Résumé
Objective To evaluate the role of local gyrification index (LGI) in the early diagnosis of Alzheimer disease(AD). Methods Thirty‐five amnestic‐type mild cognitive impairment patients (aMCI group), 34 mild AD patients (mild AD group) and 33 healthy volunteers (normal control group) were studied. All patients underwent high resolution MRI examination and mini‐mental state examination (MMSE). Using surface‐based morphometry, the FreeSurfer was employed to access LGI of vertex over every participant′s whole cortical surface, then we calculated the mean LGI (mLGI) of each subject′s left and right hemisphere separately. Taking age, gender and educational year as covariance, analysis of covariance was used to compare the difference of mLGI of left and right brain among 3 groups, then Bonferroni was done between every two groups. Analysis of covariance was applied to compare the difference of LGI of every participant among 3 groups, and Monte Carlo method was employed to perform multiple comparison corrections. The correlations between the MMSE scores and LGIs of the three groups were analyzed. Results Compared with normal control group(left 3.03±0.12,right 3.02±0.13), the mLGI of hemispheres in mild AD group(left 2.94±0.11,right 2.93±0.10) decreased respectively(P<0.05). The difference of mLGI of hemispheres between aMCI group(left 2.96 ± 0.10, right 2.96 ± 0.09) and normal control group had no statistical significance(P>0.05). The difference of mLGI of hemispheres between aMCI group and mild AD group also had no statistical significance(P>0.05). The aMCI group showed decrease of LGI in some brain regions located at the right temporal lobe, bilateral frontal and parietal lobe compared with the normal control group. While compared with aMCI group, decreased LGIs was presented in some brain regions located at bilateral temporal, occipital, frontal lobe and the right parietal lobe of mild AD group. There was a positive correlation between MMSE scores and LGIs of some brain regions in the bilateral temporal, occipital lobe, the left frontal lobe and the right parietal lobe in the three groups. Conclusion LGI is conductive in the early diagnosis of AD and can serve as an imaging marker for monitoring disease progresses.
Résumé
Objective To analyze the brain structure changes of the first-episode obsessive compulsive disorder (OCD) patients who were scanned by three-dimensional structure magnetic resonance imaging.Methods According to the diagnostic criteria of OCD in American Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-Ⅳ),the fist-episode obsessive compulsive disorder patients as case group(OCD,n=26) and the adult healthy volunteers as control group (control group,n=25) were selected.All subjects were assessed with Yale-Brown obsessive-compulsive scale(Y-BOCS),Hamilton Anxiety rating Scale (HAMA) and Hamilton Depression Rating Scale(HAMD),and then,they received 3D-MRI scanning runs.All the data was processed with freesurfer software and analyzed about cerebral cortical volume,cortical thickness,cortical surface area,the local gyrification index and subcortical nuclei volume.Results Compared with control group,the cerebral cortical thickness of OCD group increased at the left postcentral gyrus ((2.223±0.118)mm),left supramarginal gyrus ((2.486 ± 0.027) mm) and left parahippocampal gyrus ((2.399±0.164)mm).The cerebral cortical surface area larged at the right inferior frontal gyrus((1.036±0.079) mm2),right paracentral lobule ((0.827 ± 0.048) mm2) and medial orbitofrontal ((0.990 ± 0.083)mm2),and decreased at right superior parietal lobule ((0.779 ± 0.040) mm2),right inferior parietal lobule ((0.767±0.093) mm2) and right inferior temporal gyrus ((0.888±0.070) mm2).The cerebral cortical volume increased at the right inferior frontal gyrus((2.330±0.223) mm3).The cerebral cortical local gyrification index decreased at right middle temporal gyrus(2.893±0.288)and left inferior temporal gyrus(2.589±0.100).Conclusion The first-episode OCD patients have multiple changes of brain structures,and this changes were priority for the frontal lobes,orbital frontal,parietal lobe,temporal lobe and hippocampus.The changes in these regions maybe have close relationship with symptoms of OCD.
Résumé
OBJECTIVES: Local gyrification reflects the early neural development of cortical connectivity, and is regarded as a potential neural endophenotype in psychiatric disorders. Several studies have suggested altered local gyrification in patients with bipolar I disorder (BD-I). The purpose of the present study was to investigate the alterations in the cortical gyrification of whole brain cortices in patients with BD-I. METHODS: Twenty-two patients with BD-I and age and sex-matched 22 healthy controls (HC) were included in this study. All participants underwent T1-weighted structural magnetic resonance imaging (MRI). The local gyrification index (LGI) of 66 cortical regions were analyzed using the FreeSurfer (Athinoula A. Martinos Center for Biomedical Imaging). One-way analysis of covariance (ANCOVA) was used to analyze the difference of LGI values between two groups adjusting for age and sex as covariates. RESULTS: The patients with BD-I showed significant hypogyria in the left pars opercularis (uncorrected-p = 0.049), the left rostral anterior cingulate gyrus (uncorrected-p = 0.012), the left caudal anterior cingulate gyrus (uncorrected-p = 0.033). However, these findings were not significant after applying the multiple comparison correction. Severity or duration of illness were not significantly correlated with LGI in the patients with BD-I. CONCLUSIONS: Our results of lower LGI in the anterior cingulate cortex and the ventrolateral prefrontal cortex in the BD-I group implicate that altered cortical gyrification in neural circuits involved in emotion-processing may contribute to pathophysiology of BD-I.