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Dynamic Optical Coherence Tomography Is a New Technique for Imaging Skin Around Lower Extremity Wounds
摘要： Chronic wounds such as venous leg ulcers invariably heal slowly and recur. In the case of venous leg ulcers, poor healing of chronic wounds is variously attributed to ambulatory hypertension, impaired perfusion and diffusion, presence of chronic inflammation at wound sites, lipodermatosclerosis, and senescence. The aim of this study was to investigate whether a new technique, optical coherence tomography (OCT), which permits imaging of blood capillaries in the peri-wound skin, can provide new insights into the pathology. OCT and its recent variant, dynamic OCT, permit rapid noninvasive depth-resolved imaging of the capillaries in the superficial dermis via a handheld probe, showing the morphology and density of vessels down to 20 μm in diameter. We used dynamic OCT to investigate 15 chronic wounds and assess characteristics of the vessels at the 4 poles around the wounds, the wound bed, adjacent dermatosclerosis, and unaffected skin. The results of the study show that both vessel morphology and density in the wound edges are dramatically different from that in healthy skin, showing clusters of glomuleri-like vessels (knot-like forms or clumps) and an absence of linear branching vessels, and also greater blood perfusion. Such vessel shapes are reported to be associated with tissue growth. The OCT imaging procedure was rapid and well tolerated by patients and provided new information not available from other devices. Thus, OCT appears to have great promise as a tool for the evaluation and study of chronic ulcers.
关键词： capillary imaging,venous leg ulcer,chronic wounds,optical coherence tomography
更新于2025-09-23 15:22:29
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Eggshell apex abnormalities caused by two different Mycoplasma synoviae genotypes and evaluation of eggshell anomalies by full-field optical coherence tomography
摘要： Background: Mycoplasma synoviae (MS) is an important poultry pathogen worldwide. This bacterium may cause eggshell changes including an altered shell surface, thinning, and increased translucency in different areas, which leads to a greater incidence of eggshell cracks and breaks. In the present study the association between experimental infection of birds with two field strains of MS from different genotypes and the production of abnormal eggs is described. The analysis of those eggshells using a full-field optical coherence tomography (FF OCT) scanner is also reported. Results: Eggshell samples were obtained from three experimental groups of chickens: one control and two infected tracheally with field strains of MS which produced abnormal eggs. In both experimental groups infected with MS a reduction of mean daily egg production by 11% was observed compared to the control group, which started at 21 to 42 dpi. Eggshell apex abnormalities increased to 24.5% of eggs and in some cases, soft-shelled eggs were produced. This study provides the first analysis of shells from anomalous eggs carried out using FF OCT, which allows three-dimensional structural imaging of an investigated sample at micrometre scale. FF OCT showed ultrastructural changes in eggshells and a smaller number of pores on the entire surface of the affected shells. Conclusions: The eggshell pathology and the concomitant egg production losses that result from infections highlight the economic significance of MS in commercial poultry. There are differences in the strains of MS which may induce eggshell apex abnormalities (EAA) and egg production losses. The use of FF OCT, which is a noninvasive measurement method based on analysis of the light backscattered from the measured object, will confer the ability to control the quality of eggshells in flocks infected with MS.
关键词： Poultry,Apex eggshell abnormalities,EAA,Mycoplasma synoviae,Full-field optical coherence tomography
更新于2025-09-23 15:22:29
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Plaque characteristics and slow flow during percutaneous coronary intervention of irregular protrusion by optical coherence tomography
摘要： Irregular protrusion on optical coherence tomography (OCT) is associated with clinical events and target lesion revascularization. We investigated clinical and procedure characteristics, plaque characteristics, slow flow after stent implantation, and clinical outcomes with irregular protrusion using OCT. Eighty-four lesions in 76 patients undergoing OCT before percutaneous coronary intervention were evaluated. Irregular protrusion was defined as protrusion of material with an irregular surface into the lumen between stent struts with a maximum height of ≥100 μm. Lesions with irregular protrusion were found in 56% (47/84). Compared with lesions without irregular protrusion, those with irregular protrusion had significantly higher low-density lipoprotein cholesterol (LDL-C) levels (108 ± 31 mg/dl vs. 95 ± 25 mg/dl, P = 0.044); a tendency toward decreased use of statins [44% (19/43) vs. 67% (22/33), P = 0.065]; significantly larger reference vessel diameter (3.12 ± 0.53 mm vs. 2.74 ± 0.63 mm, P = 0.004); more frequent slow flow after stent implantation [38% (18/47) vs. 11% (4/37), P = 0.006]; higher incidence of thin-cap fibroatheromas [TCFAs; 49% (23/47) vs. 5% (2/37), P < 0.001]; plaque rupture [40% (19/47) vs. 16% (6/37), P = 0.018]; and a tendency higher incidence of 1-year adverse clinical outcomes (death, acute myocardial infarction, acute coronary syndrome, or target lesion revascularization) [12% (5/43) vs. 0% (0/33), P = 0.075]. In conclusion, irregular protrusion on OCT was associated with high plaque vulnerability, higher LDL-C, less frequent use of statin, larger vessel diameter, slow flow after stent implantation, and 1-year adverse clinical outcomes.
关键词： Slow flow,Optical coherence tomography,Irregular protrusion
更新于2025-09-23 15:22:29
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Macrophage uptake switches on OCT contrast of superparamagnetic nanoparticles for imaging of atherosclerotic plaques
摘要： Background: Optical coherence tomography (OCT) is an intravascular, high-resolution imaging technique that is used to characterize atherosclerotic plaques. However, the identification of macrophages as important markers of inflammation and plaque vulnerability remains difficult. Here, we investigate whether the uptake of very small iron oxide particles (VSOP) in macrophages, that cluster in phagolysosomes and allow high-quality magnetic resonance imaging (MRI) of atherosclerotic plaques, and uptake of ferumoxytol nanoparticles enhance detection of macrophages by OCT. Materials and methods: RAW 264.7 macrophage cells were incubated with VSOP (1 and 2 mM Fe) that have been clinically tested and ferumoxytol (8.9 mM Fe) that is approved for iron deficiency treatment and currently investigated as an MRI contrast agent. The light scattering of control macrophages, nanoparticle-labeled macrophages (2,000,000 in 500 μL) and nanoparticle suspensions was measured in synchronous wavelength scan mode using a fluorescence spectrophotometer. For OCT analyses, pellets of 8,000,000 non-labeled, VSOP-labeled and ferumoxytol-labeled RAW 264.7 macrophages were imaged and analyzed on an OPTIS? OCT imaging system. Results: Incubation with 1 and 2 mM VSOP resulted in uptake of 7.1±1.5 and 12±1.5 pg Fe per cell, which increased the backscattering of the macrophages in spectrophotometry 2.5- and 3.6-fold, whereas incubation with 8.9 mM Fe ferumoxytol resulted in uptake of 6.6±2 pg Fe per cell, which increased the backscattering 1.5-fold at 700 nm. In contrast, backscattering of non-clustered nanoparticles in suspension was negligible. Accordingly, OCT imaging could visualize significantly increased backscattering and signal attenuation of nanoparticle-labeled macrophages in comparison with controls. Conclusion: We conclude that VSOP and, to a lesser extent, ferumoxytol increase light scattering and attenuation when taken up by macrophages and can serve as a multimodal imaging probe for MRI and OCT to improve macrophage detection in atherosclerotic plaques by OCT in the future.
关键词： intravascular,magnetic resonance imaging,multimodal imaging,optical coherence tomography,vulnerability,inflammation
更新于2025-09-23 15:22:29
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The correlation between visual acuity outcomes and optical coherence tomography parameters following surgery for diabetic epiretinal membrane and taut posterior hyaloid
摘要： Purpose: To evaluate the relationship between visual outcomes and the determinants detected by spectral domain optical coherence tomography (OCT) in eyes with epiretinal membrane (ERM) and/or taut posterior hyaloid (TPH) that underwent pars plana vitrectomy (PPV). Materials and methods: A total of 30 participants with diabetic ERM and TPH were included in the study. All study participants underwent PPV. Preoperative and postoperative best corrected visual acuity (BCVA), peripapillary retinal nerve fiber layer (RNFL), macular RNFL, ganglion cell layer, inner plexiform layer, and ganglion cell complex thicknesses were measured in each participant. Linear regression analyses were performed to determine the association between the OCT parameters and the visual acuity measured at the time of the OCT measurement. Results: The postoperative BCVA logarithm of the minimum angle of resolution (logMAR) values were statistically higher than the preoperative values in the ERM group and TPH group (P=0.001 and P<0.001, respectively). The postoperative BCVA logMAR value was negatively correlated with average RNFL, inferior RNFL thicknesses, and image quality (P=0.002, P=0.004, and P=0.006, respectively). The preoperative and postoperative BCVA logMAR value difference was not correlated with age and all of the OCT parameters measured (P>0.05). Conclusion: This study shows that achievement of better peripapillary RNFL thickness results in better visual outcome after PPV and ERM/TPH removal.
关键词： retinal nerve fiber layer,ganglion cell complex,optical coherence tomography,taut posterior hyaloid,diabetic epiretinal membrane
更新于2025-09-23 15:22:29
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Estimation of Intraocular Lens Power Calculation after Myopic Corneal Refractive Surgery: Using Corneal Height in Anterior Segment Optical Coherence Tomography
摘要： Purpose: To investigate the feasibility of estimating effective lens position (ELP) and calculating intraocular lens power using corneal height (CH), as measured using anterior segment optical coherence tomography (AS-OCT), in patients who have undergone corneal refractive surgery. Methods: This study included 23 patients (30 eyes) who have undergone myopic corneal refractive surgery and subsequent successful cataract surgery. The CH was measured with AS-OCT, and the measured ELP (ELPm) was calculated. Intraocular lens power, which could achieve actual emmetropia (Preal), was determined with medical records. Estimated ELP (ELPest) was back-calculated using Preal, axial length, and keratometric value through the SRK/T formula. After searching the best-fit regression formula between ELPm and ELPest, converted ELP and intraocular lens power (ELPconv, Pconv) were obtained and then compared to ELPest and Preal, respectively. The proportion of eyes within a defined error was investigated. Results: Mean CH, ELPest, and ELPm were 3.71 ± 0.23, 7.74 ± 1.09, 5.78 ± 0.26 mm, respectively. The ELPm and ELPest were linearly correlated (ELPest = 1.841 × ELPm – 2.018, p = 0.023, R = 0.410) and ELPconv and Pconv agreed well with ELPest and Preal, respectively. Eyes within ±0.5, ±1.0, ±1.5, and ±2.0 diopters of the calculated Pconv, were 23.3%, 66.6%, 83.3%, and 100.0%, respectively. Conclusions: Intraocular lens power calculation using CH measured with AS-OCT shows comparable accuracy to several conventional methods in eyes following corneal refractive surgery.
关键词： Intraocular lens power calculation,Corneal height,Corneal refractive surgery,Effective lens position,Anterior segment optical coherence tomography
更新于2025-09-23 15:22:29
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Structural and Functional Outcomes in Chronic Central Serous Chorioretinopathy Treated with Photodynamic Therapy
摘要： Purpose: To study the retinal pigment epithelium (RPE) and retinal alterations in chronic central serous chorioretinopathy treated with photodynamic therapy, and its correlation with functional parameters such as best-corrected visual acuity (BCVA) and contrast sensitivity (CS). Methods: Retrospective, noncomparative, consecutive evaluation by optical coherence tomography and its correlation with BCVA and CS in 31 eyes of 26 patients. Results: In all affected patients, 88.5% were male with a mean age of 42.9 years. The right eye was involved in 64.5% of cases, bilateral in 19% and 73.9% were hyperopic (spherical refraction between 0 and +5.0 diopters). Of these cases, 51.5% had peri-RPE abnormalities, 17.3% hyperreflective substances at RPE, 19.4% RPE atrophy, 55.3% foveolar atrophy, 3.1% pigment epithelial detachment, 5.2% subretinal fluid persistence, 8.3% fibrin deposits, 68.4% photoreceptor inner and outer segment line interruption and 31.1% external limiting membrane interruption. Conclusions: Time evolution and number of outbreaks were related to the decrease in foveal and chorodial thickness and in those with worse BCVA and CS. RPE abnormalities and atrophy were related to the age of onset of symptoms. Photoreceptor elongation has been correlated with poor BCVA and inner and outer segment line destructuring and interruption with poor CS.
关键词： Photochemotherapy,Contrast sensitivity,Visual acuity,Central serous chorioretinopathy,Optical coherence tomography
更新于2025-09-23 15:22:29
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Posterior Vitreous Structures Evaluated by Swept-source Optical Coherence Tomography with En Face Imaging
摘要： Purpose: To evaluate posterior vitreous structures using swept-source (SS) optical coherence tomography (OCT) with en face imaging. Methods: We retrospectively reviewed OCT images of healthy individuals who did not have intra-ocular disease. We obtained high-definition horizontal and vertical line scans crossing the fovea and 3D scans using SS-OCT, with the 3D scan centered between the fovea and the optic-nerve head. An enhanced vitreous visualization function was used to highlight vitreous structures. En face mode was used to measure the area of Martegiani (AM) and bursa premacularis (BP). We performed all measurements using a built-in function of the viewing software. Results: We enrolled 24 eyes from 12 healthy individuals. The mean patient age was 28.7 ± 4.6 years (range, 24 to 39 years). The mean AM and BP areas were 5.73 ± 0.88 and 18.76 ± 6.95 mm2, respectively. In en face imaging, AM shape was most frequently a vertical oval (18 / 22, 81.8%), while the predominant BP shape was round (16 / 20, 80.0%). AM was in contact with the optic disc, either at the temporal-disc margin (13 eyes, 59.1%) or the nasal optic-disc margin (9 eyes, 40.9%). Conclusions: Posterior vitreous structures, such as AM and BP, were readily visualized using en face imaging with SS-OCT. Investigating normal vitreous configuration might help in understanding changes in vitreous structures associated with retinal pathology.
关键词： Area of Martegiani,Bursa premacularis,En face,Swept-source optical coherence tomography,Vitreous body
更新于2025-09-23 15:22:29
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In Vivo 3D Imaging of Retinal Neovascularization Using Multimodal Photoacoustic Microscopy and Optical Coherence Tomography Imaging
摘要： The pathological process of neovascularization of the retina plays a critical role in causing vision loss in several diseases, including diabetes, retinal vein occlusion, and sickle cell disease. Retinal neovascularization can lead to vitreous hemorrhage and retinal detachment, yet the pathological process of neovascularization is a complex phenomenon under active investigation. Understanding and monitoring retinal neovascularization is critically important in clinical ophthalmology. This study describes a novel multimodal ocular imaging system which combines photoacoustic microscopy (PAM) and a spectral domain optical coherence tomography (SD-OCT) to improve the visualization of retinal neovascularization (RNV), their depth, and the surrounding anatomy in living rabbits. RNV was induced in New Zealand rabbits by intravitreal injection of vascular endothelial growth factor (VEGF). The retinal vasculature before and after injection at various times was monitored and evaluated using multimodal imaging including color fundus photography, fluorescein angiography (FA), OCT, and PAM. In vivo experiments demonstrate that PAM imaging distinctly characterized the location as well as the morphology of individual RNV with high contrast at a safe laser energy of 80 nJ. SD-OCT was used to identify a cross-sectional structure of RNV. In addition, dynamic changes in the retinal morphology and retinal neovascularization were observed at day 4, 5, 6, 7, 9, 11, 14, 28, and day 35 after VEGF injection. PAM demonstrated high-resolution optical absorption of hemoglobin and vascular imaging of the retina and choroid with increased depth of penetration. With the current multimodal imaging system, RNV can be easily visualized in both 2D and 3D angiography. This multimodal ocular imaging system provides improved characterization of the microvasculature in a safe manner in larger rabbit eyes.
关键词： PAM,VEGF,multimodal imaging,optical coherence tomography,photoacoustic microscopy,retinal neovascularization,vascular endothelial growth factor,OCT
更新于2025-09-23 15:22:29
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A Quantum Field Approach for Advancing Optical Coherence Tomography Part I: First Order Correlations, Single Photon Interference, and Quantum Noise
摘要： Optical coherence tomography has become an important imaging technology in cardiology and ophthalmology, with other applications under investigations. Major advances in optical coherence tomography (OCT) imaging are likely to occur through a quantum field approach to the technology. In this paper, which is the first part in a series on the topic, the quantum basis of OCT first order correlations is expressed in terms of full field quantization. Specifically first order correlations are treated as the linear sum of single photon interferences along indistinguishable paths. Photons and the electromagnetic (EM) field are described in terms of quantum harmonic oscillators. While the author feels the study of quantum second order correlations will lead to greater paradigm shifts in the field, addressed in part II, advances from the study of quantum first order correlations are given. In particular, ranging errors are discussed (with remedies) from vacuum fluctuations through the detector port, photon counting errors, and position probability amplitude uncertainty. In addition, the principles of quantum field theory and first order correlations are needed for studying second order correlations in part II.
关键词： Plaque,Quantum mechanics,Interferometry,Ophthalmology,Noise,Vacuum,Cardiology,Arthritis,Optical coherence tomography
更新于2025-09-23 15:22:29