Elucidating the aberrant brain regions in bipolar disorder using T1-weighted/T2-weighted magnetic resonance ratio images

Ishida, Takuya; Donishi, Tomohiro; Iwatani, Jun; Yamada, Shinichi; Takahashi, Shun; Ukai, Shigeo; Shinosaki, Kazuhiro; Tomita, Masaki; Kaneoke, Yoshiki

doi:10.1016/j.pscychresns.2017.03.006

Cited by 20 publications

(13 citation statements)

References 62 publications

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“…Our findings are supported by the correspondence between cortical patterns of T1w/T2w and myelin (Glasser et al, 2016;Glasser & Van Essen, 2011). Further, the T1w/T2w ratio technique has been used to map the myelin content of the cerebral cortex (Glasser & Van Essen, 2011), and to study the effects of aging Lee et al, 2015;Shafee et al, 2015) and disease (Ganzetti, Wenderoth, & Mantini, 2015;Ishida et al, 2017;Iwatani et al, 2015). However, to date, there have been no investigations of subcortical T1w/T2w in healthy adults across the adult lifespan.…”

Section: Possible Biological and Functional Correlatessupporting

confidence: 77%

MR‐based age‐related effects on the striatum, globus pallidus, and thalamus in healthy individuals across the adult lifespan

Tullo

Patel

Devenyi

et al. 2019

Human Brain Mapping

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While numerous studies have used magnetic resonance imaging (MRI) to elucidate normative age‐related trajectories in subcortical structures across the human lifespan, there exists substantial heterogeneity among different studies. Here, we investigated the normative relationships between age and morphology (i.e., volume and shape), and microstructure (using the T1‐weighted/T2‐weighted [T1w/T2w] signal ratio as a putative index of myelin and microstructure) of the striatum, globus pallidus, and thalamus across the adult lifespan using a dataset carefully quality controlled, yielding a final sample of 178 for the morphological analyses, and 162 for the T1w/T2w analyses from an initial dataset of 253 healthy subjects, aged 18–83. In accordance with previous cross‐sectional studies of adults, we observed age‐related volume decrease that followed a quadratic relationship between age and bilateral striatal and thalamic volumes, and a linear relationship in the globus pallidus. Our shape indices consistently demonstrated age‐related posterior and medial areal contraction bilaterally across all three structures. Beyond morphology, we observed a quadratic inverted U‐shaped relationship between T1w/T2w signal ratio and age, with a peak value occurring in middle age (at around 50 years old). After permutation testing, the Akaike information criterion determined age relationships remained significant for the bilateral globus pallidus and thalamus, for both the volumetric and T1w/T2w analyses. Our findings serve to strengthen and expand upon previous volumetric analyses by providing a normative baseline of morphology and microstructure of these structures to which future studies investigating patients with various disorders can be compared.

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Section: Possible Biological and Functional Correlatessupporting

confidence: 77%

MR‐based age‐related effects on the striatum, globus pallidus, and thalamus in healthy individuals across the adult lifespan

Tullo

Patel

Devenyi

et al. 2019

Human Brain Mapping

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“…Disorders with a strong demyelinating component such as MS, have consistently showed lower T1‐w/T2‐w values in pathologically vulnerable regions (Beer et al, ; Nakamura et al, ; Righart et al, ). Additionally, lowered T1‐w/T2‐w ratios in several brain regions in schizophrenia (Ganzetti et al, ; Iwatani et al, ) and bipolar disorder patients (Ishida et al, ) have been identified. Recent transcriptomic studies have further observed correlations of the T1‐w/T2‐w intensity in the cortex with expression of genes associated with cortical microcircuit specialization and myelin (Burt et al, ; Ritchie, Pantazatos, & French, ).…”

Section: Discussionmentioning

confidence: 99%

Gray matter T1‐w/T2‐w ratios are higher in Alzheimer's disease

Pelkmans

Dicks

Barkhof

et al. 2019

Human Brain Mapping

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Myelin determines the conduction of neuronal signals along axonal connections in networks of the brain. Loss of myelin integrity in neuronal circuits might result in cognitive decline in Alzheimer's disease (AD). Recently, the ratio of T1‐weighted by T2‐weighted MRI has been used as a proxy for myelin content in gray matter of the cortex. With this approach, we investigated whether AD dementia patients show lower cortical myelin content (i.e., a lower T1‐w/T2‐w ratio value). We selected structural T1‐w and T2‐w MR images of 293 AD patients and 172 participants with normal cognition (NC). T1‐w/T2‐w ratios were computed for the whole brain and within 90 automated anatomical labeling atlas regions using SPM12, compared between groups and correlated with the neuronal injury marker tau in cerebrospinal fluid (CSF) and Mini Mental State Examination (MMSE). In contrast to our hypothesis, AD patients showed higher whole brain T1‐w/T2‐w ratios than NC, and regionally in 31 anatomical areas (p < .0005; d = 0.21 to 0.48), predominantly in the inferior parietal lobule, angular gyrus, anterior cingulate, and precuneus. Regional higher T1‐w/T2‐w values were associated with higher CSF tau concentrations (p < .0005; r = .16 to .22) and worse MMSE scores (p < .0005; r = −.16 to −.21). These higher T1‐w/T2‐w values in AD seem to contradict previous pathological findings of demyelination and disconnectivity in AD. Future research should further investigate the biological processes reflected by increases in T1‐w/T2‐w values.

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“…Recently, an immunocytochemistry study of post-mortem brains showed that T1w/T2w values correlate with myelin levels (Nakamura et al, 2017). The T1w/T2w ratio has also been used to estimate in vivo myelin degeneration in patients with schizophrenia (Ganzetti et al, 2015;Iwatani et al, 2015), multiple sclerosis (Beer et al, 2016), and bipolar disorder (Ishida et al, 2017). Further, the method has been used to demonstrate that higher estimated myelin within the cerebral cortex is associated with reduced intra-subject variability on speeded tasks (Grydeland et al, 2013).…”

Section: Accepted Manuscriptmentioning

confidence: 99%

More highly myelinated white matter tracts are associated with faster processing speed in healthy adults

Chopra

Shaw

et al. 2018

NeuroImage

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The objective of this study was to investigate whether the estimated myelin content of white matter tracts is predictive of cognitive processing speed and whether such associations are modulated by age. Associations between estimated myelin content and processing speed were assessed in 570 community-living individuals (277 middle-age, 293 older-age). Myelin content was estimated in-vivo using the mean T1w/T2w magnetic resonance ratio, in six white matter tracts (anterior corona radiata, superior corona radiata, pontine crossing tract, anterior limb of the internal capsule, genu of the corpus callosum, and splenium of the corpus callosum). Processing speed was estimated by extracting a principal component from 5 separate tests of processing speed. It was found that estimated myelin content of the bilateral anterior limb of the internal capsule and left splenium of the corpus callosum were significant predictors of processing speed, even after controlling for socio-demographic, health and genetic variables and correcting for multiple comparisons. One SD higher in the estimated myelin content of the anterior limb of the internal capsule was associated with 2.53% faster processing speed and within the left splenium of the corpus callosum with 2.20% faster processing speed. In addition, significant differences in estimated myelin content between middle-age and older participants were found in all six white matter tracts. The present results indicate that myelin content, estimated in vivo using a neuroimaging approach in healthy older adults, is sufficiently precise to predict variability in processing speed in behavioural measures.

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Elucidating the aberrant brain regions in bipolar disorder using T1-weighted/T2-weighted magnetic resonance ratio images

Cited by 20 publications

References 62 publications

MR‐based age‐related effects on the striatum, globus pallidus, and thalamus in healthy individuals across the adult lifespan

MR‐based age‐related effects on the striatum, globus pallidus, and thalamus in healthy individuals across the adult lifespan

Gray matter T1‐w/T2‐w ratios are higher in Alzheimer's disease

More highly myelinated white matter tracts are associated with faster processing speed in healthy adults

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