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Background: The anterior cingulate cortex (ACC) seems to play an important role in behavioral deficits and executive dysfunctions in patients with behavioral variant frontotemporal dementia (bvFTD), while its specific and independent contribution requires clarification. Objective: To identify whether ACC abnormalities in gray matter (GM) volume and standardized uptake value ratio (SUVR) images are associated with disease severity of bvFTD, by analyzing hybrid T1 and 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET). Methods: We enrolled 21 bvFTD patients and 21 healthy controls in the study. Each subject underwent a hybrid PET/MRI study and a standardized neuropsychologic assessment battery. GM volume and SUVR are voxel-wise calculated and compared. Then we estimate the mean value inside ACC for further partial Pearson’s correlation to explore the association between GM volume/SUVR of the ACC and severity of behavioral deficit as well as executive dysfunction. Results: ACC was shown to be involved in both atrophy and hypometabolism patterns. The partial Pearson’s correlation analysis showed that the SUVR of the ACC was strongly correlated with frontal behavior inventory total score (left r = –0.85, right r = –0.85, p

Study Objectives Although sympathetic hyperactivity with preserved parasympathetic activity has been extensively recognized in fatal familial insomnia (FFI), the symptoms of parasympathetic nervous system failure observed in some patients are difficult to explain. Using heart rate variability (HRV), this study aimed to discover evidence of parasympathetic dysfunction in patients with FFI and the difference of parasympathetic activity between patients with FFI and Creutzfeldt–Jakob disease (CJD). Methods This study enrolled nine patients with FFI, eight patients with CJD and 18 healthy controls (HCs) from May 2013 to August 2020. All participants underwent a nocturnal video-polysomnography with lead II electrocardiography, and the data were analyzed using linear and nonlinear indices of HRV during both wake and sleep states. Results Compared to the HC and CJD groups, the FFI group had a continuously higher heart rate with a lower amplitude of oscillations. The low frequency (LF)/high frequency (HF) ratio and ratio of SD1 to SD2 and correlation dimension D2 (CD2) were significantly different in the FFI group compared to the HC group. The root mean square of successive differences (RMSSD), HF and SD1 in the FFI group were significantly lower than in the HC group. RMSSD, SD1, and CD2 in the FFI group were all significantly lower than in the CJD group. Conclusions Cardiovascular dysautonomia in FFI may be partly attributable to parasympathetic abnormalities, not just sympathetic activation. HRV may be helpful as a noninvasive, quantitative, and effective autonomic function test for FFI diagnosis.

Glucose metabolism reduction and brain volume losses are widely reported in Alzheimer’s disease (AD). Considering that neuroimaging changes in the hippocampus and default mode network (DMN) are promising important candidate biomarkers and have been included in the research criteria for the diagnosis of AD, it is hypothesized that atrophy and metabolic changes of the abovementioned regions could be evaluated concurrently to fully explore the neural mechanisms underlying cognitive impairment in AD. Twenty-three AD patients and Twenty-four age-, sex- and education level-matched normal controls underwent a clinical interview, a detailed neuropsychological assessment and a simultaneous 18F-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET)/high-resolution T1-weighted magnetic resonance imaging (MRI) scan on a hybrid GE SIGNA PET/MR scanner. Brain volume and glucose metabolism were examined in patients and controls to reveal group differences. Multiple linear regression models were employed to explore the relationship between multiple imaging features and cognitive performance in AD. The AD group had significantly reduced volume in the hippocampus and DMN regions (P < 0.001) relative to that of normal controls determined by using ROI analysis. Compared to normal controls, significantly decreased metabolism in the DMN (P < 0.001) was also found in AD patients, which still survived after controlling for gray matter atrophy (P < 0.001). These findings from ROI analysis were further confirmed by whole-brain confirmatory analysis (P < 0.001, FWE-corrected). Finally, multiple linear regression results showed that impairment of multiple cognitive tasks was significantly correlated with the combination of DMN hypometabolism and atrophy in the hippocampus and DMN regions. This study demonstrated that combining functional and structural features can better explain the cognitive decline of AD patients than unimodal FDG or brain volume changes alone. These findings may have important implications for understanding the neural mechanisms of cognitive decline in AD.

Posterior cortical atrophy (PCA) is widely considered as an atypical variant of Alzheimer disease and is characterized by a progressive decline in visual function. PCA has been investigated from the standpoints of brain structure and metabolism, but tau deposition and its relationship to disease severity still remain unclear. Here, we used a novel tau ligand, [18F]PI2620, to visualize tau deposition in a PCA patient. The results showed that high [18F]PI2620 uptake in posterior cortical regions was associated with clinical manifestations, morphologic changes in the brain observed by magnetic resonance imaging (MRI), and hypometabolism detected by [18F] fluorodeoxyglucose (FDG) positron emission tomography (PET). This is the first report demonstrating a clinical anatomical correspondence between [18F]PI2620 PET results, clinical manifestations, MRI, and [18F]FDG PET findings in a Chinese patient with PCA. The results also support the utility of [18F]PI2620 for visualizing tau aggregation in PCA.

Background : To explore the patterns of white matter (WM) alterations using diffusion tensor imaging (DTI) in the preclinical stage of familial Creutzfeldt-Jakob disease (fCJD) . Methods: 7 asymptomatic carriers of PRNP G114V mutation and 6 non-carriers from the same fCJD kindred were recruited at baseline. Follow-up was obtained in 7 asymptomatic carriers and 2 non-carriers 2 years later. We also included 10 symptomatic CJD patients and 10 age-and gender-matched healthy controls out of the kindred to observe the overlapping patterns of WM between asymptomatic carriers and symptomatic CJD patients. All subjects received clinical, neuropsychological assessments, electroencephalogram (EEG) tests, and DTI at baseline and follow-up. Tract-based spatial statistics (TBSS) was used in DTI study for whole-brain voxel wise analysis of fractional anisotropy (FA) and mean diffusivity (MD) in WM. Results were compared in three groups: baseline carriers against non-carriers (baseline analysis), changes after 2 years in carriers (follow-up analysis), and differences between symptomatic CJD patients and healthy controls (CJD patients analysis). Results: Neither the carriers nor the non-carriers develop any neurological symptoms during 2 years follow-up. Baseline analysis showed no group differences between carriers and non-carriers in MD and FA. Follow-up analysis showed significant increased MD in left inferior fronto-occipital fasciculus, left uncinate fasciculus, bilateral superior longitudinal fasciculus, and bilateral corticospinal tract (p Conclusion: Integrity involvement within multiple WM tracts could be detected in preclinical stage of fCJD.

Backgroud Posterior cortical atrophy (PCA) is a rare neurodegenerative disease characterized by impairments in visual processing and in other relatively selective posterior cortical functions, mainly involving occipito-parietal regions. As the most common and important clinical manifestation, simultanagnosia is a profound inability of a patient with PCA to integrate multiple visual elements and to precept the global precedence within a scene. With few reports, the structural and functional changes in the brain associated with simultanagnosia are still yet comprehended more fully.Methods This study recruited 18 PCA patients with simultanagnosia, 29 patients with Alzheimer’s disease (AD) and 20 cognitively normal controls (NC). All subjects underwent a full neuropsychological evaluation, picture-/computer-based simultanagnosia tests, structural and resting-state functional MRI. Grey matter volume (GMV) was assessed by voxel-based morphometry, while seed based intrinsic functional connectivity (iFC) was evaluated based on the PCA-specific grey matter injuries in contrast to AD. Finally, the correlations between the statistically significant structural or functional MRI features and the simultanagnosia were evaluated in PCA patients.Results We found that, between PCA and AD patients, there was no significant difference in clinical dementia rating, immediate memory and delayed memory, while the marked difference was exhibited in neuropsychological assessments, and also in the picture-based and computer-based test score (P