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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
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Vertical Hyperreflective Lesions on Optical Coherence Tomography in Vitreoretinal Lymphoma
摘要： IMPORTANCE Vitreoretinal lymphoma is a diagnostic challenge and the pathophysiology is still unclear. OBJECTIVE To describe an imaging finding seen on optical coherence tomography (OCT) of patients with vitreoretinal lymphoma. DESIGN, SETTING, AND PARTICIPANTS This case series study was a retrospective medical record review of patients who received a diagnosis of vitreoretinal lymphoma at the Department of Ophthalmology at Northwestern University between July 2014 and January 2016. MAIN OUTCOMES AND MEASURES Optical coherence tomography findings in vitreoretinal lymphoma. RESULTS We identified 7 patients (4 women [57.1%]; mean [range] age, 62.4 [45-75] years; 12 eyes) with intraocular lymphoma involving the retina (5 patients [71.4%] with primary vitreoretinal or central nervous system lymphoma with ocular involvement, 1 patient [14.3%] with testicular lymphoma with secondary central nervous system lymphoma and vitreoretinal lymphoma, and 1 patient [14.3%] with secondary vitreoretinal lymphoma). We identified vertical hyperreflective lesions that showed moderate or high reflectivity and affected all layers of the neuroretina in 5 patients (7 of 12 eyes [58.3%]). These often preceded the development of subretinal pigment epithelial deposits and were often localized around second-order and third-order retinal vessels. In most cases, they resolved with minimal or no scarring after the initiation of chemotherapy. CONCLUSIONS AND RELEVANCE Vertical hyperreflective lesions are a common physical finding on OCT in eyes with vitreoretinal lymphoma.
关键词： optical coherence tomography,vertical hyperreflective lesions,vitreoretinal lymphoma
更新于2025-09-23 15:21:01
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Retinal Thickness Changes throughout the Natural History of Drusen in Age-related Macular Degeneration
摘要： SIGNIFICANCE: Drusen are associated with retinal thinning in age-related macular degeneration (AMD). These changes, however, have mostly been examined at single time points, ignoring the evolution of drusen from emergence to regression. Understanding the full breadth of retinal changes associated with drusen will improve understanding of disease pathogenesis. PURPOSE: The purpose of this study was to assess how the natural history of drusen affects retinal thickness, focusing on the photoreceptor and retinal pigment epithelium (RPE) layers. METHODS: Spectral domain optical coherence tomography of subjects with intermediate AMD (n = 50) who attended the Centre for Eye Health, Sydney, Australia, for two separate visits (476 ± 16 days between visits) was extracted. Scans were automatically segmented with manufacturer software then assessed for drusen that had emerged, grown, or regressed between visits. For each identified lesion, the thickness of each retinal layer at the drusen peak and at adjacent drusen-free areas (150 μm nasal and temporal to the druse) was compared between visits. RESULTS: Before drusen emergence, the RPE was significantly thicker at the drusen site (14.2 ± 2.6%) compared with neighboring drusen-free areas. There was a 71% sensitivity of RPE thickening predicting drusen emergence. Once drusen emerged, significant thinning of all outer retinal layers was observed, consistent with previous studies. Drusen growth was significantly correlated with thinning of the outer retina (r = ?0.38, P < .001). Drusen regression resulted in outer retinal layers returning to thicknesses not significantly different from baseline. CONCLUSIONS: The natural history of drusen is associated with RPE thickening before drusen emergence, thinning of the outer nuclear layer as well as photoreceptor and RPE layers proportional to drusen growth, and return to baseline thickness after drusen regression. These findings have useful clinical applications, providing a potential marker for predicting drusen emergence for AMD prognostic and intervention studies and highlighting that areas of normal retinal thickness in AMD may be former sites of regressed drusen.
关键词： spectral domain optical coherence tomography,drusen,age-related macular degeneration,retinal thickness
更新于2025-09-23 15:21:01
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Intra-slice motion correction of intravascular OCT images using deep features
摘要： Intra-slice motion correction is an important step for analyzing volume variations and pathological formations from intravascular imaging. Optical Coherence Tomography (OCT) has been recently introduced for intravascular imaging and assessment of coronary artery disease. 2D cross-sectional OCT images of coronary arteries play a crucial role to characterize the internal structure of the tissues. Adjacent images could be compounded, however they might not fully match due to motion, which is a major hurdle for analyzing longitudinally each tissue in 3D. The aim of this study is to develop a robust tissue matching based motion correction approach from a sequence of 2D intracoronary OCT images. Our motion correction technique is based on the correlation between deep features obtained from Convolutional Neural Network (CNN) for each frame of a sequence. The optimal transformation of each frame is obtained by maximizing the similarity between the tissues of reference and moving frames. The results show a good alignment of the tissues after applying CNN features and determining the transformation parameters.
关键词： Deep Features,Optical Coherence Tomography (OCT),Coronary Artery,Motion Correction,Tissue Characterization
更新于2025-09-23 15:21:01
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Evaluation of marginal and internal fit of acrylic bridges using optical coherence tomography
摘要： Background: The potential of non-invasive optical coherence tomography (OCT) as a tool for assessment of fit of indirect reconstructions is not fully explored. Objectives: The objectives were to investigate the feasibility and validity of OCT, and to measure the internal and marginal fit of acrylic bridges fabricated using direct and indirect digitalization. Methods: The accuracy of the employed swept source OCT (wavelength: 1310nm) was assessed by comparing with an object with known dimensions. Validity was assessed by comparing OCT measurements on replica, mimicking the cement film thickness, with stereomicroscopic measurements. The reconstructions were placed on the abutments without cementation. The internal and marginal fit of acrylic bridges from direct and indirect digitalization techniques were then assessed by obtaining 5 OCT B-scans per abutment tooth at pre-defined positions located 250 μm apart. The marginal and internal cement gaps were measured using image-processing software (ImageJ). Mean and standard deviation were calculated for both groups and t-test assuming unequal variances was carried out. The level of significance was defined at 0.05. Results: A strong linear correlation (r = 0.865) between OCT and stereomicroscopy was found. T-test showed significantly (P < 0.01) better internal fit of bridges made from indirect digitalization, but no difference in marginal fit. Conclusion: OCT is a feasible and valid tool for investigating internal and marginal fit of acrylic dental reconstructions. Better internal fit was observed in bridges fabricated using the direct digitalization technique. No difference in marginal fit was found between the two fabrication methods.
关键词： Accuracy,Dental marginal fit,Replica technique,Optical coherence tomography,Dental internal fit,Acrylic Resins
更新于2025-09-23 15:21:01
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Semivariogram and Semimadogram functions as descriptors for AMD diagnosis on SD-OCT topographic maps using Support Vector Machine
摘要： Background: Age-related macular degeneration (AMD) is a degenerative ocular disease that develops by the formation of drusen in the macula region leading to blindness. This condition can be detected automatically by automated image processing techniques applied in spectral domain optical coherence tomography (SD-OCT) volumes. The most common approach is the individualized analysis of each slice (B-Scan) of the SD-OCT volumes. However, it ends up losing the correlation between pixels of neighboring slices. The retina representation by topographic maps reveals the similarity of these structures with geographic relief maps, which can be represented by geostatistical descriptors. In this paper, we present a methodology based on geostatistical functions for the automatic diagnosis of AMD in SD-OCT. Methods: The proposed methodology is based on the construction of a topographic map of the macular region. Over the topographic map, we compute geostatistical features using semivariogram and semimadogram functions as texture descriptors. The extracted descriptors are then used as input for a Support Vector Machine classifier. Results: For training of the classifier and tests, a database composed of 384 OCT exams (269 volumes of eyes exhibiting AMD and 115 control volumes) with layers segmented and validated by specialists were used. The best classification model, validated with cross-validation k-fold, achieved an accuracy of 95.2% and an AUROC of 0.989. Conclusion: The presented methodology exclusively uses geostatistical descriptors for the diagnosis of AMD in SD-OCT images of the macular region. The results are promising and the methodology is competitive considering previous results published in literature.
关键词： CAD-x,Semivariogram,Medical images,Semimadogram,Optical coherence tomography
更新于2025-09-23 15:21:01
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Value of optical coherence tomography in the detection of macular pathology before the removal of silicone oil
摘要： Purpose: To assess the pathological macular changes with optical coherence tomography (OCT) before the removal of silicone oil (SiO) in eyes that had undergone pars plana vitrectomy for complicated forms of retinal detachment (RD). Patients and methods: Subjects included 48 patients (51 eyes) with complicated RD including proliferative vitreoretinopathy, proliferative diabetic retinopathy, recurrent RD, penetrating trauma, uveitis, giant retinal tears, and macular holes. All the eyes had undergone SiO injection. Furthermore, all eyes had been planned for the removal of SiO 6–12 months after the primary surgery. Finally, all eyes had a fundus examination and OCT examination before the silicone oil removal. Results: OCT findings indicated epiretinal membrane in 41% of the eyes, macular edema in 17%, macular detachment in 13.5%, macular thinning in 13.5%, macular holes in 10%, and subretinal membranes in 2%. Preoperative OCT was normal in only 12% of the eyes, while a clinical fundus examination was normal in 43% (P0.001). Eyes with normal OCT had significantly better mean logMAR (0.35) than eyes with pathological changes detected through OCT (1.28; P0.001). Surgical modifications were made during the removal of SiO in 74.5% of the eyes. Conclusion: OCT detected significantly more pathological changes than a clinical fundus examination. This had an impact on both surgical step modification during the removal of SiO and predictability of visual outcome after the removal of SiO.
关键词： optical coherence tomography,pars plana vitrectomy,silicone oil,proliferative diabetic retinopathy,proliferative vitreoretinopathy
更新于2025-09-23 15:21:01