scholarly journals White Matter Changes in Bipolar Disorder, Alzheimer Disease, and Mild Cognitive Impairment: New Insights from DTI

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Aikaterini Xekardaki ◽  
Panteleimon Giannakopoulos ◽  
Sven Haller
Keyword(s):  
Bipolar Disorder ◽  
White Matter ◽  
Alzheimer Disease ◽  
Structural Changes ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Basic Principles ◽  
Diffusion In Brain ◽  
Diffusion Tensor Imaging Dti

Neuropathological and neuroimaging studies have reported significant changes in white matter in psychiatric and neurodegenerative diseases. Diffusion tensor imaging (DTI), a recently developed technique, enables the detection of microstructural changes in white matter. It is a noninvasivein vivotechnique that assesses water molecules' diffusion in brain tissues. The most commonly used parameters are axial and radial diffusivity reflecting diffusion along and perpendicular to the axons, as well as mean diffusivity and fractional anisotropy representing global diffusion. Although the combination of these parameters provides valuable information about the integrity of brain circuits, their physiological meaning still remains controversial. After reviewing the basic principles of DTI, we report on recent contributions that used this technique to explore subtle structural changes in white matter occurring in elderly patients with bipolar disorder and Alzheimer disease.

scholarly journals In Vivo Characterization of Cortical and White Matter Microstructural Pathology in Growth Hormone-Secreting Pituitary Adenoma

2021 ◽  
Vol 11 ◽  
Author(s):  
Taoyang Yuan ◽  
Jianyou Ying ◽  
Chuzhong Li ◽  
Lu Jin ◽  
Jie Kang ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Pituitary Adenoma ◽  
White Matter ◽  
Diffusion Tensor ◽  
Critical Role ◽  
Mean Diffusivity ◽  
Occipital Cortex ◽  
Test Surface ◽  
Neuropsychological Dysfunction

BackgroundThe growth hormone (GH) and insulin-like-growth factor 1 (IGF-1) axis has long been recognized for its critical role in brain growth, development. This study was designed to investigate microstructural pathology in the cortex and white matter in growth hormone-secreting pituitary adenoma, which characterized by excessive secretion of GH and IGF-1.Methods29 patients with growth hormone-secreting pituitary adenoma (acromegaly) and 31 patients with non-functional pituitary adenoma as controls were recruited and assessed using neuropsychological test, surface-based morphometry, T1/T2-weighted myelin-sensitive magnetic resonance imaging, neurite orientation dispersion and density imaging, and diffusion tensor imaging.ResultsCompared to controls, we found 1) acromegaly had significantly increased cortical thickness throughout the bilateral cortex (pFDR < 0.05). 2) T1/T2-weighted ratio in the cortex were decreased in the bilateral occipital cortex and pre/postcentral central gyri but increased in the bilateral fusiform, insular, and superior temporal gyri in acromegaly (pFDR < 0.05). 3) T1/T2-weighted ratio were decreased in most bundles, and only a few areas showed increases in acromegaly (pFDR < 0.05). 4) Neurite density index (NDI) was significantly lower throughout the cortex and bundles in acromegaly (pTFCE < 0.05). 5) lower fractional anisotropy (FA) and higher mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) in extensive bundles in acromegaly (pTFCE < 0.05). 6) microstructural pathology in the cortex and white matter were associated with neuropsychological dysfunction in acromegaly.ConclusionsOur findings suggested that long-term persistent and excess serum GH/IGF-1 levels alter the microstructure in the cortex and white matter in acromegaly, which may be responsible for neuropsychological dysfunction.

scholarly journals White matter abnormalities of corpus callosum in patients with bipolar disorder and suicidal ideation

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Ran Zhang ◽  
Xiaowei Jiang ◽  
Miao Chang ◽  
Shengnan Wei ◽  
Yanqing Tang ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
White Matter ◽  
Suicidal Ideation ◽  
Corpus Callosum ◽  
Diffusion Tensor ◽  
The Body ◽  
Pathophysiological Mechanism ◽  
The Relationship ◽  
Diffusion Tensor Imaging Dti

Abstract Objective Although many studies have shown that the corpus callosum (CC) may play an important role in bipolar disorder (BD) and suicide, the pathophysiological mechanism of BD underlying suicidal behavior is still unclear. This study aimed to explore the relationship between the CC, and BD and suicidal ideation using diffusion tensor imaging (DTI). Method A total of 203 participants (47 BD patients with suicidal ideation, 59 with BD without suicidal ideation, and 97 healthy controls [HC]) underwent DTI scanning at a single site. We examined the white matter integrity of the CC in the three groups. Results A comparison among groups showed that BD patients with suicidal ideation had significant lower fractional anisotropy (FA) values than those of BD without suicidal ideation and HCs in the body and genu of the CC, and FA values of BD without suicidal ideation were significantly lower than those of HCs. However, in the splenium of corpus callosum, no difference was found between BD without suicidal ideation and HCs. Conclusions Our findings add to the evidence suggesting that the CC plays a key role in BD with suicidal ideation, especially with respect to the role of the genu and body of the CC subserving emotion regulation.

scholarly journals Magnetic resonance diffusion tensor imaging in psychiatry: a narrative review of its potential role in diagnosis

2020 ◽  
Author(s):  
Piotr Podwalski ◽  
Krzysztof Szczygieł ◽  
Ernest Tyburski ◽  
Leszek Sagan ◽  
Błażej Misiak ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Potential Role ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Water Molecules ◽  
Mental Diseases ◽  
The Brain ◽  
Diffusion Tensor Imaging Dti

Abstract Diffusion tensor imaging (DTI) is an imaging technique that uses magnetic resonance. It measures the diffusion of water molecules in tissues, which can occur either without restriction (i.e., in an isotropic manner) or limited by some obstacles, such as cell membranes (i.e., in an anisotropic manner). Diffusion is most often measured in terms of, inter alia, fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD). DTI allows us to reconstruct, visualize, and evaluate certain qualities of white matter. To date, many studies have sought to associate various changes in the distribution of diffusion within the brain with mental diseases and disorders. A better understanding of white matter integrity disorders can help us recognize the causes of diseases, as well as help create objective methods of psychiatric diagnosis, identify biomarkers of mental illness, and improve pharmacotherapy. The aim of this work is to present the characteristics of DTI as well as current research on its use in schizophrenia, affective disorders, and other mental disorders.

scholarly journals Loss of white matter integrity reflects tau accumulation in Alzheimer disease defined regions

Neurology ◽  
2018 ◽  
Vol 91 (4) ◽  
pp. e313-e318 ◽  
Author(s):  
Jeremy F. Strain ◽  
Robert X. Smith ◽  
Helen Beaumont ◽  
Catherine M. Roe ◽  
Brian A. Gordon ◽  
...  
Keyword(s):  
White Matter ◽  
Alzheimer Disease ◽  
Gray Matter ◽  
Structural Integrity ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Cognitively Impaired ◽  
Cognitively Normal ◽  
Advanced Stages ◽  
Amyloid Aβ

ObjectiveWhite matter (WM) projections were assessed from Alzheimer disease (AD) gray matter regions associated with β-amyloid (Aβ), tau, or neurodegeneration to ascertain relationship between WM structural integrity with Aβ and/or tau deposition.MethodsParticipants underwent diffusion tensor imaging (DTI), PET Aβ ([18F]AV-45 [florbetapir]), and PET tau ([18F]AV-1451 [flortaucipir]) imaging. Probabilistic WM summary and individual tracts were created from either a composite or individual gray matter seed regions derived from Aβ, tau, and neurodegeneration. Linear regressions were performed for Aβ, age, tau and WM hyperintensities (WMH) to predict mean diffusivity (MD) or fractional anisotropy (FA) from the corresponding WM summaries or tracts.ResultsOur cohort was composed of 59 cognitively normal participants and 10 cognitively impaired individuals. Aβ was not associated with DTI metrics in WM summary or individual tracts. Age and WMH strongly predicted MD and FA in several WM regions, with tau a significant predictor of MD only in the anterior temporal WM.ConclusionTau, not Aβ, was associated with changes in anterior temporal WM integrity. WMH, a proxy for vascular damage, was strongly associated with axonal damage, but tau independently contributed to the model, suggesting an additional degenerative mechanism within tracts projecting from regions vulnerable to AD pathology. WM decline was associated with early tau accumulation, and further decline may reflect tau propagation in more advanced stages of AD.

scholarly journals Involvement of cortico-efferent tracts in flail arm syndrome: a tract-of-interest-based DTI study

2021 ◽  
Author(s):  
Angela Rosenbohm ◽  
Kelly Del Tredici ◽  
Heiko Braak ◽  
Hans-Jürgen Huppertz ◽  
Albert C. Ludolph ◽  
...  
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Statistical Comparison ◽  
Specific Analysis ◽  
Cerebral Pathology ◽  
Propagation Pattern ◽  
Als Patients ◽  
Lateral Sclerosis ◽  
Diffusion Tensor Imaging Dti

Abstract Background Flail arm syndrome is a restricted phenotype of motor neuron disease that is characterized by progressive, predominantly proximal weakness and atrophy of the upper limbs. Objective The study was designed to investigate specific white matter alterations in diffusion tensor imaging (DTI) data from flail arm syndrome patients using a hypothesis-guided tract-of-interest-based approach to identify in vivo microstructural changes according to a neuropathologically defined amyotrophic lateral sclerosis (ALS)-related pathology of the cortico-efferent tracts. Methods DTI-based white matter mapping was performed both by an unbiased voxel-wise statistical comparison and by a hypothesis-guided tract-wise analysis of fractional anisotropy (FA) maps according to the neuropathological ALS-propagation pattern for 43 flail arm syndrome patients vs 43 ‘classical’ ALS patients vs 40 matched controls. Results The analysis of white matter integrity demonstrated regional FA reductions for the flail arm syndrome group predominantly along the CST. In the tract-specific analysis according to the proposed sequential cerebral pathology pattern of ALS, the flail arm syndrome patients showed significant alterations of the specific tract systems that were identical to ‘classical’ ALS if compared to controls. Conclusions The DTI study including the tract-of-interest-based analysis showed a microstructural involvement pattern in the brains of flail arm syndrome patients, supporting the hypothesis that flail arm syndrome is a phenotypical variant of ALS.

Adverse childhood experiences influence white matter microstructure in patients with bipolar disorder

2014 ◽  
Vol 44 (14) ◽  
pp. 3069-3082 ◽  
Author(s):  
F. Benedetti ◽  
I. Bollettini ◽  
D. Radaelli ◽  
S. Poletti ◽  
C. Locatelli ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
White Matter ◽  
Adverse Childhood Experiences ◽  
Diffusion Tensor ◽  
Structural Connectivity ◽  
Adult Life ◽  
Mean Diffusivity ◽  
Childhood Experiences ◽  
Axial Diffusivity ◽  
Adverse Childhood

BackgroundBipolar disorder (BD) is associated with adverse childhood experiences (ACE), which worsen the lifetime course of illness, and with signs of widespread disruption of white matter (WM) integrity in adult life. ACE are associated with changes in WM microstructure in healthy humans.MethodWe tested the effects of ACE on diffusion-tensor imaging (DTI) measures of WM integrity in 80 in-patients affected by a major depressive episode in the course of BD. We used whole-brain tract-based spatial statistics in the WM skeleton with threshold-free cluster enhancement of DTI measures of WM microstructure: axial, radial and mean diffusivity, and fractional anisotropy.ResultsACE hastened the onset of illness. We observed an inverse correlation between the severity of ACE and DTI measures of axial diffusivity in several WM fibre tracts contributing to the functional integrity of the brain and including the corona radiata, thalamic radiations, corpus callosum, cingulum bundle, superior longitudinal fasciculus, inferior fronto-occipital fasciculus and uncinate fasciculus.ConclusionsAxial diffusivity reflects the integrity of axons and myelin sheaths, and correlates with functional connectivity and with higher-order abilities such as reasoning and experience of emotions. In patients with BD axial diffusivity is increased by lithium treatment. ACE might contribute to BD pathophysiology by hampering structural connectivity in critical cortico-limbic networks.

Abstract P64: Longitudinal Brain Structural Changes After Stroke

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Kyle C Kern ◽  
Clinton B Wright ◽  
Richard Leigh
Keyword(s):  
Ischemic Stroke ◽  
White Matter ◽  
Stroke Volume ◽  
Brain Atrophy ◽  
Structural Changes ◽  
Diffusion Tensor ◽  
Brain Mri ◽  
Mean Diffusivity ◽  
Intracranial Volume ◽  
Post Stroke

Background: Stroke causes focal and diffuse structural brain changes that may contribute to subsequent cognitive decline and dementia. We hypothesize that MRI structural measures can detect continued cerebral degeneration over the first year after stroke. We identify predictors for progression of brain atrophy, leukoaraiosis and diffusion tensor imaging (DTI) metrics. Methods: Patients with ischemic stroke were enrolled prospectively in an observational study that included serial brain MRI. Patients underwent MRI FLAIR and DTI at the time of acute stroke and were followed for at least 9 months with multiple MRIs between 30 days and 15 months post-stroke. We used FLAIR to measure brain atrophy as the percent brain parenchymal fraction (BPF) of the total intracranial volume (TICV) and white matter hyperintensity volume (WMHV) as a percentage of TICV. DTI was used to calculate Peak Skeletonized Mean Diffusivity (PSMD), a global measure of white matter integrity previously validated in cerebral small vessel disease. Longitudinal changes in BPF, WMHV or PSMD were measured from 30 days post-stroke onward using linear regression models that included age, stroke volume, baseline BPF and WMHV as predictors. Results: Twenty-six patients had a median of 4 follow-ups over 9-15 months. Median age was 74 years (range 51-84) and 38% were women. Mean stroke volume was 4.5cc (0 - 30cc). Mean BPF was 78% (72 - 86%) and mean baseline WMHV was 1.1% (0.1 - 3.9%). BPF was associated with age and declined by 0.7% per year (t(111) = 2.7, p = 0.007). Progression was associated with baseline BPF (t(111) = -3.4, p < 0.001). WMHV in the non-stroke hemisphere was associated with age and increased by 0.10% per year (t(87) = -5.8, p < 0.001). Accumulation was associated with age (t(87) = 5.8, p < 0.001). PSMD was associated with baseline WMHV and had a relative increase of 1.9% per year in the non-stroke hemisphere and 4.5% in the stroke hemisphere (t(174) = -2.1, p = 0.03). Progression was associated with age (t(174) = 2.3, p = 0.03) and stroke volume (t(174) = 2.4, p = 0.02). Conclusions: During the months after ischemic stroke, BPF, WMHV and PSMD can detect persistent structural changes that may reflect later phases of stroke injury or ongoing contributions of aging, silent ischemia, or neurodegeneration.

Diffusion tensor imaging in schizophrenia

2008 ◽  
Vol 23 (4) ◽  
pp. 255-273 ◽  
Author(s):  
Marinos Kyriakopoulos ◽  
Theodoros Bargiotas ◽  
Gareth J. Barker ◽  
Sophia Frangou
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Diffusion Tensor ◽  
Brain Regions ◽  
Basic Principles ◽  
Future Directions ◽  
White Matter Abnormalities ◽  
Non Invasive ◽  
Brain White Matter ◽  
Diffusion Tensor Imaging Dti

AbstractDiffusion tensor imaging (DTI) is a magnetic resonance imaging technique that is increasingly being used for the non-invasive evaluation of brain white matter abnormalities. In this review, we discuss the basic principles of DTI, its roots and the contribution of European centres in its development, and we review the findings from DTI studies in schizophrenia. We searched EMBASE, PubMed, PsychInfo, and Medline from February 1998 to December 2006 using as keywords ‘schizophrenia’, ‘diffusion’, ‘tensor’, and ‘DTI’. Forty studies fulfilling the inclusion criteria of this review were included and systematically reviewed. White matter abnormalities in many diverse brain regions were identified in schizophrenia. Although the findings are not completely consistent, frontal and temporal white matter seems to be more commonly affected. Limitations and future directions of this method are discussed.

scholarly journals Myelination of major white matter tracts continues beyond childhood—combining tractography and myelin water imaging

2019 ◽  
Author(s):  
Tobias W. Meissner ◽  
Erhan Genç ◽  
Burkhard Mädler ◽  
Sarah Weigelt
Keyword(s):  
White Matter ◽  
Middle Childhood ◽  
Diffusion Tensor ◽  
Late Childhood ◽  
White Matter Tracts ◽  
Water Fraction ◽  
White Matter Maturation ◽  
Myelin Water Fraction ◽  
Diffusion Tensor Imaging Dti

AbstractAxonal myelination is a key white matter maturation process as it increases conduction velocity, synchrony, and reliability. While diffusion tensor imaging (DTI) is sensitive to myelination, it is also sensitive to unrelated microstructural properties, thus hindering straightforward interpretations. Myelin water imaging (MWI) provides a more reliable and direct in vivo measure of myelination. Although early histological studies show protracted myelination from childhood to adulthood, reliable tract-specific in vivo evidence from MWI is still lacking. Here, we combine MWI and DTI tractography to investigate myelination in middle childhood, late childhood, and adulthood in 18 major white matter tracts. In the vast majority of major white matter tracts, myelin water fraction continued to increase beyond late childhood. Our study provides first in vivo evidence for protracted myelination beyond late childhood.

scholarly journals Diffusion MRI Changes in the Healthy Aging Canine Brain

2020 ◽  
Author(s):  
Erica F. Barry ◽  
John P. Loftus ◽  
Wen-Ming Luh ◽  
Mony J. de Leon ◽  
Sumit N. Niogi ◽  
...  
Keyword(s):  
White Matter ◽  
Diffusion Mri ◽  
Healthy Aging ◽  
Parietal Lobe ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Human Aging ◽  
Age Related ◽  
Age Related Changes

AbstractWhite matter dysfunction and degeneration have been a topic of great interest in healthy and pathological aging. While ex vivo studies have investigated age-related changes in canines, little in vivo canine aging research exists. Quantitative diffusion MRI such as diffusion tensor imaging (DTI) has demonstrated aging and neurodegenerative white matter changes in humans. However, this method has not been applied and adapted in vivo to canine populations. This study aimed to test the hypothesis that white matter diffusion changes frequently reported in human aging are also found in aged canines. The study used Tract Based Spatial Statistics (TBSS) and a region of interest (ROI) approach to investigate age related changes in fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AxD) and radial diffusivity (RD). The results show that, compared to younger animals, aged canines have significant decreases in FA in parietal and temporal regions as well as the corpus callosum and fornix. Additionally, AxD decreases were observed in parietal, frontal and midbrain regions. Similarly, an age-related increase in RD was observed in the right parietal lobe while MD decreases were found in the midbrain. These findings suggest that canine samples offer a model for healthy human aging as they exhibit similar white matter diffusion tensor changes with age.

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