Layer‐specific microstructural patterns of anterior hippocampus in Alzheimer's disease with ex vivo diffusion <scp>MRI</scp> at 14.1 <scp>T</scp>

Zhao, Zhiyong; Zhang, Lei; Luo, Wanrong; Cao, Zuozhen; Zhu, Qinfeng; Kong, Xueqian; Zhu, Keqing; Zhang, Jing; Wu, Dan

doi:10.1002/hbm.26062

Cited by 5 publications

(5 citation statements)

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“…[ 66 , 67 ] For instance, the 14 T MRI has been utilized to study structural changes in the hippocampus of human brains with Alzheimer's disease. [ 68 ]…”

Section: Discussionmentioning

confidence: 99%

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Micron‐resolution Imaging of Cortical Bone under 14 T Ultrahigh Magnetic Field

Pang

Yin

et al. 2023

Advanced Science

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Compact, mineralized cortical bone tissues are often concealed on magnetic resonance (MR) images. Recent development of MR instruments and pulse techniques has yielded significant advances in acquiring anatomical and physiological information from cortical bone despite its poor 1H signals. This work demonstrates the first MR research on cortical bones under an ultrahigh magnetic field of 14 T. The 1H signals of different mammalian species exhibit multi‐exponential decays of three characteristic T2 or T2* values: 0.1–0.5 ms, 1–4 ms, and 4–8 ms. Systematic sample comparisons attribute these T2/T2* value ranges to collagen‐bound water, pore water, and lipids, respectively. Ultrashort echo time (UTE) imaging under 14 T yielded spatial resolutions of 20–80 microns, which resolves the 3D anatomy of the Haversian canals. The T2* relaxation characteristics further allow spatial classifications of collagen, pore water and lipids in human specimens. The study achieves a record of the spatial resolution for MR imaging in bone and shows that ultrahigh‐field MR has the unique ability to differentiate the soft and organic compartments in bone tissues.

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“…[ 66 , 67 ] For instance, the 14 T MRI has been utilized to study structural changes in the hippocampus of human brains with Alzheimer's disease. [ 68 ]…”

Section: Discussionmentioning

confidence: 99%

“…[66,67] For instance, the 14 T MRI has been utilized to study structural changes in the hippocampus of human brains with Alzheimer's disease. [68] On the other hand, there are several limitations of ultrahigh field MRI. First, ultrahigh magnetic field MRI (>7 T) has not been approved in clinical use.…”

Section: Discussionmentioning

confidence: 99%

Micron‐resolution Imaging of Cortical Bone under 14 T Ultrahigh Magnetic Field

Pang

Yin

et al. 2023

Advanced Science

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“…An recent ex-vivo human brain study in AD using T2-weighted MRI found signi cant relationships between phosphorylated tau and cortical thickness in primary visual cortices, temporal pole, insular cortex, and posterior cingulate gyri[62]. Our previous ex-vivo studies in the human hippocampus revealed signi cant correlations between magnetic susceptibility and Aβ/Tau content in AD and PART, as well as between dMRI measurements and Aβ/Tau content in AD[25, 63]. These ndings indicate that changes in MRI could re ect the effects of Aβ or Tau or both on the brain.…”

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confidence: 85%

“…More importantly, ex-vivo MRI enables direct MRI-histology correlation of the same human brain. Our recent studies found layer-speci c microstructural changes in the hippocampus that signi cantly correlated with Aβ/Tau protein content in AD samples [25]. However, the aforementioned ex-vivo dMRI studies all focused on speci c small tissue blocks and did not characterize how layerspeci c Aβ/Tau deposition affects the cortical microstructure across the whole hemisphere.…”

Section: Introductionmentioning

confidence: 97%

Layer-dependent effect of Aβ-pathology on cortical microstructure with ex-vivo human brain diffusion MRI at 7 Tesla

Zhao,

Cao,

Zhu

et al. 2023

Preprint

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Background The laminar-specific distributions of Aβ and Tau deposition in the neocortex of Alzheimer’s disease (AD) have been established. However, direct evidence about the effect of AD pathology on cortical microstructure is lacking in human studies. Methods We performed high-resolution T2-weighted and diffusion-weighted MRI (dMRI) on fifteen ex-vivo whole-hemisphere specimens, including eight cases with an AD pathology, three cases with primary age-related tauopathy (PART) and four healthy controls (HCs). Using the diffusion tensor model, we evaluated microstructure patterns in six layers of grey matter cortex and performed MRI-histology correlation analysis across cortical layers. Results Aβ-positive cases exhibited higher diffusivity than Aβ-negative cases (PART and HC) in selected cortical regions, particularly in the inferior frontal cortex. Both Aβ/Tau depositions and dMRI-based microstructural markers demonstrated distinct cortical layer-dependent and region-specific patterns. A significant positive correlation was observed between increased diffusivity and Aβ burden across six cortical layers, but not with Tau burden. Furthermore, the mean diffusivity in layer-V of the inferior frontal cortex significantly increased with the Amyloid stage. Conclusion Our findings demonstrate a layer-dependent effect of Aβ-pathology on cortical microstructure of the human brain, which may be used to serve as early markers of AD pathology.

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“…43 From these DTI data, fractional anisotropy (FA) values were calculated as a measure of the directionality and coherence of water molecule diffusion within the white matter tracts. 44 FA is a widely used scalar metric derived from the diffusion tensor, which provides valuable insights into the microstructural organization and integrity of white matter fibers. 45 Lower FA values are generally associated with disruptions or disorganization of white matter pathways, which can occur in various neurological conditions, including dementia.…”

Section: Methodsmentioning

confidence: 99%

Multimodal dementia identification using lifestyle and brain lesions, a machine learning approach

Akbarifar,

Maghsoudpour,

Mohammadian

et al. 2024

AIP Advances

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Dementia diagnosis often relies on expensive and invasive neuroimaging techniques that limit access to early screening. This study proposes an innovative approach for facilitating early dementia screening by estimating diffusion tensor imaging (DTI) measures using accessible lifestyle and brain imaging factors. Conventional DTI analysis, though effective, is often hindered by high costs and limited accessibility. To address this challenge, fuzzy subtractive clustering identified 14 influential variables from the Lifestyle for Brain Health and Brain Atrophy and Lesion Index frameworks, encompassing demographics, medical conditions, lifestyle factors, and structural brain markers. A multilayer perceptron (MLP) neural network was developed using these selected variables to predict fractional anisotropy (FA), a DTI metric reflecting white matter integrity and cognitive function. The MLP model achieved promising results, with a mean squared error of 0.000 878 on the test set for FA prediction, demonstrating its potential for accurate DTI estimation without costly neuroimaging techniques. The FA values in the dataset ranged from 0 to 1, with higher values indicating greater white matter integrity. Thus, a mean squared error of 0.000 878 suggests that the model’s predictions were highly accurate compared to the observed FA values. This multifactorial approach aligns with the current understanding of dementia’s complex etiology influenced by various biological, environmental, and lifestyle factors. By integrating readily available data into a predictive model, this method enables widespread, cost-effective screening for early dementia risk assessment. The proposed accessible screening tool could facilitate timely interventions, preventive strategies, and efficient resource allocation in public health programs, ultimately improving patient outcomes and caregiver burden.

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Layer‐specific microstructural patterns of anterior hippocampus in Alzheimer's disease with ex vivo diffusion MRI at 14.1 T

Cited by 5 publications

References 65 publications

Micron‐resolution Imaging of Cortical Bone under 14 T Ultrahigh Magnetic Field

Micron‐resolution Imaging of Cortical Bone under 14 T Ultrahigh Magnetic Field

Layer-dependent effect of Aβ-pathology on cortical microstructure with ex-vivo human brain diffusion MRI at 7 Tesla

Multimodal dementia identification using lifestyle and brain lesions, a machine learning approach

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