Objective:To investigate the effects of apolipoprotein E (APOE) ε4 allele on β-amyloid (Aβ) deposition in subcortical structures and functional connectivity (FC) between brain regions in patients with Alzheimer′s disease (AD). Methods:Forty-three patients with probable mild/moderate AD were prospectively enrolled from the First Medical Centre, Chinese PLA General Hospital between January 2023 and October 2023, including 23 APOE ε4+ patients (12 males and 11 females, age (74.8±8.4) years), 20 APOE ε4- patients (14 males and 6 females, age (77.6±8.9) years) and 20 normal cognitive volunteers (NC) (15 males and 5 females, age (75.3±6.2) years). All subjects underwent 11C-Pittsburgh compound B (PIB) PET/MR brain imaging. The differences of gray matter volume (GMV) in subcortical structures (hippocampus, amygdala) among the three groups were analyzed by one-way analysis of variance and least significant difference (LSD) t test. Independent-sample t test and Pearson correlation analysis were used to analyze difference in Aβ deposition between APOE ε4+ patients and APOE ε4- patients, and the correlation between subcortical structure and brain FC. Results:The GMV of bilateral amygdala between NC group and APOE ε4+ gene carrier group, and between APOE ε4+ and APOE ε4- gene carrier groups were significantly different ( F=6.43, P=0.002; P values: 0.002, 0.003). Significant difference of GMV was observed in the bilateral hippocampus among three groups ( F=5.34, P=0.030). Abnormal PIB uptake was detected in both the hippocampus and amygdala of both APOE ε4+ and APOE ε4- gene carrier groups, with a more pronounced effect observed in the APOE ε4+ group ( t values: 3.14, 2.19, P values: 0.032, 0.009). Taking the hippocampus as the seed point, there was no obvious abnormality in the whole brain connectivity map among APOE ε4+, APOE ε4- carriers and NC groups. With the amygdala as the seed point, the whole brain connectivity in the APOE ε4+ gene carrier group was significantly reduced, and the connectivity between the amygdala and the cingulate gyrus, parietal lobe and temporal lobe was significantly reduced in the APOE ε4+ gene carrier group compared with NC group, while the connectivity between the amygdala and the whole brain was not significantly reduced in the APOE ε4- gene carrier group. Aβ deposition in amygdala was positively correlated with FC coefficients of frontal brain regions, gyrus rectus, right middle occipital gyrus and left temporal lobe ( r values: 0.56-0.70, all P<0.05). Conclusion:APOE influences GMV and Aβ deposition of hippocampus and amygdala, and FC of amygdala, and may be involved in the pathological mechanism of cognitive impairment.

Stroke at the acute stage is a major cause of disability in adults, and is associated with dysfunction of brain networks. However, the mechanisms underlying changes in brain connectivity in stroke are far from fully elucidated. In the present study, we investigated brain metabolism and metabolic connectivity in a rat ischemic stroke model of middle cerebral artery occlusion (MCAO) at the acute stage using F-fluorodeoxyglucose positron emission tomography. Voxel-wise analysis showed decreased metabolism mainly in the ipsilesional hemisphere, and increased metabolism mainly in the contralesional cerebellum. We used further metabolic connectivity analysis to explore the brain metabolic network in MCAO. Compared to sham controls, rats with MCAO showed most significantly reduced nodal and local efficiency in the ipsilesional striatum. In addition, the MCAO group showed decreased metabolic central connection of the ipsilesional striatum with the ipsilesional cerebellum, ipsilesional hippocampus, and bilateral hypothalamus. Taken together, the present study demonstrated abnormal metabolic connectivity in rats at the acute stage of ischemic stroke, which might provide insight into clinical research.
Acute Disease ; Animals ; Brain ; diagnostic imaging ; metabolism ; Brain Mapping ; Disease Models, Animal ; Fluorodeoxyglucose F18 ; Glucose ; metabolism ; Infarction, Middle Cerebral Artery ; diagnostic imaging ; metabolism ; Male ; Neural Pathways ; diagnostic imaging ; metabolism ; Positron-Emission Tomography ; Radiopharmaceuticals ; Random Allocation ; Rats, Sprague-Dawley

Positron emission tomography (PET) imaging of functional metabolism has been widely used to investigate functional recovery and to evaluate therapeutic efficacy after stroke. The voxel intensity of a PET image is the most important indicator of cellular activity, but is affected by other factors such as the basal metabolic ratio of each subject. In order to locate dysfunctional regions accurately, intensity normalization by a scale factor is a prerequisite in the data analysis, for which the global mean value is most widely used. However, this is unsuitable for stroke studies. Alternatively, a specified scale factor calculated from a reference region is also used, comprising neither hyper- nor hypo-metabolic voxels. But there is no such recognized reference region for stroke studies. Therefore, we proposed a totally data-driven automatic method for unbiased scale factor generation. This factor was generated iteratively until the residual deviation of two adjacent scale factors was reduced by < 5%. Moreover, both simulated and real stroke data were used for evaluation, and these suggested that our proposed unbiased scale factor has better sensitivity and accuracy for stroke studies.
Animals ; Computer Simulation ; Disease Models, Animal ; Female ; Fluorodeoxyglucose F18 ; Image Processing, Computer-Assisted ; methods ; Infarction, Middle Cerebral Artery ; diagnostic imaging ; Male ; Positron-Emission Tomography ; methods ; Rats ; Rats, Sprague-Dawley ; Stroke ; diagnostic imaging

Objective To analyze the relationship between the brain functional alterations of patients with Cushing's disease (CD) and patients' mental symptom by applying the Evaluating Emotional Scales and task functional magnetic resonance imaging (Task fMRI).Methods Task fMRI was performed on 8 patients with diagnosed CD admitted in the Department of Endocrinology of Chinese PLA General Hospital from Nov. 2015 to Nov. 2016 and 21 healthy people with matched age, gender and education level as control. Meanwhile, Self-Rating Depression Scale (SDS), Self-Rating Anxiety Scale (SAS), Positive and Negative Affective Scale (PANAS) and Cushing Quality of Life Scale (Cushing QOL) were obtained to assess the brain functions.Results Significant depression and anxiety were observed in patients with CD, and their positive affective score was substantially lower while the negative affective score was relatively higher compared with that in the controls. Task fMRI revealed that, when watching the positive pictures, the activation degree of left cerebellum and right postcentral gyrus weakened in CD patients than in the controls, and the positive correlations existed between the activation degree of left cerebellum and the 16 o'clock adrenocorticotrophic hormone (ACTH) level, and between the activation degree of right postcentral gyrus and the urinary free cortisol (UFC) level in CD patients. In contrast, when watching the negative pictures, the activation degree of left cerebellum, bilateral parahippocampal gyrus and left inferior frontal gyrus was weakened in CD patients than in the controls, and the activation degree of left cerebellum was negatively correlated to the 0 o'clock cortisol level and SAS score, but is positively correlated to the UFC level. When watching the neutral pictures, the activation degree of left cerebellum and left parahippocampal gyrus was weakened in CD patients than in the controls.Conclusions CD patients may have impaired brain function with depression and anxiety mental symptoms. By Task fMRI, it can be found that the weakened activation degree of left inferior frontal gyrus, right postcentral gyrus, bilateral parahippocampal gyrus and left cerebellum may be related to CD patients' mental symptoms.

Purpose To explore the role of posterior cingulate cortex (PCC) dysfunction in the pathogenesis of depression and its relationship with the clinical features of depression by analyzing the effective connection among the inner areas of PCC of patients in depression.Materials and Methods The spectral dynamic causal model (spDCM) was used to analyze the resting state functional magnetic resonance imaging (fMRI) data from the PCC inner areas Brodmann area (BA) 23,BA29,BA30,BA31 in the major depressive disorder group (MDD,n=23) and healthy control group (HC,n=36).Results Compared with HC group,the strength of BA30 self-connection of MDD group existed significant difference (t=2.53,P＜0.05).In MDD group,the connection of BA23 toward BA31 had abnormal activation,and the abnormal inhibition occurred in BA23 toward BA30;compared with HC group and after a＜0.05 Hz correction,there were significant differences in the bi-directional connections for BA23 and BA31,BA39 and BA31,BA30 and BA31,and in the unidirectional connections for BA23 to BA31,BA30 to BA23,BA30 to BA29 in MDD group.Conelusion The effective connection and connective nodes and edges in the inner areas of PCC in the depression disorder patients were abnormal.

Objective: To assess the feasibility of coronary lfow reserve (CFR) detection by SPECT myocardial perfusion imaging using a self developed software with preliminary clinical veriifcation. Methods: CFR calculation software was developed according to Mat lab guide. A total of 16 patients were enrolled including 13 male and 3 female at the mean age of (58±11) years . CAG conifrmed that 25 coronary branches were with stenosis>50% and 23 branches were without stenosis. 2-day ATP/rest99mTc-sestamibi dynamic SPECT myocardial perfusion imaging was conducted to detect CFR. First transit counts were used to sketch the interested pulmonary artery segments and to obtain the arterial input curve of contrast agent as total PAC reached to heart. Reconstructed short-axis images were divided into 3 sections to sketch interested territories (ROI) and to obtain RMC at each territory. Estimated CFR was expressed by the ratio of MBF=RMC/PAC followed by calculating the ratio of MFR=MBFstress/MBFrest. Results: The difference between simulated value and true value could be ignored which conifrmed that our program may accurately measure CFR. The reproducibility by different operators (r=0.986) and the same operator (r=0.983) was good. CFR value in non-stenosis branches were higher than stenosis branches (1.28 ± 0.19) vs (1.10 ± 0.27),P=0.008 and CFR value in stenosis branches was negatively related to stenosis degree (r=-0.5,P=0.02). Conclusion: Our self developed software is reliable for CFR detection by SPECT myocardial perfusion imaging; preliminary study showed good application prospect in clinical practice.

BACKGROUNDDiffusion tensor imaging can evaluate white matter function in human brain. Fractional anisotropy is the most important parameter. This study aimed to find regional reduction of fractional anisotropy (FA) with aging in the whole brain and the changing rules of anisotropy with aging.

METHODSFifty volunteers from 20 to 75 years old were divided into five consecutive age groups; a young group and four senior groups. FA values were calculated with diffusion tensor imaging (DTI) studio software. The difference of FA between the young group and the four senior groups were analyzed by analysis of voxel-level height threshold in Statistic Parametric Mapping (SPM), and the regions with decreased FA were obtained. The FA values of these regions were then extracted using an in-house developed program, and a multiple linear regression model was built to assess the influence of age and sex on the FA values of these regions.

RESULTSEight regions, including frontal lobe, postcentral gyrus, optic radiation, hippocampus, cerebella hemisphere, corona radiate, corpus callosum and internal capsule, were found to have decreased FA. There was a strong negative correlation between age and the FA in the frontal lobe, postcentral gyrus, optic radiation, hippocampus, and cerebella hemisphere, while a weaker negative correlation in the corona radiate, corpus callosum, and internal capsule was found. The FA reduction in the frontal lobe, postcentral gyrus, optic radiation, hippocampus and cerebella hemisphere were found earlier than in the corona radiate, corpus callosum and internal capsule. There was no correlation between sex and FA in these regions.

CONCLUSIONSThe FA in the subcortical white matter area reduces earlier than that in deep white matter. The areas with decreased FA continuously enlarge with aging. The FAs in these regions have a strong negative correlation with age.

Adult ; Aged ; Aging ; physiology ; Brain ; pathology ; Diffusion Magnetic Resonance Imaging ; methods ; Female ; Humans ; Male ; Middle Aged ; White Matter ; pathology ; Young Adult

Positron emission tomography (PET) has become basic support equipment in clinical and many other scientific research fields and has been a hot research field at present. Tomography reconstruction algorithm is a key component of PET, and most PETs use statistical iterative reconstruction algorithms from sinograms data currently. However, tomography reconstruction from list-mode data possesses many unique advantages, and it has caused great attention and is in the process of rapid development and improvementin recently. We eventually achieved list-mode tomography reconstruction in this paper, using experimental data of small animal PET scanner Eplus-166, exploiting S-LMEM algorithm and orthogonal distance-based ray-tracer. The results demonstrated that image resolution and contrast recovery achieved inherent properties of the scanner and on-the-fly ray-tracing methods is feasible for dynamic reconstruction.
Algorithms ; Humans ; Image Processing, Computer-Assisted ; Imaging, Three-Dimensional ; methods ; Models, Theoretical ; Positron-Emission Tomography ; methods

ObjectivesTo identify the related abnormalities of gray matter in pediatric patients with Tourette syndrome (TS) by using the optimized voxel-based morphometry (VBM).Methods Three dimensional T1WI was acquired in 31 TS children (28 boys,3 girts,mean age 8 years,range 4-15 years) and 50 age- and sex-matched controls on a 1.5 Tesla Philips scanner. Images were pre-processed and analyzed using a version of VBM 2 in SPM 2.The whole brain gray matter volume was compared between the study and control group by using t-test.Multivariate linear regression analysis was used for analyzing the correlation between the change of grey matter volume within each brain region (mm3 ) and YGTSS score and course of disease of TS patients.Statistical analyses were performed by using SPSS 13.0.ResultsUsing VBM,significant increases in gray matter volumes in left superior parietal lobule, right cerebellar hemisphere and left parahippocampal gyrus were detected in TS patients,and the volume changes were 4059,2126 and 84 mm3 ( t =3.93,3.71,3.58,P ＜ 0.05 ) respectively.Compared to the control group,decreased grey matter volumes were found in medulla and left pons,and the volume changes were 213 and 117 mm3( t =3.53,3.48,P ＜ 0.05 )respectively.Tic severity was not correlated with any volume changes of gray matter in brain (P ＞ 0.05,a small volume correction,KE ≥ 10 voxel).Tic course was negatively correlated with the gray matter volume of left parahippocampal gyrus ( Beta =- 0.391,P =0.039 ).ConclusionsUsing VBM technique,the gray matter abnormalities can be revealed in TS patients without obvious lesions on conventional MR imaging.The increasing volume of temporal and parietal lobes and cerebellar may be an adaptive anatomical change in response to experiential demand. The gray matter volume of the parahippocampal gyrus may be used as one potential objective index for evaluating the prognosis of TS.

OBJECTIVE: To determine the brain function and structure in patinets with first-episode panic disorder (PD). METHODS: All subjects (24 PD patients and 24 healthy subjects) received MRI scan and emotional counting Stroop task during the functional magnetic resonance imaging. Blood oxygenation level dependent functional magnetic resonance imaging and voxel-based morphometric technology were used to detect the gray matter volume. RESULTS: Compared with the healthy controls, left thalamus, left medial frontal gyrus, left anterior cingulate gyrus, left inferior frontal gyrus, left insula (panic-related words vs. neutral words) lacked activation in PD patients, but the over-activation were found in right brain stem, right occipital lobe/lingual gyrus in PD patients. Compared with the healthy controls, the gray matter volume in the PD patients significantly decreased in the left superior temporal gyrus, right medial frontal gyrus, left medial occipital gyrus, dorsomedial nucleus of left thalamus and right anterior cingulate gyrus. There was no significantly increased gray matter volume in any brain area in PD patients. CONCLUSION PD patients have selective attentional bias in processing threatening information due to the depression and weakening of the frontal cingulated gyrus.
Adolescent ; Adult ; Brain ; pathology ; physiopathology ; Case-Control Studies ; Female ; Frontal Lobe ; physiopathology ; Gyrus Cinguli ; physiopathology ; Humans ; Magnetic Resonance Imaging ; methods ; Male ; Panic Disorder ; pathology ; physiopathology ; Young Adult