Midbrain/pons area ratio and clinical features predict the prognosis of progressive Supranuclear palsy.

BACKGROUND: Progressive supranuclear palsy (PSP) is a rare movement disorder with poor prognosis. This retrospective study aimed to characterize the natural history of PSP and to find predictors of shorter survival and faster decline of activity of daily living. METHOD: All patients recruited fulfilled the movement disorder society (MDS) clinical diagnostic criteria for PSP (MDS-PSP criteria) for probable and possible PSP with median 12 years. Data were obtained including age, sex, date of onset, age at onset (AAO), symptoms reported at first visit and follow-up, date of death and date of institutionalization. Magnetic resonance imaging was collected at the first visit. Endpoints were death and institutionalization. Kaplan-Meier method and Cox proportional hazard model were used to explore factors associated with early death and institutionalization. RESULTS: Fifty-nine patients fulfilling MDS-PSP criteria were enrolled in our study. Nineteen patients (32.2%) had died and 31 patients (52.5%) were institutionalized by the end of the follow-up. Predictors associated with poorer survival were late-onset PSP and decreased M/P area ratio. Predictors associated with earlier institutionalization were older AAO and decreased M/P area ratio. CONCLUSION: Older AAO and decreased M/P area ratio were predictors for earlier dearth and institutionalization in PSP. The neuroimaging biomarker M/P area ratio was a predictor for prognosis in PSP.

White Matter Hyperintensities Predict Cognitive Decline: A Community-Based Study.

INTRODUCTION: White matter hyperintensities (WMHs) were commonly seen in brain magnetic resonance imaging (MRI) of the elderly. Many studies found that WMHs were associated with cognitive decline and dementia. However, the association between WMHs in different brain regions and cognitive decline remains debated. METHODS: We explored the association of the severity of WMHs and cognitive decline in 115 non-demented elderly (≥50 years old) sampled from the Wuliqiao Community located in urban area of Shanghai. MRI scans were done during 2009-2011 at the beginning of the study. Severity of WMHs in different brain regions was scored by Improved Scheltens Scale and Cholinergic Pathways Hyperintensities Scale (CHIPS). Cognitive function was evaluated by Mini-Mental State Examination (MMSE) every 2 to 4 years during 2009-2018. RESULTS: After adjusting for confounding factors including age, gender, education level, smoking status, alcohol consumption, depression, hypertension, diabetes, hyperlipidemia, brain infarcts, brain atrophy, apoE4 status, and baseline MMSE score, periventricular and subcortical WMH lesions as well as WMHs in cholinergic pathways were significantly associated with annual MMSE decline ( p < 0.05), in which the severity of periventricular WMHs predicted a faster MMSE decline (-0.187 points/year, 95% confidence interval: -0.349, -0.026, p = 0.024). CONCLUSIONS: The severity of WMHs at baseline was associated with cognitive decline in the non-demented elderly over time. Interventions on WMH lesions may offer some benefits for cognitive deterioration.

Des hyper-signaux de la substance blanche prédicteurs du déclin cognitif : une étude menée dans une communauté locale.Introduction: Des hyper-signaux de la substance blanche (HSSB) peuvent généralement être observés lors d'examens d'imagerie par résonnance magnétique (IRM) effectués chez des personnes âgées. Plusieurs études ont également montré que les HSSB étaient associés au déclin cognitif et à la démence. Cela dit, le lien pouvant exister entre ces HSSB détectés dans diverses régions cérébrales et le déclin cognitif demeure sujet à débat. Méthodes: Nous avons décidé d'explorer l'association existant entre l'intensité des HSSB et le déclin cognitif chez 115 personnes âgées n'étant pas atteintes de démence (≥50 ans). Ces personnes avaient été recrutées au sein du quartier de Wuliqiao situé dans le grand Shanghai. Signalons que ces examens d'IRM ont été effectués au début de cette étude entre 2009 et 2011. L'intensité des HSSB dans diverses régions cérébrales a été mesurée au moyen des échelles suivantes : la Improved Scheltens Scale et la Cholinergic Pathways Hyperintensities Scale (CHIPS). En ce qui concerne la fonction cognitive, elle a été évaluée à l'aide du test de Folstein (ou mini-mental state examination) tous les 2 à 4 ans entre 2009 et 2018. Résultats: Une fois la prise en compte d'un certain nombre de facteurs de confusion (l'âge, le sexe, le niveau de scolarité, le tabagisme, la consommation d'alcool, la dépression, l'hypertension, le diabète, l'hyperlipidémie, des accidents ischémiques cérébraux, une atrophie du cerveau, la situation de l'allèle 4 du gène ApoE et le score initial au test de Folstein), il est apparu que des lésions révélées par des hyper-signaux des régions péri-ventriculaire et sous-corticale, de même que des hyper-signaux détectés dans les voies cholinergiques, étaient nettement associés à des résultats en baisse au test de Folstein en cours d'année (p < 0,05). Fait à noter, l'intensité des HSSB de la région péri-ventriculaire a aussi permis de prédire un déclin plus rapide des scores au test de Folstein (- 0,187 points/année, IC 95 % : - 0,349 - 0,026; p = 0,024). Conclusions: L'intensité des HSSB observée au début de cette étude a été associée au fil du temps au déclin cognitif de personnes âgées n'étant pas atteintes de démence. Il est donc possible que des interventions ciblant des lésions révélées par des HSSB puissent offrir certains bienfaits quand il est question de déclin cognitif.

Dentate nucleus iron deposition is a potential biomarker for tremor-dominant Parkinson's disease.

Parkinson's disease (PD) is a heterogeneous neurodegenerative disorder with variable clinicopathologic phenotypes and underlying neuropathologic mechanisms. Each clinical phenotype has a unique set of motor symptoms. Tremor is the most frequent initial motor symptom of PD and is the most difficult symptom to treat. The dentate nucleus (DN) is a deep iron-rich nucleus in the cerebellum and may be involved in PD tremor. In this study, we test the hypothesis that DN iron may be elevated in tremor-dominant PD patients using quantitative susceptibility mapping. Forty-three patients with PD [19 tremor dominant (TD)/24 akinetic rigidity (AR) dominant] and 48 healthy gender- and age-matched controls were recruited. Multi-echo gradient echo data were collected for each subject on a 3.0-T MR system. Inter-group susceptibility differences in the bilateral DN were investigated and correlations of clinical features with susceptibility were also examined. In contrast with the AR-dominant group, the TD group was found to have increased susceptibility in the bilateral DN when compared with healthy controls. In addition, susceptibility was positively correlated with tremor score in drug-naive PD patients. These findings indicate that iron load within the DN may make an important contribution to motor phenotypes in PD. Moreover, our results suggest that TD and AR-dominant phenotypes of PD can be differentiated on the basis of the susceptibility of the DN, at least at the group level. Copyright © 2016 John Wiley & Sons, Ltd.

Improved Neuroimaging Atlas of the Dentate Nucleus.

The dentate nucleus (DN) of the cerebellum is the major output nucleus of the cerebellum and is rich in iron. Quantitative susceptibility mapping (QSM) provides better iron-sensitive MRI contrast to delineate the boundary of the DN than either T2-weighted images or susceptibility-weighted images. Prior DN atlases used T2-weighted or susceptibility-weighted images to create DN atlases. Here, we employ QSM images to develop an improved dentate nucleus atlas for use in imaging studies. The DN was segmented in QSM images from 38 healthy volunteers. The resulting DN masks were transformed to a common space and averaged to generate the DN atlas. The center of mass of the left and right sides of the QSM-based DN atlas in the Montreal Neurological Institute space was -13.8, -55.8, and -36.4 mm, and 13.8, -55.7, and -36.4 mm, respectively. The maximal probability and mean probability of the DN atlas with the individually segmented DNs in this cohort were 100 and 39.3%, respectively, in contrast to the maximum probability of approximately 75% and the mean probability of 23.4 to 33.7% with earlier DN atlases. Using QSM, which provides superior iron-sensitive MRI contrast for delineating iron-rich structures, an improved atlas for the dentate nucleus has been generated. The atlas can be applied to investigate the role of the DN in both normal cortico-cerebellar physiology and the variety of disease states in which it is implicated.

Association of Brachial-Ankle Pulse Wave Velocity with Asymptomatic Intracranial Arterial Stenosis in Hypertension Patients.

BACKGROUND: Intracranial arterial stenosis is a common cause of ischemic stroke in Asians. We therefore sought to explore the relationship of brachial-ankle pulse wave velocity and intracranial arterial stenosis in 834 stroke-free hypertensive patients. METHODS: Intracranial arterial stenosis was evaluated through computerized tomographic angiography. Brachial-ankle pulse wave velocity was measured by an automated cuff device. RESULTS: The top decile of brachial-ankle pulse wave velocity was significantly associated with intracranial arterial stenosis (P = .027, odds ratio = 1.82; 95% confidence interval: 1.07-3.10). The patients with the top decile of brachial-ankle pulse wave velocity showed 56% higher risk for the presence of intracranial arterial stenosis to the whole population, which was more significant in patients younger than 65 years old. We also found that brachial-ankle pulse wave velocity related to both intracranial arterial stenosis and homocysteine. CONCLUSION: Our study showed the association of brachial-ankle pulse wave velocity with asymptomatic intracranial arterial stenosis in hypertension patients, especially in relative younger subjects. Brachial-ankle pulse wave velocity might be a relatively simple and repeatable measurement to detect hypertension patients in high risk of intracranial arterial stenosis.

Region-specific disturbed iron distribution in early idiopathic Parkinson's disease measured by quantitative susceptibility mapping.

In Parkinson's disease (PD), iron elevation in specific brain regions as well as selective loss of dopaminergic neurons is a major pathologic feature. A reliable quantitative measure of iron deposition is a potential biomarker for PD and may contribute to the investigation of iron-mediated PD. The primary purpose of this study is to assess iron variations in multiple deep grey matter nuclei in early PD with a novel MRI technique, quantitative susceptibility mapping (QSM). The inter-group differences of susceptibility and R2* value in deep grey matter nuclei, namely head of caudate nucleus (CN), putamen (PUT), global pallidus (GP), substantia nigra (SN), and red nucleus (RN), and the correlations between regional iron deposition and the clinical features were explored in forty-four early PD patients and 35 gender and age-matched healthy controls. Susceptibility values were found to be elevated within bilateral SN and RN contralateral to the most affected limb in early PD compared with healthy controls (HCs). The finding of increased susceptibility in bilateral SN is consistent with work on a subgroup of patients at the earliest clinical detectable state (Hoehn and Yahr [1967]: Neurology 17:427-442; Stage I). However, increased R2* values were only seen within SN contralateral to the most affected limb in the PD group when compared with controls. Furthermore, bilateral SN magnetic susceptibility positively correlated with disease duration and UPDRS-III scores in early PD. This finding supports the potential value of QSM as a non-invasive quantitative biomarker of early PD.

Prognostic value of mild asymptomatic intracranial atherosclerosis stenosis in patients with hypertension.

BACKGROUND AND AIMS: Mild asymptomatic intracranial atherosclerotic stenosis (aICAS) is common in Chinese patients with hypertension. However, there are no data on its prognostic value in this population. The aim of the present study was to clarify the prevalence and associated cardiovascular risk factors of mild aICAS and determine its prognostic value for overall and cardiovascular mortality in patients with hypertension. METHODS: In total, 1813 participants were evaluated for aICAS using computed tomographic angiography. The predictive effect of mild to severe aICAS on all-cause and cardiovascular mortality was evaluated using Kaplan-Meier survival curves and Cox regression analyses. RESULTS: The prevalence rate of mild aICAS was 35.7%. Poorly controlled hypertension, in combination with diabetes and dyslipidemia, was associated with aICAS. Patients with aICAS had an independently significant increase in the risk of all-cause and cardiovascular death, with adjusted hazard ratios (HRs) for mild to severe stenosis ranging from 1.52 to 3.03 for all-cause death and from 2.48 to 6.38 for cardiovascular death. Among the patients with mild aICAS, only those with more than two stenoses had increased mortality after adjustment, with an HR of 2.35 (95% CI: 1.36-4.04) for total death and 4.41 (95% CI: 1.78-10.93) for cardiovascular death. CONCLUSIONS: A significant association between mild aICAS and mortality in stroke-free patients with hypertension was revealed. The results indicate that mild aICAS might be an imaging marker for cerebrovascular lesions in patients with hypertension and poor control of blood pressure and lipids in this population requires further research.

Fibroblast growth factor 23 is a predictor of aortic artery calcification in maintenance hemodialysis patients.

BACKGROUND: Our study aimed to investigate the factors associated with elevated plasma FGF23 (cFGF23) levels in maintenance hemodialysis (MHD) patients and to determine whether plasma FGF23 level is related to aortic artery calcification (AAC). METHODS: This study included 120 MHD patients and 20 controls. The FGF23 level was measured using a C-terminal assay and AAC was detected by a lateral lumbar X-ray plain. RESULTS: Plasma FGF23 levels were significantly higher among dialysis patients compared to controls: FGF23 level of 27691.42 ± 55646.41 RU/mL in MHD patients versus 49.89 ± 23.94 RU/mL in health people. Significant correlations were observed between FGF23 levels and vintage, intact parathyroid hormone (iPTH), serum phosphate, total calcium, 25(OH)D, urea nitrogen (BUN), and serum creatinine (SCR). Stepwise multiple regression analysis showed that the independent parameters associated with FGF23 level were serum phosphate, total calcium, parathyroid hormone (PTH), SCR, and prealbumin. There were 73 patients (60.83%) with visible calcification in the abdominal aorta. Bivariate analysis showed that AAC score correlated with FGF23, phosphate, total calcium, vintage, age, and diastolic blood pressure. Forward logistic analysis showed that the independent parameters associated with AAC were age, total protein, and Lg FGF23. CONCLUSION: Plasma FGF23 level is significant increased in hemodialysis patients and is independently associated with AAC.

Using proton magnetic resonance spectroscopy to identify mild cognitive impairment.

BACKGROUND: Single-volume proton magnetic resonance spectroscopy (1H MRS) has considerable diagnostic potential for Alzheimer's disease (AD). This study investigated 1H MRS in specific regions of the brain, the posterior cingulate gyri (PCG) and the hippocampus, in patients with AD, amnestic mild cognitive impairment (aMCI), and in normal control subjects. METHODS: 1H MRS analysis was carried out on 47 patients with AD, 32 patients with aMCI and 56 normal control subjects (NC group). Volumes of the PCG and hippocampus were assessed, and the metabolic signals of N-acetylaspartate (NAA), choline compounds (Cho), myo-inositol (mI), and creatine (Cr) were quantified. RESULTS: In the PCG, differences between the test groups were found in NAA/Cr, Cho/Cr, mI/Cr and NAA/mI ratios. Group differences were also found in mI/Cr and NAA/mI ratios in the left hippocampus, and in mI/Cr and NAA/mI ratios in the right hippocampus. NAA/Cr ratios increased in the PCG between AD and aMCI patients, and between aMCI and NC patients. Conversely, mI/Cr ratios in the PCG and left hippocampus decreased across AD, aMCI, and NC subjects. In discriminate and ROC (Receiver Operating Characteristic) analyses, a NAA/Cr ratio of ≤ 1.50 in the PCG indicated optimal potential for discriminating between aMCI patients and normal control subjects. Discriminating potential was also found to be high for a NAA/mI ratio in the PCG of ≤ 2.72. Despite significant differences between NC and aMCI patients in the mI/Cr ratio in the PCG and in the NAA/mI ratio in the left hippocampus, their sensitivity and specificity were all lower than 75%. CONCLUSION: Proton MRS of the PCG using the NAA/Cr ratio as a metabolic marker indicates considerable potential for distinguishing between aMCI and NC subjects.

Could iron accumulation be an etiology of the white matter change in Alzheimer's disease: using phase imaging to detect white matter iron deposition based on diffusion tensor imaging.

BACKGROUND/AIMS: To investigate if and where abnormal iron accumulation in white matter fibers occurs in patients with Alzheimer's disease (AD) by phase imaging and to relate these findings to white matter tract degeneration assessed by diffusion tensor imaging. METHODS: Twenty-five patients with AD and 20 normal controls underwent phase imaging and diffusion tensor imaging with a 3.0-tesla system. White matter fibers including fornix (Fx), genu of corpus callosum (GCC), splenium of corpus callosum (SCC), bilateral posterior cingulum (PC), superior longitudinal fasciculus (SLF), inferior longitudinal fasciculus (ILF) and frontal occipital fasciculus (IOF) were measured on a fractional anisotropy (FA) map, mean diffusivity (MD) map and phase map. RESULTS: Significantly decreased phase values and FA values in the Fx and PC regions were found in the AD group. The phase value in Fx had a moderately positive correlation with the FA value (r = 0.666, p = 0.000) in the AD group. Meanwhile, phase values in PC showed positive correlation with FA values (right side: r = 0.436, p = 0.033; left side: r = 0.458, p = 0.022, respectively). CONCLUSION: Iron accumulation of Fx and PC regions was significantly positively correlated with FA value, indicating that abnormal iron deposition may be one of the causes of white matter disruption in AD.

Diffusion-weighted MR imaging of kidneys in patients with chronic kidney disease: initial study.

OBJECTIVE: To prospectively evaluate the feasibility of diffusion-weighted (DW) magnetic resonance (MR) imaging in the assessment of renal function in patients with chronic kidney disease (CKD). METHODS: Seventy-two healthy volunteers and 43 patients underwent coronal echo-planar DW MR imaging of the kidneys with a single breath-hold time of 16 s. The patients were grouped according to five stages as indicated by the K/DOQI CKD (kidney disease outcome quality initiative). The apparent diffusion coefficient (ADC) value of the kidneys was calculated with high b values (b = 500 s/mm(2)). The ADC values were compared between patients and healthy volunteers, and among different stages. For statistical analysis, Student's t tests, ANOVA, Pearson's correlation tests, and Spearman's correlation tests were used. RESULTS: No difference between the cortex and medulla could be observed on DW images of all volunteers. Patients with CKD had significantly lower renal ADC (t = -4.383, P = 0.000) than volunteers. The ADC values of kidneys were significantly lower than normal at most stages of CKD, except CKD1. There was a negative correlation between the ADCs and serum creatinine (sCr) level (P = 0.000) amongst the patients. CONCLUSION: Diffusion-weighted MR imaging is feasible in the assessment of renal function, especially in the detection of early stage renal failure of CKD.

Determining gastric cancer resectability by dynamic MDCT.

PURPOSE: Multi-detector row CT (MDCT) has been widely used to detect primary lesions and to evaluate TNM staging. In this study we evaluated the accuracy of dynamic MDCT in the preoperative determination of the resectability of gastric cancer. METHODS: MDCT was used to image 350 cases of gastric cancer diagnosed by biopsy before surgery. MDCT findings regarding TNM staging and resectability were correlated with surgical and pathological findings. RESULTS: The accuracy of MDCT for staging gastric cancer was high, especially for tumour stage T1 (94.3%), lymph node stage N2 (87.3%), and for predicting distant metastases (>96.6%). When resectability was considered to be the outcome, the total accuracy of MDCT was 87.4%, sensitivity was 89.7% and specificity was 76.7%. Results showed high sensitivity for identifying peritoneal seeding (90.0%) and for predicting liver metastasis (80.0%). CONCLUSION: Dynamic enhanced MDCT is useful for TNM staging of gastric cancers and for predicting tumour respectability preoperatively.

Fluid-Attenuated Inversion Recovery Vascular Hyperintensities in Transient Ischemic Attack within the Anterior Circulation.

PURPOSE: The aim of the present study was to evaluate the relationship of fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVH) with haemodynamic abnormality and severity of arterial stenosis in patients with transient ischemic attack (TIA) of the carotid artery system. Patients and Methods. Consecutive inpatients (N = 38) diagnosed with TIAs of the carotid system in a 4-year period (2014-2017) were retrospectively analysed in our study and divided into FVH-negative and FVH-positive groups based on the presence of FVH sign. Each inpatient had undergone magnetic resonance imaging (MRI) followed by computed tomography (CT) perfusion imaging studies. We investigated the degree of arterial stenosis, number of stenosis, watershed regions, and related CT perfusion indexes, including hypoperfusion regions, mean transit time (MTT), cerebral blood flow (CBF), and cerebral blood volume (CBV). Spearman rank correlation was performed between FVHs score, the degree of arterial stenosis, and CT perfusion indexes with significant difference. RESULTS: Thirty-one patients (81.6%) observed with FVH sign were assigned to the FVH-positive group. The hypoperfusion regions, MTT, and CBF values were significantly different between the FVH-negative group and FVH-positive groups. Spearman correlation analysis showed significant positive correlations between hypoperfusion regions, MTT, and FVHs scores (r = 0.755 and 0.674, respectively, p < 0.01); a moderate negative correlation was found between CBF and FVHs scores (r = 0.755 and 0.674, respectively, p < 0.01); a moderate negative correlation was found between CBF and FVHs scores (r = 0.755 and 0.674, respectively, p < 0.01); a moderate negative correlation was found between CBF and FVHs scores (. CONCLUSION: Hyperintense vessels on FLAIR were closely associated with hypoperfused regions, MTT, and CBF values, which indicated that the presence of FVHs could be an important and convenient imaging marker of haemodynamic impairment in patients with TIA.

Increased iron-deposition in lateral-ventral substantia nigra pars compacta: A promising neuroimaging marker for Parkinson's disease.

BACKGROUND: To date there are no validated MRI biomarkers to assist diagnosis of Parkinson's disease (PD). Our aim was to investigate PD related iron changes in the substantia nigra pars compacta (SNpc) as defined by neuromelanin-sensitive MR contrast. METHODS: Thirty-nine PD participants and 33 healthy controls were scanned at 3.0-T using a 16-echo gradient echo sequence to create R2* maps for the evaluation of iron content to find the overlap with a neuromelanin based SNpc mask. The SNpc overlap percentage with the R2* map, and the R2* values in both the whole SNpc and the overlap volume were compared between PD and control groups, and correlated with clinical features for PD participants. Finally, the diagnostic performance of the SNpc overlap percentage was evaluated using ROC analysis. RESULTS: PD related iron changes mostly occur in the lateral-ventral part of the neuromelanin SNpc. The R2* values in the whole SNpc and the SNpc overlap volume, and the SNpc overlap percentage were larger in PD participants than in controls. Furthermore, the SNpc overlap percentage was positively correlated with the disease duration in PD. The SNpc overlap percentage provided excellent diagnostic accuracy for discriminating PD participants from controls (AUC = 0.93), while the R2* values in the whole SNpc or the overlap volume were less effective. CONCLUSION: The overlap between the iron content as determined by R2* mapping and neuromelanin in the substantia nigra pars compacta has the potential to be a neuroimaging biomarker for diagnosing Parkinson's disease.

[Hydrogen proton MR spectroscopy of posterior portion cingulate gyrus of patients with Alzheimer's disease: a case control study].

OBJECTIVE: To investigate the characteristics of hydrogen proton magnetic resonance spectroscopy (H-MRS) in posterior portion cingulate gyrus and the correlations thereof with the results of mini-mental state examination (MMSE), Alzheimer disease assessment scale-cognitive (ADAS-cog) in patients with mild-moderate Alzheimer's disease (AD). METHODS: H-MRS in posterior portion cingulate gyrus was conducted in gender, age, and educational background-matched 24 patients with AD, 8 patients with vascular dementia (VD), and 11 normal controls (NC group) to measure the values of NAA (N-acetyl aspartate)myo-inositol (mI), and creatine and phosphocreatine (Cr). All the 4 subjects underwent MMSE and assessment with ADAS-cog as well. The correlations among these results were assessed. RESULTS: The NAA/Cr ratios in posterior portion cingulate gyrus of the AD and VD groups were (1.24 +/- 0.12) and (1.25 +/- 0.15) respectively, both significantly lower than that of the NC group [(1.46 +/- 0.19), P = 0.003, P = 0.017] without significant difference between the AD and VD groups (P = 0.800). The mI/Cr value of the AD group was (0.74 +/- 0.15), not significantly different from that of the VD group [(0.65 +/- 0.15), P = 0.153], and significantly higher than that of the NC group [(0.62 +/- 0.09), P = 0.007], however, the mI/Cr value of the VD group was not significantly different from that of the NC group (P = 0.662). If the NAA/Cr ratio < 1.31 was used as criteria of AD, the positive predictive value of AD was 73% and negative predictive value was 71%. The NAA/Cr ratio was positively correlated with the MMSE score (r = 0.731, P = 0.000), and negatively correlated with the ADAS-cog score (r = -0.541, P = 0.011). CONCLUSIONS: The NAA/Cr ratio decreases in the posterior portion cingulate gyrus of AD patients, and has statistical significant correlations with the score of MMSE and ADAS-cog. The H-MRS characteristics of posterior portion cingulate gyrus cannot effectively differentiate the early AD from early VD.

Abnormal Dynamic Functional Connectivity Associated With Subcortical Networks in Parkinson's Disease: A Temporal Variability Perspective.

Parkinson's disease (PD) is a neurodegenerative disease characterized by dysfunction in distributed functional brain networks. Previous studies have reported abnormal changes in static functional connectivity using resting-state functional magnetic resonance imaging (fMRI). However, the dynamic characteristics of brain networks in PD is still poorly understood. This study aimed to quantify the characteristics of dynamic functional connectivity in PD patients at nodal, intra- and inter-subnetwork levels. Resting-state fMRI data of a total of 42 PD patients and 40 normal controls (NCs) were investigated from the perspective of the temporal variability on the connectivity profiles across sliding windows. The results revealed that PD patients had greater nodal variability in precentral and postcentral area (in sensorimotor network, SMN), middle occipital gyrus (in visual network), putamen (in subcortical network) and cerebellum, compared with NCs. Furthermore, at the subnetwork level, PD patients had greater intra-network variability for the subcortical network, salience network and visual network, and distributed changes of inter-network variability across several subnetwork pairs. Specifically, the temporal variability within and between subcortical network and other cortical subnetworks involving SMN, visual, ventral and dorsal attention networks as well as cerebellum was positively associated with the severity of clinical symptoms in PD patients. Additionally, the increased inter-network variability of cerebellum-auditory pair was also correlated with clinical severity of symptoms in PD patients. These observations indicate that temporal variability can detect the distributed abnormalities of dynamic functional network of PD patients at nodal, intra- and inter-subnetwork scales, and may provide new insights into understanding PD.

Computerized cognitive training for Chinese mild cognitive impairment patients: A neuropsychological and fMRI study.

BACKGROUND: Computerized multi-model training has been widely studied for its effect on delaying cognitive decline. In this study, we designed the first Chinese-version computer-based multi-model cognitive training for mild cognitive impairment (MCI) patients. Neuropsychological effects and neural activity changes assessed by functional MRI were both evaluated. METHOD: MCI patients in the training group were asked to take training 3-4 times per week for 6 months. Neuropsychological and resting-state fMRI assessment were performed at baseline and at 6 months. Patients in both groups were continuously followed up for another 12 months and assessed by neuropsychological tests again. RESULTS: 78 patients in the training group and 63 patients in the control group accomplished 6-month follow-up. Training group improved 0.23 standard deviation (SD) of mini-mental state examination, while control group had 0.5 SD decline. Addenbrooke's cognitive examination-revised scores in attention (p = 0.002) and memory (p = 0.006), as well as stroop color-word test interference index (p = 0.038) and complex figure test-copy score (p = 0.035) were also in favor of the training effect. Difference between the changes of two groups after training was not statistically significant. The fMRI showed increased regional activity at bilateral temporal poles, insular cortices and hippocampus. However, difference between the changes of two groups after another 12 months was not statistically significant. CONCLUSIONS: Multi-model cognitive training help MCI patients to gained cognition benefit, especially in memory, attention and executive function. Functional neuroimaging provided consistent neural activation evidence. Nevertheless, after one-year follow up after last training, training effects were not significant. The study provided new evidence of beneficial effect of multi-model cognitive training.

Diffusion tensor imaging correlates with proton magnetic resonance spectroscopy in posterior cingulate region of patients with Alzheimer's disease.

BACKGROUND/AIMS: To compare proton magnetic resonance spectroscopy ((1)H-MRS) and diffusion tensor imaging (DTI) findings in the posterior cingulate regions in patients with Alzheimer's disease (AD). METHODS: 17 patients with mild AD, 20 with moderate to severe AD and 20 cognitively normal aging subjects (CN) underwent single-voxel MRS and DTI examinations. A region of interest was positioned in the posterior cingulate regions. Ratios of N-acetylaspartate (NAA), myo-inositol (mI), and choline to creatine (Cr) were measured. Mean spectroscopy data and DTI values (fractional anisotropy, FA, and mean diffusivity, MD) were analyzed with nonparametric testing. RESULTS: The group with mild AD showed a significantly lower FA value in the left posterior cingulum compared to CN. The group with moderate to severe AD revealed significantly decreased FA values and increased MD values in both the left and right cingulum compared to the group with mild AD. Partial correlation analysis revealed a positive correlation between mI/Cr and left-side FA values in the group with mild AD and a negative correlation between NAA/Cr and right-side MD values in the group with moderate to severe AD. CONCLUSION: There are different regional and temporal patterns in AD, resulting from gliosis or axonal loss. Combining MRS with DTI could provide valuable information to better understand the AD process.

Advanced gastric cancer and perfusion imaging using a multidetector row computed tomography: correlation with prognostic determinants.

OBJECTIVE: To investigate the relationship between the perfusion CT features and the clinicopathologically determined prognostic factors in advanced gastric cancer cases. MATERIALS AND METHODS: A perfusion CT was performed on 31 patients with gastric cancer one week before surgery using a 16-channel multi-detector CT (MDCT) instrument. The data were analyzed with commercially available software to calculate tumor blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability surface (PS). The microvessel density (MVD), was evaluated by immunohistochemical staining of the surgical specimens with anti-CD34. All of the findings were analyzed prospectively and correlated with the clinicopathological findings, which included histological grading, presence of lymph node metastasis, serosal involvement, distant metastasis, tumor, node, metastasis (TNM) staging, and MVD. The statistical analyses used included the Student's t-test and the Spearman rank correlation were performed in SPSS 11.5. RESULTS: The mean perfusion values and MVD for tumors were as follows: BF (48.14+/-16.46 ml/100 g/min), BV (6.70+/-2.95 ml/100 g), MTT (11.75+/-4.02 s), PS (14.17+/-5.23 ml/100 g/min) and MVD (41.7+/-11.53). Moreover, a significant difference in the PS values was found between patients with or without lymphatic involvement (p = 0.038), as well as with different histological grades (p = 0.04) and TNM stagings (p = 0.026). However, BF, BV, MTT, and MVD of gastric cancer revealed no significant relationship with the clinicopathological findings described above (p > 0.05). CONCLUSION: The perfusion CT values of the permeable surface could serve as a useful prognostic indicator in patients with advanced gastric cancer.

Preliminary application of whole body diffusion weighted imaging in screening metastasis.

OBJECTIVE: To investigate the feasibility of whole body diffusion weighted imaging (WB-DWI) in screening metastasis. METHODS: WB-DWI was performed in 24 patients diagnosed with various types of primary tumors. The three-dimensional maximum intensity projection reconstruction and black-and-white flip technique were used to observe metastatic lesions, and the results were compared with those of bone scintigraphy. RESULTS: By WB-DWI scanning sequence at b = 800 s/mm2, all the bone lesions found by bone scintigraphy in the cohort were well identified, and other lesions of soft tissue and organs were also well demonstrated. Its screening capability was equivalent with bone scintigraphy in screening metastases in bones (P = 0.062). CONCLUSION: WB-DWI was practicable with the parameter settings attempted in metastases screening.