Angiography Optical Coherence Research Articles

Non-Neovascular Subretinal Fluid with Serous Retinal Pigment Epithelial Detachment: Wait or Treat

Introduction: To describe the course of subretinal fluid (SRF) in eye with serous pigment epithelial detachment (serous PED) in the absence of macular neovascularization (non-neovascular AMD). Method: This is a retrospective case study included one eye with non-neovascular SRF associated with serous PED. Swept source optical coherence tomography (SS-OCT) and optical coherence angiography (OCTA) were obtained at baseline and follow up with qualitative and quantitative analysis of macula, pigment epithelial detachment (PED), subretinal fluid (SRF) and the presence or absence of macular neovascular membrane (MNV) in addition to other multimodal imaging modalities like fluorescein angiography (FA) and fundus auto fluorescence (FAF). Results: Our 66-year-old female has presented with left serous (PED) with apical (SRF) and no MNV on OCTA with baseline best corrected vision (BCVA) in Log MAR = 0.5. The SS-OCT, OCTA, and BCVA were stable over the initial five-month follow-up observation period with no MNV (non-neovascular SRF). One month later, the patient received an intravitreal anti-VEGF injection outside our clinic. 1-month post-outside clinic anti-VEGF injection, SS-OCT showed a small RPE tear with flattening of RPE detachment and preservation of BCVA =0.5. In the 3rd month post-outside clinic anti-VEGF injection, the SS-OCT showed slight flattening of RPE detachment with an obvious increase in SRF, still negative MNV on the OCTA associated with a drop in BCVA to 0.3. The decision was made to give the patient an initial three loading doses of aflibercept injections .The SS-OCT post 2nd aflibercept injection showed complete resolution and drying out of SRF, with an improvement of BCVA to 0.5. we continue completing the loading phase and then the patient was placed on treat and extend regimen (T&E). After the fifth aflibercept injection, the PED was completely flattened with appearance of MNV on OCTA after resolution of SRF. Conclusion: Many published studies provide preliminary data about non-neovascular AMD with SRF. SRF could be present in the absence of MNV due to RPE decompensation or RPE pump failure. However, the non-neovascular SRF could be transformed with time into a neovascular one with the presence of MNV. Multimodal imaging approach is essential in differentiating non-neovascular versus neovascular SRF and avoiding unnecessary antiVEGF injections.

Retinal Microvasculature in Systemic Sclerosis Patients and the Correlation between Nailfold Capillaroscopic Findings and Optical Coherence Angiography Results.

Background: The comparison of retinal perfusion in the eyes of patients with systemic sclerosis (SSc) and in healthy controls using optical coherence tomography angiography (OCTA). The correlation between nailfold capillaroscopy results and OCTA findings among SSc. Methods: The study enrolled 31 patients with systemic sclerosis and 41 healthy controls. OCTA was performed in both groups to assess the retinal vasculature in the superficial (SCP) and deep (DCP) capillary plexuses and the foveal avascular zone (FAZ) area. Nailfold capillaroscopy (NC) was performed in SSc patients and compared to the FAZ area and the superficial and the deep vessel density. Results: In the SSc group, the parafoveal vessel density in DCP was significantly higher in relation to the mean value (p < 0.0001) and in each quadrant of the macula (p < 0.0001) compared to healthy subjects (p < 0.0001). The patients with early scleroderma patterns in capillaroscopy had a larger superficial and deep FAZ (p = 0.0104, p = 0.0076, respectively) than those with active and late patterns. There was a statistically significant difference in the FAZ when comparing early to active (p < 0.0001) and early to late scleroderma patterns (p < 0.0001). A statistically significant difference was found in the type of interstitial lung disease and the deep FAZ area (p = 0.0484). SSc patients with nonspecific interstitial pneumonia (NSIP) had a larger FAZ than those with usual interstitial pneumonia (UIP) (p = 0.0484). Moreover, NSIP cases had a higher parafoveal mean superficial vessel density than those with UIP (p = 0.0471). Conclusions: Our investigation showed that the peripheral microvascular system correlates with ocular microcirculatory impairment. The results indicate the important role of OCTA in the diagnosis, monitoring, and prognosis of microvascular changes in SSc.

Utilization of Imaging Modalities in the Diagnosis of Melanoma: A Scoping Review.

Melanomas arise de novo or in the context of a precursor lesion. Lesions typically grow radially and then undergo a vertical growth phase proceeding to local invasion and metastasis. This review describes the utility of different imaging modalities in diagnosis and melanocytic lesion monitoring. A literature search was performed in November 2023 utilizing EMBASE, Medline, and PubMed. The PRISMA diagram demonstrates the review process. Reflectance confocal microscopy (RCM) utilizes near-infrared light to help diagnose dermatologic lesions. RCMwas found to demonstrate nearly two times the positive predictive value compared to dermoscopy. The introduction of the Berlin Ultrasound (US) Morphology Criteria permitted a 65-80% improvement in diagnostic sensitivity. US with fine-needle aspiration cytology (FNAC) accurately predicts the necessity for sentinel lymph node biopsy and lymphadenectomy, sparing patients with metastasis and prompting biopsy for equivocal lesions. Single-photon emission computed tomography/computed tomography (SPECT/CT) is an adjunctive tool to anatomically and functionally assess lymphatic invasion. SPECT/CT improves the detection of sentinel nodes while decreasing operating time and improving cosmetic outcomes. 18F-fluorodeoxyglucose(18F-FDG) positron emission tomography/computed tomography (PET/CT) with small voxel reconstruction demonstrated increased specificity and sensitivity for detecting in-transit metastases of melanomas, specifically in the limbs. Dermoscopy allows providers to cost-effectively recognize common lesion patterns. Multiphoton microscopy assigns a weight-based score based on malignant features. Optical coherence angiography captures images of vessels to help diagnose equivocal lesions. Utilization of imaging techniques may increase diagnostic accuracy, reduce unnecessary procedures, and help guide treatment plans. Additional research is needed to further characterize the utility of these techniques in order to improve the diagnosis and treatment of melanomas.

Evaluation of retinal angioarchitectonics by optical coherence angiography and its diagnostic value in functional amblyopia

AIM: This study aimed to evaluate the density parameters of the superficial and deep plexuses of the retina, choriocapillary layer, and avascular zone in eyes with amblyopia of various origins and paired fellow eyes.&#x0D; MATERIAL AND METHODS: The study included 40 patients aged 616 (mean, 8.723.04) years. All patients were divided into 2 groups: group 1 included amblyopic, dysbinocular, and anisometropic eyes (n=48), and group 2 (control group) included paired fellow eyes without amblyopia (n=32). The density of the superficial and deep vascular plexuses of the retina, choriocapillary layer, and avascular zone parameters (area, perimeter, and circumference) were evaluated using spectral optical coherence tomography (RS-3000 Advance 2, Nidek, Japan). Correlation analysis was performed using Pearsons linear correlation coefficient (r).&#x0D; RESULTS: No significant differences were found in the density of the superficial and deep retinal vessels, choriocapillary layer, and avascular zone parameters of the retina in eyes amblyopia of various origins compared with paired fellow eyes (p 0.05). No correlation was found between retinal perfusion data and functional and anatomical parameters of amblyopic eyes.&#x0D; CONCLUSION: No relationship was noted between the vascular parameters of the posterior pole of the eye and the maximally corrected visual acuity, which confirms the absence of changes in retinal perfusion in amblyopia and excludes its role in the pathogenesis.

Comparison between Fluorescein Fundus angiography, Optical Coherence Tomography and Optical Coherence Angiography in Detecting Macular Ischemia in Diabetic Macular Edema

Comparison between Fluorescein Fundus angiography, Optical Coherence Tomography and Optical Coherence Angiography in Detecting Macular Ischemia in Diabetic Macular Edema

Assessing the effects of prenatal poly-drug exposure on fetal brain vasculature using optical coherence angiography.

Maternal exposure to drugs during pregnancy is known to have detrimental effects on the fetus. Alcohol (ethanol) and nicotine are two of the most commonly co-abused substances during pregnancy, and prenatal poly-drug exposure is common due, in part, to the prevalence of unplanned pregnancies. The second trimester is a critical period for fetal neurogenesis and angiogenesis. When drug exposure occurs during this time, fetal brain development is affected. Several behavioral, morphological, and functional studies have evaluated the changes in fetal brain development due to exposure to these drugs individually. However, research on the combined effects of ethanol and nicotine is far more limited, specifically on fetal vasculature changes and development. We use correlation mapping optical coherence angiography (cm-OCA) to evaluate acute changes in fetal brain vasculature caused by maternal exposure to a combination of ethanol and nicotine. Ethanol (16.6% v/v, at a dose of ) and nicotine (at a dose of ) were administered to pregnant mice after initial cm-OCA measurements in utero. Subsequent measurements were taken at 5-min intervals for a total period of 45min. Results from these experiments were compared to results from our previous studies in which the mother was exposed to only ethanol (dose: ) or nicotine (dose: ). While results from exposure to ethanol or nicotine independently showed vasoconstriction, no significant change in vasculature was observed with combined exposure. Results suggested antagonistic effects of ethanol and nicotine on fetal brain vasculature.

Ocular retinal findings in asymptomatic patients with antiphospholipid syndrome secondary to systemic lupus erythematosus.

The objective is to perform a multimodal ophthalmological evaluation, including optical coherence angiography (OCTA), asymptomatic APS secondary to SLE (APS/SLE), and compare to SLE patients and control group (CG). We performed a complete structural/functional ophthalmological evaluation using OCTA/microperimetry exam in all participants. One hundred fifty eyes/75 asymptomatic subjects [APS/SLE (n = 25), SLE (n = 25), and CG (n = 25)] were included. Ophthalmologic abnormalities occurred in 9 (36%) APS/SLE, 11 (44%) SLE, and none of CG (p < 0.001). The most common retinal finding was Drusen-like deposits (DLDs) exclusively in APS/SLE and SLE (16% vs. 24%, p = 0.75) whereas severe changes occurred solely in APS/SLE [2 paracentral acute middle maculopathy (PAMM) and 1 homonymous quadrantanopsia]. A trend of higher frequency of antiphospholipid antibody (aPL) triple positivity (100% vs. 16%, p = 0.05) and higher mean values of adjusted Global Antiphospholipid Syndrome Score (aGAPSS) (14 ± 0 vs. 9.69 ± 3.44, p = 0.09) was observed in APS/SLE with PAMM vs. those without this complication. We identified that ophthalmologic retinal abnormalities occurred in more than 1/4 of asymptomatic APS/SLE and SLE. DLDs are the most frequent with similar frequencies in both conditions whereas PAMM occurred exclusively in APS/SLE patients. The possible association of the latter condition with aPL triple positivity and high aGAPSS suggests these two conditions may underlie the retinal maculopathy. Our findings in asymptomatic patients reinforce the need for early surveillance in these patients. Key Points • Retinal abnormalities occur in more than 1/4 of asymptomatic APS/SLE and SLE patients. • The occurrence of PAMM is possibly associated with APS and DLDs with SLE. • Presence of aPL triple positivity and high aGAPSS seem to be risk factors for PAMM.

Neuroprotection for Nonarteritic Central Retinal Artery Occlusion: Lessons from Acute Ischemic Stroke.

Nonarteritic central retinal artery occlusion (NA-CRAO) is a variant of acute ischemic stroke (AIS) and is a cause of sudden severe loss of vision. There are guidelines by the American Heart Association and the American Stroke Association for the care of CRAO patients. This review explores the basis of retinal neuroprotection for CRAO and its potential for improving the outcome of NA-CRAO. Recently, there have been significant advances in research into the use of neuroprotection to treat retinal diseases, including retinal detachment, age-related macular degeneration, and inherited retinal diseases. Also, neuroprotective research in AIS has been extensive, and newer drugs tested, including Uric acid, Nerinetide, and Otaplimastat, with promising results. Progress in cerebral neuroprotection after AIS offers hope for retinal neuroprotection after CRAO; and a possibility of extrapolating research findings from AIS into CRAO. Combining neuroprotection and thrombolysis can extend the therapeutic window for NA-CRAO treatment and potentially improve outcomes. Experimented neuroprotection for CRAO includes Angiopoietin (Comp Ang1), KUS 121, Gene therapy (XIAP), and hypothermia. Efforts in the field of neuroprotection for NA-CRAO should focus on better imaging to delineate the penumbra after an acute episode of NA-CRAO (using a combination of high-definition optical coherence angiography and electrophysiology). Also, research should explore details of pathophysiologic mechanisms involved in NA-CRAO, allowing for further neuroprotective intervention, and closing the gap between preclinical and clinical neuroprotection.

Chick Chorioallantoic Membrane as a Patient-Derived Xenograft Model for Uveal Melanoma: Imaging Modalities for Growth and Vascular Evaluation

Patient-derived tumor xenografts (PDXs) have emerged as valuable preclinical in vivo models in oncology as they largely retain the polygenomic architecture of the human tumors from which they originate. Although animal models are accompanied by cost and time constraints and a low engraftment rate, PDXs have primarily been established in immunodeficient rodent models for the in vivo assessment of tumor characteristics and of novel therapeutic cancer targets. The chick chorioallantoic membrane (CAM) assay represents an attractive alternative in vivo model that has long been used in the research of tumor biology and angiogenesis, and can overcome some of these limitations. In this study, we reviewed different technical approaches for the establishment and monitoring of a CAM-based uveal melanoma PDX model. Forty-six fresh tumor grafts were acquired after enucleation from six uveal melanoma patients and were implanted onto the CAM on ED7 with Matrigel and a ring (group 1), with Matrigel (group 2), or natively without Matrigel or a ring (group 3). Real-time imaging techniques, such as various ultrasound modalities, optical coherence tomography, infrared imaging, and imaging analyses with Image J for tumor growth and extension, as well as color doppler, optical coherence angiography, and fluorescein angiography for angiogenesis, were performed on ED18 as alternative monitoring instruments. The tumor samples were excised on ED18 for histological assessment. There were no significant differences between the three tested experimental groups regarding the length and width of the grafts during the development period. A statistically significant increase in volume (p = 0.0007) and weight (p = 0.0216) between ED7 and ED18 was only documented for tumor specimens of group 2. A significant correlation of the results for the cross-sectional area, largest basal diameter, and volume was documented between the different imaging and measurement techniques and the excised grafts. The formation of a vascular star around the tumor and of a vascular ring on the base of the tumor was observed for the majority of the viable developing grafts as a sign of successful engraftment. The establishment of a CAM-PDX uveal melanoma model could elucidate the biological growth patterns and the efficacy of new therapeutic options in vivo. The methodological novelty of this study, investigating different implanting techniques and exploiting advances in real-time imaging with multiple modalities, allows precise, quantitative assessment in the field of tumor experimentation, underlying the feasibility of CAM as an in vivo PDX model.

Preclinical-grade microendoscope for optical coherence tomography and angiography inside the bladder

We present a preclinical-grade, forward-viewing endomicroscope for in-contact optical coherence tomography (OCT) and optical coherence angiography (OCA) imaging through the working channel of a conventional cystoscope. Beam scanning is achieved with a fiber scanner driven by a tubular piezoelectric actuator. A focusing lens at the fiber tip helps engineering of the operation frequency within a compact probe length to avoid lateral undersampling. Microstructuring of fused silica through selective laser-induced etching was used for manufacturing a self-aligning housing for the probe head. The entire micro-optical system is assembled and encapsulated within a custom-developed sterilizable packaging with 4.5 mm outer diameter. The presented design and fabrication strategy can be used for any forward-viewing probe, independent of its imaging modalities. We demonstrate OCT imaging within a 2.1-mm diameter field of view at a transverse resolution of 19 μm and microvasculature visualization through OCA. The presented probe’s mechanical characteristics and optical performance make it particularly attractive for outpatient care use in the detection of tissue pathology inside the bladder. The presented fabrication methodology provides a reliable strategy for enabling preclinical trials with endoscopic imaging probes.

Commentary: Optical coherence angiography in intermediate uveitis: What is the scope?

Intermediate uveitis is a subset of uveitis where the vitreous is the primary site of inflammation. It is associated with an infection or systemic disease.[1] The disease affects individuals in all age groups but predominantly affects the third to the fourth decade.[2] In India, the incidence of intermediate uveitis is 1.4/100,000 and its prevalence is 0.25%.[3] Ocular inflammation can cause vascular occlusion, ischemia, capillary leak, and alteration of cellular mediators. Due to the sequalae of uveitis, sight-threatening ocular complications such as macula edema are seen. Early identification, treatment, and monitoring play a crucial role in visual recovery. Regardless of the anatomical location of uveitis, the most common complication of uveitis is macula edema. This is due to the release of inflammatory cytokines that disrupt the inner and outer blood-retina barrier. These changes occur even in anterior uveitis, presumably due to diffusion of inflammatory mediators in the vitreous. Imaging in uveitis is a game changer in the practice patterns of uveitis. Pro-imaging strategies have helped the clinician improvise the quality of eye care and play an important tool in management of ocular inflammation. With the advent of optical coherence tomography angiography (OCTA), an insight into the retinal microvascular changes provides additional information in the pathophysiological changes in uveitis.[4] Based on the definition of intermediate uveitis, the primary site of inflammation is in the vitreous and peripheral retina.[1] Acquiring images of the pars plana, ciliary body, and the peripheral retina is beyond the reach of OCTA. Though there are numerous studies on the microvasculature changes on OCTA in various retinal diseases, little is known about the changes in intermediate uveitis. However, a recent study analyzed the quantitative analyses of macular vascular structures in intermediate uveitis. They demonstrated significantly reduced vascular density in both superficial and deep retinal layers in intermediate uveitis patients [Table 1].[5]Table 1: Studies on OCTA in intermediate uveitisIn a case–control study on intermediate uveitis, reduced vascular density and complexity in superficial as well as deep retinal layers and altered choriocapillaris perfusion were detected. These alterations in OCTA indicates an impairment of the macular microvasculature even in the absence of macular edema.[6] Tian et al.[7] also reported that intermediate uveitis and vasculitis presented with reduced central vessel density. On OCTA, capillary non-perfusion and reduced perfusion was observed more in the choroid, choriocapillaris, and deep capillary plexus than in the superficial capillary plexus. Intermediate uveitis with vasculitis presented more with non-perfusion and hypoperfusion in the deep capillary plexus and superficial capillary plexus than intermediate uveitis without vasculitis. Ischemia on fluorescein angiogram was associated with non-perfusion on wide-field OCTA in superficial and deep capillary plexus. Tian et al.[8] reported another prospective: a cross-sectional study to evaluate vascular changes in patients with intermediate uveitis with or without vasculitis (wide-field montage and central 3 × 3 mm slabs). Though the wide-field images gave important information about peripheral vascular changes, their lower resolution limited the detectability of flow alterations compared to the high resolution of the central scans. Microvascular changes in eyes with intermediate uveitis were found at the level of the superficial capillary plexus, deep capillary plexus, the choriocapillaris, and the choroid. Also, a change of central vascular density found in the central scans did not correlate to alterations found on wide-field OCTA. They also concluded that rather than the presence of an epiretinal membrane and a macula edema, intermediate uveitis had an alteration on the foveal avascular zone size. Capillary changes may be also found beyond the posterior pole on wide-field OCTA. The differences in capillary density and morphology that was detected in uveitis patients shows that the effects of intraocular inflammation can be quantitatively measured even within a 3 × 3 mm2 parafoveal window.[8] Along with investigating the gross changes in the peripheral retina with wide-field imaging studies, OCTA assessment of changes in the parafoveal capillary density and branching complexity provides a unique assessment of disease severity that is not otherwise available. Surprisingly, not only the retinal vasculature is altered but also the choriocapillaris and the choroid is affected in intermediate uveitis. This definitely indicates that long-term studies on this domain are needed. Data on active eyes with intermediate uveitis are sparse. Hence, we would need to evaluate the disease activity which can be visualized using OCTA.

Optical coherence angiography of optic disc in eyes with primary open‐angle glaucoma and normal tension glaucoma with equal levels of structural damage

AbstractPurpose: To compare visual field (VF), nerve fibre and ganglion cell loss and changes in peripapillary vasculature in age matched patients with normal‐tension (NTG) and high tension glaucoma (HTG) at an equal level of glaucomatous structural damage of the optic nerve head (ONH).Methods: For the present study a retrospective analysis of patients with NTG and HTG was performed. One eye of each patient was randomly assigned for further analysis. To provide a reliable case by case match of HTG and NTG eyes, an equal optic disk size as measured by available spectral‐domain OCT system (RTVue XR OCT Avanti System; Optovue Inc., Fremont, CA) and an equal estimated excavation of the optic disk were chosen. Optic nerve head parameters, retinal nerve fibre layer (RNFL) ganglion cell (GCC) thickness and vessel densities (VD) in the peripapillary area were measured automatically by OCT with a respective software. Forty eyes with NTG, were matched according to the same glaucomatous ONH damage based on cup to disc ratio rim area and disc size with 40 eyes with HTG.Results: Mean age of patients was 68.5 ± 12 (27–84) years. The visual field index, RNFL, GCC thickness and peripapillary VDs in the HTG eyes were similar to those in the NTG eyes (mean VFI 79.6 vs. 78.8 p = 0.84, mean RNFL thickness 71.5 vs. 72.05 μm p = 0.87, mean GCC thickness 76.2 vs. 74.5 μm p = 0.62, mean peripapillary VD 43.6 vs. 43.8% p = 0.87). There was no difference in sectoral RNFL thickness and peripapillary VDs between HTG and NTG. In both groups, univariate regression analysis using the Pearson correlation coefficient showed VFI significantly correlated with RNFL thickness (NTG r = 0.423 p = 0.006 HTG r = 0.514 p = 0.002), and peripapillary VD (NTG r = 0.793 p &lt; 0.001 HTG p = 0.534 p = 0.001) in both groups but with GCC thickness (NTG r = 0.585 p &lt; 0.001) only in eyes with NTG.Conclusions: At an equal level of glaucomatous structural damage of the ONH indicated by cup to disk ratio and RNFL thickness, NTG patients seem to have same losses of peripapillary vasculature. Visual field index correlated with RNFL thickness and peripapillary vessel density in both groups.

The Role of the Inner Nuclear Layer for Perception of Persisting Tiling Inside a Monocular Scotoma.

We report two patients, one with and one without long-term persistent tiling inside an arcuate macular scotoma. In both cases, the scotoma was caused by a cilioretinal artery occlusion. Both patients were almost identical regarding the location and extent of the scotoma. In both cases, there was a comparable degree of atrophy on optical coherence tomography for the retinal nerve fibre, ganglion cell, and inner plexiform layers. The main difference was the preservation of the inner nuclear layer in the patient with persistent tiling. In this patient, optical coherence angiography demonstrates preserved perfusion of the superior vascular plexus, which was not the case in the patient with the negative scotoma who also had atrophy of the inner nuclear layer. Recreational use of cannabinoid enhanced the intensity of perceived tiling in the relative scotoma of the first patient. A review of the literature suggests that the persistent tiling described in our case is different to teichopsias of retinal or cerebral origin. These data suggest that persistent monocular tiling in a scotoma arises from retinal circuit activity that requires the preservation of the inner nuclear layer. Future research should investigate this functional-structural relationship in other diseases, including glaucoma.

Real-Time Infrared Spectroscopic Measurement of Natural Moisturizing Factor

Real-Time Infrared Spectroscopic Measurement of Natural Moisturizing Factor

Investigation of ocular microstructural changes according to disease severity in patients with chronic obstructive pulmonary disease

ObjectifVérifier les variations de l’épaisseur des couches de fibres nerveuses rétiniennes (RNFL) et de la densité vasculaire dans la rétine et le disque optique en présence de bronchopneumopathie chronique obstructive (BPCO). MéthodesAinsi, 66 patients présentant une BPCO et 54 sujets sains appariés pour l’âge et le sexe ont pris part à cette étude transversale prospective. Les patients présentant une BPCO ont été divisés en 3 sous-groupes (atteinte légère, modérée ou grave) d'après les paramètres spirométriques figurant dans les lignes directrices de la Global Initiative for Chronic Obstructive Lung Disease. On a eu recours à l'angiographie-tomographie par cohérence optique (OCTA) pour mesurer l’épaisseur des RNFL, l'aire de la zone fovéale avasculaire (ZFA) de même que la densité vasculaire du plexus capillaire superficiel, du plexus capillaire profond et du plexus capillaire péripapillaire radial. Les résultats ont ensuite été comparés d'un groupe à l'autre. RésultatsOn n'a noté aucune différence significative entre les patients du groupe BPCO et les sujets témoins en ce qui a trait à l'aire de la ZFA ou à l’épaisseur des RNFL (p = 0,891 et p = 0,896, respectivement). La densité vasculaire des patients du sous-groupe BPCO grave était moins élevée dans le plexus capillaire superficiel, comparativement aux autres groupes, mais la différence n’était pas significative (p > 0,05). La densité vasculaire dans le plexus capillaire profond ne différait pas significativement d'un groupe à l'autre dans la région fovéale (p > 0,05), mais était significativement moins élevée dans tous les quadrants parafovéaux chez les patients présentant une BPCO grave. La densité vasculaire dans le plexus capillaire péripapillaire radial était également moins élevée en présence de BPCO grave, surtout dans la région péripapillaire (p = 0,044). ConclusionBien que la BPCO soit d'abord et avant tout une affection pulmonaire, les tissus de l’œil semblent compter parmi ceux qui sont touchés pendant l’évolution naturelle de la maladie. Les effets sont plus prononcés en présence de BPCO grave et se manifestent dans le plexus capillaire profond et dans le plexus capillaire péripapillaire radial.

Monitoring of the state of intramural intestinal vessels in acute mesenteric ischemia with optical coherence angiography

Background. Objective data on the state of intramural microvessels are needed to select an effective therapy for the intestine reversibly damaged by mesenteric occlusion.&#x0D; Aim. To monitor the condition of the small intestine blood vessels in acute mesenteric ischemia using the method of optical coherence angiography.&#x0D; Material and methods. The study was carried out on male rats weighing 215315 g (n=17) on a model of acute mesenteric ischemia. Monitoring of the microvascular bed was performed using the optical coherence angiography before ischemia modeling and 60, 120, and 180 minutes after the onset of ischemia. The data were evaluated by calculating the total length (L, mm) and area (S, mm2) of vessels on angiograms, as well as the S/L ratio, an index of vessel diameter that provides information about the diameter of vessels regardless of their length, what means it is sensitive to their dilation/spasm. The significance of differences in quantitative characteristics was assessed using the MannWhitney and KruskalWallis criteria.&#x0D; Results. In the devascularized sector, the state of the vascular wall changed in different directions for 180 minutes, as evidenced by statistically significant changes in the parameters L, S and their ratio. During the first hour of ischemia, the median S/L ratio decreased by 9.2%. By the 120th minute of ischemia development, the S/L ratio recovered and did not differ statistically from the initial values (p=0.339). After 180 minutes, there was a trend towards an increase in the diameter of the remaining perfused vessels the median S/L on angiograms in the devascularized sector exceeded the initial level by 12.9% (p=0.045).&#x0D; Conclusion. Areas of the small intestine, localized at the border of spread of ischemia, according to the optical coherence angiography, are characterized by multidirectional changes in the total length and area of the intramural vessels; during the first hour of ischemia, functional changes predominate, probably due to an increase in the tonus of the vascular wall; after 180 minutes of observation, signs of irreversible dilatation of microvessels are recorded.

An in-vivo depth-resolved imaging of developing zebrafish microstructure and microvasculature using swept-source optical coherence tomography angiography

Zebrafish as vertebrate model has applications in the fields of embryology, oncology, toxicology, molecular genetics and drug discovery due to its high homology with the human genome. The zebrafish embryogenesis presents a propitious model for concurrent visualization of developmental stages in vivo owing to transparency and ex-utero development of the embryo. Developments in imaging tools and techniques focus on providing real-time quantitative imaging. The present work demonstrates depth-resolved imaging of developing zebrafish using swept-source optical coherence tomography (SSOCT). The SSOCT system provides an axial resolution of 4.5 µm and an imaging depth of 3.26 mm. The paper also presents imaging of the developing larval microvasculature using a 1 µm swept-source optical coherence tomography angiography (ssOCTA). A phase-contrast technique of optical coherence angiography calculates the phase differences between consecutive B-scans taken at single location. This technique detects motion induced by moving scatterers. We have also performed depth-resolved OCT angiography to resolve the minute vasculature better. The SSOCT system can capture the detailed microstructures and microvasculature of model organisms in-vivo.

Longitudinal in-vivo quantification of tumour microvascular heterogeneity by optical coherence angiography in pre-clinical radiation therapy

Stereotactic body radiotherapy (SBRT) is an emerging cancer treatment due to its logistical and potential therapeutic benefits as compared to conventional radiotherapy. However, its mechanism of action is yet to be fully understood, likely involving the ablation of tumour microvasculature by higher doses per fraction used in SBRT. In this study, we hypothesized that longitudinal imaging and quantification of the vascular architecture may elucidate the relationship between the microvasculature and tumour response kinetics. Pancreatic human tumour xenografts were thus irradiated with single doses of 10, 20 and 30 Gy to simulate the first fraction of a SBRT protocol. Tumour microvascular changes were monitored with optical coherence angiography for up to 8 weeks following irradiation. The temporal kinetics of two microvascular architectural metrics were studied as a function of time and dose: the diffusion-limited fraction, representing poorly vascularized tissue >150 μm from the nearest detected vessel, and the vascular distribution convexity index, a measure of vessel aggregation at short distances. These biological metrics allowed for dose dependent temporal evaluation of tissue (re)vascularization and vessel aggregation after radiotherapy, showing promise for determining the SBRT dose–response relationship.

Оценка показателя плотности сосудистой сети лимбальной области с помощью окт-ангиографии у пациентов с миопией и миопическим астигматизмом, перенесшим эксимерлазерную коррекцию зрения

Purpose. To assess the state of blood flow density in the limbal region in patients with myopia and myopic astigmatism before and after excimer laser vision correction using the Nidek RS-3000 AngioScan optical coherence tomograph. Material and methods. A total of 22 patients aged 18 to 37 years with myopia and myopic astigmatism of varying degrees were examined, who underwent excimer laser vision correction. Additionally, the blood flow density of the limbal region was studied in the preoperative and early postoperative periods using the Nidek RS-3000 AngioScan optical coherence tomograph using a module for scanning the anterior segment of the eye. Results. After 1 hour after excimer laser vision correction, there was a decrease in blood flow density of the limbal region in all 4 analyzed sectors (upper, lower, temporal, nasal), after 1 day there was an increase in blood flow indicators, tending to preoperative values. We were unable to identify the dependence of the degree of blood flow on the method of formation of the corneal flap. Conclusion. With the help of OCT angioregime, you can assess the state of the blood flow of the limb. In the first hour after laser vision correction, blood flow indicators changed in all 4 studied sectors, with a tendency to decrease, and recovered to preoperative indicators 1 day after surgery. Keywords: optical coherent angiography of the limbal region, excimer laser vision correction, femtolaser vision correction, myopia, myopic astigmatism.

Оценка показателей кровотока лимбальной области с помощью ангиорежима оптического когерентного томографа у пациентов с миопией и миопическим астигматизмом, перенесших эксимерлазерную коррекцию зрения

Purpose. To assess the state of blood flow in the limbal area in patients with myopia and myopic astigmatism before and after excimer laser vision correction using the Nidek RS-3000 AngioScan optical coherence tomograph. Material and methods. A total of 22 patients aged 18 to 37 with different degrees of myopia and myopic astigmatism who underwent excimer laser vision correction were examined. Additionally, the blood flow of the limbal area was studied in the preoperative and early postoperative periods using the Nidek RS-3000 AngioScan optical coherence tomograph using a module for scanning the anterior segment of the eye. Results. One hour after excimer laser vision correction, there is a decrease in blood flow of the limbal area in all 4 analyzed sectors (upper, lower, temporal, nasal), after 1 day there is an increase in blood flow indicators, tending to preoperative values. We were unable to identify the dependence of the degree of blood flow on the method of formation of the corneal flap. Conclusion. Using OCT angioregime it is possible to assess the condition of limb blood flow. In the first hour after laser vision correction blood flow parameters change in all 4 studied sectors, with a tendency to decrease, and recover to preoperative values 1 day after the surgery. Key words: optical coherent angiography of the limbal area, excimer laser vision correction, femtolaser vision correction, myopia, myopic astigmatism.