saratov State Univ. (Russian Federation), Tomsk State Univ. (Russian Federation), Institute of Precision Mechanics and Control of the RAS (Russian Federation)
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