scholarly journals Impact of corneal parameters, refractive error and age on density and morphology of the subbasal nerve plexus fibers in healthy adults

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anna M. Roszkowska ◽  
Adam Wylęgała ◽  
Romana Gargano ◽  
Rosaria Spinella ◽  
Leandro Inferrera ◽  
...  
Keyword(s):  
Nerve Fiber ◽  
Refractive Error ◽  
Fiber Length ◽  
Inverse Correlation ◽  
Significant Negative Correlation ◽  
Nerve Plexus ◽  
Fiber Density ◽  
Fiber Analysis ◽  
Positive Correlations

AbstractThe purpose of this study was to analyze corneal sub-basal nerve plexus (SBNP) density and morphology and their relationships with corneal parameters and refractive status. In this single center study, in vivo confocal microscopy (IVCM) was performed in 76 eyes of 38 healthy subjects aged 19–87 (mean age 34.987 ± 1.148). Nerve fiber analysis was performed using Confoscan 4 microscope with semi-automated software (Nidek Technologies, Italy) The nerve fiber length (NFL) µm/mm2, nerve fiber density (NFD) no./mm2, tortuosity coefficient (TC), and nerve beadings density (NBD) no./mm were considered. Relationship between SBNP parameters and corneal curvature, thickness, diameter, and refraction were analyzed. Additionally, the association with gender, laterality and age were determined. NFL was inversely correlated with age (r = − 0.528, p < 0.001), myopic refractive error (spherical value) (r = − 0.423, p < 0.001), and cylindrical power (r = − 0.340, p = 0.003). NFD was inversely correlated with age (r = − 0.420, p < 0.001) and myopic refractive error (r = − 0.341, p = 0.003). NBD showed a low inverse correlation with cylindrical power (r = − 0.287, p = 0.012) and a slight positive correlation with K (r = 0.230, p = 0.047). TC showed a significant negative correlation between age (r = − 0.500, p < 0.001) and myopic refractive error (r = − 0.351, p = 0.002). Additionally, there were strong positive correlations between NFL and NFD (r = 0.523, p < 0.001), NFL and TI (r = 0.603, p < 0.001), and NFD and TC (r = 0.758, p < 0.001). Multiple regression analysis revealed age to be the most significant factor affecting SBNP density (B = − 0.467, p = 0.013) and length (B = − 61.446, p < 0.001); myopic refractive error reduced both SBNP density (B = − 2.119, p = 0.011) and length (B = − 158.433, p = 0.016), while gender and laterality had no significant effects (p > 0.005). SBNP fiber length decreases with age, myopic refractive error and cylindrical power. SBNP fiber density reduces with age and myopic refractive error. Corneal nerve parameters are not influenced by gender or laterality.

scholarly journals Increased extracellular fluid is associated with white matter fiber degeneration in CADASIL: in vivo evidence from diffusion magnetic resonance imaging

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Xinfeng Yu ◽  
Xinzhen Yin ◽  
Hui Hong ◽  
Shuyue Wang ◽  
Yeerfan Jiaerken ◽  
...  
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Small Vessel Disease ◽  
Extracellular Fluid ◽  
Free Water ◽  
Inverse Correlation ◽  
Brain Regions ◽  
Fiber Density ◽  
Four Levels

Abstract Background White matter hyperintensities (WMHs) are one of the hallmarks of cerebral small vessel disease (CSVD), but the pathological mechanisms underlying WMHs remain unclear. Recent studies suggest that extracellular fluid (ECF) is increased in brain regions with WMHs. It has been hypothesized that ECF accumulation may have detrimental effects on white matter microstructure. To test this hypothesis, we used cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) as a unique CSVD model to investigate the relationships between ECF and fiber microstructural changes in WMHs. Methods Thirty-eight CADASIL patients underwent 3.0 T MRI with multi-model sequences. Parameters of free water (FW) and apparent fiber density (AFD) obtained from diffusion-weighted imaging (b = 0 and 1000 s/mm2) were respectively used to quantify the ECF and fiber density. WMHs were split into four subregions with four levels of FW using quartiles (FWq1 to FWq4) for each participant. We analyzed the relationships between FW and AFD in each subregion of WMHs. Additionally, we tested whether FW of WMHs were associated with other accompanied CSVD imaging markers including lacunes and microbleeds. Results We found an inverse correlation between FW and AFD in WMHs. Subregions of WMHs with high-level of FW (FWq3 and FWq4) were accompanied with decreased AFD and with changes in FW-corrected diffusion tensor imaging parameters. Furthermore, FW was also independently associated with lacunes and microbleeds. Conclusions Our study demonstrated that increased ECF was associated with WM degeneration and the occurrence of lacunes and microbleeds, providing important new insights into the role of ECF in CADASIL pathology. Improving ECF drainage might become a therapeutic strategy in future.

scholarly journals Combining In Vivo Corneal Confocal Microscopy with Deep Learning-based Analysis Reveals Sensory Nerve Fiber Loss in Acute SIV Infection

2020 ◽  
Author(s):  
Megan E. McCarron ◽  
Rachel L. Weinberg ◽  
Jessica M. Izzi ◽  
Suzanne E. Queen ◽  
Stuti L. Misra ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Deep Learning ◽  
Confocal Microscopy ◽  
Nerve Fiber ◽  
Fiber Length ◽  
Sensory Nerve ◽  
Corneal Confocal Microscopy ◽  
Siv Infection ◽  
Corneal Nerve

AbstractPurposeTo characterize corneal subbasal nerve plexus morphologic features using in vivo corneal confocal microscopy (IVCM) in normal and SIV-infected macaques and to implement automated assessments using novel deep learning-based methods customized for macaque studies.MethodsIn vivo corneal confocal microscopy images were collected from both male and female age-matched specific-pathogen free rhesus and pigtailed macaques housed at the Johns Hopkins University breeding colony using the Heidelberg HRTIII with Rostock Corneal Module. We also obtained repeat IVCM images of 12 SIV-infected animals including pre-infection and 10 day post-SIV infection time-points. All IVCM images were analyzed using a novel deep convolutional neural network architecture developed specifically for macaque studies.ResultsDeep learning-based segmentation of subbasal nerves in IVCM images from macaques demonstrated that corneal nerve fiber length (CNFL) and fractal dimension measurements did not differ between species, but pigtailed macaques had significantly higher baseline corneal nerve fiber tortuosity than rhesus macaques (P = 0.005). Neither sex nor age of macaques was associated with differences in any of the assessed corneal subbasal nerve parameters. In the SIV/macaque model of HIV, acute SIV infection induced significant decreases in both corneal nerve fiber length and fractal dimension (P= 0.01 and P= 0.008 respectively).ConclusionsThe combination of IVCM and objective, robust, and rapid deep-learning analysis serves as a powerful noninvasive research and clinical tool to track sensory nerve damage, enabling early detection of neuropathy. Adapting the deep-learning analyses to human corneal nerve assessments will refine our ability to predict and monitor damage to small sensory nerve fibers in a number of clinical settings including HIV, multiple sclerosis, Parkinson’s disease, diabetes, and chemotherapeutic neurotoxicity.

scholarly journals Comparing the results of manual and automated quantitative corneal neuroanalysing modules for beginners

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Po-Ying Wu ◽  
Jo-Hsuan Wu ◽  
Yi-Ting Hsieh ◽  
Lin Chih-Chieh Chen ◽  
Ting Cheng ◽  
...  
Keyword(s):  
Nerve Fiber ◽  
Correlation Coefficient ◽  
Intraclass Correlation ◽  
Fiber Density ◽  
Nerve Branch ◽  
Observer Reliability ◽  
Automated Method ◽  
Corneal Nerve ◽  
Branch Density

AbstractThis study aimed to evaluate the reliability of in vivo confocal microscopic neuroanalysis by beginners using manual and automated modules. Images of sub-basal corneal nerve plexus (SCNP) from 108 images of 18 healthy participants were analyzed by 7 beginner observers using manual (CCMetrics, [CCM]) and automated (ACCMetrics, [ACCM]) module. SCNP parameters analyzed included corneal nerve fiber density (NFD), corneal nerve branch density (NBD), corneal nerve fiber length (NFL), and tortuosity coefficient (TC). The intra-observer repeatability, inter-observer reliability, inter-module agreement, and left–right eye symmetry level of SCNP parameters were examined. All observers showed good intra-observer repeatability using CCM (intraclass correlation coefficient [ICC] > 0.60 for all), except when measuring TC. Two observers demonstrated especially excellent repeatability in analyzing NFD, NBD, and NFL using manual mode, indicating the quality of interpretation may still be observer-dependent. Among all SCNP parameters, NFL had the best inter-observer reliability (Spearman’s rank-sum correlation coefficient [SpCC] and ICC > 0.85 for the 3 original observers) and left–right symmetry level (SpCC and ICC > 0.60). In the additional analysis of inter-observer reliability using results by all 7 observers, only NFL showed good inter-observer reliability (ICC = 0.79). Compared with CCM measurements, values of ACCM measurements were significantly lower, implying a poor inter-module agreement. Our result suggested that performance of quantitative corneal neuroanalysis by beginners maybe acceptable, with NFL being the most reliable parameter, and automated method cannot fully replace manual work.

scholarly journals Deep Learning-Based Analysis of Macaque Corneal Sub-Basal Nerve Fibers in Confocal Microscopy Images

2019 ◽  
Author(s):  
Jonathan D. Oakley ◽  
Daniel B. Russakoff ◽  
Megan E. McCarron ◽  
Rachel L. Weinberg ◽  
Jessica M. Izzi ◽  
...  
Keyword(s):  
Deep Learning ◽  
Confocal Microscopy ◽  
Nerve Fiber ◽  
Ground Truth ◽  
Automated Analysis ◽  
Nerve Fibers ◽  
Fiber Analysis ◽  
Quantitative Measurements ◽  
Nerve Fiber Analysis

AbstractPurposeTo describe and assess different deep learning-based methods for automated measurement of macaque corneal sub-basal nerves using in vivo confocal microscopy (IVCM).MethodsThe automated assessment of corneal nerve fiber length (CNFL) in IVCM images is of increasing clinical interest. These measurements are important biomarkers in a number of diseases including diabetes mellitus, human immunodeficiency virus, Parkinson’s disease and multiple sclerosis. Animal models of these and other diseases play an important role in understanding the disease processes as efforts toward developing new and effective therapeutics are made. And while automated methods exist for nerve fiber analysis in clinical data, differences in anatomy and image quality make the macaque data more challenging and has motivated the work reported here.Toward this goal, nerves in macaque corneal IVCM images were manually labelled using an ImageJ plugin (NeuronJ). Different deep convolutional neural network (CNN) architectures were evaluated for accuracy relative to the ground truth manual tracings. The best performing model was used on separately acquired macaque ICVM images to additionally compare inter-reader variability.ConclusionsDeep learning-based segmentation of sub-basal nerves in IVCM images shows excellent correlation to manual segmentations in macaque data. The technique is indistinguishable across readers and paves the way for more widespread adoption of objective automated analysis of sub-basal nerves in IVCM.Translational RelevanceQuantitative measurements of corneal sub-basal nerves are important biomarkers for disease screening and management. This work reports on different approaches that, in using deep learning-based techniques, leverage state of the art analysis methods to demonstrate performance akin to human graders. In application, the approach is robust, rapid and objective, offering utility to a variety of clinical studies using IVCM.

scholarly journals Early Alterations of Corneal Subbasal Plexus in Uncomplicated Type 1 Diabetes Patients

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Domenico Schiano Lomoriello ◽  
Irene Abicca ◽  
Mariacristina Parravano ◽  
Daniela Giannini ◽  
Benedetta Russo ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Diabetic Retinopathy ◽  
Confocal Microscopy ◽  
Nerve Fiber ◽  
Fiber Length ◽  
Diabetes Complications ◽  
Corneal Confocal Microscopy ◽  
Subbasal Nerve Plexus

Purpose. The purpose of our study is to describe the in vivo corneal confocal microscopy characteristics of subbasal nerve plexus in a highly selected population of patients affected by type 1 diabetes mellitus (T1DM) without any microvascular diabetes complications.Methods. We included 19 T1DM patients without diabetic peripheral neuropathy, diabetic autonomic neuropathy, diabetic retinopathy, and microalbuminuria. All patients underwent in vivo corneal confocal microscopy and blood analysis to determine subbasal nerve plexus parameters and their correlation with clinical data. We compared the results with 19 healthy controls.Results. The T1DM group showed a significant decrease of the nerve fiber length (P=0.032), the nerve fiber length density (P=0.034), the number of fibers (P=0.005), and the number of branchings (P=0.028), compared to healthy subjects. The nerve fiber length, nerve fiber length density, and number of fibers were directly related to the age at onset of diabetes and inversely to the duration of DM. BMI (body mass index) was highly related to the nerve fiber length (r = −0.6,P=0.007), to the nerve fiber length density (r = −0.6,P=0.007), and to the number of fibers (r = −0.587,P=0.008). No significant correlations were found between the corneal parameters and HbA1c.Conclusions. Early subclinical fiber corneal variation could be easily detected using in vivo corneal confocal microscopy, even in type 1 diabetes without any microvascular diabetes complications, including diabetic peripheral neuropathy, diabetic autonomic neuropathy, diabetic retinopathy, and microalbuminuria.

scholarly journals In-vivo imaging of retinal nerve fiber layer vasculature: imaging - histology comparison

2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Drew Scoles ◽  
Daniel C Gray ◽  
Jennifer J Hunter ◽  
Robert Wolfe ◽  
Bernard P Gee ◽  
...  
Keyword(s):  
Nerve Fiber ◽  
Retinal Nerve Fiber Layer ◽  
In Vivo Imaging ◽  
Fiber Layer ◽  
Nerve Fiber Layer ◽  
Retinal Nerve Fiber

scholarly journals Sex-related differences in response to masseteric injections of glutamate and nerve growth factor in healthy human participants

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abdelrahman M. Alhilou ◽  
Akiko Shimada ◽  
Camilla I. Svensson ◽  
Peter Svensson ◽  
Malin Ernberg ◽  
...  
Keyword(s):  
Nmda Receptors ◽  
Nerve Fiber ◽  
Masseter Muscle ◽  
Pain Sensitivity ◽  
Nerve Fibers ◽  
Receptor Expression ◽  
Healthy Human ◽  
Neurophysiological Mechanisms ◽  
Human Participants ◽  
Positive Correlations

AbstractThe neurophysiological mechanisms underlying NGF-induced masseter muscle sensitization and sex-related differences in its effect are not well understood in humans. Therefore, this longitudinal cohort study aimed to investigate the effect of NGF injection on the density and expression of substance P, NMDA-receptors and NGF by the nerve fibers in the human masseter muscle, to correlate expression with pain characteristics, and to determine any possible sex-related differences in these effects of NGF. The magnitude of NGF-induced mechanical sensitization and pain during oral function was significantly greater in women than in men (P < 0.050). Significant positive correlations were found between nerve fiber expression of NMDA-receptors and peak pain intensity (rs = 0.620, P = 0.048), and expression of NMDA-receptors by putative nociceptors and change in temporal summation pain after glutamate injection (rs = 0.561, P = 0.003). In women, there was a significant inverse relationship between the degree of NGF-induced mechanical sensitization and the change in nerve fiber expression of NMDA-receptors alone (rs = − 0.659, P = 0.013), and in combination with NGF (rs = − 0.764, P = 0.001). In conclusion, women displayed a greater magnitude of NGF-induced mechanical sensitization that also was associated with nerve fibers expression of NMDA-receptors, when compared to men. The present findings suggest that, in women, increased peripheral NMDA-receptor expression could be associated with masseter muscle pain sensitivity.

scholarly journals Morphometric Nerve Fiber Analysis and Aging Process of the Human Abducent Nerve

1998 ◽  
Vol 74 (6) ◽  
pp. 337-343 ◽  
Author(s):  
Yoshiharu SAWABE ◽  
Kiyoshi MATSUMOTO ◽  
Noboru GOTO ◽  
Naruhito OTSUKA ◽  
Nobusuke KOBAYASHI
Keyword(s):  
Nerve Fiber ◽  
Aging Process ◽  
Fiber Analysis ◽  
Nerve Fiber Analysis ◽  
Abducent Nerve
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