White Matter Network Alterations in Alzheimer’s Disease Patients

Lama, Ramesh Kumar; Lee, Sang‐Woong

doi:10.3390/app10030919

Cited by 7 publications

(4 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Network alterations of structural connections in participants with EMCI, LMCI and AD, compared with the HC group, were explored using NBS analysis. The results are consistent with previous findings that structural network disturbances begin in the limbic regions (Lama & Lee, 2020; Mallio et al, 2015). Furthermore, the present study provides additional insight into the time course of structural degradation.…”

Section: Discussionsupporting

confidence: 93%

A novel method for PET connectomics guided by fibre‐tracking MRI: Application to Alzheimer's disease

Sun,

Naismith,

Meikle

et al. 2024

Human Brain Mapping

View full text Add to dashboard Cite

This study introduces a novel brain connectome matrix, track‐weighted PET connectivity (twPC) matrix, which combines positron emission tomography (PET) and diffusion magnetic resonance imaging data to compute a PET‐weighted connectome at the individual subject level. The new method is applied to characterise connectivity changes in the Alzheimer's disease (AD) continuum. The proposed twPC samples PET tracer uptake guided by the underlying white matter fibre‐tracking streamline point‐to‐point connectivity calculated from diffusion MRI (dMRI). Using tau‐PET, dMRI and T1‐weighted MRI from the Alzheimer's Disease Neuroimaging Initiative database, structural connectivity (SC) and twPC matrices were computed and analysed using the network‐based statistic (NBS) technique to examine topological alterations in early mild cognitive impairment (MCI), late MCI and AD participants. Correlation analysis was also performed to explore the coupling between SC and twPC. The NBS analysis revealed progressive topological alterations in both SC and twPC as cognitive decline progressed along the continuum. Compared to healthy controls, networks with decreased SC were identified in late MCI and AD, and networks with increased twPC were identified in early MCI, late MCI and AD. The altered network topologies were mostly different between twPC and SC, although with several common edges largely involving the bilateral hippocampus, fusiform gyrus and entorhinal cortex. Negative correlations were observed between twPC and SC across all subject groups, although displaying an overall reduction in the strength of anti‐correlation with disease progression. twPC provides a new means for analysing subject‐specific PET and MRI‐derived information within a hybrid connectome using established network analysis methods, providing valuable insights into the relationship between structural connections and molecular distributions.Practitioner Points New method is proposed to compute patient‐specific PET connectome guided by MRI fibre‐tracking. Track‐weighted PET connectivity (twPC) matrix allows to leverage PET and structural connectivity information. twPC was applied to dementia, to characterise the PET nework abnormalities in Alzheimer's disease and mild cognitive impairment.

show abstract

Section: Discussionsupporting

confidence: 93%

A novel method for PET connectomics guided by fibre‐tracking MRI: Application to Alzheimer's disease

Sun,

Naismith,

Meikle

et al. 2024

Human Brain Mapping

View full text Add to dashboard Cite

show abstract

“…This opens up new possibilities for the multimodal imaging system to include the results of the H&Estained sample in the multimodal data evaluation for tissue research and diagnostic within ex-vivo applications. Those applications are not limited to the separation of GM and WM although structural changes within GM and/or WM are indicative for patients with HIV [85], multiple sclerosis [86], and Alzheimer's disease [87,88]. Ex-vivo applications of any tissue section for research and diagnostic purposes are possible.…”

Section: Discussionmentioning

confidence: 99%

Design of a Multimodal Imaging System and Its First Application to Distinguish Grey and White Matter of Brain Tissue. A Proof-of-Concept-Study

et al. 2021

View full text Add to dashboard Cite

Multimodal imaging gains increasing popularity for biomedical applications. This article presents the design of a novel multimodal imaging system. The centerpiece is a light microscope operating in the incident and transmitted light mode. Additionally, Raman spectroscopy and VIS/NIR reflectance spectroscopy are adapted. The proof-of-concept is realized to distinguish between grey matter (GM) and white matter (WM) of normal mouse brain tissue. Besides Raman and VIS/NIR spectroscopy, the following optical microscopy techniques are applied in the incident light mode: brightfield, darkfield, and polarization microscopy. To complement the study, brightfield images of a hematoxylin and eosin (H&E) stained cryosection in the transmitted light mode are recorded using the same imaging system. Data acquisition based on polarization microscopy and Raman spectroscopy gives the best results regarding the tissue differentiation of the unstained section. In addition to the discrimination of GM and WM, both modalities are suited to highlight differences in the density of myelinated axons. For Raman spectroscopy, this is achieved by calculating the sum of two intensity peak ratios (I2857 + I2888)/I2930 in the high-wavenumber region. For an optimum combination of the modalities, it is recommended to apply the molecule-specific but time-consuming Raman spectroscopy to smaller regions of interest, which have previously been identified by the microscopic modes.

show abstract

“… 30 31 Local WM network disruption in the SMA and putamen has also been reported previously in AD. 32 The SMA is one of the neural correlates of verbal short-term memory in AD, 33 and the putamen has also been reported to be associated with cognitive impairment in AD. 34 A previous WM network study found decreased local efficiency in the right occipital area, 35 similarly to our results.…”

Section: Discussionmentioning

confidence: 99%

Alterations of Structural Network Efficiency in Early-Onset and Late-Onset Alzheimer’s Disease

Heo,

Yoon,

Kim

et al. 2024

J Clin Neurol

View full text Add to dashboard Cite

Background and Purpose Early- and late-onset Alzheimer’s disease (EOAD and LOAD, respectively) share the same neuropathological hallmarks of amyloid and neurofibrillary tangles but have distinct cognitive features. We compared structural brain connectivity between the EOAD and LOAD groups using structural network efficiency and evaluated the association of structural network efficiency with the cognitive profile and pathological markers of Alzheimer’s disease (AD). Methods The structural brain connectivity networks of 80 AD patients (47 with EOAD and 33 with LOAD) and 57 healthy controls were reconstructed using diffusion-tensor imaging. Graph-theoretic indices were calculated and intergroup differences were evaluated. Correlations between network parameters and neuropsychological test results were analyzed. The correlations of the amyloid and tau burdens with network parameters were evaluated for the patients and controls. Results Compared with the age-matched control group, the EOAD patients had increased global path length and decreased global efficiency, averaged local efficiency, and averaged clustering coefficient. In contrast, no significant differences were found in the LOAD patients. Locally, the EOAD patients showed decreases in local efficiency and the clustering coefficient over a wide area compared with the control group, whereas LOAD patients showed such decreases only within a limited area. Changes in network parameters were significantly correlated with multiple cognitive domains in EOAD patients, but only with Clinical Dementia Rating Sum-of-Boxes scores in LOAD patients. Finally, the tau burden was correlated with changes in network parameters in AD signature areas in both patient groups, while there was no correlation with the amyloid burden. Conclusions The impairment of structural network efficiency and its effects on cognition may differ between EOAD and LOAD.

show abstract

White Matter Network Alterations in Alzheimer’s Disease Patients

Cited by 7 publications

References 41 publications

A novel method for PET connectomics guided by fibre‐tracking MRI: Application to Alzheimer's disease

A novel method for PET connectomics guided by fibre‐tracking MRI: Application to Alzheimer's disease

Design of a Multimodal Imaging System and Its First Application to Distinguish Grey and White Matter of Brain Tissue. A Proof-of-Concept-Study

Alterations of Structural Network Efficiency in Early-Onset and Late-Onset Alzheimer’s Disease

Contact Info

Product

Resources

About