Keywords: Dementia, Dementia

Motivation: Arterial stiffening and pulsatility serve as important markers of vascular dysfunction. Oblique-sagittal PC-MRI (OS PC-MRI) is a technique that provides a one-stop-shop approach for multiple vascular metrics.

Goal(s): This study aims to investigate the association of carotid vascular metrics measured by OS PC-MRI with cognitive impairment and cerebral perfusion in an elderly cohort. 

Approach: OS PC-MRI data were collected on 40 elderly participants, who also underwent cognitive tests. Cerebral perfusion was measured using 3D pCASL. Pulse wave velocity(cPWV), pulsatility index(PI), and damping factor(DF) were calculated.

Results: Our results showed increased cPWV and reduced cDF were associated with cognitive impairment and reduced cerebral perfusion. 

Impact: OS PC-MRI measures multiple vascular metrics including cPWV, PI, and cDF within two minutes, which shows strong associations with cognitive impairment and cerebral perfusion, consistent with previous findings. This study suggests OS PC-MRI could be promising to study vascular dysfunction.

Keywords: Other Neurodegeneration, Brain, Disorder of Arousal, Biomarkers, Brain Connectivity, fMRI (resting state), Functional connectivity, Metabolism, Neuroscience, Spectroscopy

Motivation: A comprehensive framework for the characterization of Disorders of Arousal (DoA) in adulthood is lacking, and the brain metabolic and functional mechanisms underlying this disorder are still unknown.

Goal(s): To fill this gap, we aimed to quantitatively investigate the cingulate cortex in DoA through advanced brain MRI, combined with thorough neuropsychological evaluations.

Approach: We collected and compared resting-state, ¹H-MRS and clinical data from adult patients diagnosed with DoA and a matched group of healthy controls.

Results: We identified metabolic and functional alterations in regions involving the limbic system and changes in the connectivity of the sensorimotor network crucial for understanding the pathology.

Impact: Through a combined MR imaging investigation and psychological assessments, we extracted results in the form of brain metabolic and functional quantitative markers that advance our knowledge on the brain alterations underlying Disorders of Arousal.

Keywords: Aging, Aging, White matter hyperintensity; Cerebral small-vessel disease

Motivation: As frequently observed in older populations, white matter hyperintensity (WMH) appears a risk factor for cognitive decline.

Goal(s): To construct normative WMH probabilistic atlases for quantifying its spatiotemporal progression and for disease detection.

Approach: We released the first set of such atlases and related trajectories, based on a large cohort of the Chinese typical aging population, with AI techniques.

Results: We validated its clinical usefulness by comparing cognitive impairment groups with the atlases, as a new tool for early Alzheimer’s disease evaluation. We also found that the WMH in deep, rather than periventricular, white matter moderated aging-induced general cognitive ability reduction.

Impact: Given normative curves summarizing WHM progression in Chinese typical aging population, clinicians can better assess abnormalities related to cerebral small-vessel diseases, detect high-risk individuals who will develop cognitive decline in the future, and conduct large-scale community screening for older population.

Keywords: Other Neurodegeneration, MR Value, AI/ML Image Reconstruction, Brain, Translational studies, Neurodegeneration

Motivation: Deep-learning-accelerated MPRAGE holds potential to enhance image resolution, reduce acquisition times, and improve diagnostic precision. However, there is currently a lack of clinical validation regarding its performance in neuroimaging.

Goal(s): To optimize and assess the performance of deep-learning-accelerated MPRAGE in comparison to Wave-CAIPI MPRAGE for non-contrast T1-weighted volumetric brain imaging.

Approach: In this prospective clinical study, we systematically optimized and implemented a novel deep-learning-accelerated MPRAGE sequence and compared against Wave-CAIPI MPRAGE, a state-of-the-art acceleration method.

Results: Deep-learning-accelerated MPRAGE enhances resolution and grey-white matter differentiation compared to Wave-CAIPI MPRAGE, with equivalent volumetric estimation in most brain regions.

Impact: Deep-learning-accelerated MPRAGE yields sharper, higher-resolution images while preserving equivalent volumetric estimations. This technique holds significant potential for deploying deep learning across various medical imaging disciplines, potentially enabling faster and more precise disease characterization.

Keywords: Dementia, Brain Connectivity, Dementia, Diabetes

Motivation: Address the common issue of cognitive decline in type 2 diabetes (T2D) patients, lacking a simple cognitive assessment method.

Goal(s): Use a connectome-based prediction model (CPM) to identify neurobiological patterns linked to cognitive performance in T2D patients.

Approach: CPM was used with leave-one-out cross-validation on a training cohort of 592 T2D patients and validated the model on two independent sets.

Results: CPM successfully predicted cognitive performance, showing replicability. We found differences in network strengths between T2D with and without MCI, indicated high diagnostic potential for MCI. In a treatment sample, the model indicated changes in network strength linked to cognitive improvement.

Impact: The whole-brain functional network strengths could serve as a potential neural biomarker of global cognitive performance in T2D.

Keywords: Other Neurodegeneration, Brain Connectivity, cerebellum; fMRI (resting state); cerebellar network

Motivation: Functional network changes of the cerebellum in patients with spinocerebellar ataxia type 3 (SCA3) have been scarcely assessed.

Goal(s): To investigate the functional topological characteristics of cerebellar network connectivity and modular changes in SCA3.

Approach: Graph theoretical method were used in this study to provide quantified topological organization and modular analyses of functional cerebellar networks.

Results: The small-world organization of the cerebellum was spared in patients with SCA3. Compared with healthy controls, increased inter-modular connectivity between frontoparietal network and dorsal somatomotor network and decreased intra-modular connectivity in cerebellar default mode network were shown in SCA3 patients.

Impact: This study displays the functional cerebellar topological network in SCA3. The abnormalities of cerebellar modular connectivity support SCA3 as a network disorder, which further enhance the interpretation of SCA3 from the perspective of neuroimaging.

Keywords: Other Neurodegeneration, Arterial spin labelling

Motivation: To explore the relationship between hippocampal perfusion asymmetry and hippocampal enlarged perivascular spaces (H-EPVS) and cognitive function  in patients with T2DM.

Goal(s): To explore the relationship between hippocampal perfusion asymmetry and H-EPVS and cognitive function  in patients with T2DM.

Approach: CBF in hippocampus,H-EPVS and cognitive function were compared between HCs and  patients with T2DM .The relationship between CBF in hippocampus, H-EPVS counts and cognitive measurement was analyzed.

Results: In patients with T2DM, hippocampal perfusion was reduced and H-EPVS counts were higher on the left side. Decreased right hippocampal perfusion and increased left H-EPVS count were associated with cognitive impairment in patients with T2DM .

Impact: Asymmetric impairment of hippocampal in patients with T2DM , and the asymmetry may be caused by a variety of mechanisms and may contribute to cognitive impairment.

Keywords: Other Neurodegeneration, Spectroscopy, Presbycusis, dynamic functional connectivity, cognitive impairment

Motivation: To learn more about neurophysiological changes in the cognitive-ear link in presbycusis.

Goal(s): To explore the role of excitation-inhibition (EI) balance and dynamic functional connectivity (dFC) in mediating the associations between hearing loss and cognitive impairment in presbycusis patients.

Approach: MRS in the auditory cortex and resting-state fMRI of whole brain in 98 presbycusis patients and 60 healthy controls were assessed.

Results: EI balance and dFC indices were statistically different between presbycusis patients and healthy controls. Hearing loss can affect cognition via a bottom-up route from ear to cognitive in a neurochemical and dFC way in presbycusis.

Impact: Shifted EI balance and dFC abnormalities play important roles in cognitive-ear link reorganization and provide evidence for sensory deprivation theory, and they can serve as a potential neuroimaging marker for predicting cognitive impairment in presbycusis patients.

Keywords: Other Neurodegeneration, Neurodegeneration

Motivation: The first gene-silencing trials for Spinocerebellar Ataxia Type-3 (SCA3) highlights the need for non-invasive biomarkers.

Goal(s): We aim to evaluate white matter (WM) tract integrity, identify early-alterations before clinical onset (preSCA3) and track disease progression over time.

Approach: Analyze fractional anisotropy (FA) and mean diffusivity (MD) in WM tracts of healthy controls, preSCA3, and SCA3 patients at cross-sectional and longitudinal visits by employing a global and along-tract analysis.

Results: While longitudinal analysis did not show relevant changes, alterations in preSCA3 in FA and MD were observed in all cerebellar peduncles and in the dentato-rubro-thalamo-cortical-tract, indicating their potential as promising stratification-biomarkers before clinical onset.

Impact: This study offers a promising approach to differentiate early-stage SCA3 before clinical onset from healthy subjects, addressing clinical scale limitations. It underscores the potential of imaging biomarkers and the necessity for further research on disease progression modeling.

Keywords: Other Neurodegeneration, Neurodegeneration

Motivation: Hemodialysis (HD) patients can cause alterations in brain structure, and often experience cognitive and sleep disorders (SD). However, the mechanism of SD in HD patients is not fully understood.

Goal(s): We aimed to assess the changes in subcortical structures of HD patients with SD and to explore the associations with cognitive.

Approach: Volumetric and vertex-wise shape analysis approaches were used to investigate the 14 subcortical structural abnormalities.

Results: Hemodialysis patients with sleep disorder exhibited significant surface reduction on the right hippocampus.

Impact: Atrophy of subcortical structures was observed in the hemodialysis patients. Right hippocampus atrophy is closely associated with sleep disorder, emphasizing the role of hippocampus as viable predictor.

Keywords: Other Neurodegeneration, Brain

Motivation: MRI parameters of the hippocampus could serve as an imaging biomarker for amyotrophic lateral sclerosis (ALS).

Goal(s): To compare hippocampal volume, fractional anisotropy (FA), mean diffusivity (MD), and T₁ between ALS and healthy controls (HC).

Approach: Postmortem in situ MRI scans at 3 Tesla were performed on five deceased ALS patients and seven deceased neurologically healthy controls (HC). MP2RAGE and DTI sequences were employed.

Results: A potentially significant difference between ALS and HC was found for T₁ in the right hippocampus and for MD in the left, right, and total hippocampus. Further research is needed to confirm this outcome.

Impact: The potential effect of amyotrophic lateral sclerosis on the hippocampal mean diffusivity and T1 might lead to the development of new MRI biomarkers. This could improve diagnosis, prognosis, and treatment strategies. Larger sample sizes are needed to validate the results.

Keywords: Other Neurodegeneration, Neurodegeneration, tau

Motivation: To improve understanding of underlying mechanisms of flortaucipir tau PET uptake.

Goal(s): To clarify the relationship between flortaucipir uptake and iron deposition in progressive supranuclear palsy (PSP).

Approach: We performed a correlation analysis between flortaucipir PET and quantitative susceptibility mapping across subcortical regions in PSP.

Results: Positive correlations between flortaucipir uptake and susceptibility were found in most subcortical regions in PSP, suggesting the possibility that some flortaucipir uptake is associated with iron in these regions.

Impact: The positive correlation between flortaucipir PET uptake and magnetic susceptibility suggests that some flortaucipir uptake in subcortical structures may be associated with iron deposition in PSP. This finding improves our understanding of the underlying mechanisms of flortaucipir PET.

Keywords: Other Neurodegeneration, Artifacts

Motivation: Cortex and spinal cord tissue are of interest in a variety of neurodegenerative diseases including Multiple Sclerosis (MS), Alzheimer’s Disease (AD), and Amyotrophic Lateral Sclerosis (ALS). These regions are low in signal to noise ratio (SNR) and generate artifacts on quantitative susceptibility maps (QSMs).

Goal(s): To demonstrate the maximum Spherical Mean Value (mSMV) algorithm as a tissue preserving initialization for susceptibility source separation.

Approach: Whole brain source separation enabled by mSMV is applied to patients with MS, AD, and ALS.

Results: The mSMV algorithm reconstructs the whole brain volume in source separations and generates susceptibility maps in agreement with existing methods.

Impact: Whole brain source separation using the maximum Spherical Mean Value (mSMV) algorithm successfully preserves full tissue volume and produces susceptibility map in strong agreement with existing methods.

Keywords: Dementia, Dementia

Motivation: Conventional diffusion MRI metrics like FA have limitations in assessing WMH lesions due to fiber orientation dispersion.

Goal(s): To improve MRI sensitivity to white matter integrity in WMH and assess its clinical relevance in predicting preclinical cognitive decline using advanced diffusion MRI.

Approach: FA and μFA maps were acquired in 54 adults using tensor-valued diffusion MRI and their quantitative correlation with cognitive decline were evaluated in WMH lesion and penumbra.

Results: While both μFA and FA differentiated WMH from other white matter regions, μFA demonstrated greater sensitivity to predict cognitive decline, suggesting its added specificity to probe white matter integrity in WMH.

Impact: Enhanced sensitivity of μFA to subtle white matter integrity and clinical aspect may offer better understanding of underlying histopathological alterations in white WMH, helping earlier detection of cerebrovascular pathology and aiding efforts to identify at-risk individuals and guide timely interventions.

Keywords: Other Neurodegeneration, Relaxometry, sickle cell disease, blood longitudinal relaxation rate, hematocrit, hemoglobin

Motivation: Blood R1 (R1_Blood) is associated with hematocrit level (Hct). However, it is unclear whether Hct of normal hemoglobin (HctA) and sickle hemoglobin (HctS) have a similar impact on R1_Blood.

Goal(s): Evaluate the impact of HctA and HctS on R1_Blood in healthy controls and SCD patients.

Approach: Multiple linear regression with R1_Blood as the dependent variable and Hct of combined hemoglobin A and F (HctAF), HctS, age, and sex as independent variables was performed.

Results: R1_Blood was associated with HctAF, HctS, age, and sex. Moreover, the association between R1_Blood and HctS was significantly different from that between R1_Blood and HctAF.

Impact: Blood R1 is essential in various MRI applications. Our findings are crucial for developing an accurate blood R1 estimation model in sickle cell disease patients.

Keywords: Aging, Translational Studies, Brain, Nicotinamide adenine dinucleotide, NAD+, Nicotinamide ribosome, NR, 1H MRS, Aging

Motivation: To determine if acute nicotinamide riboside (NR) supplementation increases cerebral nicotinamide adenine dinucleotide (NAD⁺) levels in the human brain.

Goal(s): To measure cerebral NAD⁺ levels before and after nicotinamide riboside supplementation using downfield ¹HMRS at 7T MRI in ten healthy volunteers.

Approach: First MR scan was performed in each healthy volunteer after overnight fasting to obtain baseline NAD⁺ levels. In the second scan on the following day, the same protocol was repeated, but with NR supplements administered orally 4 hours before the scan.

Results: An increase in mean NAD⁺ concentration was observed with NR supplementation, compared to the baseline (0.458±0.053 vs 0.392±0.058mM; p<0.001).

Impact: The preliminary results from this study show that oral NR supplementation increases NAD⁺ levels in brain and demonstrates the potential of downfield ¹HMRS for noninvasive quantification of cerebral NAD⁺ and monitoring the effects of NR supplementation on cerebral NAD⁺ levels.