1. 1-24 of 1222 1 2 3 4 ... 49 50 51 »
    1. Microvascular changes in the recurrent cystoid macular edema secondary to posterior noninfectious uveitis on optical coherence tomography angiography

      Microvascular changes in the recurrent cystoid macular edema secondary to posterior noninfectious uveitis on optical coherence tomography angiography

      Background: Posterior uveitis represents the second most frequent type of uveitis (15-30% of all uveitis). Noninfectious posterior uveitis complicated with secondary cystoid macular edema (CME) affects the visual prognosis negatively. The objective of the current study is to detect possible microvascular changes causing relapsing uveitis-related CME using optical coherence tomography angiography (OCTA). Methods: This is an interventional, observational, retrospective study with 1 year follow-up. Patients with noninfectious, posterior uveitis-related CME undergoing dexamethasone (DEX) implant were evaluated. Following the DEX-implant were carried out control visits after 1 month, 2-months, 4-months, 6-months, and for up 1-year. A total of 76 eyes of ...

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    2. Automatic Segmentation and Measurement of Choroid Layer in High Myopia for OCT Imaging Using Deep Learning

      Automatic Segmentation and Measurement of Choroid Layer in High Myopia for OCT Imaging Using Deep Learning

      Automatic segmentation and measurement of the choroid layer is useful in studying of related fundus diseases, such as diabetic retinopathy and high myopia. However, most algorithms are not helpful for choroid layer segmentation due to its blurred boundaries and complex gradients. Therefore, this paper aimed to propose a novel choroid segmentation method that combines image enhancement and attention-based dense (AD) U-Net network. The choroidal images obtained from optical coherence tomography (OCT) are pre-enhanced by algorithms that include flattening, filtering, and exponential and linear enhancement to reduce choroid-independent information. Experimental results obtained from 800 OCT B-scans of the choroid layers from ...

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    3. A comparison of macular ganglion cell and retinal nerve fibre layer optical coherence tomographic parameters as predictors of visual outcomes of surgery for pituitary tumours

      A comparison of macular ganglion cell and retinal nerve fibre layer optical coherence tomographic parameters as predictors of visual outcomes of surgery for pituitary tumours

      Purpose: The prognostic value of optical coherence tomography (OCT) of the macular ganglion cell layer (mGGL) versus peripapillary retinal nerve fibre layers (pRNFL) following chiasmal decompression is unclear. This study is the largest comparison of the two parameters to date and aims to clarify how their performance as covariates compare in predictive models of long-term visual outcomes following pituitary or parasellar tumour surgical resection. Methods: This was a prospective, two-year, longitudinal cohort study in a single centre tertiary hospital setting. Participants with MRI evidence of pituitary or parasellar tumour compression of the optic chiasm who underwent surgical decompression, were enrolled ...

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    4. One-year follow-up of optical coherence tomography angiography microvascular findings: macular telangiectasia type 2 versus tamoxifen retinopathy

      One-year follow-up of optical coherence tomography angiography microvascular findings: macular telangiectasia type 2 versus tamoxifen retinopathy

      Purpose: To compare microstructural and microvascular changes in eyes with macular telangiectasia type 2 (MacTel2) and in those with tamoxifen retinopathy (TR) at baseline and at the 1-year follow-up using optical coherence tomography (OCT) and OCT angiography (OCTA). Methods: We followed up patients diagnosed with MacTel2 or TR for at least 1 year. We included 17 patients with MacTel2 (31 eyes) and 15 with TR (25 eyes) who discontinued tamoxifen use after a TR diagnosis. We performed OCT and OCTA at baseline and after 1 year. Results: Patients with MacTel2 and TR showed intraretinal cavitation, ellipsoid zone (EZ) loss, and ...

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    5. Dark halo, a new biomarker in macular neovascularization: comparison between OCT angiography and ICGA—a pilot prospective study

      Dark halo, a new biomarker in macular neovascularization: comparison between OCT angiography and ICGA—a pilot prospective study

      Purpose To compare optical coherence tomography angiography (OCTA) and indocyanine green angiography (ICGA) in terms of reliability in detecting dark halo in patients affected by age-related macular degeneration (AMD) complicated with type 1 macular neovascularization (MNV). Methods Eighty-nine eyes of 89 patients were analyzed at the University of Naples Federico II between January 2018 and October 2021. Each patient underwent a complete ophthalmological evaluation including fluorescein angiography, ICGA, spectral domain optical coherence tomography (SD-OCT), and OCTA. OCTA and ICGA images of dark halo were compared. The paired Student’s test and intraclass correlation coefficients were used to evaluate the differences ...

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    6. Fully-Automatic 3D Intuitive Visualization of Age-Related Macular Degeneration Fluid Accumulations in OCT Cubes

      Fully-Automatic 3D Intuitive Visualization of Age-Related Macular Degeneration Fluid Accumulations in OCT Cubes

      Age-related macular degeneration is the leading cause of vision loss in developed countries, and wet-type AMD requires urgent treatment and rapid diagnosis because it causes rapid irreversible vision loss. Currently, AMD diagnosis is mainly carried out using images obtained by optical coherence tomography. This diagnostic process is performed by human clinicians, so human error may occur in some cases. Therefore, fully automatic methodologies are highly desirable adding a layer of robustness to the diagnosis. In this work, a novel computer-aided diagnosis and visualization methodology is proposed for the rapid identification and visualization of wet AMD. We adapted a convolutional neural ...

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    7. Optical Coherence Tomography Angiography for Biomarker Indices in Diabetes (Book Chapter)

      Optical Coherence Tomography Angiography for Biomarker Indices in Diabetes (Book Chapter)

      Optical coherence tomography angiography (OCTA) visualizes the structure and flow of retinal vasculature using motion contrast. Diabetic retinopathy (DR), commonly present in one-third of the patients with diabetes, is a major microvascular complication of diabetes mellitus caused by retinal ischemia and vascular hyperpermeability. Microvasculature changes, such as foveal avascular zone enlargement and decrease in vascular density of the deep capillary plexus, have been identified in diabetic eyes without clinical retinopathy. OCTA of nonproliferative DR shows morphologically well-defined microaneurysms and intraretinal vascular shunts around perfusion dropouts at the deep capillary plexus level. In proliferative DR, OCTA visualizes detailed features and extent ...

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    8. Comparison of acquisition rate and agreement of axial length with two swept-source optical coherence tomographers and a partial coherence interferometer

      Comparison of acquisition rate and agreement of axial length with two swept-source optical coherence tomographers and a partial coherence interferometer

      Purpose To assess the acquisition rate and agreement of axial length (AL) measurements with the OA-2000, Anterion, and IOLMaster 500 in cataractous patients. Methods In total, 298 eyes of 191 cataractous patients were enrolled and scanned with the three devices in random order. The success rate of AL measurements per device was calculated and a chi-square test was utilized to identify the differences in acquisition rate between the three devices. Logistic regression analysis was applied to evaluate the association of different cataract types and severity with the AL measurement acquisition rate. Bland–Altman plots were mapped to appraise the agreement ...

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    9. Intravitreal dexamethasone: variation of surgical technique and prevention of ocular complications with ASOCT follow-up

      Intravitreal dexamethasone: variation of surgical technique and prevention of ocular complications with ASOCT follow-up

      Purpose: To verify the correct decision-making procedure on performing an intravitreal injection by investigating the in vivo wound morphology and evolution of 22-gauge wounds after dexamethasone oblique injection with anterior segment optical coherence tomography (OCT). Design: Prospective, observational consecutive case series. Methods: Subjects underwent a dexamethasone injection at University Eye Clinic of Turin. All the injections have been performed in an oblique (aka beveled or angled) fashion. Patients were divided according to the number of injections already performed with dexamethasone. Group 1 consisted of patients at the first injection, group 2 of patients at a second or more injection always ...

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    10. Comparison of OCT imaging in children with foveal hypoplasia born full term versus preterm

      Comparison of OCT imaging in children with foveal hypoplasia born full term versus preterm

      Purpose: It is unknown if foveal hypoplasia in full-term born children differs in structure and function from that observed in children born preterm. We compared macular structure and visual function in children with history of prematurity and full-term children diagnosed with foveal hypoplasia. Methods: We compared three groups of subjects (3-18 years old): (1) full-term hypoplasia (FH, n = 56, gestational age ≥ 36 weeks); (2) preterm hypoplasia (n = 57, gestational age ≤ 31 weeks, birth weight ≤ 1500 g); (3) control (n = 54), full-term normal. Using spectral-domain optical coherence tomography volume-scan images, macular structure within 3 mm of Early-Treatment-Diabetic-Retinopathy-Study circle was segmented. Total ...

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    11. Optical Coherence Tomography in Cerebrovascular Disease: Open up New Horizons

      Optical Coherence Tomography in Cerebrovascular Disease: Open up New Horizons

      Optical coherence tomography (OCT), based on the backscattering or reflection of near-infrared light, enables an ultra-high resolution of up to 10 μm. The successful application of OCT in coronary artery diseases has sparked increasing interest in its implementation in cerebrovascular diseases. OCT has shown promising potential in the atherosclerotic plaque structure characterization, plaque rupture risk stratification, pre-stenting and post-stenting evaluation, and long-term follow-up in extracranial and intracranial atherosclerotic stenosis (ICAS). In hemorrhagic cerebrovascular diseases, OCT plays an important role in the structure evaluation, rupture risk stratification, and healing and occlusion evaluation following initial treatment in intracranial aneurysms (IAs). In this ...

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    12. Outcome of a polymer-free drug-coated coronary stent in bifurcation lesions—Pilot registry with serial OCT imaging

      Outcome of a polymer-free drug-coated coronary stent in bifurcation lesions—Pilot registry with serial OCT imaging

      Background: Polymer-free and carrier-free drug-coated stents (DCS) represent a novel therapeutic option for the treatment of coronary artery disease. The objective of this pilot registry is to evaluate the safety and efficacy of DCS implantation in bifurcation lesions. Methods: Overall, 23 consecutive patients with 24 lesions received a Biolimus A9-coated DCS for coronary bifurcation lesions. Patients were examined with quantitative coronary angiography (QCA) and optical coherence tomography (OCT) at 3-6 months of follow-up. Results: A total of 23 patients with 24 bifurcation lesions were included in this study. Nine (33.3%) lesions of eight patients revealed angiographical target lesion failure ...

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    13. Mixed pyramid attention network for nuclear cataract classification based on anterior segment OCT images

      Mixed pyramid attention network for nuclear cataract classification based on anterior segment OCT images

      Nuclear cataract (NC) is a leading ocular disease globally for blindness and vision impairment. NC patients can improve their vision through cataract surgery or slow the opacity development with early intervention. Anterior segment optical coherence tomography (AS-OCT) image is an emerging ophthalmic image type, which can clearly observe the whole lens structure. Recently, clinicians have been increasingly studying the correlation between NC severity levels and clinical features from the nucleus region on AS-OCT images, and the results suggested the correlation is strong. However, automatic NC classification research based on AS-OCT images has rarely been studied. This paper presents a novel ...

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    14. Evaluation of ocular surface epithelial and stromal thicknesses in psoriasis using anterior segment optical coherence tomography

      Evaluation of ocular surface epithelial and stromal thicknesses in psoriasis using anterior segment optical coherence tomography

      Purpose To evaluate the epithelial and stromal thicknesses of conjunctiva and cornea in psoriatic patients with anterior segment optical coherence tomography (AS-OCT), Methods In this cross-sectional study, 61 patients with psoriasis and 42 age-matched, healthy individuals were enrolled. The epithelial and stromal thicknesses of both inferotemporal bulbar conjunctiva and central cornea were measured using AS-OCT. Results Both the tear breakup time and Schirmer-1 test values were significantly lower in the psoriasis group compared with the controls ( p  < 0.05). The epithelial thickness of conjunctiva and cornea did not differ between psoriasis and control groups ( p  > 0.05). The central corneal ...

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    15. Performance evaluation of various deep learning based models for effective glaucoma evaluation using optical coherence tomography images

      Performance evaluation of various deep learning based models for effective glaucoma evaluation using optical coherence tomography images

      Glaucoma is the dominant reason for irreversible blindness worldwide, and its best remedy is early and timely detection. Optical coherence tomography has come to be the most commonly used imaging modality in detecting glaucomatous damage in recent years. Deep Learning using Optical Coherence Tomography Modality helps in predicting glaucoma more accurately and less tediously. This experimental study aims to perform glaucoma prediction using eight different ImageNet models from Optical Coherence Tomography of Glaucoma. A thorough investigation is performed to evaluate these models' performances on various efficiency metrics, which will help discover the best performing model. Every net is tested on ...

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    16. Retino-choroidal evaluation of the macular region in eyes with tubercular serpiginous-like choroiditis using swept-source optical coherence tomography angiography

      Retino-choroidal evaluation of the macular region in eyes with tubercular serpiginous-like choroiditis using swept-source optical coherence tomography angiography

      Aim: To analyse the alterations in retino-choroidal angioarchitecture in eyes with active tubercular serpiginous-like choroiditis (TB-SLC) using swept-source optical coherence tomography angiography (SS-OCTA). Methods: This prospective cross-sectional study enrolled 34 eyes diagnosed with TB-SLC and 34 age-matched healthy controls. Data acquisition with SS-OCTA using the PLEX Elite 9000 (Carl Zeiss Meditec Inc., Dublin, CA, USA) with a 6 × 6 mm pattern centered on the foveal center was done. Automated retinal vessel length density (VLD) and perfusion density (PD) and foveal avascular zone architecture were obtained from the ARI hub. Choroidal vascularity index (CVI) and choriocapillaris flow deficits (CCFD) were obtained ...

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    17. Noninvasive oral cancer screening based on local residual adaptation network using optical coherence tomography

      Noninvasive oral cancer screening based on local residual adaptation network using optical coherence tomography

      Oral cancer is known as one of the relatively common malignancy types worldwide. Despite the easy access of the oral cavity to examination, the invasive biopsy is still essential for final diagnosis, which requires laborious operation and complicated trained specialists. With the development of deep learning, the artificial intelligence (AI) technique is applied for oral cancer examinations and alleviates the workload of manual screening on biopsy. However, existing computer-aided oral cancer diagnostic methods focus on oral cavity environment photos and histology images, which require complicated operations for doctors and are invasive and painful for patients. As a noninvasive, real-time imaging ...

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    18. Surgical biomicroscopy-guided intra-operative optical coherence tomography (iOCT) image super-resolution

      Surgical biomicroscopy-guided intra-operative optical coherence tomography (iOCT) image super-resolution

      Purpose: Intra-retinal delivery of novel sight-restoring therapies will require the precision of robotic systems accompanied by excellent visualisation of retinal layers. Intra-operative Optical Coherence Tomography (iOCT) provides cross-sectional retinal images in real time but at the cost of image quality that is insufficient for intra-retinal therapy delivery.This paper proposes a super-resolution methodology that improves iOCT image quality leveraging spatiotemporal consistency of incoming iOCT video streams. Methods: To overcome the absence of ground truth high-resolution (HR) images, we first generate HR iOCT images by fusing spatially aligned iOCT video frames. Then, we automatically assess the quality of the HR images ...

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    19. Regression patterns of central serous chorioretinopathy using en face optical coherence tomography

      Regression patterns of central serous chorioretinopathy using en face optical coherence tomography

      Purpose To study the regression patterns of subretinal fluid (SRF) in central serous chorioretinopathy (CSCR) on sequential en face optical coherence tomography (OCT) and its relationship to leak locations. Methods Retrospective study on patients with acute CSCR. Inclusion criteria were (i) availability of data, sequential OCT and OCT angiography (B scan and en face OCT) every 2 weeks until resolution of SRF or 6 months, whichever is earlier; (ii) single active leak. Exclusion criteria were (i) presence of macular neovascularization or atypical CSCR, (ii) diffuse pigment epitheliopathy, (iii) multiple leaks. Serial en face OCT scans were evaluated and the area ...

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    20. Optical cohorence tomography angiography findings in carotid artery stenosis

      Optical cohorence tomography angiography findings in carotid artery stenosis

      Aim To investigate vascular density (VD) changes in the superficial (SCP) and deep capillary plexus (DCP), radial peripapillar capillary plexus (RPCP), Foveal avascular zone (FAZ) and thickness changes of peripapillary retinal nerve fiber layer (ppRNFL) and choroid (CT) using optical coherence tomography angiography (OCTA) ipsilateral eyes of patient with internal carotid artery stenosis (ICAS) and to compare the obtained values with kontralateral eyes of patients with İCAS and healthy individuals. Methods This prospective cross-sectional case–control study was conducted in 43 patients with a diagnosis of unilateral ICAS and 47 age- and sex-matched healthy subjects. The patients were divided into ...

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    21. Optical coherence tomography angiography quantification of choriocapillaris blood-flow after half-fluence photodynamic therapy for chronic central serous chorioretinopathy

      Optical coherence tomography angiography quantification of choriocapillaris blood-flow after half-fluence photodynamic therapy for chronic central serous chorioretinopathy

      Purpose: To quantitatively analyze characteristics of choriocapillaris flow using spectral domain optical coherence tomography angiography (SD-OCTA) in eyes with chronic central serous chorioretinopathy (CSC) before and after treatment by photodynamic therapy (PDT). Methods: Retrospective interventional study. Macular 3X3 SD-OCT scans were analyzed in eyes diagnosed with chronic CSC before and after treatment with half-fluence PDT. The choriocapillaris en face slabs were extracted from the SD-OCTA device after manual segmentation. En face choriocapillaris flow images were compensated with en face choriocapillaris structure images. Phansalkar local thresholding method was then used with a radius of 4 and 8 pixels. Percentage of flow ...

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    22. Retinal imaging with optical coherence tomography in multiple sclerosis: novel aspects

      Retinal imaging with optical coherence tomography in multiple sclerosis: novel aspects

      Optical coherence tomography (OCT) is of increasing interest in the clinical assessment of multiple sclerosis (MS) patients beyond the scope of clinical studies. In this narrative review, we discuss novel changes of OCT parameters during acute optic neuritis and the disease course of MS patients. OCT images document the changes of retinal layers during an episode of acute optic neuritis and can therefore provide valuable insights into the pathophysiology. Moreover, MS patients show progredient thinning of retinal layers throughout the disease. The thinning is accelerated through relapses as well as disease progression without relapse. The OCT parameters are also associated ...

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    23. Classification of gastric cancerous tissues by a residual network based on optical coherence tomography images

      Classification of gastric cancerous tissues by a residual network based on optical coherence tomography images

      Optical coherence tomography (OCT) is a noninvasive, radiation-free, and high-resolution imaging technology. The intraoperative classification of normal and cancerous tissue is critical for surgeons to guide surgical operations. Accurate classification of gastric cancerous OCT images is beneficial to improve the effect of surgical treatment based on the deep learning method. The OCT system was used to collect images of cancerous tissues removed from patients. An intelligent classification method of gastric cancerous tissues based on the residual network is proposed in this study and optimized with the ResNet18 model. Four residual blocks are used to reset the model structure of ResNet18 ...

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    24. A systematic survey of advances in retinal imaging modalities for Alzheimer’s disease diagnosis

      A systematic survey of advances in retinal imaging modalities for Alzheimer’s disease diagnosis

      Recent advances in retinal imaging pathophysiology have shown a new function for biomarkers in Alzheimer’s disease diagnosis and prognosis. The significant improvements in Optical coherence tomography (OCT) retinal imaging have led to significant clinical translation, particularly in Alzheimer’s disease detection. This systematic review will provide a comprehensive overview of retinal imaging in clinical applications, with a special focus on biomarker analysis for use in Alzheimer’s disease detection. Articles on OCT retinal imaging in Alzheimer’s disease diagnosis were identified in PubMed, Google Scholar, IEEE Xplore, and Research Gate databases until March 2021. Those studies using simultaneous retinal ...

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