Structural and Functional Thalamic Changes in Parkinson's Disease With Mild Cognitive Impairment

Background The thalamus is a key node of deep gray matter and previous studies have demonstrated that it is involved in the modulation of cognition. Purpose To investigate the volume changes of the thalamus and its subregions and altered thalamus functional connectivity patterns in Parkinson's disease (PD) patients with and without mild cognitive impairment (MCI). Study Type Prospective. Population Thirty‐three patients with MCI ( PD‐MCI ), 36 PD patients having no cognitive impairment ( PD‐NCI ), 21 healthy controls ( HCs ). Sequence 3.0T MRI scanner; 3D T 1 ‐weighted fast spoiled gradient recalled echo ( 3D T 1 ‐FSPGR ); resting‐state fMRI Assessment Voxel‐based morphometry (VBM) was performed to calculate the volume of the thalamus and its subregions. The left and right total thalamus were considered seeds and seed‐based functional connectivity (FC) was analyzed. Additionally, correlations between volumes and cognitive performance and between FC values and cognitive performance were examined separately. Statistical Test Analysis of covariance (ANCOVA); two‐sample t ‐tests; partial correlation analysis. Results The volumes of the total thalamus (PD‐MCI vs. PD‐NCI vs. HCs: 18.39 ± 1.67 vs. 19.63 ± 1.79 vs. 19.47 ± 1.35) and its subregions were significantly reduced in PD‐MCI as compared to PD‐NCI (total thalamus: P = 0.002) and HCs (total thalamus: P = 0.012). Compared with PD‐NCI, PD‐MCI showed increased FC between the thalamus and bilateral middle cingulate cortex and left posterior cingulate cortex, and decreased FC between thalamus and the left superior occipital gyrus, left cuneus, left precuneus, and left middle occipital gyrus. Volumes of thalamus and the subregions, as well as the FC of thalamus with the identified regions, were significantly correlated ( P < 0.05, FDR‐corrected) with neuropsychological scores in PD patients. Data Conclusion We noted volume loss and altered FC of thalamus in PD‐MCI patients, and these changes were correlated with global cognitive performance. Level of Evidence 2 Technical Efficiency Stage 2 J. Magn. Reson. Imaging 2020;52:1207–1215.