Disrupted resting-state spontaneous neural activity in stable COPD

Abstract

Introduction and aim: Abnormal brain structure and function in COPD has been reported on MRI. However, the deficit in local synchronization of spontaneous activity in patients with stable COPD remains unknown. The main aim of the present study was to explore spontaneous brain activity in patients with COPD compared with normal controls using the regional homogeneity (ReHo) method based on resting-state functional MRI.

Methods: Nineteen patients with stable COPD and 20 well-matched (including age, sex, and number of years of education) normal controls who were recruited for the present study underwent resting-state functional MRI examinations and a series of neuropsychological and clinical assessments. The ReHo method was used to assess the strength of local brain signal synchrony. The mean ReHo values in brain areas with abnormal ReHo were evaluated with a receiver operating characteristic curve. The relationships between the brain regions with altered ReHo values and the clinical and neuropsychological parameters in COPD patients were assessed using Pearson's correlation.

Results: Patients with COPD showed significantly lower ReHo values in the left occipital lobe and the right lingual, bilateral precuneus, and right precentral gyrus. The result of receiver operating characteristic curve analysis showed that the altered average ReHo values have high efficacy for distinguishing function. The mean lower ReHo values in the precuneus gyrus showed a significant positive correlation with FEV₁%, FEV₁/FVC, and orientation function but a significant negative correlation with arterial partial pressure of carbon dioxide.

Conclusion: The COPD patients demonstrated abnormal synchrony of regional spontaneous activity, and the regions with abnormal activity were all correlated with visual processing pathways, which might provide us with a new perspective to further understand the underlying pathophysiology of cognitive impairment in patients with COPD.

Keywords: blood oxygen-level-dependent; chronic obstructive pulmonary disease; regional homogeneity; resting-state functional magnetic resonance imaging; visual processing pathways.

Figure 1

The differences map in ReHo between COPD patients and NC groups (two-tailed GRF correction, voxel-level P <0.01, and cluster-level P <0.05) is shown in axial position. The blue areas indicate lower ReHo values. Abbreviations: GRF, Gaussian random field theory; NC, normal control; ReHo, regional homogeneity.

Figure 2

Significant abnormal activity map observed in the left occipital lobe, the right lingual, the bilateral precuneus, and the right precentral gyrus between patients with COPD and NCs (two-tailed, GRF correction, voxel-level P <0.01, and cluster-level P <0.05) in three-dimensional image. Abbreviations: GRF, Gaussian random field theory; NCs, normal controls.

Figure 3

Mean ReHo signal values for altered regional brain areas between COPD patients and NCs. Abbreviations: NCs, normal controls; ReHo, regional homogeneity.

Figure 4

ROC curve analysis of the mean ReHo values for abnormal activity brain regions. Notes: The AUCs were 0.829 for the occipital lobe, 0.784 for the lingual, 0.866 for the precuneus, and 0.85 for the precentral gyrus. The sensitivity and specificity of the occipital lobe were 85.0% and 73.7%. The sensitivity and specificity of the lingual were 95.0% and 63.2%. The sensitivity and specificity of the precuneus were 75.0% and 89.5%. The sensitivity and specificity of the precentral gyrus were 70.0% and 94.7%. Abbreviations: AUC, area under the curve; ReHo, regional homogeneity; ROC, receiver operating characteristic.

Figure 5

There was a significant correlation between the ReHo values in the precuneus and the clinical parameters (PaCO₂, FEV₁/FVC, FEV₁%, orientation) in the stable COPD patients. Abbreviations: PaCO₂, arterial partial pressure of carbon dioxide; ReHo, regional homogeneity.