Altered Functional Connectivity of the Primary Visual Cortex in Patients With Iridocyclitis and Assessment of Its Predictive Value Using Machine Learning

Chen-Xing Qi,Yan Tong,Xin Huang,Yin Shen

doi:10.3389/fimmu.2021.660554

Abstract

PurposeTo explore the intrinsic functional connectivity (FC) alteration of the primary visual cortex (V1) between individuals with iridocyclitis and healthy controls (HCs) by the resting-state functional magnetic resonance imaging (fMRI) technique, and to investigate whether FC findings be used to differentiate patients with iridocyclitis from HCs.MethodsTwenty-six patients with iridocyclitis and twenty-eight well-matched HCs were recruited in our study and underwent resting-state fMRI examinations. The fMRI data were analyzed by Statistical Parametric Mapping (SPM12), Data Processing and Analysis for Brain Imaging (DPABI), and Resting State fMRI Data Analysis Toolkit (REST) software. Differences in FC signal values of the V1 between the individuals with iridocyclitis and HCs were compared using independent two-sample t-tests. Significant differences in FC between two groups were chosen as classification features for distinguishing individuals with iridocyclitis from HCs using a support vector machine (SVM) classifier that involved machine learning. Classifier performance was evaluated using permutation test analysis.ResultsCompared with HCs, patients with iridocyclitis displayed significantly increased FC between the left V1 and left cerebellum crus1, left cerebellum 10, bilateral inferior temporal gyrus, right hippocampus, and left superior occipital gyrus. Moreover, patients with iridocyclitis displayed significantly lower FC between the left V1 and both the bilateral calcarine and bilateral postcentral gyrus. Patients with iridocyclitis also exhibited significantly higher FC values between the right V1 and left cerebellum crus1, bilateral thalamus, and left middle temporal gyrus; while they displayed significantly lower FC between the right V1 and both the bilateral calcarine and bilateral postcentral gyrus (voxel-level P<0.01, Gaussian random field correction, cluster-level P<0.05). Our results showed that 63.46% of the participants were correctly classified using the leave-one-out cross-validation technique with an SVM classifier based on the FC of the left V1; and 67.31% of the participants were correctly classified based on the FC of the right V1 (P<0.001, non-parametric permutation test).ConclusionPatients with iridocyclitis displayed significantly disturbed FC between the V1 and various brain regions, including vision-related, somatosensory, and cognition-related regions. The FC variability could distinguish patients with iridocyclitis from HCs with substantial accuracy. These findings may aid in identifying the potential neurological mechanisms of impaired visual function in individuals with iridocyclitis.

Highlights

Iridocyclitis is the most common pattern of anterior uveitis among the general population and is characterized by the presence of an inflammatory phenotype within the anterior eye segment that involves the iris and ciliary body [1]
The support vector machine (SVM) classification model applying the leave-one-out cross-validation (LOOCV) method achieved a total accuracy of 63.46%, sensitivity of 69.23%, and specificity of 65.22%
We examined whether differences in functional connectivity (FC) between individuals with iridocyclitis and healthy controls (HCs) could serve as a classification feature to discriminate those groups, based on a machine learning approach using a SVM classifier

Summary

Introduction

Iridocyclitis is the most common pattern of anterior uveitis among the general population and is characterized by the presence of an inflammatory phenotype within the anterior eye segment that involves the iris and ciliary body [1]. The typical clinical features of patients with iridocyclitis include eye redness, eye pain, blurred vision, and photophobia. Many affected patients have no evidence of an underlying disorder and their disease is considered idiopathic; iridocyclitis is often associated with autoimmunity. Human leucocyte antigen (HLA-B27) is a critical risk factor for the onset of iridocyclitis; notably, approximately 40-70% of patients with anterior uveitis are HLA-B27 positive, whereas this proportion is only 8-10% of healthy individuals [3]. Iridocyclitis is commonly related to HLA-B27-associated systemic immune-mediated diseases, including ankylosing spondylitis, inflammatory bowel disease and reactive arthritis [4, 5]. Topical or systemic corticosteroids are often used; steroid sparing current treatment modalities include disease-modifying anti-rheumatic drugs, such as conventional or synthetic biological drugs [6]

Methods

Results

Discussion

Conclusion