Quantifying cerebral blood flow changes using arterial spin labeling: A comparative study of idiopathic rapid eye movement sleep behavior disorder and Parkinson's disease.

INTRODUCTION: Idiopathic rapid eye movement sleep behavior disorder (iRBD) and Parkinson's disease (PD) have been found to have changes in cerebral perfusion and overlap of some of the lesioned brain areas. However, a consensus regarding the specific location and diagnostic significance of these cerebral blood perfusion alternations remains elusive in both iRBD and PD. The present study evaluated the patterns of cerebral blood flow changes in iRBD and PD. MATERIAL AND METHODS: A total of 59 right-handed subjects were enrolled, including 15 patients with iRBD, 20 patients with PD, and 24 healthy controls (HC). They were randomly divided into groups at a ratio of 4 to 1 for training and testing. A PASL sequence was employed to obtain quantitative cerebral blood flow (CBF) maps. The CBF values were calculated from these acquired maps. In addition, AutoGluon was employed to construct a classifier for CBF features selection and classification. An independent t-test was performed for CBF variations, with age and sex as nuisance variables. The performance of the feature was evaluated using receiver operating characteristic (ROC) curves. A significance level of P < 0.05 was considered significant. CBF in several brain regions, including the left median cingulate and paracingulate gyri and the right middle occipital gyrus (MOG), showed significant differences between PD and HC, demonstrating good classification performance. The combined model that integrates all features achieved even higher performance with an AUC of 0.9380. Additionally, CBF values in multiple brain regions, including the right MOG and the left angular gyrus, displayed significant differences between PD and iRBD. Particularly, CBF values in the left angular gyrus exhibited good performance in classifying PD and iRBD. The combined model achieved improved performance, with an AUC of 0.8533. No significant differences were found in brain regions when comparing CBF values between iRBD and HC subjects. CONCLUSIONS: ASL-based quantitative CBF change features can offer reliable biomarkers to assist in the diagnosis of PD. Regarding the characteristic of CBF in the right MOG, it is anticipated to serve as an imaging biomarker for predicting the progression of iRBD to PD.

Lower fractional dimension in Alzheimer's disease correlates with reduced locus coeruleus signal intensity.

This study aimed to determine the pattern of fractional dimension (FD) in Alzheimer's disease (AD) patients, and investigate the relationship between FD and the locus coeruleus (LC) signal intensity.A total of 27 patients with AD and 25 healthy controls (HC) were collected to estimate the pattern of fractional dimension (FD) and cortical thickness (CT) using the Computational Anatomy Toolbox (CAT12), and statistically analyze between groups on a vertex level using statistical parametric mapping 12. In addition, they were examined by neuromelanin sensitive MRI(NM-MRI) technique to calculate the locus coeruleus signal contrast ratios (LC-CRs). Additionally, correlations between the pattern of FD and LC-CRs were further examined.Compared to HC, AD patients showed widespread lower CT and FD Furthermore, significant positive correlation was found between local fractional dimension (LFD) of the left rostral middle frontal cortex and LC-CRs. Results suggest lower cortical LFD is associated with LCCRs that may reflect a reduction due to broader neurodegenerative processes. This finding may highlight the potential utility for advanced measures of cortical complexity in assessing brain health and early identification of neurodegenerative processes.

Decreased locus coeruleus signal associated with Alzheimer's disease based on neuromelanin-sensitive magnetic resonance imaging technique.

Objective: Neuromelanin-sensitive magnetic resonance imaging (NM-MRI) technique was used to detect the changes of the locus coeruleus (LC) signals in Alzheimer's disease patients (AD), and to analyze its correlation with cognitive function. Materials and methods: A total of 27 patients with AD, 15 patients with mild cognitive impairment (MCI), and 25 healthy controls (HC) were examined by NM-MRI technique. ImageJ software was used to measure the LC signals. The locus coeruleus signal contrast ratios (LC-CRs) were calculated, along with the measurement of neuropsychological scales. Results: The LC-CRs of AD patients were significantly different from that of HC (p = 0.007, 95% CI: -0.053∼-0.007). However, such significant differences were not observed between MCI and HC (p = 1.000, 95% CI: -0.030∼0.024), AD and MCI (p = 0.050, 95% CI: -0.054∼0.000). Furthermore, a significant positive correlation was identified between LC-CRs and MMSE sub item Drawing (r = 0.484, p = 0.011) in the AD group, MoCA sub item Attention (r = 0.519, p = 0.047) in the MCI group. The area under the curve of LC-CRs in the diagnosis of AD was 0.749 (p = 0.002, 95% CI: 0.618∼0.880), with a sensitivity of 85.2% and a specificity of 56.0%. Conclusion: The NM-MRI technique could quantify the pathological degenerations of the LC in AD. Such LC degenerations can be employed to distinguish AD from healthy elderly.

Surface hydroxyl groups functionalized graphite carbon nitride for high efficient removal of diquat dibromide from water.

In the study, we present a quick potassium hydroxide heat treatment approach to optimize the "melon" framework of graphite carbon nitride and modify the surface properties by functionalization of hydroxyl groups. The hydroxyl groups functionalized g-CN samples have been applied as bifunctional materials for efficient elimination of diquat dibromide herbicide through synergistic adsorption/photodegradation processes. The structural characterizations of the as-obtained samples, combined with the detailed diquat dibromide herbicide adsorption study, reveal that the surface hydroxyl groups are the active sites for the diquat dibromide adsorption, which account for the much enhanced saturation adsorption capacities of 159.3 mg g-1 at 25 °C and pH = 7 (more than 110 times improvement compared with pristine carbon nitride). Furthermore, the grafted surface hydroxyl groups and optimized planar structures endow the functionalized samples with the advantageous properties of efficient photoinduced charge transfer and separation, low interface resistance, and high photoresponse. Consequently, the deep mineralization of diquat dibromide herbicide was achieved over the bifunctional materials (total removal ratios were ~ 97.1% after 240 min visible-light irradiation). This work not only demonstrates the feasibility of hydroxyl groups functionalized graphite carbon nitride for elimination of herbicide pollutants but also offers new insights to better design efficient and durable materials for environmental remediation.