1. Articles from Home

    qims.amegroups.com

  2. 1-26 of 26
    1. 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 ...

      Read Full Article
    2. 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 ...

      Read Full Article
    3. 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 ...

      Read Full Article
    4. 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 ...

      Read Full Article
    5. 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 ...

      Read Full Article
    6. 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 ...

      Read Full Article
    7. 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 ...

      Read Full Article
    8. 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 ...

      Read Full Article
    9. 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 ...

      Read Full Article
      Mentions: Fudan University
    10. 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 ...

      Read Full Article
    11. 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 ...

      Read Full Article
    12. 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 ...

      Read Full Article
    13. 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 ...

      Read Full Article
    14. 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 ...

      Read Full Article
    15. 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 ...

      Read Full Article
    16. Quantitative assessment of rat bone regeneration using complex master-slave optical coherence tomography

      Quantitative assessment of rat bone regeneration using complex master-slave optical coherence tomography

      ackground: The need for hard and soft tissues in oral implantology determined the development of methods and techniques to increase bone volume and their quality with different alternative materials used as substituents of patient’s natural bone. In addition, laser radiation can be used to accelerate the repair of fractures and to produce an increased volume of formed callus, as well as an increased bone mineral density. Methods: The aim of this work is to evaluate the capability of an in-house developed multimodal complex master slave (CMS) enhanced swept source (SS) optical coherence tomography (OCT) imaging instrument to analyze the ...

      Read Full Article
    17. Optical coherence tomography correlates multiple measures of tissue damage following acute burn injury

      Optical coherence tomography correlates multiple measures of tissue damage following acute burn injury

      Background: The visual assessment of burned skin is inherently subjective, and whilst a number of imaging modalities have identified quantifiable parameters to characterize vascular and structural changes following burn damage, none have become common place in the assessment protocol. Here, we use optical coherence tomography (OCT)-based angiography (OCTA) to introduce novel correlations between vessel depth, i.e., the depth of functional blood vessels beneath the tissue surface, edema depth, i.e., the depth of interstitial fluid buildup beneath the tissue surface, and tissue injury depth, i.e., the depth of collagen denaturation beneath the tissue surface, following burn injury ...

      Read Full Article
    18. Designing visible-light optical coherence tomography towards clinics

      Designing visible-light optical coherence tomography towards clinics

      Background: The capabilities of visible-light optical coherence tomography (vis-OCT) in noninvasive anatomical and functional retinal imaging have been demonstrated by multiple groups in both rodents and healthy human subjects. Translating laboratory prototypes to an integrated clinical-environment-friendly system is required to explore the full potential of vis-OCT in disease management. Methods: We developed and optimized a portable vis-OCT system for human retinal imaging in clinical settings. We acquired raster- and circular-scan images from both healthy and diseased human eyes. Results: The new vis-OCT provided high-quality retinal images of both subjects without any known eye diseases and patients with various retinal diseases ...

      Read Full Article
    19. Multi-scale and -contrast sensorless adaptive optics optical coherence tomography

      Multi-scale and -contrast sensorless adaptive optics optical coherence tomography

      Background: The roles of the retinal microvasculature and the retinal pigment epithelium (RPE) in maintaining the health and metabolic activity of the retina lend great clinical value to their high-resolution visualization. Methods: By integrating polarization diversity detection (PDD) into multi-scale and -contrast sensorless adaptive optics optical coherence tomography (MSC-SAO-OCT), we have developed a novel multi-contrast SAO OCT system for imaging pigment in the RPE as well as flow in the retinal capillaries using OCT angiography (OCTA). Aberration correction was performed based on the image quality using transmissive deformable optical elements. Results: MSC-SAO-OCTA imaging was performed at multiple fields-of-view (FOVs) with ...

      Read Full Article
    20. Revealing the morphology and function of the cochlea and middle ear with optical coherence tomography

      Revealing the morphology and function of the cochlea and middle ear with optical coherence tomography

      Optical coherence tomography (OCT) has revolutionized physiological studies of the hearing organ, the vibration and morphology of which can now be measured without opening the surrounding bone. In this review, we provide an overview of OCT as used in the otological research, describing advances and different techniques in vibrometry, angiography, and structural imaging.

      Read Full Article
    21. Optical coherence tomography imaging of cardiac substrates

      Optical coherence tomography imaging of cardiac substrates

      Cardiovascular disease is the leading cause of morbidity and mortality in the United States. Knowledge of a patient’s heart structure will help to plan procedures, potentially identifying arrhythmia substrates, critical structures to avoid, detect transplant rejection, and reduce ambiguity when interpreting electrograms and functional measurements. Similarly, basic research of numerous cardiac diseases would greatly benefit from structural imaging at cellular scale. For both applications imaging on the scale of a myocyte is needed, which is approximately 100 µm × 10 µm. The use of optical coherence tomography (OCT) as a tool for characterizing cardiac tissue structure and function has been ...

      Read Full Article
    22. The evaluation of spontaneous Descemet’s membrane reattachment using swept-source optical coherence tomography: a case report

      The evaluation of spontaneous Descemet’s membrane reattachment using swept-source optical coherence tomography: a case report

      A 29-year old man presented with a history of facial burn in August of 2017. Slit lamp examination revealed significant central corneal stromal scarring in the right eye. The patient received deep anterior lamellar keratoplasty (DALK) in the right eye. Three weeks post operatively, the patient was found to have recurrent corneal edema on slit lamp exam, and standard anterior segment optical coherence tomography (OCT) revealed a central detachment of Descemet’s membrane.

      Read Full Article
    23. Ultra-wide optical coherence tomography angiography in diabetic retinopathy

      Ultra-wide optical coherence tomography angiography in diabetic retinopathy

      Background: To implement an ultra-wide optical coherence tomography angiography imaging (UW-OCTA) modality in eyes with diabetic retinopathy (DR) with the aim of quantifying the burden of microvascular disease at baseline and subsequent clinic visits. Methods: UW-OCTA was implemented on a 1,060 nm swept source (SS) OCTA engine running at 100 kHz A-line rate with a motion tracking mechanism. A montage scanning protocol was used to capture a 100-degree field of view (FOV) using a 4×4 grid of sixteen total individual 6×6 mm 2 scans. Typical OCTA images with a FOV of 3×3, 6×6 and 12 ...

      Read Full Article
    24. Optical coherence tomography angiography monitors human cutaneous wound healing over time

      Optical coherence tomography angiography monitors human cutaneous wound healing over time

      Background: In vivo imaging of the complex cascade of events known to be pivotal elements in the healing of cutaneous wounds is a difficult but essential task. Current techniques are highly invasive, or lack the level of vascular and structural detail required for accurate evaluation, monitoring and treatment. We aimed to use an advanced optical coherence tomography (OCT)-based angiography (OCTA) technique for the non-invasive, high resolution imaging of cutaneous wound healing. Methods: We used a clinical prototype OCTA to image, identify and track key vascular and structural adaptations known to occur throughout the healing process. Specific vascular parameters, such ...

      Read Full Article
    25. Optic nerve head perfusion in normal eyes and eyes with glaucoma using optical coherence tomography-based microangiography

      Optic nerve head perfusion in normal eyes and eyes with glaucoma using optical coherence tomography-based microangiography

      Background: To investigate the differences of perfusion in the optic nerve head (ONH) between normal and glaucomatous eyes using optical microangiography (OMAG) based optical coherence tomography (OCT) angiography technique. Methods: One eye from each subject was scanned with a 68 kHz Cirrus 5000 HD-OCT-based OMAG prototype system centered at the ONH (Carl Zeiss Meditec Inc, Dublin, CA, USA). Microvascular images were generated from the OMAG dataset by detecting the differences in OCT signal between consecutive B-scans. The pre-laminar layer (preLC) was isolated by a semi-automatic segmentation program. En face OMAG images for preLC were generated using signals with highest blood ...

      Read Full Article
    26. Optical coherence tomography based microangiography findings in hydroxychloroquine toxicity

      Optical coherence tomography based microangiography findings in hydroxychloroquine toxicity

      Optical coherence tomography based microangiography (OMAG) is a new, non-invasive imaging modality capable of providing three dimentional (3D) retinal and choroidal microvascular maps without a need for exogenous dye. In this study, we evaluated the retinal and choroidal microvascular architecture of the macula in a patient with hydroxychloroquine (HCQ) toxicity using OMAG. Detailed microvascular information of the retina and the underlying choroid showed loss of parafoveal outer retinal vasculature with sparing of the central fovea vasculature.

      Read Full Article
    1-26 of 26
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks