Deep Vessels Research Articles

Comparison of Retinochoroidal Vascular and Structural Changes after Half-Dose Photodynamic Therapy versus Half-Fluence Photodynamic Therapy Based on Optical Coherence Tomography Angiography in Eyes with Chronic Central Serous Chorioretinopathy

Purpose: The aim of this study is to compare the efficacy of half-fluence photodynamic therapy (PDT) and half-dose PDT on the choroidal structure via perfusion of the retinal plexus and choriocapillaris in eyes with chronic central serous chorioretinopathy (cCSCR). Materials and Methods: This retrospective study included 43 eyes in 43 patients with cCSCR. Patients in group 1 received half-fluence (verteporfin 6 mg m⁻²) PDT and those in group 2 received half-dose (verteporfin 3 mg m⁻²) PDT. Enhanced depth imaging optical coherence tomography and optical coherence tomography angiography (OCTA) images were recorded 1 day before and 3 months after PDT. Total choroidal area (TCA), luminal area (LA), and stromal area (SA) were calculated using Image J software. Results: From baseline to 3 months post PDT TCA decreased from 2.43 ± 0.47 mm² to 2.08 ± 0.59 mm² (p < 0.001), LA decreased from 1.78 ± 0.11 mm² to 1.54 ± 0.26 mm² (p < 0.001), and SA decreased from 0.76 ± 0.33 mm² to 0.53 ± 0.37 mm² (p < 0.001) in group 1. Choriocapillaris vascular density measured via OCTA increased from 37.82 ± 10.99 at the initial visit to 44.96 ± 15.34 at month 3 after half-fluence PDT administered to the fovea (p < 0.001). Deep capillary plexus vessel density was 32.49 ± 11.36 at baseline and increased to 43.27 ± 11.40 at month 3 after half-fluence PDT administered to the fovea (p < 0.001) in group 1. TCA decreased to 2.00 mm² ± 0.51 mm² from 2.39 mm² ± 0.43 mm² (p < 0.001), LA decreased to 1.53 ± 0.29 mm² from 1.74 ± 0.16 mm² (p = 0.019). Although SA decreased from 0.76 ± 0.33 mm² to 0.53 ± 0.37 mm² in group 2, the difference was not significant (p = 0.07). Based on OCTA, choriocapillaris vascular density increased from 43.68 ± 10.38 mm² at baseline to 47.46 ± 6.42 mm² at 3 months after half-dose PDT onto the fovea (p = 0.049). Deep capillary plexus vessel density increased from 34.37 ± 9.36 mm² at the initial visit to 38.17 ± 8.81 mm² 3 months after half-dose PDT onto the fovea (p = 0.046) in group 2. At 3 months, post-PDT subretinal fluid (SRF) was significantly higher resolution in group 1 than in group 2 (p = 0.021). Conclusions: OCTA shows there is a significant increase in deep capillary plexus and choriocapillaris perfusion 3 months after both half-fluence PDT and half-dose PDT. Although there was a significant decrease in LA in both groups, based on OCTA there was a significant decrease in SA, a significant increase in choriocapillaris and deep capillary perfusion in group 1; therefore, the level of SRF resolution at month 3 post PDT might explain its higher incidence in group 1.

Evaluating Distribution of Foveal Avascular Zone Parameters Corrected by Lateral Magnification and Their Associations with Retinal Thickness.

PurposeTo examine the distribution of foveal avascular zone (FAZ) parameters, with and without correction for lateral magnification, in a large cohort of healthy young adults.DesignCross-sectional, observational cohort study.ParticipantsA total of 504 healthy adults, 27 to 30 years of age.MethodsParticipants underwent a comprehensive ophthalmic examination including axial length measurement and OCT angiography (OCTA) imaging of the macula. OCT angiography images of combined superficial and deep retinal vessel plexuses were processed via a custom software to extract foveal avascular zone area (FAZA) and foveal density-300 (FD-300), the vessel density in a 300-μm wide annulus surrounding the FAZ, with and without correction for lateral magnification. Bland–Altman analyses were performed to examine the effect of lateral magnification on FAZA and FD-300, as well as to evaluate the interocular agreement in both parameters. Linear mixed-effects models were used to examine the relationship between retinal thicknesses and OCTA parameters.Main Outcome MeasuresThe FAZA and FD-300, corrected for lateral magnification.ResultsThe mean (standard deviation [SD]) of laterally corrected FAZA and FD-300 was 0.22 mm2 (0.10 mm2) and 51.9% (3.2%), respectively. Relative to uncorrected data, 55.6% of corrected FAZA showed a relative change > 5%, whereas all FD-300 changes were within 5%. There was good interocular symmetry (mean right eye–left eye difference, 95% limits of agreement [LoA]) in both FAZA (0.006 mm2, -0.05 mm2, to 0.07 mm2) and FD-300 (-0.05%, -5.39%, to 5.30%). There were significant negative associations between central retinal thickness and FAZA (β = -0.0029), as well as between central retinal thickness and FD-300 (β = -0.044), with the relationships driven by inner, not outer, retina.ConclusionsWe reported lateral magnification adjusted normative values for FAZA and FD-300 in a large cohort of young, healthy eyes. Clinicians should strongly consider accounting for lateral magnification when evaluating FAZA. Good interocular agreement in FAZA and FD-300 suggests the contralateral eye can be used as control data.

RETİNOPATİ BULGUSU OLMAYAN TİP 2 DİYABETLİ HASTALARDA RETİNAL MİKROVASKÜLER FARKLILIKLAR: OPTİK KOHERANS TOMOGRAFİ ANJİOGRAFİ ÇALIŞMASI

Objective&#x0D; We aimed to determine early microvascular changes&#x0D; in type 2 diabetes mellitus patients without clinically&#x0D; apparent retinopathy by optical coherence tomography&#x0D; angiography.&#x0D; Material and Methods&#x0D; 80 eyes of patients with diabetes mellitus and without&#x0D; clinically apparent retinopathy, and 80 eyes of age&#x0D; and sex-matched healthy participants were included&#x0D; in this observational case-control study. Vessel&#x0D; density in superficial and deep retinal vessel plexus,&#x0D; foveal avascular zone area, and choriocapillaris flow&#x0D; area in a macular 6.00 × 6.00 mm scan size were&#x0D; evaluated and compared.&#x0D; Results&#x0D; The groups were similar for age and gender (p=0.971&#x0D; and p=1.000, respectively). The mean duration of&#x0D; diabetes was 10.38±6.31 years (range, 1-25 years)&#x0D; in the study group. Choriocapillaris flow area was&#x0D; significantly lower in the study group than in the&#x0D; control group (p

Morphology and Vessel Density of the Macula in Preterm Children Using Optical Coherence Tomography Angiography.

Background: Retinal morphology changes may be associated with prematurity and can lead to visual impairment. Optical coherence tomography angiography may contribute to understanding the pathomechanism of structural and vascular retinal impairment in premature children. The aim of this study was to assess an influence of prematurity, neonatal clinical characteristics, and a history of retinopathy of prematurity (ROP) on the morphology and retinal vascularity of macula in children. Methods: A case–control study of 123 preterm children and 86 full-term children was performed. The age of the subjects was 10.45 years (IQR: 8.12–12.77), while the age of the control group was 11.78 years (IQR: 8.81–13.79). Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA, angio-OCT) were performed using RTVueXR Avanti (Optovue, Fremont, CA, USA). Ganglion cell complex (GCC), foveal thickness (FT), parafoveal thickness (PFT), size of foveal avascular zone (FAZ) in superficial plexus, superficial capillary vessel density (sVD), deep capillary vessel density (dVD), central choroidal thickness (CCT), and presence of macular hypoplasia were analyzed. The association between OCT/angio-OCT results and clinical characteristics including the degree of ROP and therapy requirements was assessed in preterm infants. Results: Foveal morphology was affected in preterm children with high incidence of foveal hypoplasia (24.77%). GCC was thinner in preterm children compared to controls: avgGG 93 μm vs. 100 μm, p < 0.001. No associations between GCC and gestational age (R = −0.085; p = 0.228) and birth weight (R = −0.054; p = 0.446) were found. FAZ in preterm group was smaller than in controls (0.13 ± 0.09 vs. 0.22 ± 0.09; p < 0.001). FAZ area correlated with gestational age (R = 0.456; p < 0.001) and birth weight (R = 0.472; p < 0.001). Deep vessel density in the fovea was higher in preterm children than in control group (p < 0.001). PFT was significantly lower in preterm children compared to control group. However, increased thickness in the fovea was noted in preterm children (p < 0.001). FT was inversely correlated with gestational age (R = −0.562; p < 0.001) and birth weight (R = −0.508, p < 0.001). CCT was lower in preterm children (312 μm vs. 337.5 μm, p < 0.001) Parameters of GCC and FT were higher in patients with ROP required treatment compared to patients without ROP and spontaneously regressed retinopathy. FAZ was smaller in patients with retinopathy than in preterm children without ROP. Conclusion: Prematurity has a significant negative impact on GCC, macular morphology, and vascularization. In premature children, decreased FAZ, increased FT, and vessel density were strongly associated with gestational age, birth weight, Apgar score, ROP stage, and treatment requirement. Optical coherence tomography angiography is a useful tool for detecting retinal changes in premature children.

Evaluation of microvascular density and retinal vessel diameter in gestational and type 2 diabetes using swept-source OCT-A technology

To assess foveal and parafoveal retinal and choroidal microvascular changes using optical coherence tomography angiography (OCTA) and changes in retinal vessel caliber in pregnant women with gestational diabetes mellitus (GDM), non-pregnant female patients with type 2 diabetes mellitus (DM2), and healthy pregnant female subjects. The study was conducted cross-sectionally and composed of three age-matched groups: 32 near-term pregnant women with GDM (GDM group), 32 non-pregnant female patients with a recent diagnosis of DM2 (DM2 group), and 32 healthy near-term pregnant female subjects. Vessel density (VD) and vessel diameter were the main outcomes. Detailed ophthalmic examinations were performed for each participant, including swept-sourceOCTA measurements consisting of superficial, deep, outer retinal and choroidal vessel density. The average VD values in the central fovea of the superficial and deep retina were significantly lower in the GDM group (P=0.001 for both, between the three groups), whereas the mean VD in the parafoveal nasal sector of the deep retina was significantly lower in the DM2 group (P=0.008, between the three groups). There were no significant differences in the foveal or parafoveal VD measurements of the outer retina and choriocapillaris (P>0.05 for all). There were statistically significant differences in the retinal venous diameter and arterial vein ratio in the GDM and DM2 groups compared to the control group (P=0.001 for all). The microvascular density changes seen on OCTA images of pregnant women with GDM are remarkable. These changes in retinal vessels appeared to occur rapidly after the onset of the metabolic impairment or might be the reflection of previous insulin resistance as well, as in recent diabetes. Our results also suggest that these changes may be more significant in a GDM pregnant woman than in a pregnant, established diabetic patient.

Retinal Microcirculation Changes in Crohn's Disease Patients under Biologics, a Potential Biomarker of Severity: A Pilot Study.

Crohn’s disease (CD) is associated with increased cardiovascular risk and the retinal microcirculation is a reflection of the systemic microcirculation. Is the retinal microcirculation altered in relation to the severity of Crohn’s disease? This cross-sectional case-controlled study was conducted in a university hospital center from November 2020 to February 2021. We prospectively included patients with moderate (biologic therapy) or severe (biologic therapy + peri-anal disease and/or digestive resection) CD and age- and sex-matched controls. Individuals with diabetes, renal disease, cardiovascular disease, ophthalmological history or poor quality images were excluded. All participants underwent OCT angiography (OCT-A) imaging (Optovue, Fremont, CA). Analysis of covariance was used. 74 CD patients (33 moderate, 41 severe) and 74 controls (66 (44.6%) men; mean (SD) age 44 (14) years) were included. Compared with the controls, the severe CD patients showed a significantly reduced mean foveal avascular zone area (p = 0.001), superficial macular capillary plexus vessel density (p = 0.009) and parafoveal thickness (p < 0.001), with no difference in mean superficial capillary flow index (p = 0.06) or deep macular capillary plexus vessel density (p = 0.67). The mean foveal avascular zone was significantly lower in the severe than the moderate CD patients (p = 0.010). OCT-A can detect alterations in retinal microcirculation in patients with severe versus moderate CD and versus age- and sex-matched controls.

Multiscale Joint Optimization Strategy for Retinal Vascular Segmentation.

The accurate segmentation of retinal vascular is of great significance for the diagnosis of diseases such as diabetes, hypertension, microaneurysms and arteriosclerosis. In order to segment more deep and small blood vessels and provide more information to doctors, a multi-scale joint optimization strategy for retinal vascular segmentation is presented in this paper. Firstly, the Multi-Scale Retinex (MSR) algorithm is used to improve the uneven illumination of fundus images. Then, the multi-scale Gaussian matched filtering method is used to enhance the contrast of the retinal images. Optimized by the Particle Swarm Optimization (PSO) algorithm, Otsu algorithm (OTSU) multi-threshold segmentation is utilized to segment the retinal image extracted by the multi-scale matched filtering method. Finally, the image is post-processed, including binarization, morphological operation and edge-contour removal. The test experiments are implemented on the DRIVE and STARE datasets to evaluate the effectiveness and practicability of the proposed method. Compared with other existing methods, it can be concluded that the proposed method can segment more small blood vessels while ensuring the integrity of vascular structure and has a higher performance. The proposed method has more obvious targets, a higher contrast, more plentiful detailed information, and local features. The qualitative and quantitative analysis results show that the presented method is superior to the other advanced methods.

Correlation of ganglion cell complex thinning with baseline deep and superficial macular vessel density in glaucoma

Background/aimsTo investigate the relationship between ganglion cell complex (GCC) thinning and baseline deep and superficial macular vessel density (VD) in glaucoma.Methods97 eyes of 69 primary open-angle glaucoma (POAG) and glaucoma...

Utilité du pédicule épigastrique inférieur profond pour le branchement microchirurgical de lambeau libre pour la couverture de la racine de la cuisse controlatéral

Thigh loss cover after carcinologic resection of sarcomas can be complex and compromise the vascular tree of the lower limb. We report a case of a patient with recurrent sarcoma of the right thigh. After multiple resections, the femur and hip joint are exposed. The superficial and deep femoral vessels are taken in the excisional piece. The reconstruction is performed by a free musculocutaneous latissimus dorsi flap, anastomosed to the deep inferior controlateral epigastric vessels. The deep inferior epigastric vessels are of sufficient length to join the contralateral hemiabdomen after dissection with a gauge allowing microsurgical anastomoses. They can serve as recipient vessels for a flap covering the contralateral thigh.

Aqueous Level of ANGPTL4 Correlates with the OCTA Metrics of Diabetic Macular Edema in NPDR.

Purpose To investigate the aqueous levels of angiogenic factors in nonproliferative diabetic retinopathy (NPDR) patients with diabetic macular edema (DME) and to ascertain their association with optical coherence tomography angiography (OCTA) metrics. Methods This study enrolled 21 NPDR eyes with DME (NPDR/DME+), 17 NPDR eyes without DME (NPDR/DME-), and 16 diabetic eyes without retinopathy (DWR). Luminex bead-based multiplex array was used to measure the levels of 25 cytokines. OCTA system with a scan area of 3 × 3 mm was used to measure retinal thickness (RT), retinal volume (RV), superficial vessel density (SVD), deep vessel density (DVD), foveal avascular zone (FAZ) area, perimeter and acircularity index. Results The levels of ANGPTL4 were significantly different among the three groups (P < 0.05), in which NPDR/DME+ group had the highest level and NPDR/DME- group had a higher level than the DWR group (all, P < 0.0167). OCTA examination showed that, compared with DWR and NPDR/DME- group, RT and RV increased and the whole/parafoveal DVD decreased in NPDR/DME+ group (all, P < 0.05). Meanwhile, NPDR/DME- group had lower parafoveal DVD than the DWR group (P < 0.05). Correlation analysis showed that the levels of ANGPTL4 were positively correlated with foveal/parafoveal RT and RV and negatively correlated with whole/parafoveal DVD in NPDR patients (all, P < 0.05). As the influencing factor of RT, RV, and DVD, every additional 103 pg/ml of ANGPTL4 was associated with an increase in foveal and parafoveal RT of 4.299 μm and 3.598 μm, respectively. Every additional 106 pg/ml of ANGPTL4 was associated with an increase in foveal and parafoveal RV of 3.371 mm3 and 17.705 mm3, respectively. Every additional 104 pg/ml of ANGPTL4 was associated with a decrease in whole and parafoveal DVD of 1.705% and 1.799%, respectively. Conclusions The level of ANGPTL4 in aqueous humor of NPDR patients with DME was significantly increased and ANGPTL4 might predict RT, RV, and parafoveal DVD of DME in NPDR patients.

Retinal findings of COVID-19 patients using ocular coherence tomography angiography two to three months after infection: Ocular appearance recovered COVID-19 patient

PurposeThe aim of this study was to evaluate the ocular disorders in COVID-19 patients, two to three months after infection. MethodsIn this cross-sectional, historically controlled study, fifty-one COVID-19 patients were compared with thirty-seven age, and gender-matched healthy individuals. After complete ophthalmological examination, all participants underwent peripapillary and macular optical coherence tomography, and optical coherence tomography angiography (OCTA) measurements (OptoVue Inc, Freemont, CA, USA). ResultsThe time between the initial onset of symptoms, and ophthalmologic examination was 63.31±15.21 (40–95 days). Ophthalmic examination of all the recovered COVID-19 patients was within normal range. None of the peripapillary and macular OCTA parameters were significantly different between the two groups with pairwise comparisons, but after adjusting for age, gender, axial length, and signal strength index (SSI), recovered COVID-19 eyes showed a significant increase in peripapillary retinal nerve fiber (RNFL) thickness, superficial, and deep macular vessel densities in parafoveal and perifoveal regions compared with healthy control eyes (p<= 0.05). Inner retinal thickness overall is higher in recovered COVID-19 eyes compared to healthy eyes after adjustment. ConclusionPatients with moderate-intensity SARS-CoV-2 pneumonia had altered peripapillary and macular vessel density compared to healthy subjects. Further investigation is warranted to analyze the correlation of these changes with disease severity as well as evolution of these changes over time.

Retinal microvasculature features in patients with Behcet\u2019s disease: a systematic review and meta-analysis

This meta-analysis aimed to analyze retinal microvasculature features in eyes with Behçet’s disease (BD) using optical coherence tomography angiography (OCTA). Electronic databases, including PubMed, Web of Science, Embase, and Cochrane Library, were comprehensively searched for published studies comparing retinal microvasculature characteristics between eyes with BD and controls. Continuous variables were calculated using the mean difference (MD) with 95% confidence interval (CI). Review Manager software (version 5.30) was used to conduct statistical analysis. A total of 13 eligible studies involving 599 eyes with BD and 622 control eyes were included in the meta-analysis. The pooled results showed that the macular whole enface superficial and deep vessel density (VD) values measured by OCTA were significantly lower in eyes with BD than in control eyes (superficial VD: MD = − 3.05, P < 0.00001; deep VD: MD = − 4.05, P = 0.0004). The foveal superficial and deep VD values were also significantly lower in the BD group than in the control group (superficial VD: MD = − 1.50, P = 0.009; deep VD: MD = − 4.25, − = 0.03). Similarly, the analysis revealed a significant reduction in the parafoveal superficial and deep VD in eyes with BD than in control eyes (superficial VD: MD = − 3.68, P < 0.00001; deep VD: MD = − 4.95, P = 0.0007). In addition, the superficial and deep foveal avascular zones (FAZs) were significantly larger in patients with BD than in controls (superficial FAZ: MD = 0.06, P = 0.02; deep FAZ: MD = 0.12, P = 0.03). The present meta-analysis found that macular whole enface VD, foveal VD, and parafoveal VD were lower in eyes with BD, and the FAZ was larger in patients with BD. The findings suggest that OCTA can assist clinicians in diagnosing and monitoring the status of patients with BD.

A Survey of Deep Learning for Retinal Blood Vessel Segmentation Methods: Taxonomy, Trends, Challenges and Future Directions

Recent advancements in deep learning architectures have extended their application to computer vision tasks, one of which is the segmentation of retinal blood vessels from retinal fundus images. This is a problem that has piqued researchers’ interest in recent times. This paper presents a review of the taxonomy and analysis of enhancement techniques used in recent works to modify and optimize the performance of deep learning retinal blood vessels segmentation methods. The objectives of this study are to critically review the taxonomies of the state-of-the-art deep learning retinal blood vessels segmentation methods, observe the trends of the enhancement techniques of recent work, identify the challenges, and suggest potential future research directions. The taxonomies focused on in this paper include optimization algorithms, regularization methods, pooling operations, activation functions, transfer learning, and ensemble learning methods. In doing this, 110 relevant papers spanning the years 2016 to 2021 are reviewed. The findings could aid future research plans, while the suggested ideas would improve the predictive accuracy of future models for automatic retinal blood vessels segmentation algorithms with good generalization ability and optimal performance.

Robust Deep 3D Blood Vessel Segmentation Using Structural Priors.

Deep learning has enabled significant improvements in the accuracy of 3D blood vessel segmentation. Open challenges remain in scenarios where labeled 3D segmentation maps for training are severely limited, as is often the case in practice, and in ensuring robustness to noise. Inspired by the observation that 3D vessel structures project onto 2D image slices with informative and unique edge profiles, we propose a novel deep 3D vessel segmentation network guided by edge profiles. Our network architecture comprises a shared encoder and two decoders that learn segmentation maps and edge profiles jointly. 3D context is mined in both the segmentation and edge prediction branches by employing bidirectional convolutional long-short term memory (BCLSTM) modules. 3D features from the two branches are concatenated to facilitate learning of the segmentation map. As a key contribution, we introduce new regularization terms that: a) capture the local homogeneity of 3D blood vessel volumes in the presence of biomarkers; and b) ensure performance robustness to domain-specific noise by suppressing false positive responses. Experiments on benchmark datasets with ground truth labels reveal that the proposed approach outperforms state-of-the-art techniques on standard measures such as DICE overlap and mean Intersection-over-Union. The performance gains of our method are even more pronounced when training is limited. Furthermore, the computational cost of our network inference is among the lowest compared with state-of-the-art.

Optoaccoustic Tomography – good news for microcirculatory research

Tomographic imaging is a well established technology in preventive medicine and biomedical research, although not without limitations and concerns. Optoacoustic tomography (OAT) is a recent development that bridges optical and sonographic techniques to solve spatial resolution in deep-tissue imaging. In addition to safety advantages, OAT allows multiple wavelength readings for natural thermoelastic chromophores. In this study, we explore Multi Spectral Optoacoustic Tomography (MSOT) capacities to simultaneously acquire three independent chromophores – deoxygenated haemoglobin (Hb), oxygenated haemoglobin (HbO2), and melanin, from healthy human volunteers, with maximal molar extinction of HbO2 at 950 nm, Hb at 750 nm and melanin at 680 nm. Later we demonstrate how image stability during acquisition is fundamental for optimal resolution, precision and consistency of high throughout MSOT data collection. From recorded scans, a workflow is layered for data evaluation. With the MSOT dedicated software results were extracted from 3D image analysis of deep (15 mm3) vessels. The possibilities offered by this new system, specially in vascular pathophysiology, are immense and can be extended beyond current knowledge.

Polisitemia Vera ile İlişkili Retina Mikrovasküler Morfolojik Değişikliklerin Optik Koherens Tomografi Anjiyografik Değerlendirmesi: Kesitsel Olgu-Kontrol Çalışması

Objective: To assess polycythaemia vera (PV)-related retinal microvascular morphological changes using optical coherence tomography angiography (OCTA). Material and Methods: In this cross-sectional case-control study, 30 PV patients (Group 1) and 30 healthy individuals (Group 2) underwent a comprehensive ophthalmological examination, followed by OCTA acquisition in Angio Retina mode (6x6 mm). Macular superficial and deep vascular plexus vessel densities (VDs) in foveal, parafoveal, and perifoveal, as well as foveal avascular zone (FAZ) area, FAZ perimeter, and foveal VD in 300-µm wide region around FAZ (FD-300) were automatically analysed using AngioVue Analytics software. Sequential measurements were compared for statistical significance. Results: Mean ages were 46.97±3.20 and 47.42±2.55 years in Groups 1 and 2, respectively (p=0.350). Group 1 had significantly increased superficial foveal VD than Group 2 (p=0.032). Besides, Group 1 had non-significantly increased VDs than Group 2 in the following areas: superficial whole (p=0.468), superficial parafoveal (p=0.692), deep foveal (p=0.752), deep perifoveal (p=0.369), FAZ perimeter (p=0.209), and FD-300 (p=0.914). The FAZ area decreased non-significantly in Group 1 compared to Group 2 (p=0.529). Conclusion: PV appears to be associated with considerable retinal microvascular morphological changes, indicating a potential hyperviscosity impact on retinal VDs that would necessitate careful consideration during PV patient evaluation.

Development and clinical usefulness of a unique red dichromatic imaging technology in gastrointestinal endoscopy: A narrative review

Image-enhanced endoscopy (IEE) allows real-time high-contrast imaging of a targeted lesion without any special equipment. Among various IEE technologies, narrow-band imaging, in which a light of shorter wavelength is used, emphasizes the surface and blood vessel patterns on the mucosal surface. This technology has been widely used in endoscopic diagnosis in the gastrointestinal tract. Red dichromatic imaging (RDI) was recently developed; it utilizes lights of longer wavelengths (520–550, 595–610, and 620–640 nm), which have weak light scattering characteristics in contrast to narrow-band imaging. RDI was designed to enhance the visibility of deep-lying blood vessels and areas of bleeding, and it has been installed in the latest Olympus endoscopy system, EVIS X1, as an advanced version of the optical-digital method that was originally developed. Improving the visibility of deep blood vessels allows more accurate evaluation of esophageal varices and the degree of inflammation in ulcerative colitis. Easier identification of a bleeding source makes hemostasis quicker and easier to accomplish during endoscopic resection procedures such as endoscopic submucosal dissection and peroral endoscopic myotomy as well as during treatment of gastrointestinal bleeding from a peptide ulcer or colon diverticulum. The authors herein review the technological development and principles, review the existing literature on RDI, and discuss the utility and effectiveness of this unique IEE technology in gastrointestinal endoscopy.

Retinal microvascular changes in patients with familial mediterranean fever: a study based on optical coherence tomography angiography

Purpose: In this study, we aimed to show whether a difference exists between retinal and choroidal microcirculation findings between patients with familial Mediterranean fever and healthy controls. Methods: Thirty-two patients with familial Mediterranean fever and 30 healthy controls were included in the study. All the patients underwent a complete ophthalmologic examination, including best-corrected visual acuity and intraocular pressure measurement. The AngioVue optical coherence tomography angiography device (Optovue, Fremont, CA) with split-spectrum amplitude-decorrelation angiography was used to evaluate and examine the retinal microvascular structure. Three-dimensional en face Optical coherence tomography angiography images were obtained by examining the macula using the 3 x 3 mm scanning protocol in the Angio Retina mode and the optic nerve using the 3 x 3 mm scanning protocol in the Angio Disk mode. All the patients’ right eyes were examined. Results: A total of 62 subjects were included in the study, of whom 32 (53.3%) were female and 30 (46.7%) were male. No statistically significant difference was found between the two groups in terms of optic nerve head or radial peripapillary capillary vessel density. On examination, the superficial capillary plexuses were statistically similar between the two groups, but the deep capillary plexus vessel density in the parafovea, superior hemi, temporal, and superior areas were significantly lower in the patients with familial Mediterranean fever. Conclusions: We found that the capillary plexus vessel density was significantly lower in the parafovea, superior hemi, temporal, and superior regions in the patients with familial Mediterranean fever than in the control group. Therefore, OCTA, a noninvasive study, may be useful for understanding the systemic effects of familial Mediterranean fever.

Demonstration of the epigastric vessels surface anatomy with equation model: An anatomical feasibility study

Introduction: The objective of this study is to design a patient-specific model to predict the location of epigastric vessels on the abdominal surface and to show clinicians safe areas before surgical intervention. Material and Methods: A total of 200 patients who underwent color Doppler ultrasound evaluation of the deep epigastric vessel before gynecological laparoscopic surgery were recruited in the study. The deep epigastric vessels were identified at three equal levels between the xiphoid and umbilicus, and five equal levels between the umbilicus and the symphysis pubis. The distance between the epigastric vessels and the midline was measured bilaterally at each level. Linear mixed effect modeling was used to assess the anatomical location of the epigastric vessels. Results: The model with waist circumference term was found to be the model with best performance metric. This model included waist circumferences as a covariate, the region of the epigastric vessel as a categorical variable, and random effects for patients. The model that calculates the expected distance from the midline of the epigastric vessels for different regions and waist circumferences are presented as “Distance to midline (cm) = 2.57 + Region A + Region B × Waist Circumference.” Discussion and Conclusion: With the equation model, we proposed, the location of the epigastric vessels can be determined specifically for the patient and the abdominopelvic regions. This model can be a guide to prevent vascular injury.

Brain Vessel Segmentation Using Deep Learning—A Review

This article provides a comprehensive review of deep learning-based blood vessel segmentation of brain. The cerebrovascular disease develops when blood arteries in the brain are compromised, resulting in severe brain injuries such as ischemic stroke, brain hemorrhages, and many more. Early detection enables patients to obtain more effective treatment before becoming critically unwell. Due to the superior efficiency and accuracy compared to manual segmentation and other computer-assisted diagnosis procedures, deep learning algorithms have been extensively deployed in brain vascular segmentation. This study examined current articles on deep learning-based brain vascular segmentation, which examined the proposed methodologies, particularly the network architectures, and determined the model trend. We evaluated challenges and crucial factors associated with the application of deep learning to brain vascular segmentation, as well as future research prospects. This paper will assist researchers in developing more sophisticated and robust models in future to develop deep learning solution.