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    1. Endoscopic optical coherence tomography angiography using inverse SNR-amplitude decorrelation features and electrothermal micro-electro-mechanical system raster scan

      Endoscopic optical coherence tomography angiography using inverse SNR-amplitude decorrelation features and electrothermal micro-electro-mechanical system raster scan

      Background: Angiogenesis is closely associated with tumor development and progression. Endoscopic optical coherence tomography angiography (OCTA) enables rapid inspection of mucosal 3D vasculature of inner organs in the early-stage tumor diagnosis; however, it is limited by instabilities of the optical signal and beam scanning. Methods: In the phase-unstable swept source OCTA (SS-OCTA), amplitude decorrelation was used to compute the motion-induced changes as motion contrast. The influence of the random noise-induced amplitude fluctuations on decorrelation was characterized as a function of inverse signal-to-noise ratio (SNR) with a multi-variate time series (MVTS) model and statistical analysis. Then, the noise-induced decorrelation artifacts in ...

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    2. Differential diagnosis of acute and chronic colitis in mice by optical coherence tomography

      Differential diagnosis of acute and chronic colitis in mice by optical coherence tomography

      Background: The differential diagnosis of acute and chronic colitis remains a common clinical problem. Optical coherence tomography (OCT) is a non-invasive, high-resolution imaging technique that can be used to measure morphological changes in the intestinal wall and estimate intestinal inflammation. We aimed to conduct an ex vivo experiment on a mouse model investigate the value of OCT as a tool for the differential diagnosis of acute and chronic colitis. Methods: Mice were administered dextran sulfate sodium salt (DSS) to construct acute and chronic colitis models. Acutely- and chronically-affected intestinal walls were scanned by OCT, and then the scanned colonic tissue ...

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    3. Mitigating the effects of choroidal hyper- and hypo-transmission defects on choroidal vascularity index assessments using optical coherence tomography

      Mitigating the effects of choroidal hyper- and hypo-transmission defects on choroidal vascularity index assessments using optical coherence tomography

      Background: Changes in choroidal vascularity index (CVI) are associated with multiple choroid-related ocular diseases. CVI is calculated as the area/volume ratio of vessels in the choroid, which could be affected by alterations in regional signal intensities due to hypo-transmission defects (hypoTDs) caused by drusen and retinal pigment epithelium (RPE) detachments, and hyper-transmission defects (hyperTDs) caused by the absence of RPE. To develop a simulation model to verify the CVI assessments in eyes with hyper/hypoTDs and demonstrate that accurate CVIs can be achieved after attenuation correction on swept-source optical coherence tomography (SS-OCT). Methods: A simulation model was developed on ...

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    4. High resolution imaging and quantification of the nailfold microvasculature using optical coherence tomography angiography (OCTA) and capillaroscopy

      High resolution imaging and quantification of the nailfold microvasculature using optical coherence tomography angiography (OCTA) and capillaroscopy

      Background: A wide range of diseases, such as systemic sclerosis, can be diagnosed by imaging the nailfold microcirculation, which is conventionally performed using capillaroscopy. This study applied optical coherence tomography angiography (OCTA) as a novel high resolution imaging method for the qualitative and quantitative assessment of the nailfold microvasculature, and compared OCTA imaging with capillaroscopy. Methods: For qualitative assessment, high resolution OCTA imaging was used to achieve images that contained a wide field of view of the nailfold microvasculature through mosaic scanning. OCTA imaging was also used to observe the characteristic changes in the microvasculature under external compression of the ...

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    5. Quantification of peripapillary vessel density in non-arteritic anterior ischemic optic neuropathy patients with optical coherence tomography angiography

      Quantification of peripapillary vessel density in non-arteritic anterior ischemic optic neuropathy patients with optical coherence tomography angiography

      Background: Quantitative assessments based on optical coherence tomographic angiography (OCTA) may have potential promising value in the early detection of non-arteritic anterior ischemic optic neuropathy (NA-AION), but there is limited information on the ability of OCTA to distinguish eyes with NA-AION. This study was conducted to evaluate the ability of measurements of peripapillary perfusion using OCTA to distinguish healthy eyes from eyes with NA-AION. Methods: In this retrospective case-control study, newly diagnosed NA-AION patients and healthy controls matched at a ratio of 1:3 by gender and age (±5 years) were enrolled from 1 September 2020 to 30 June 2021 ...

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    6. Comparison of choroidal hyperreflective spots on optical coherence tomography images between both eyes of normal subjects

      Comparison of choroidal hyperreflective spots on optical coherence tomography images between both eyes of normal subjects

      Background: Advancement of optical coherence tomography (OCT) technology allows for better in vivo visualization of the choroidal architecture, which comprises vessels and stroma. However, most OCT studies using image binarization methods have focused only on choroidal vessels represented by dark pixels. This study aimed to compare the distribution of choroidal hyperreflective spots on swept-source OCT (SS-OCT) images between both eyes of normal subjects. Methods: In this observational comparative study, we included SS-OCT images of healthy subjects, which were prospectively obtained to compare images among the devices. SS-OCT images acquired using PLEX Elite 9000 and DRI-OCT Triton were analyzed. En-face OCT ...

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      Mentions: Korea University
    7. Ocular microvascular alteration in Sjögren syndrome

      Ocular microvascular alteration in Sjögren syndrome

      Background: Sjögren syndrome (SjS) is a systemic disease affecting exocrine, including ocular lacrimal, glands. It is uncertain whether ocular microvascular alterations are associated with this disease. In this study, we evaluated retinal and conjunctival microvascular changes in SjS patients using optical coherence tomography angiography (OCTA). Methods: Twelve SjS patients (24 eyes) and 12 normal controls (24 eyes) were recruited to this study. Three-dimensional conjunctival and retinal OCTA images of each eye were captured and microvascular density was calculated. Each image was analyzed by retinal area based on the early treatment of diabetic retinopathy study method (R, S, L, and ...

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    8. Baseline retinal thickness measurements with a novel integrated imaging system (concurrent optical coherence tomography and fundus photography) positively correlates with spectralis optical coherence tomography

      Baseline retinal thickness measurements with a novel integrated imaging system (concurrent optical coherence tomography and fundus photography) positively correlates with spectralis optical coherence tomography

      Background: Traditionally fundus photographs and optical coherence tomography (OCT) are obtained separately during evaluation of retinal pathology. We describe a novel integrated imaging system (Monaco, Optos) that records both OCT as well as fundus photography concurrently. The present study aims to measure retinal thickness and compare it to OCT obtained with traditional spectral domain OCT in subjects without known retinal disease to establish normative data for clinical use. Methods: In this cross sectional study, fundus photographs and OCT was obtained concurrently in 34 eyes in healthy patients without any known retinal disease with integrated imaging system. OCT with spectralis was ...

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      Mentions: Optos
    9. Interocular asymmetry of choroidal thickness and vascularity index measurements in normal eyes assessed by swept-source optical coherence tomography

      Interocular asymmetry of choroidal thickness and vascularity index measurements in normal eyes assessed by swept-source optical coherence tomography

      Background: To investigate the symmetry of interocular choroidal thickness and vascularity index measurements in normal eyes using swept-source optical coherence tomography (SS-OCT). Cross-sectional and observational study. This study included 244 eyes of 122 normal adults with ages uniformly distributed from 19 to 89 years. Methods: SS-OCT imaging was performed using a scanning pattern of 12×12 mm. Mean choroidal thickness (MCT) and choroidal vascularity index (CVI) measurements in the entire scanning region were obtained using a validated and published automatic method. The correlation and differences (including signed and absolute differences) between bilateral MCT and CVI measurements were analyzed at the ...

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    10. Optic nerve head injury and optical coherence tomography angiography

      Optic nerve head injury and optical coherence tomography angiography

      Dear editors, We wrote this letter to discuss the microvascular abnormalities related to optic nerve head (ONH) injury visualized by optical coherence tomography angiography (OCTA). With the advent of OCTA, different fundus vasculature levels in the macular region can be displayed precisely and noninvasively to investigate its mechanisms. OCTA is a promising diagnostic approach for detecting inflammatory, ischemic, and compressive optic neuropathies ( 1 ). However, the potential relationship between parapapillary microvascular dysfunction and ONH injury is still unclear and should be investigated by combined structural and functional OCT. The macula and the ONH’s different microvasculature results in a weaker association ...

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    11. A modified measuring method to investigate the choriocapillaris flow void of polypoidal choroidal vasculopathy with swept source optical coherence tomography angiography

      A modified measuring method to investigate the choriocapillaris flow void of polypoidal choroidal vasculopathy with swept source optical coherence tomography angiography

      Background: To propose a modified method to investigate the flow void of polypoidal choroidal vasculopathy (PCV) choriocapillaris. Methods: This paper involves a retrospective study. Included 30 PCV affect eyes, 30 old control eyes, 20 young control eyes, 15 affect eyes with anti-VEGF intravitreal injection treatment, and 8 fellow eyes of anti-VEGF intravitreal injection treatment group. After the choriocapillaris slab [10 µm thick starting 30 µm beneath to the retinal pigment epithelium (RPE)-fit reference] was extracted from macular optical coherence tomography angiography 6×6-mm scans, the flow void was segmented by the Phansalkar method. We analyzed the flow void sizes-frequency ...

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    12. Quantitative research on the interaction between cerebral edema and peripheral cerebral blood perfusion using swept-source optical coherence tomography

      Quantitative research on the interaction between cerebral edema and peripheral cerebral blood perfusion using swept-source optical coherence tomography

      Background: Ischemic cerebral edema (CE) is a major leading cause of death in patients with ischemic stroke. The CE progression is closely related to the local cerebral blood perfusion (LCBP) level surrounding the edema area. Quantitative studying the interaction between the CE and peripheral LCBP may provide new inspiration for control and even treatment of CE. Methods: Photothrombosis ischemia mouse model was established and observed for 9 hours using swept-source optical coherence tomography (SS-OCT). OCT-based angiography and OCT-based attenuation imaging techniques were used to reconstruct the angiograms reflecting the cerebral blood perfusion (CBP) level and optical attenuation coefficient (OAC) maps ...

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    13. Optical coherence tomography angiography measures blood pulsatile waveforms at variable tissue depths

      Optical coherence tomography angiography measures blood pulsatile waveforms at variable tissue depths

      Background: Photoplethysmography (PPG) is routinely used to detect the blood pulse signal from skin tissue beds in clinics. However, the origin of the PPG signal remains controversial. The purpose of this study is to explore optical coherence tomography angiography (OCTA) to indicate pulsatile waveforms in the papillary plexus and dermal plexus separately under different hand elevations. Method: Optical microangiography (OMAG) algorithm was used to obtain a 3D OCTA signals, from which the depth-resolved pulsatile blood flow signals were extracted from different skin vascular plexus. The systolic amplitude, crest time, and delta T were measured from the OCTA pulsatile signals when ...

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    14. Optical coherence tomography angiography distortion correction in widefield montage images

      Optical coherence tomography angiography distortion correction in widefield montage images

      Background: Optical coherence tomography (OCT) imaging is inherently susceptible to distortion artifacts due to the natural curvature of the eye. This study proposes a novel model for widefield OCT angiography (OCTA) distortion correction and analyzes the effects of this correction on quantification metrics. Methods: Widefield OCTA images were obtained on normal subjects at five fixation spatial positions. Radial and field distortion correction were applied and images stitched together to form a corrected widefield montage image. Vessel area density (VAD), vessel complexity index (VCI), and flow impairment area were quantified on the original and corrected montage images. Results: This model allows ...

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    15. Automatic 3D adaptive vessel segmentation based on linear relationship between intensity and complex-decorrelation in optical coherence tomography angiography

      Automatic 3D adaptive vessel segmentation based on linear relationship between intensity and complex-decorrelation in optical coherence tomography angiography

      Background: Vascular quantitative metrics have been widely used in the preclinical studies and clinical applications (e.g., the diagnosis and treatment of port wine stain, PWS), which require accurate vessel segmentation. An automatic 3D adaptive vessel segmentation is in need for a reproducible and objective quantification of the optical coherence tomography angiography (OCTA) image. Methods: Human skin imaging was performed with a lab-built optical coherence tomography (OCT) system. Rather than separately applying the conventional 2-step (intensity and binarization) thresholding in the decorrelation-contrast OCTA, we proposed a 3D adaptive threshold using the linear relationship between the local intensity and complex-decorrelation which ...

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    16. Robust three-dimensional registration on optical coherence tomography angiography for speckle reduction and visualization

      Robust three-dimensional registration on optical coherence tomography angiography for speckle reduction and visualization

      Background: In the clinical applications of optical coherence tomography angiography (OCTA), the repeated scanning and averaging method can provide better contrast with reduced speckle noises in the final results, which are useful for visualizing and quantifying vascular components with high accuracy, reproducibility, and reliability. However, the inevitable patient motion presents a challenge to this method. The objective of this study is to meet this challenge by introducing a 3D registration method to register optical coherence tomography (OCT)/OCTA scans for precise volume averaging of multiple scans to improve the signal-to-noise ratio (SNR) and increase quantification accuracy. Methods: The proposed method ...

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    17. Imaging human skin autograft integration with optical coherence tomography

      Imaging human skin autograft integration with optical coherence tomography

      Background: Skin autografting is a common clinical procedure for reconstructive surgery. Despite its widespread use, very few studies have been conducted to non-invasively evaluate and monitor the vascular and structural features of skin grafts. This study, therefore, aims to demonstrate the potential of optical coherence tomography (OCT) alongside OCT-based angiography (OCTA) to non-invasively image and monitor human skin graft health and integration over time. Methods: An in-house-built clinical prototype OCT system was used to acquire OCT/OCTA images from patients who underwent split-thickness skin graft surgery following severe burn damage to the skin. The OCT imaging was carried out at ...

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    18. Optical coherence tomography for the early detection of colorectal dysplasia and cancer: validation in a murine model

      Optical coherence tomography for the early detection of colorectal dysplasia and cancer: validation in a murine model

      Background: There is an urgent need to develop a non-invasive imaging technique for detecting colorectal dysplasia and cancer. Technology for early and real-time microscopic assessments to select the most representative biopsy sites would also be of clinical value. In this study, we explored the sensitivity of optical coherence tomography (OCT) in detecting local lesions to demonstrate its potential for the early detection of colorectal dysplasia and cancer. Methods: An azoxymethane/dextran sodium sulfate mouse model of colorectal carcinogenesis was utilized. Mice were imaged by OCT, and colorectal tissue sections were observed with hematoxylin and eosin staining. The results of the ...

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      Mentions: Fudan University
    19. Efficacy of endotracheal tube suctioning in intubated intensive care unit patients determined by in vivo catheter-based optical coherence tomography—a pilot study

      Efficacy of endotracheal tube suctioning in intubated intensive care unit patients determined by in vivo catheter-based optical coherence tomography—a pilot study

      Background: Mechanical ventilation using an endotracheal tube (ETT) is one of the critical interventions given to patients in the intensive care unit (ICU). ETTs are associated with the formation of biofilms, placing patients at increased risk for developing ventilator-associated pneumonia (VAP). ETT suctioning is used to remove secretions, reduce bacterial colonization, and reduce the rate of biofilm formation. However, current standard-of-care suctioning procedures do not adequately eliminate all secretions from the ETT. Methods: This observational study was conducted in a cohort of 4 subjects admitted to the ICU and intubated with an ETT, irrespective of ethnicity, gender, or race. A ...

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    20. Optical coherent tomography to evaluate the degree of inflammation in a mouse model of colitis

      Optical coherent tomography to evaluate the degree of inflammation in a mouse model of colitis

      Background: There is an urgent need to develop a noninvasive imaging technique for the diagnosis of early inflammatory lesions or early and real-time microscopic assessment before selecting the most representative biopsy sites. Methods: In this study, a dextran sulfate sodium colitis model was developed, and intestinal histological damage scores measured the degree of inflammation in colitis. According to these scores, 6 parameters were designed for hematoxylin and eosin (HE) sections based on morphological changes, and 2 parameters were designed for optical coherence tomography (OCT) images to measure submucosal edema by morphological changes to evaluate inflammation degrees in the colon. Spearman ...

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    21. State-of-the-art in retinal optical coherence tomography image analysis

      State-of-the-art in retinal optical coherence tomography image analysis

      Optical coherence tomography (OCT) is an emerging imaging modality that has been widely used in the field of biomedical imaging. In the recent past, it has found uses as a diagnostic tool in dermatology, cardiology, and ophthalmology. In this paper we focus on its applications in the field of ophthalmology and retinal imaging. OCT is able to non-invasively produce cross-sectional volumetric images of the tissues which can be used for analysis of tissue structure and properties. Due to the underlying physics, OCT images suffer from a granular pattern, called speckle noise, which restricts the process of interpretation. This requires specialized ...

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    22. Handheld swept-source optical coherence tomography with angiography in awake premature neonates

      Handheld swept-source optical coherence tomography with angiography in awake premature neonates

      Background: Retinopathy of prematurity (ROP) can lead to retinal detachment and severe vision loss and is a common cause of childhood blindness. Optical coherence tomography angiography (OCTA) is a non-invasive imaging modality that can be used to detect potential abnormalities in the microvasculature in this population. The objective of this study is to assess the feasibility of a newly developed handheld swept source OCT (SS-OCT) device to successfully acquire structural vitreoretinal and retinal microvascular images in awake premature infants. Methods: OCT and OCTA images were acquired at the time of routine ROP examinations from awake, unsedated preterm infants in the ...

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    23. Characterizing optical coherence tomography speckle fluctuation spectra of mammary organoids during suppression of intracellular motility

      Characterizing optical coherence tomography speckle fluctuation spectra of mammary organoids during suppression of intracellular motility

      Background: An understanding of how the mammary gland responds to toxicant and drug exposures can shed light on mechanisms of breast cancer initiation/progression and therapeutic effectiveness, respectively. In this study, we employed noninvasive, label-free and high-throughput optical coherence tomography speckle fluctuation spectroscopy (OCT-SFS) to track exposure-response relationships in three-dimensional (3D) mammary epithelial organoid models. Methods: OCT-SFS is sensitive to relatively high speed (~0.16–8 µm/min) motions of subcellular light scattering components occurring over short (~2–114 s) time scales, termed “intracellular motility.” In this study, OCT speckle fluctuation spectra are quantified by two metrics: the intracellular motility ...

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    24. Innovative use of optical coherence tomography catheter via nipple orifice: a case report of first intraductal images of florid ductal hyperplasia

      Innovative use of optical coherence tomography catheter via nipple orifice: a case report of first intraductal images of florid ductal hyperplasia

      The incidence of malignancy in patients with pathologic nipple discharge (PND) varies from 1% to 23% (1). Currently, methylene blue dye or lacrimal probe guided isolated duct excision is still the standard treatment of PND. Majority of those patients are not with cancer-involved ducts and have unnecessary surgery to reveal the definitive histopathology. With conventional imaging, it is not possible to understand whether those ducts involve cancer or not (2). It is well established that ductoscopy is a novel technique that could diagnose a single papilloma; however, it is insufficient to diagnose an in situ or invasive cancer (3,4 ...

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    1-24 of 35 1 2 »
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