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Characterization of Long Working Distance Optical Coherence Tomography for Imaging of Pediatric Retinal Pathology
摘要： Purpose: We determined the feasibility of fovea and optic nerve head imaging with a long working distance (LWD) swept source optical coherence tomography (OCT) prototype in adults, teenagers, and young children. Methods: A prototype swept source OCT system with a LWD (defined as distance from the last optical element of the imaging system to the eye) of 350 mm with custom fixation targets was developed to facilitate imaging of children. Imaging was performed in 49 participants from three age groups: 26 adults, 16 children 13 to 18 years old (teenagers), and seven children under 6 years old (young children) under an approved institutional review board protocol. The imaging goal was to acquire high quality scans of the fovea and optic nerve in each eye in the shortest time possible. OCT B-scans and volumes of the fovea and optic nerve head of each eligible eye were captured and graded based on four categories (lateral and axial centration, contrast, and resolution) and on ability to determine presence or absence of pathology. Results: LWD-OCT imaging was successful in 88 of 94 eligible eyes, including seven of 10 eyes of young children. Of the successfully acquired OCT images, 83% of B-scan and volumetric images, including 86% from young children, were graded as high-quality scans. Pathology was observed in high-quality OCT images. Conclusions: The prototype LWD-OCT system achieved high quality retinal imaging of adults, teenagers, and some young children with and without pathology with reasonable alignment time. Translational Relevance: The LWD-OCT system can facilitate imaging in children.
关键词： pediatric imaging,retinal imaging,long working distance,optical coherence tomography
更新于2025-09-23 15:21:01
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Optical coherence tomography: Translation from 3D-printed vascular models of the anterior cerebral circulation to the first human images of implanted surface modified flow diverters
摘要： Background: The new generation of flow diverters includes a surface modification with a synthetic biocompatible polymer, which makes the device more biocompatible and less thrombogenic. Optical coherence tomography (OCT) can be used to visualize perforators, stent wall apposition, and intra-stent thrombus. Unfortunately real world application of this technology has been limited because of the limited navigability of these devices in the intracranial vessels. In this report, we share our experience of using 3D-printed neurovascular anatomy models to simulate and test the navigability of a commercially available OCT system and to show the application of this device in a patient treated with the new generation of surface modified flow diverters. Material and methods: Navigability of OCT catheters was tested in vitro using four different 3D-printed silicone replicas of the intracranial anterior circulation, after the implantation of surface modified devices. Intermediate catheters were used in different tortuous anatomies and positions. After this assessment, we describe the OCT image analysis of a Pipeline Shield for treating an unruptured posterior communicating artery (PCOM) aneurysm. Results: Use of intermediate catheters in the 3D-printed replicas was associated with better navigation of the OCT catheters in favorable anatomies but did not help as much in unfavorable anatomies. OCT image analysis of a PCOM aneurysm treated with Pipeline Embolization Device Shield demonstrated areas of unsatisfactory apposition with no thrombus formation. Conclusions: OCT improves the understanding of the flow diversion technology. The development of less thrombogenic devices, like the Pipeline Flex with Shield Technology, reinforces the need for intraluminal imaging for neurovascular application.
关键词： Pipeline device,Aneurysm,optical coherence tomography
更新于2025-09-23 15:21:01
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Review of Biomedical Applications of Contactless Imaging of Neonates Using Infrared Thermography and Beyond
摘要： The sick preterm infant monitoring is an intriguing job that medical staff in Neonatal Intensive Care Units (NICU) must deal with on a daily basis. As a standards monitoring procedure, preterm infants are monitored via sensors and electrodes that are ?rmly attached to their fragile and delicate skin and connected to processing monitors. However, an alternative exists in contactless imaging to record such physiological signals (we call it as Physio-Markers), detecting super?cial changes and internal structures activities which can be used independently of, or aligned with, conventional monitors. Countless advantages can be gained from unobtrusive monitoring not limited to: (1) quick data generation; (2) decreasing physical and direct contact with skin, which reduces skin breakdown and minimizes risk of infection; and (3) reduction of electrodes and probes connected to clinical monitors and attached to the skin, which allows greater body surface-area for better care. This review is an attempt to build a solid ground for and to provide a clear perspective of the potential clinical applications of technologies inside NICUs that use contactless imaging modalities such as Visible Light Imaging (VLI), Near Infrared Spectroscopy (NIRS), and Infrared Thermography (IRT).
关键词： infrared thermography,physio-features,short-wave infrared,optical coherence tomography,preterm infants,visible light,NICU,tissue optics,near-infrared,neonatal imaging
更新于2025-09-23 15:21:01
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Comparing fundus autofluorescence and infrared imaging findings of peripheral retinoschisis, schisis detachment, and retinal detachment
摘要： Purpose: The primary goal of this study was to identify characteristic features of peripheral degenerative retinoschisis (RS), schisis detachment (SD) and retinal detachment (RD) on both fundus autofluorescence (FAF) and infrared (IR) imaging, using spectral domain optical coherence tomography (SD-OCT) imaging of the peripheral retina as the confirmatory imaging tool. Methods: This is a descriptive case series study. A total of 27 eyes of 22 patients were included. Thirteen eyes of 10 patients diagnosed with RS, 4 eyes of 3 patients diagnosed with SD, and 10 eyes of 9 patients diagnosed with RD were included. Patients with images of poor quality were excluded. Heidelberg Spectralis HRA + OCT machine (Heidelberg Engineering, Heidelberg, Germany) were used to acquire the images. Results: All conditions appeared as areas of hypo-AF on FAF and hypo-reflectance on IR imaging. Accentuated vasculature of the lesion was noted with IR imaging due to elevation of the RS and RD, which was less frequently observed with FAF. On FAF, a hyper-AF leading edge around the RS lesion indicated the presence of intraretinal or subretinal fluid and an extension of the RS. Retinal breaks/holes were best visualized with IR imaging. SD-OCT confirmed the diagnosis in all performed cases. Conclusions: We were unable to differentiate between RS and RD based solely on findings from FAF and IR imaging. However, the combination of them with SD-OCT can assist in the diagnosis of RS from RD and in the evaluation of RS progression. OCT remains the main modality imaging to differentiate these conditions.
关键词： Retinoschisis,Retinal detachment,Fundus autofluorescence,Infrared imaging,Spectral domain optical coherence tomography,Schisis detachment
更新于2025-09-23 15:21:01
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[Lecture Notes in Computer Science] Pattern Recognition and Computer Vision Volume 11256 (First Chinese Conference, PRCV 2018, Guangzhou, China, November 23-26, 2018, Proceedings, Part I) || Automated and Robust Geographic Atrophy Segmentation for Time Series SD-OCT Images
摘要： Geographic atrophy (GA), mainly characterized by atrophy of the retinal pigment epithelium (RPE), is an advanced form of age-related macular degeneration (AMD) which will lead to vision loss. Automated and robust GA segmentation in three-dimensional (3D) spectral-domain optical coherence tomography (SD-OCT) images is still an enormous challenge. This paper presents an automated and robust GA segmentation method based on object tracking strategy for time series SD-OCT volumetric images. Considering the sheer volume of data, it is unrealistic for experts to segment GA lesion region manually. However, in our proposed scenario, experts only need to manually calibrate GA lesion area for the ?rst moment of each patient, and then the GA of the following moments will be automatically detected. In order to fully embody the outstanding features of GA, a new sample construction method is proposed for more e?ectively extracting histogram of oriented gradient (HOG) features to generate random forest models. The experiments on SD-OCT cubes from 10 eyes in 7 patients with GA demonstrate that our results have a high correlation with the manual segmentations. The average of correlation coe?cients and overlap ratio for GA projection area are 0.9881 and 82.62%, respectively.
关键词： HOG features,Spectral-domain optical coherence tomography,Image segmentation,Geographic atrophy
更新于2025-09-23 15:21:01
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[Texts and Readings in Physical Sciences] Open Quantum Systems Volume 20 (Dynamics of Nonclassical Evolution) || Quantum Tunneling
摘要： Tunneling is a bona?de quantum mechanical e?ect [175, 176]. Since it involves barrier penetration, it is also an inherently non-perturbative process. It serves a crucial role in the test of quantum coherence in macroscopic regimes, also known as Macroscopic Quantum Coherence (MQC) [68]. Development in technology has made the concept of tunneling crucial to the development of devices on the nanoscopic, nanometre 10?9m range, and mesoscopic, upto a few microns μm, scales. Further, tunneling has important rami?cations to almost all branches of physics, such as atomic, molecular, condensed matter physics as well as to quantum ?eld theory and cosmology. A very powerful technique for dealing with tunneling is the semiclassical approximation, which we detail below. Tunneling processes can be broadly classi?ed into two categories: coherent and incoherent tunneling. Coherent tunneling phenomena involve the coherent overlap of wavefunctions located in individual domains, such as, ground states of potential wells, and separated by energy barriers. Incoherent tunneling involves scattering between reservoirs or decay of metastable states into the continuum and hence no overlap of the wavefunction. Tunneling has two perspectives: time independent energy domain considerations and that invoking the time dependent dynamics.
关键词： Macroscopic Quantum Coherence,Semiclassical Approximation,Quantum Tunneling,Incoherent Tunneling,Coherent Tunneling
更新于2025-09-23 15:21:01
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Cataract quantification using swept-source optical coherence tomography
摘要： To develop and evaluate a cataract quantification method using a swept-source optical coherence tomography (SS-OCT) device (IOLMaster 700).
关键词： SS-OCT,swept-source optical coherence tomography,IOLMaster 700,LOCS II,cataract quantification
更新于2025-09-23 15:21:01
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Clinical significance of healed plaque detected by optical coherence tomography: a 2-year follow-up study
摘要： Recent studies have shown that healed plaque at the culprit lesion detected by optical coherence tomography (OCT) is a sign of pan-vascular vulnerability and advanced atherosclerosis. However, the clinical significance of healed plaque is unknown. A total of 265 patients who had OCT imaging of a culprit vessel and 2-year clinical follow-up data were included. Patients were stratified based on the presence or absence of a layered plaque phenotype, defined as layers of different optical density by OCT at either culprit or non-culprit lesions. The association between layered plaque and major adverse cardiac events (MACE), defined as cardiac death, acute coronary syndromes (ACS), or revascularization, was studied. Among 265 patients, 96 (36.2%) had the layered plaque phenotype. Layered plaque was more frequently observed in stable angina pectoris patients than in ACS patients (57.8%vs. 25.1%, p < 0.001). The average clinical follow-up period was 672 ± 172 days. Cumulative MACE was significantly higher in patients with layered plaque (p = 0.041), which was primarily driven by the high revascularization rate at 2 years (p = 0.002). Multivariate regression analysis showed that presence of layered plaque and low-density lipoprotein cholesterol levels were independently associated with an increased risk of revascularization (p = 0.026, p = 0.008, respectively). Patients with healed plaque in the culprit vessel had a higher incidence of revascularization, as compared to those without healed plaque, at 2 years.
关键词： Healed plaque,Layered plaque,Revascularization,Optical coherence tomography
更新于2025-09-23 15:21:01
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Ergebnisse spektraler optischer Koh?renztomografie bei den mit Chloroquin behandelten Patienten mit systemischem Lupus erythematodes
摘要： Purpose To recognise possible retinal changes in patients with SLE treated with chloroquine phosphate, as depending on the duration of treatment. Methods The study included 41 patients (82 eyes) who received treatment for SLE with chloroquine or hydroxychloroquine phosphate and had not previously been diagnosed with retinal pathology. Participants were divided into two groups according to the duration of treatment. The first group included 18 patients (36 eyes) treated for up to five years and the second group consisted of 23 patients (46 eyes) treated from five to twenty years. We performed a thorough eye exam, including best-corrected visual acuity, colour vision, visual field examination, dilated fundus examination, auto-fluorescence imaging, color fundus photography and spectral domain optical coherence tomography. Results Mean duration of treatment in the first group was 2.79 ± 1.37 years, and in the second group 8.67 ± 2.26 years. The difference in central retinal thickness between the two groups was not statistically significant (p > 0.05). Comparison of parafoveal thickness between the two groups was statistically non-significant in all quadrants (p > 0.05). Visual field examination, autofluorescence images and colour fundus photographs were without noteworthy pathology. Conclusion Our results indicate that there were no significant changes in retinal structure between groups that depended on the duration of treatment. Hence, we can conclude that a yearly follow-up of these patients is sufficient to discover possible preclinical maculopathy.
关键词： systemic lupus erythematosus,hydroxychloroquine,retinal toxicity,optical coherence tomography
更新于2025-09-23 15:21:01
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Anterior Segment Optical Coherence Tomography of Previously Operated Extraocular Muscles
摘要： Background and Purpose: To assess the possibility of determining the insertion distance from the limbus of previously operated extraocular rectus muscles (EOM) with the Heidelberg Spectralis anterior segment optical coherence tomography (AS-OCT). Patient and Method: Subjects with a history of previous strabismus surgery underwent AS-OCT of the EOM before planned additional strabismus surgery. The EOM insertion distances from the limbus were measured pre-operatively on the AS-OCT and compared to the caliper distance measured during the strabismus surgery. Results: Ten previously operated muscles on nine subjects underwent AS-OCT before subsequent additional strabismus surgery. Four additional un-operated muscles subsequently operated on, were also imaged with the AS-OCT pre-operatively. Subject ages ranged from 13-52 years old (mean± SD; 27.9 ± 13.2). The muscle insertion could be definitely identified in 6/10 muscles previously operated and 4/4 un-operated muscles. The difference between the two measurements oflimbus to insertion in previously operated muscles was :-:;1mm in 3/6, and :-:;1.5mm in 6/6; <1mm in 4/4 un-operated muscles. Of the four insertions not readily identifiable, two revealed the presence of the muscle with scar tissue; the other two, the muscle insertions, were not visible, which showed that the muscle was at least a minimal amount from the limbus. Conclusion: Our study showed that the Heidelberg AS-OCT is capable of imaging previously operated EOM, which can give valuable information to the strabismus surgeon. The information from the AS-OCT was useful in all cases. The insertion to limbus measurements between pre-operative and intra-operative were within 1.5mm in all ofthe cases that the muscle insertion was able to be identified. The ability to accurately image EOM insertions has significant implications for the pre-operative procedure planning in previously operated and complicated strabismus patients.
关键词： extraocular muscle,anterior segment optical coherence tomography,strabismus surgery
更新于2025-09-23 15:21:01