<p>Altered Intrinsic Brain Activities in Patients with Diabetic Retinopathy Using Amplitude of Low-frequency Fluctuation: A Resting-state fMRI Study</p>

Abstract

Objective: The current study aimed to apply the amplitude of low-frequency fluctuation (ALFF) method for investigating the spontaneous brain activity alterations and their relationships with clinical features in patients with diabetic retinopathy (DR). Patients and Methods: In total, 35 patients with DR (18 males and 17 females) and 38 healthy control (HC) subjects (18 males and 20 females) were enrolled in this study. All participants underwent resting-state functional magnetic resonance imaging (rs-fMRI) scanning, respectively. The ALFF method was used to assess the spontaneous brain activity, while the mean ALFF signal values of patients with DR and HCs were classified by the receiver operating characteristic (ROC) curve. Correlation analysis was performed to calculate the relationship between the observed mean ALFF values of the altered regions in patients with DR and their clinical features. Results: Compared with the HCs, patients with DR had significantly lower ALFF values in the left and right middle occipital gyrus (MOG). In contrast, patients with DR showed higher ALFF values in the left cerebellum (CER), left inferior temporal gyrus (ITG) and left hippocampus (Hipp). However, no relationship was observed between the mean ALFF signal values of the altered regions and clinical manifestations in the patients with DR. Conclusion: We mainly found that patients with DR showed abnormal intrinsic brain activities in the left and right MOG, left CER, left ITG and left Hipp, which might provide useful information for explaining neural mechanisms in patients with DR.

Regional Spontaneous Neural Activity Alterations in Type 2 Diabetes Mellitus: A Meta-Analysis of Resting-State Functional MRI Studies

“…First, the former meta-analysis included only five original studies and seven datasets that investigated the regional functional activity alterations using ALFF/fALFF and ReHo. Our study with a larger sample included 16 original studies and 19 datasets, and many of the newly included studies reported hypoactivity in the medial superior frontal gyrus (Liu et al, 2016;Wang et al, 2019;Shi et al, 2020;Zhang Y. Q. et al, 2020) and hyperactivity in the cerebellum (Liao et al, 2019;Wang et al, 2019;Qi et al, 2020;Shi et al, 2020;Zhang Y. Q. et al, 2020). Second, the previous meta-analysis included both regional activity and functional connectivity measurements as well as perfusion modality, whereas this meta-analysis enrolled only studies using ALFF/fALFF and ReHo indices reflecting the regional spontaneous neural activity, avoiding heterogeneity of the included studies (Xia et al, 2017).…”

“…A total of 47 articles were identified through the systematic literature search, and Figure 1 shows the details of study selection process. We finally included 16 studies (19 T2DM datasets and 15 healthy controls datasets) in the final meta-analysis (Xia et al, 2013;Cui et al, 2014;Wang et al, 2014Wang et al, , 2019Zhou et al, 2014;Liu et al, 2016;Peng et al, 2016;Wang Y. F. et al, 2017;Wang Z. L. et al, 2017;Liao et al, 2019;Liu Y. et al, 2020;Qi et al, 2020;Shi et al, 2020;Xiong et al, 2020;Zhang Y. Q. et al, 2020). In two studies of ReHo, the analysis was performed in two different T2DM subgroups (Peng et al, 2016;Xiong et al, 2020), and in another study, the analysis was performed with ALFF and ReHo (Cui et al, 2014).…”

“…For example, increased regional activity has been found in the lingual gyrus, middle temporal gyrus, and precuneus (Wang et al, 2014;Zhou et al, 2014;Wang Z. L. et al, 2017;Liu Y. et al, 2020), whereas decreased activity in these regions has also been reported (Xia et al, 2013;Cui et al, 2014;Wang Y. F. et al, 2017), and yet more studies have identified no changes (Liu et al, 2016;Liao et al, 2019;. This inconsistency resulted in part from small samples and from studying patients with various comorbidities, such as microangiopathy, including retinopathy, nephropathy, and peripheral neuropathy (Xia et al, 2013;Cui et al, 2014;Wang Z. L. et al, 2017;Liao et al, 2019;Qi et al, 2020); vitreous hemorrhage (Shi et al, 2020;Zhang Y. Q. et al, 2020); mild cognitive impairment (Zhou et al, 2014;Xiong et al, 2020); cirrhosis (Wang Y. F. et al, 2017); hypertension (Cui et al, 2014;Zhou et al, 2014); and dyslipidemia (Wang et al, 2014), which were known to alter brain function (Weissenborn et al, 2004;Umegaki et al, 2012;Umemura et al, 2013;Friedman et al, 2014;Muela et al, 2017). Thus, the central question of how the brain regional function manifests remains unaddressed in T2DM.…”

Aberrant Interhemispheric Functional Connectivity in Diabetic Retinopathy Patients

“…The functional magnetic resonance imaging method provides a new opportunity for non-invasive research on functional and structural changes of brain in vivo . Qi et al (2020) demonstrated that DR had significantly altered brain neural activity changes in the middle occipital gyrus, the left cerebellum, the left inferior temporal gyrus, and the left hippocampus. Dai et al (2017) reported that DR patients had abnormal functional connectivity (FC) within visual and cognition networks.…”

Application of advanced magnetic resonance imaging in glaucoma: a narrative review

“…For example, a recent study by Minosse et al using optical coherence tomography (OCT) found a significant correlation between Rs-fMRI and VF, and RNFL and the macular RGCs layer (25). Other studies have found changes of Rs-fMRI in some patients with ocular diseases, suggesting the potential neural mechanism of ocular diseases (26)(27)(28)(29)(30).…”