The Abnormal Alternations of Brain Imaging in Patients with Chronic Obstructive Pulmonary Disease: A Systematic Review

Abstract

Background: Cognitive impairment (CI) is an important extrapulmonary complication in patients with chronic obstructive pulmonary disease (COPD). Multimodal Neuroimaging Examination can display changes in brain structure and functions in patients with COPD.

Objective: The purpose of this systematic review is to provide an overview of the variations in brain imaging in patients with COPD and their potential relationship with CI. Furthermore, we aim to provide new ideas and directions for future research.

Methods: Literature searches were performed using the electronic databases PubMed, Scopus, and ScienceDirect. All articles published between January 2000 and November 2021 that met the eligibility criteria were included.

Results: Twenty of the 23 studies focused on changes in brain structure and function. Alterations in the brain's macrostructure are manifested in the bilateral frontal lobe, hippocampus, right temporal lobe, motor cortex, and supplementary motor area. The white matter microstructural changes initially appear in the bilateral frontal subcortical region. Regarding brain function, patients with COPD exhibited reduced frontal cerebral perfusion and abnormal alterations in intrinsic brain activity in the bilateral posterior cingulate cortex, precuneus, right lingual gyrus, and left anterior central gyrus. Currently, there is limited research related to brain networks.

Conclusion: CI in patients with COPD may present as a type of dementia different from Alzheimer's disease, which tends to manifest as frontal cognitive decline early in the disease. Further studies are required to clarify the neurobiological pathways of CI in patients with COPD from the perspective of brain connectomics based on the whole-brain system in the future.

Keywords: Alzheimer’s disease; brain imaging; chronic obstructive pulmonary disease; cognitive impairment; mechanism.

Fig. 1

Flowchart of literature search and selection of the articles.

Fig. 2

Distribution of cortical changes in COPD patients. Compared to the normal controls, cortical atrophy in COPD patients is concentrated in bilateral hippocampus (red), right opercular part (pink)/triangular part of the inferior frontal gyrus (green), left precuneus (purple), bilateral middle frontal gyrus (brown), right thalamus (blue), right superior (gray)/middle temporal gyrus (orange), right superior frontal gyrus (blackish green), bilateral calcarine (cyan), bilateral orbital inferior frontal gyrus (yellow), left orbital superior frontal gyrus (magenta), and right fusiform gyrus (indigo). Compared with the dominant hemispheres, the structural changes in the non-dominant hemispheres were more obvious. The lesions in the frontal lobe are prominent.

Fig. 3

Altered white matter fiber tracts in one COPD patient. The integrity of nine fiber bundles was altered: bilateral superior/posterior corona radiata, splenium/genu/body of corpus callosum, bilateral cingulum, bilateral occipitofrontal fasciculus.