Aging-related cerebral microvascular changes visualized using ultrasound localization microscopy in the living mouse

Aging-related cognitive decline is an emerging health crisis; however, no established unifying mechanism has been identified for the cognitive impairments seen in an aging population. A vascular hypothesis of cognitive decline has been proposed but is difficult to test given the requirement of high-fidelity microvascular imaging resolution with a broad and deep brain imaging field of view, which is restricted by the fundamental trade-off of imaging penetration depth and resolution. Super-resolution ultrasound localization microscopy (ULM) offers a potential solution by exploiting circulating microbubbles to achieve a vascular resolution approaching the capillary scale without sacrificing imaging depth. In this report, we apply ULM imaging to a mouse model of aging and quantify differences in cerebral vascularity, blood velocity, and vessel tortuosity across several brain regions. We found significant decreases in blood velocity, and significant increases in vascular tortuosity, across all brain regions in the aged cohort, and significant decreases in blood volume in the cerebral cortex. These data provide the first-ever ULM measurements of subcortical microvascular dynamics in vivo within the context of the aging brain and reveal that aging has a major impact on these measurements.

The relationship between carotid intima-media thickness and microvascular changes in retinal zones and optic disc in patients with type 1 diabetes mellitus

Purpose The aim of this study was to detect early retinal vascular changes with optical coherence tomography angiography (OCTA) in type 1 diabetes mellitus (T1DM) patients without diabetic retinopathy and to evaluate the correlation of the results with carotid intima-media thickness (IMT). Design This is a case–control and cross-sectional study. Methods This study included 38 adult patients with T1DM, and 38 age and gender-matched healthy controls. Retinal and optic disc (OD) measurements were taken using OCTA. The carotid artery IMT of each patient was measured using Doppler ultrasonography. Superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel density, foveal avascular zone (FAZ), non-flow area (NFA) and foveal density (FD) were analysed in the fovea centred 6 × 6 mm macular area. The superficial capillary plexus and DCP were also scanned centred on the peripapillary region. The correlations between OCTA measurements and carotid IMT, duration of DM and haemoglobin A1c levels in patients with T1DM were evaluated. Results The mean values for carotid IMT were significantly higher in diabetic patients than in controls ( p < 0.001). The mean values for vessel density SCP, DCP and OD were significantly lower in the diabetic group ( p < 0.05). There were correlations between the carotid IMT and duration of T1DM and the evaluated parameters of OCTA. Conclusion Microvascular changes in the SCP and DCP in patients with T1DM without DR offer important data. OCTA can be used to detect early microvascular changes in patients with T1DM without DR. In addition, a relationship was found between SCP vascular dropout and carotid IMT.

Comparison of Different Metrics for the Identification of Vascular Changes in Diabetic Retinopathy Using OCTA

Retinal vessel metrics identifying microvascular changes such as vessel closure (VC) have shown potential clinical value by identifying eyes with diabetic retinopathy (DR) at different severity levels and at increased risk for disease progression to more severe stages. We compare the performance of 11 different metrics, which include 2 metrics supplied by the manufacturer, based on OCTA for identification of VC in different Early Treatment for Diabetic Retinopathy Study (ETDRS) severity groups. OCTA en-face slabs from 84 healthy eyes (70 ± 4.8 years) and 78 eyes of diabetic individuals (67 ± 7.5 years) were processed using different methods that include abnormal intercapillary spaces (AIS), vessel density (VD), and nine metrics extracted from the en-face slab. The best separation between the eyes with DR and the control group was obtained in the superficial capillary plexus (SCP), with the full retina (FR) also performing well. In the SCP, the metrics that show better performance were the AIS and the VD with a value of area under curve (AUC) equal to 0.89 [95% CI 0.84–0.94] and 0.85 [95% CI 0.79–0.91], respectively, indicating that the VD metric supported by the manufacturer is satisfactory. The values of these metrics on the different ETDRS groups show a progressive increase in VC, which is correlated with disease severity.

The Role of Conjunctival Microvasculation Combined with Echocardiography in Evaluating Pulmonary Arterial Hypertension in Systemic Lupus Erythematosus

Objective. To explore the role of conjunctival microvasculation combined with echocardiography in evaluating the prognosis of pulmonary arterial hypertension in systemic lupus erythematosus (SLE-PAH). Methods. We prospectively compared the conjunctival microvascular changes in 17 SLE-PAH patients and 34 SLE patients without PAH in our hospital from January 2020 to December 2020, and we observed the characteristics of conjunctival microvascular changes in SLE-PAH patients. We analyzed the correlation between the corresponding conjunctival microvascular changes and cardiopulmonary function and evaluated the predictive value of the vessel density (VD) and the microvascular flow index (MFI) of conjunctival microvasculation combined with echocardiography in SLE-PAH. Results. Compared with SLE patients without PAH, the ischemic areas in conjunctival microvasculation were significantly increased in SLE-PAH patients. The VD and MFI of conjunctival microvasculation are significantly correlated with N-terminal prohormone of brain natriuretic peptide and 6-minute walking distance. Combined with the VD and MFI, it can improve the accuracy of echocardiography in assessing the risk of death due to SLE-PAH (94.1% vs. 82.2%). Conclusion. The ischemic area, VD, and MFI of conjunctival microvasculation in SLE-PAH patients can indicate the occurrence of severe SLE-PAH and improve the accuracy of echocardiography in evaluating the prognosis of SLE-PAH.

Assessment of the microvasculature in poppers maculopathy

Purpose To investigate a possible microvascular component of poppers maculopathy (PMP) using optical coherence tomography angiography (OCTA). Methods Twelve patients suffering from poppers maculopathy were included. Health records, optical coherence tomography (OCT), and OCTA data was gathered and compared to a healthy control group (HC). PMP lesion type was determined by manifestation in OCT. OCTA-based evaluation of retinal vascular plexus and choriocapillaris (CC) was executed. Vessel density (VD) and vessel length density (VLD) in superficial and deep capillary plexus (SCP, DCP), as well as flow deficits (FD), within the foveal avascular zone (FAZ) in CC were assessed. Results Median age of PMP patients was 40 (min 24; max 64) years, all male. Eleven patients presented with ellipsoid zone-type lesions; one patient showed a vitelliform-type lesion. No qualitative microvascular changes between PMP patients and HC were identified. Quantitative values for VD and VLD of SCP and DCP did not differ in between the two groups. The analysis of FDs in CC showed no deviation from PMP patients to HC. Conclusions No vascular anomalies in qualitative and quantitative analysis in OCTA were detected in PMP patients. The constitution of the CC within FAZ of PMP patients does not differ from HC when assessed as FD.

Posterior segment manifestations and imaging features of COVID-19

Background: To report the posterior segment (uvea and retinal) manifestations and imaging characteristics of eyes of patients with and after coronavirus disease 2019 (COVID-19).Methods: We searched the PubMed/MEDLINE database to identify relevant articles using the following search terms: COVID-19, SARS-CoV-2, retina, uvea, optic nerve, retinal findings, posterior segment manifestations, and endophthalmitis. Articles published from December 1, 2019, to May 30, 2021, and indexed in PubMed/MEDLINE were screened.Results: For the purpose of this review, we included clinical features of 26 case reports and 8 case series. The posterior segment manifestations reported included cotton wool spots, retinal hemorrhages, central serous retinopathy, papillophlebitis, optic neuritis, panuveitis, multifocal retinitis, necrotizing retinitis, central retinal artery/vein occlusion, and Purtschner like retinopathy. In this review, we have also included optical coherence tomography angiography (OCTA) features that have been described in COVID-19 patients with pneumonia.Conclusions: COVID-19 patients can experience uveo-retinal manifestations even after recovery. These patients, even if asymptomatic for eye symptoms, should undergo an eye evaluation to rule out posterior segment involvement. OCTA performed in these patients revealed microvascular changes in the superficial and deep retinal plexuses. Some of these patients may require anticoagulant or antiplatelet therapy.

Use of nailfold video-capillaroscopy in Polycythemia vera

Objectives: In this study, we aimed to investigate capillary vessel diameters and structural changes of capillaries by using nailfold video-capillaroscopy in patients with Polycythemia Vera. Patients and Methods: This cross-sectional study was conducted with 24 patients (19 males, 5 females; mean age: 62.5±2 years; range, 50.2 to 68 years) with Polycythemia vera and 15 healthy controls (11 males, 4 females; mean age: 40±2 years; range, 36 to 44 years) between June 2016 and February 2017. Nailfold video-capillaroscopy was performed by an experienced rheumatologist, blinded to clinical data. The apical, arterial, and venous limb diameters of capillaries were measured and microvascular changes of capillaries were scored. Results: When capillaries were evaluated in terms of morphological structures, giant capillary was detected 67% in the patients with Polycythemia vera, while it was not detected in the control group. The arterial, venous and apical diameters of the capillaries were significantly higher in the patients with Polycythemia vera compared to the control group [(38.33 µm vs. 21.23 µm, p <0.001), (48.41 µm vs. 27.48 µm p <0.001), (55.80 µm etc. 36.61 µm, p <0.001), respectively]. Conclusion: The presence of giant capillaries and the marked increase of arterial, venous, and apical diameters of capillaries seem to be related to Polycythemia vera.

Optical coherence tomography-angiography in diabetic retinopathy diagnosis and monitoring

Optical coherence tomography-angiography is a modern noninvasive method of 3D imaging and quantitative analysis of the retinal and choroidal microvasculature. It allows detecting manifestation and progression of diabetic retinopathy, planning treatment and evaluating its results.Optical coherence tomography angiography expands our understanding of microvascular changes in retinal vascular plexuses at different disease stages and deepens the understanding of its pathogenesis.