Vessel Length Density Research Articles

Analysis and comparison of retinal vascular parameters under different glucose metabolic status based on deep learning.

To develop a deep learning-based model for automatic retinal vascular segmentation, analyzing and comparing parameters under diverse glucose metabolic status (normal, prediabetes, diabetes) and to assess the potential of artificial intelligence (AI) in image segmentation and retinal vascular parameters for predicting prediabetes and diabetes. Retinal fundus photos from 200 normal individuals, 200 prediabetic patients, and 200 diabetic patients (600 eyes in total) were used. The U-Net network served as the foundational architecture for retinal artery-vein segmentation. An automatic segmentation and evaluation system for retinal vascular parameters was trained, encompassing 26 parameters. Significant differences were found in retinal vascular parameters across normal, prediabetes, and diabetes groups, including artery diameter (P=0.008), fractal dimension (P=0.000), vein curvature (P=0.003), C-zone artery branching vessel count (P=0.049), C-zone vein branching vessel count (P=0.041), artery branching angle (P=0.005), vein branching angle (P=0.001), artery angle asymmetry degree (P=0.003), vessel length density (P=0.000), and vessel area density (P=0.000), totaling 10 parameters. The deep learning-based model facilitates retinal vascular parameter identification and quantification, revealing significant differences. These parameters exhibit potential as biomarkers for prediabetes and diabetes.

Conjunctival microvascular alteration in patients with coronary artery disease assessed using optical coherence tomographic angiography

BackgroundTo quantify conjunctival microvascular characteristics obtained by optical coherence tomographic angiography (OCTA) and investigate their relationship with the presence and severity of coronary artery disease (CAD). MethodsThis cross-sectional study included 103 consecutive CAD patients confirmed by coronary angiography and 125 non-CAD controls. The temporal conjunctivas along the limbus of each participant were scanned using OCTA. Quantification of conjunctival microvasculature was performed by AngioTool software. The severity of the disease was evaluated using SYNTAX and Gensini scores. ResultsCompared to the controls, the CAD group exhibited significantly lower vessel area density (30.22 ± 3.34 vs. 26.70 ± 4.43 %, p < 0.001), lower vessel length density (6.39 ± 0.77 vs. 5.71 ± 0.89/m, p < 0.001), lower junction density (3.44 ± 0.56 vs. 3.05 ± 0.63/m, p < 0.001), and higher lacunarity (0.11 ± 0.03 vs. 0.14 ± 0.05, p < 0.001). Among all participants, lower vessel area density, lower vessel length density, lower junction density, and higher lacunarity were associated with greater odds of having CAD; the adjusted ORs (95 % confidence intervals) per one SD decrease were 2.71 (1.71, 4.29), 2.51(1.61, 3.90), 2.06 (1.39, 3.05), and 0.36 (0.23, 0.58), respectively. Among CAD patients, junction density was negatively associated with the Gensini score (r = −0.359, p = 0.037) and the Syntax score (r = −0.350, p = 0.042) in women but not in men (p > 0.05). ConclusionsConjunctival microvascular characteristics were significantly associated with the presence of CAD. Junction density significantly associated with the severity of CAD among women patients.

A gender-based analysis of retinal microvascular alterations in patients with diabetes mellitus using OCT angiography

PurposeTo assess the difference in microvascular changes between males and females with diabetes mellitus (DM) without diabetic retinopathy (NoDR) and with mild-to-moderate non-proliferative diabetic retinopathy (NPDR) using Optical Coherence Tomography Angiography (OCT-A). DesignRetrospective cross-sectional study. Methods267 DM patients, 133 females (49.81 %), 111 with NoDR (41.57 %) and 156 NPDR (58.43 %) were included. Foveal-centered 3 × 3 mm OCT-A images corresponding to the superficial (SCP), intermediate (ICP) and deep capillary plexus (DCP), and full retinal (RET) slab were used for analysis. For each slab, FAZ area, perimeter, and circularity index (CI) were determined, following manual delineation of the FAZ; perfusion (PD) and vessel density (VD), fractal dimension (FD), vessel length density (VLD), geometric perfusion deficits (GPD) were also computed. Flow voids (FV) were determined in the choriocapillaris plexus; and perfused capillary density (PCD) in the RET slab. ResultsFemales showed larger FAZ CI in SCP and greater FAZ area and perimeter than males in NPDR group. Males had higher central macular thickness than females in NPDR group. All density metrics at the level of ICP and DCP were affected in the NPDR group with no gender differences. Of note, the same significant findings were found in type 1 DM patients, and not in type 2 DM patients. ConclusionsOur OCT-A findings suggest significant microvascular changes in females with NPDR compared to males, but no such differences in patients without DR. Therefore, gender-related vascular alterations might be present in early stages of DR with potential role.

Retinal vascular reactivity in carriers of X-linked inherited retinal disease - a study using optical coherence tomography angiography.

Female carriers of X-linked inherited retinal diseases (IRDs) can show highly variable phenotypes and disease progression. Vascular reactivity, a potential disease biomarker, has not been investigated in female IRD carriers. In this study, functional optical coherence tomography angiography (OCT-A) was used to dynamically assess the retinal microvasculature of X-linked IRD carriers. Genetically confirmed female carriers of IRDs (choroideremia or X-linked retinitis pigmentosa), and healthy women were recruited. Macular angiograms (3x3mm, Zeiss Plex Elite 9000) were obtained in 36 eyes of 15 X-linked IRD female carriers and 21 age-matched control women. Two tests were applied to test vascular reactivity: (i) mild hypoxia and (ii) handgrip test, to induce a vasodilatory or vasoconstrictive response, respectively. Changes to vessel density (VD) and vessel length density (VLD) were independently evaluated during each of the tests for both the superficial and deep capillary plexuses. In the control group, the superficial and deep VD decreased during the handgrip test (p<0.001 and p=0.037, respectively). Mean superficial VLD also decreased during the handgrip test (p=0.025), while the deep plexus did not change significantly (p=0.108). During hypoxia, VD and VLD increased in the deep plexus (p=0.027 and p=0.052, respectively) but not in the superficial plexus. In carriers, the physiologic vascular responses seen in controls were not observed in either plexus during either test, with no difference in VD or VLD noted (all p>0.05). Functional OCT-A is a useful tool to assess dynamic retinal microvascular changes. Subclinical impairment of the physiological vascular responses seen in carriers of X-linked IRDs may serve as a valuable clinical biomarker.

Superficial ocular vascular changes after orbital decompression in patients with thyroid ophthalmopathy measured by anterior segment OCT angiography; an observational study

Thyroid eye disease (TED) is a common ophthalmologic manifestation of thyroid dysfunction. Despite various imaging techniques available, there hasn't been a widely adopted method for assessing the anterior segment vasculature in TED patients. Our study aimed to evaluate alterations in ocular surface circulation following orbital decompression surgery in TED patients and investigate factors influencing these changes. Using anterior segment optical coherence tomography-angiography (AS-OCTA), we measured ocular surface vascularity features, including vessel density (VD), vessel diameter index (VDI), and vessel length density (VLD), both before and after decompression surgery, alongside standard ophthalmic examinations. Our AS-OCTA analysis revealed a significant decrease in most of the temporal vasculature measurements six weeks post-surgery (p < 0.05). However, differences in the nasal region were not statistically significant. These findings indicate notable changes in ocular surface circulation following orbital decompression in TED patients, which may have implications for intraocular pressure (IOP) control and ocular surface symptoms management. AS-OCTA holds promise as a tool for evaluating the effectiveness of decompression surgery and assessing the need for further interventions.

The Effect of Perinatal High‐Dose Erythropoietin on Retinal Structural and Vascular Characteristics in Children Born Preterm

To study the long-term effects of perinatal high-dose recombinant human erythropoietin (rhEPO) on macular structural and vascular development in preterm children. Randomized, double-blind clinical trial follow-up plus cohort study. Setting: Department of Ophthalmology, University Hospital Zurich, Zurich, Switzerland. extremely or very preterm born children aged 7-15 years from an ongoing neuropediatric study (EpoKids). These had been previously randomized to receive either high-dose rhEPO or placebo perinatally. participation in the EpoKids Study, written informed consent (IC). previous ocular trauma or surgery; retinal or developmental disease unrelated to prematurity. Term-born children of comparable age were enrolled as a healthy control (HC) group. term birth, IC. any ocular or visual abnormality, high refractive error. Examiners were blinded regarding intervention status until completion of all analyses. (Participants/guardians remain blinded). Spectral-domain OCT scans (Heidelberg Spectralis system) and OCTA imaging (Zeiss PlexElite 9000) were obtained. Ophthalmological and orthoptic examinations excluded ocular comorbidities. OCT (central retinal thickness, CRT; total macular volume, TMV), superficial plexus OCTA (foveal avascular zone, FAZ; vessel density, VD; vessel length density, VLD) parameters and foveal hypoplasia grade according to published criteria. Macular vessel density parameters (VD and VLD) were significantly lower (p =0.015, CI-95: 0.01 to 0.06 and p=0.015, CI-95: 0.74 to 3.64) in the EPO group (n= 52) when compared to placebo (n=35). No other significant differences were observed between the EPO and placebo group. When comparing the intervention subgroups to HC we found six significant differences in OCT and OCTA parameters (FAZ, VD, VLD and CRT comparing HC and EPO group; FAZ and CRT when comparing HC and placebo group). Early high-dose rhEPO in infants born extremely or very preterm affects macular vessel density parameters compared to placebo. Premature birth (regardless of intervention status) affects retinal structure and vascular development. Our findings on macular vascular development do not contraindicate the administration of early high-dose EPO in preterm infants. For further understanding of the role of EPO on macular development and its clinical significance, future studies are needed.

Structural and functional characterization of retinal impairment in T1DM patients without diabetic retinopathy: a 3-year longitudinal study.

To analyze the progression of structural and functional retinal impairment in type 1 diabetes mellitus (T1DM) patients with no clinical signs of diabetic retinopathy (DR) during a 3-year follow-up. This was an observational longitudinal study. Post-pediatric T1DM patients without clinical signs of DR, and sex- and age-matched healthy subjects were recruited at San Raffaele Hospital (Milan, Italy). Each patient underwent a comprehensive ophthalmological evaluation, including optical coherence tomography (OCT), OCT-angiography (OCT-A), retinal static and dynamic vessel analysis (DVA), and microperimetry. 21 eyes of 21 T1DM patients (10 females; 24 ± 2years old), and 21 age and sex-matched healthy subjects were enrolled. At baseline, T1DM eyes revealed a significantly decreased vessel length density using OCT-A (p < 0.001 and p = 0.046 in 3 × 3 and 6 × 6mm images) and a significantly increased vessel density index (p = 0.013 and p = 0.087 in 3 × 3 and 6 × 6mm images) of deep capillary plexus. DVA detected a significantly decreased vessel response to flicker light (p = 0.002). A significantly increased thickness of ganglion cellular layer 6-mm-diameter subfields in inferior and superior quadrants was found in diabetic patients (p < 0.001 in both subfields). At 3-years-follow-up no significant longitudinal changes were disclosed in all analyses. Concomitant subclinical microvascular and neurodegenerative damages could be early signs of DR onset that precede functional alterations and clinical signs of DR development. These alterations demonstrated a stable trend over time.

Race/Ethnicity Analysis of Vascular Alterations in Optical Coherence Tomography Angiography in Diabetic Patients

ABSTRACT Purpose Racial and ethnic minorities have a higher prevalence of diabetic retinopathy (DR) and present at advanced stages of disease. In an urban hospital population, we investigated microvascular differences in optical coherence tomography angiography (OCTA) between racial/ethnic groups while adjusting for socioeconomic status (SES). Methods 3 × 3 mm2 macular OCTA scans were obtained for analysis of foveal avascular zone (FAZ) area, FAZ perimeter as well as superficial (SCP) and deep capillary plexus (DCP) vessel density (VD), vessel length density (VLD), and adjusted flow index (AFI). SES was measured using the Area Deprivation Index. Multivariable regression models were used to adjust estimates for relevant confounders. Results 217 non-diabetic and 1,809 diabetic patients were included in the study, consisting of 42.2% Hispanic, 24.9% non-Hispanic (NH) Asian, 6.8% NH Black, 9.7% NH White and 16.3% Other patients. NH White was used as the reference group. Hispanic, NH Asian, and NH Black patients had significantly greater FAZ areas and FAZ perimeters, and lower DCP VD and VLD, among both non-diabetic and diabetic patients (Benjamini-Hochberg adjusted P-values <0.05). The addition of SES scores in the models did not modify any regressions significantly. Conclusions In patients with and without diabetes, racial and ethnic minorities have significant retinal microvasculature differences when compared to NH White patients, regardless of SES. These differences are pronounced in DCP and may predispose racial/ethnic minorities to worse outcomes in DR, thus widening disparities in ophthalmic care.

Relationship between macular perfusion and lesion distribution in diabetic retinopathy

Background/objectivesTo assess the relationship between macular vessel density metrics and foveal avascular zone (FAZ) characteristics on optical coherence tomography angiography (OCTA) and lesion distribution in eyes with diabetic retinopathy (DR).Subjects/methodsPatients with DR who underwent both Optos ultrawidefield (UWF) pseudocolor imaging and macular OCTA (Cirrus Angioplex, 6 × 6 mm) were included in this cross-sectional observational study. The distribution of DR lesions was assessed by comparing each of the peripheral ETDRS extended fields (3–7) against their corresponding ETDRS field, hence eyes were defined as either having predominantly peripheral lesions (PPL) or predominantly central lesions (PCL). En face OCTA images from the superficial and deep capillary plexuses (SCP and DCP) were then analysed using Image J software. Perfusion density (PD), vessel length density (VLD), and fractal dimensions (FD) were calculated following binarization and skeletonization of the images.ResultsOut of 344 eyes, 116 (33.72%) eyes had PPL and 228 (66.28%) eyes had PCL. For all DRSS levels, VLD, PD, and FD were not significantly different between eyes with PPL and PCL. The FAZ in eyes with PPL, however, was found to be more circular in shape compared to eyes with PCL (p = 0.037).ConclusionAlthough the presence of PPL has been associated with a higher risk for diabetic retinopathy progression, the macular perfusion is similar in eyes with PPL and PCL. The FAZ is more circular in eyes with PPL, but the clinical relevance of this difference remains to be defined.

Evaluation of the vascular and cardiac effects of treatment with copaiba oil and white pitch: a perspective for reducing oxidative stress and improving cardiac microstructure

Autism is a neuropsychiatric disorder that develops in childhood and may have associated comorbidities, such as heart disease. As a treatment, alternative therapy means are being sought to conventional methods. For study purposes, autism has been induced through gestational exposure to valproic acid. With the aim of evaluating the vascular and cardiac effects of treatment with copaiba essential oil and white pitch caused by gestational exposure to valproic acid, on the 13th day of pregnancy, the rats in the negative control group received water and those in the experimental groups received valproic acid (600 mg/kg), intraperitoneally, once. The male puppies were divided into six groups: negative and positive controls; vehicle; treated with copaiba oil; with white pitch oil and copaiba oil associated with white pitch. TERRA® oils were administered via gavage for 30 consecutive days. As a result, a reduction in superoxide dismutase, catalase and creatine kinase and an increase in total antioxidant activity and malondialdehyde were verified. Presence of myocarditis, vacuolation and necrosis of cardiomyocytes. There was no significant change in area and diameter, but there was an increase in the volume density and length of cardiomyocytes and a decrease in the volume density of blood vessels and interstices and the length density of blood vessels. Thus, exposure to valproic acid during the intrauterine period caused changes in the cardiac microstructure. However, the use of copaíba and white pitch essential oils led to oxidative and nitrosative stress, and the combination of the two oils has promising results in reversing this condition.

Assessing Bioprinted Functionalized Grafts for Biological Tendon Augmentation In Vitro.

Tendinopathy, characterized by inflammatory and degenerative changes, presents challenges in sports and medicine. In addressing the limitations of conservative management, this study focuses on developing tendon grafts using extrusion bioprinting with platelet-rich plasma (PRP)-infused hydrogels loaded with tendon cells. The objective is to understand paracrine interactions initiated by bioprinted tendon grafts in either inflamed or non-inflamed host tissues. PRP was utilized to functionalize methacrylate gelatin (GelMA), incorporating tendon cells for graft bioprinting. Bioinformatic analyses of overexpressed proteins, predictive of functional enrichment, revealed insights into PRP graft behavior in both non-inflamed and inflamed environments. PRP grafts activated inflammatory pathways, including Interleukin 17 (IL-17), neuroinflammation, Interleukin 33 (IL-33), and chemokine signaling. Interleukin 1 beta (IL-1b) in the graft environment triggered p38 mitogen-activated protein kinase (MAPK) signaling, nuclear factor kappa light chain enhancer of activated B cells (NF-kB) canonical pathway, and Vascular Endothelial Growth Factor (VEGF) signaling. Biological enrichment attributed to PRP grafts included cell chemotaxis, collagen turnover, cell migration, and angiogenesis. Acellular PRP grafts differed from nude grafts in promoting vessel length, vessel area, and junction density. Angiogenesis in cellular grafts was enhanced with newly synthesized Interleukin 8 (IL-8) in cooperation with IL-1b. In conclusion, paracrine signaling from PRP grafts, mediated by chemokine activities, influences cell migration, inflammation, and angiogenic status in host tissues. Under inflammatory conditions, newly synthesized IL-8 regulates vascularization in collaboration with PRP.

Prediction of Functional and Anatomic Progression in Lamellar Macular Holes

PurposeTo use artificial intelligence to identify imaging biomarkers for anatomical and functional progression of lamellar macular hole (LMH) and to elaborate a deep learning (DL) model based on optical coherence tomography (OCT) and OCT angiography (OCTA) for prediction of visual acuity (VA) loss in untreated LMHs. DesignMulticentric retrospective observational study ParticipantsPatients >18 years old diagnosed with idiopathic LMHs with availability of good quality OCT and OCTA acquisitions at baseline and a follow up>2 years were recruited. MethodsA DL model based on soft voting of two separate models (OCT and OCTA-based respectively) was trained for identification of cases with VA loss> 5 ETDRS letters (attributable to LMH progression only) during a 2-years follow-up. Biomarkers of anatomical and functional progression of LMH were evaluated with regression analysis, feature learning(support vector machine(SVM) model) and visualization maps. Main Outcome measuresEllipsoid zone(EZ) damage, volumetric tissue loss (TL), vitreopapillary adhesion (VPA), epiretinal proliferation, central macular thickness (CMT), parafoveal vessel density (VD) and vessel length density (VLD) of retinal capillary plexa, choriocapillaris (CC) flow deficit density (FDD). ResultsFunctionally progressing LMHs (VA-PROG group, 41/139 eyes (29.5%)) showed higher prevalence of EZ damage, higher volumetric TL, higher prevalence of VPA, lower superficial capillary plexus(SCP) VD and VLD and higher CC FDD compared to functionally stable LMHs (VA-STABLE group,98/139 eyes (70.5%)). The DL and SVM models showed 92.5% and 90.5% accuracy respectively. The best performing features in the SVM were EZ damage, TL, CC FDD and parafoveal SCP VD. Epiretinal proliferation and lower CMT were risk factors for anatomical progression only. ConclusionsDL can accurately predict functional progression of untreated LMHs over 2 years. The use of AI might improve our understanding of the natural course of retinal diseases. Integrity of CC and SCP might play an important role in the progression of LMHs.

Retinal Microvascular Alterations in Hidradenitis Suppurativa Patients: A Pilot Study Using Optical Coherence Tomography Angiography.

Background: Hidradenitis suppurativa (HS) is a relapsing-remitting inflammatory disease characterized by the progression of asymptomatic nodules to deep-seated lesions and fistula formation that leads to suppuration and scarring. Optical coherence tomography angiography (OCTA) is a new non-invasive imaging technique that carefully analyzes retinal microvasculature networks with high-resolution imaging. Recent studies have demonstrated that retinal vessel density and retinal perfusion reflect systemic inflammatory responses. This study's aim was to analyze OCTA-derived retinal microvasculature parameters to understand if patients affected by HS and without any relevant ocular or systemic comorbidities showed impaired retinal vascular function and morphology. Method: We performed a case-control study of HS patients and age- and sex-matched control cohort. A total of 20 eyes from 10 HS patients and 30 eyes from 15 healthy controls were analyzed, and OCTA-derived microvasculature parameters were compared between groups. Results: OCTA images showed that HS patients, compared to healthy controls, were typically characterized by higher values of the foveal avascular zone (FAZ) both in the superficial capillary plexus (SCP) and in the deep capillary plexus (DCP), and by lower values of vessel density (VD)-SCP, VD-DCP, and vessel length density (VLD)-SCP in the foveal region. These findings partially reflect changes that have been demonstrated in diabetic patients that could be induced by a protracted metabolic or systemic inflammatory dysregulation. Conclusions: In conclusion, OCTA enables large-scale, non-invasive visual screening and follow-up of the retinal vasculature features, providing a new strategy for the prevention and monitoring of visual changes in HS patients.

Quantitative Analysis of the Vasculature and Cone Photoreceptors in Subjects With Diabetes Without Diabetic Retinopathy

Purpose To characterize any differences in the vasculature and cone photoreceptor packing geometry (CPG) between subjects with diabetes without/no diabetic retinopathy (NDR) and healthy controls. Methods Eight NDR and five controls were enrolled. Optical coherence tomography angiography (OCTA) taken at the macula was used to measure vessel density, vessel length density, and vessel density index (VDI) in three vascular plexuses, namely, the superficial vascular plexus, intermediate capillary plexus, and deep capillary plexus (DCP). The choriocapillaris (CC) flow deficit (FD) was also measured. OCTA images were binarized and processed to extrapolate the parafovea and parafoveal quadrants and the OCTA indices mentioned above. The CC was processed with six different radii to quantify FD. Adaptive optics - scanning laser ophthalmoscopy images were acquired and processed to extract CPG indices, i.e., cone density (CD), cone-to-cone spacing (CS), linear dispersion index, heterogeneity packing index and percent of cells with six neighbors at 3.6° in the temporal retina. Results In all eyes, statistically significant differences were found (i) in parafoveal FD across the six radii (p < 0.001) and (ii) in the correlation between the parafoveal temporal quadrant (PTQ) DCP VDI and CS (r = 0.606, p = 0.048). No other significant correlations were found. For OCTA or CPG indices, no significant differences were found between the cohorts in the parafovea or parafoveal quadrants. Conclusions CS is the most sensitive CPG index for detecting alterations in the cone mosaic. The DCP and the cone photoreceptors are significantly correlated, indicating that alterations in the DCP can affect the cones. Future work elucidating the vascular alterations and neurodegeneration present in diabetic eyes should focus on the DCP and multiple CPG indices, not solely CD. Moreover, such alterations are highly localized, hence using larger regions e.g. parafovea versus smaller areas, such as the PTQ, will potentially mask significant correlations.

Choriocapillaris and Retinal Vascular Alterations in Presymptomatic Alzheimer's Disease.

To compare optical coherence tomography angiography (OCTA) retina metrics between cognitively healthy subjects with pathological versus normal cerebrospinal fluid (CSF) Aβ42/tau ratios. Swept-source OCTA scans were collected using the Zeiss PLEX Elite 9000 and analyzed on 23 cognitively healthy (CH) subjects who had previously undergone CSF analysis. Thirteen subjects had a pathological Aβ42/tau (PAT) ratio of <2.7132, indicative of presymptomatic Alzheimer's disease (AD), and 10 had a normal Aβ42/tau (NAT) ratio of ≥2.7132. OCTA en face images of the superficial vascular complex (SVC) and deep vascular complex were binarized and skeletonized to quantify the perfusion density (PD), vessel length density (VLD), and fractal dimension (FrD). The foveal avascular zone (FAZ) area was calculated using the SVC slab. Choriocapillaris flow deficits (CCFDs) were computed from the en face OCTA slab of the CC. The above parameters were compared between CH-PATs and CH-NATs. Compared to CH-NATs, CH-PATs showed significantly decreased PD, VLD, and FrD in the SVC, with a significantly increased FAZ area and CCFDs. Swept-source OCTA analysis of the SVC and CC suggests a significant vascular loss at the CH stage of pre-AD that might be an indicator of a neurodegenerative process initiated by the impaired clearance of Aβ42 in the blood vessel wall and by phosphorylated tau accumulation in the perivascular spaces, a process that most likely mirrors that in the brain. If confirmed in larger longitudinal studies, OCTA retinal and inner choroidal metrics may be important biomarkers for assessing presymptomatic AD.

Relationship between visual acuity and OCT angiography parameters in diabetic retinopathy eyes after treatment.

To assess the relationship between visual acuity and OCT angiography parameters in diabetic retinopathy eyes after treatment, and to analyze the relative factors in PDR eyes. A total of 89 eyes, including 42 eyes with non-PDR (NPDR), and 47 eyes after vitrectomy with PDR were included and underwent OCTA. All images were processed by Python or FIJI. Multivariable linear regression models were used to analyze the associations between postoperative BCVA and OCTA parameters in PDR patients. Postoperative OCTA parameters including deep capillary plexus (DCP) parafoveal and perifoveal vessel density (VD), DCP parafoveal and perifoveal vessel length density (VLD), DCP fractal dimension (FD), choriocapillaris plexus (CCP) VD, CCP VLD, were significantly lower in the PDR group than in the NPDR group. In the superficial capillary plexus (SCP), we found a negative correlation between the postoperative BCVA and VD (parafovea: β coefficient = -0.351, p = 0.023; perifovea: β coefficient = -0.338, p = 0.036). Perifoveal VLD (β coefficient = -0.343, p = 0.031) and FD (β coefficient = -0.375, p = 0.016) of the SCP were also negatively correlated with postoperative BCVA. Regarding the DCP, perifoveal VD (β coefficient = -0.396, p = 0.008), perifoveal VLD (β coefficient = -0.334, p = 0.025), vessel tortuosity (VT) (β coefficient = -0.369, p = 0.015) were negatively correlated with postoperative BCVA. In CCP, VLD (β coefficient = -0.373, p = 0.023) and number of flow voids (β coefficient = -0.334, p = 0.036) exhibited a negative association with postoperative BCVA. Postoperative BCVA of PDR patients was related to OCTA parameters of the SCP (parafoveal and perifoveal VD, perifoveal VLD and FD), DCP (perifoveal VD, VLD, and VT) and CCP (VLD and number of flow voids).

Response of Diabetic Macular Edema to Anti-VEGF Medications Correlates with Improvement in Macular Vessel Architecture Measured with OCT Angiography

PurposeImprovement in best corrected visual acuity (BCVA) and central subfield thickness (CST) have been well documented after intravitreal injection of anti-VEGF medications in diabetic macular edema (DME), however their effect on the vasculature of the macula in diabetic retinopathy (DR) remains poorly understood. Our aim was to explore the effect of intravitreal injection of anti-VEGF on parameters of retinal vascular microstructure in DR with optical-coherence tomography angiography (OCT-A). DesignRetrospective study of adult patients with DME that were treated with anti-VEGF intravitreal injections at the University of Illinois at Chicago between 2017-2022. Subjects, Participants, and/or Controls41 eyes from 30 patients with non-proliferative or proliferative DR with a mean age of 58.83 ± 11.71years, mean number of intravitreal injections of 2.8 ± 1.4, and mean follow up of 6.5 ± 1.7 months. Methods, Intervention, or TestingImageJ was employed to measure parameters of retinal vascular microstructure in OCT-A images, which included perfusion density, vessel length-density (VLD), vessel diameter, and FAZ characteristics (area, perimeter, circularity). Student’s T-tests and ANOVA were used to determine statistical significance. Main Outcome MeasuresA primary analysis was performed comparing the mean of each parameter of all patients as a single group at the beginning and end of the study period. A subgroup analysis was then performed after stratifying patients based on visual improvement, change in CST, prior injection history, and number of injections. ResultsEyes demonstrated statistical improvement in BCVA logMAR score and CST after anti-VEGF treatment. Primary analysis showed a reduction in the vessel diameter of the superficial and deep retinal vasculature as well as an increase in the circularity of the FAZ within the superficial retinal vasculature after anti-VEGF treatment. Subgroup analysis revealed that eyes with improvement in BCVA exhibited reduced vessel diameter in the superficial retinal vasculature and that eyes with the largest decrease in CST displayed increased perfusion density and VLD in the deep retinal vasculature. ConclusionsIntravitreal injection of anti-VEGF agents to treat DME improved parameters of retinal vascular microstructure on OCT-A over a period of 3-9 months, and this effect was most pronounced in eyes that experienced improvement in BCVA and CST.

Baseline imaging characteristics and early structural changes in macula on rhegmatogenous retinal detachment

Animal models have demonstrated that structural changes affect the macula during peripheral rhegmatogenous retinal detachment. This study aimed to assess photoreceptors, retinal and choriocapillaris perfusion in non-macula involving rhegmatogenous retinal detachment by analyzing en-face images from structural OCTA segmented at the ellipsoid zone (EZ) level, calculating (1) “normalized” reflectivity as a surrogate biomarker of photoreceptor damage (2) perfusion density (PD), vessel length density (VLD) and vessel diameter index (VDI) of superficial capillary plexus (SCP) and deep capillary plexus (DCP) (3) perfusion density of choriocapillaris (PDCC). Twenty-one eyes affected by macula-on rhegmatogenous retinal detachment (RRD) were enrolled at the University “G. d’Annunzio”, Chieti-Pescara. The fellow unaffected eye was used as control. The mean age at the onset of RRD was 60.09 ± 10.22 (range 34–83). Compared with fellow eyes, we found lower EZ “normalized” reflectivity in macula-on (0.42 ± 0.15 in fellow eyes and 0.31 ± 0.09 in macula on p = 0.004). The affected eye was also characterized by impaired perfusion in SCP (17.26 ± 3.34% in macula on and 20.56 ± 3.62% in the fellow eye p = 0.004) and CC (50.21 ± 6.20% in macula on the eye and 57.43 ± 6.20% in the fellow eye p = 0.004). Macula-on rhegmatogenous retinal detachment has subclinical changes in photoreceptors, SCP, and CC. Future longitudinal studies should evaluate if early changes could impact post-operative macular function.

Longitudinal Characteristics of Choroidal Neovascular Membrane in Pediatric Patients

To report the clinical and imaging characteristics, including optical coherence tomography angiography (OCTA), and treatment outcomes of choroidal neovascular membranes (CNVMs) in children. Retrospective clinical cohort study. Thirty eyes from 25 children (56% girls) with CNVM from 2 centers were examined from 2005 to 2022. Clinical features, imaging findings, treatment regimens, and outcomes are described. The most common causes of CNVM were idiopathic (48%) and inflammatory (20%). At diagnosis, most CNVMs were unilateral (80%), active (83.3%), and juxtafoveal (46.7%). Twenty-five eyes (83.3%) of 21 patients (84%) were treated. The most common first-line treatment was intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) (92%), with a retreatment rate of 52.2% at an average of 237 days. The average number of total injections per eye was 2.3. Injections were safely administered in the clinic (52.2%). A gain of 3 lines or 15 ETDRS (Early Treatment Diabetic Retinopathy Study) letters was observed at final visit. The average duration of follow-up was 56.46 ± 42.51 months. No ocular or systemic complication related to treatment was reported. Sixteen eyes (64%) had OCTA images at both presentation and final visit, which showed a decrease in CNVM vessel density and vessel-length density, and in the height of retinal pigment epithelium detachment (RPED). There are a variety of underlying etiologies for pediatric CNVMs, which are most often unilateral. Treatment with intravitreal anti-VEGF can be beneficial and does not often require frequent or chronic dosing. OCTA demonstrated a decrease in the CNVM vessel density and vessel-length density as well as in the height of RPED.

3D QUANTITATIVE CHARACTERIZATION OF THE HUMAN MENISCAL VASCULAR NETWORK USING X-RAY MICRO-COMPUTED TOMOGRAPHY

A comprehensive understanding of the self-repair abilities of menisci and their overall function in the knee joint requires three-dimensional information. However, previous investigations of the meniscal blood supply have been limited to two-dimensional imaging methods, which fail to accurately capture tissue complexity. In this study, micro-CT was used to analyse the 3D microvascular structure of the meniscus, providing a detailed visualization and precise quantification of the vascular network.A contrast agent (μAngiofil®) was injected directly into the femoral artery of cadaver legs to provide the proper contrast enhancement. First, the entire knee joint was analysed with micro-CT, then to increase the applicable resolution the lateral and medial menisci were excised and investigated with a maximum resolution of up to 4 μm. The resulting micro-CT datasets were analysed both qualitatively and quantitatively. Key parameters of the vascular network, such as vascular volume fraction, vessel radius, vessel length density, and tortuosity, were separately determined for the lateral and medial meniscus, and their four circumferential zones defined by Cooper.In accordance with previous literature, the quantitative micro-CT data confirm a decrease in vascular volume fraction along the meniscal zones. The highest concentration of blood vessels was measured in the meniscocapsular region 0, which is characterized by vascular segments with a significantly larger average radius. Furthermore, the highest vessel length density observed in zone 0 suggests a more rapid delivery of oxygen and nutrients compared to other regions. Vascular tortuosity was detected in all circumferential regions, indicating the occurrence of vascular remodelling in all tissue areas.In conclusion, micro-CT is a non-invasive imaging technique that allows for the visualization of the internal structure of an object in three dimensions. These advanced 3D vascular analyses have the potential to establish new surgical approaches that rely on the healing potential of specific areas of the meniscus.Acknowledgements: The authors acknowledge R. Hlushchuk, S. Halm, and O. Khoma from the University of Bern for their help with contrast agent perfusions.