Microstructures in striato-thalamo-orbitofrontal circuit in methamphetamine users

2017 ◽  
Vol 58 (11) ◽  
pp. 1378-1385 ◽  
Author(s):  
Yadi Li ◽  
Haibo Dong ◽  
Feng Li ◽  
Gaoyan Wang ◽  
Wenhua Zhou ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Repeated Measures ◽  
Diffusion Tensor ◽  
Psychiatric Symptoms ◽  
Mean Diffusivity ◽  
Microstructural Changes ◽  
Structural Space ◽  
Magnetic Resonance Imaging Mri ◽  
Microstructural Integrity ◽  
Diffusion Tensor Imaging Dti

Background Striato-thalamo-orbitofrontal (STO) circuit plays a key role in the development of drug addiction. Few studies have investigated its microstructural abnormalities in methamphetamine (MA) users. Purpose To evaluate the microstructural changes and relevant clinical relevance of the STO circuit in MA users using diffusion tensor imaging (DTI). Material and Methods Twenty-eight MA users and 28 age-matched normal volunteers were enrolled. 3T magnetic resonance imaging (MRI) was employed to obtain structural T1-weighted (T1W) imaging and diffusion-tensor imaging (DTI) data. Freesurfer software was used for automated segmentation of the bilateral nucleus accumbens (NAc), thalami, and orbitofrontal cortex (OFC). Four DTI measures maps, fractional anisotropy (FA), mean diffusivity (MD), axial diffusion (AD), and radial diffusion (RD) were generated and non-linearly co-registered to structural space. Comparisons of DTI measures of the STO circuit were carried out between MA and controls using repeated measures analysis of variance. Correlation analyses were performed between STO circuit DTI measures and clinical characteristics. Results The MA group had significant FA reduction in the bilateral NAc, OFC, and right thalamus ( P < 0.05). Lower left OFC FA and right NAc FA/AD were associated with longer duration of MA use. Lower right OFC FA was associated with younger age at first MA use. Higher FA and lower MD/RD in the thalamus, as well as higher left OFC RD, were associated with increased psychiatric symptoms. Conclusion The STO circuit has reduced microstructural integrity in MA users. Microstructural changes in the thalamus may compensate for dysfunction in functionally connected cortices, which needs further investigation.

Diffusion tensor imaging of cerebral white matter in patients with myotonic dystrophy

2005 ◽  
Vol 46 (1) ◽  
pp. 104-109 ◽  
Author(s):  
H. Fukuda ◽  
J. Horiguchi ◽  
C. Ono ◽  
T. Ohshita ◽  
J. Takaba ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Myotonic Dystrophy ◽  
Normal Control ◽  
Diffusion Tensor ◽  
Age At Onset ◽  
Mean Diffusivity ◽  
Magnetic Resonance Images ◽  
Microstructural Changes ◽  
Control Subjects

Purpose: To determine whether myotonic dystrophy (MyD) patients have diffusion tensor abnormalities suggestive of microstructural changes in normal‐appearing white matter (NAWM). Material and Methods: Conventional and diffusion tensor magnetic resonance images of the brain were obtained in 19 MyD patients and 19 age‐matched normal control subjects. Fractional anisotropy (FA) and mean diffusivity (MD) values were calculated in white matter lesions (WMLs) and NAWM in MyD patients and in the white matter of normal control subjects. Differences between WML and NAWM values and between MyD patient and control subject values were analyzed statistically. Results: Significantly lower FA and higher MD values were found in all regions of interest in the NAWM of MyD patients than in the white matter of control subjects ( P<0.01), as well as significantly lower FA and higher MD values in WMLs than in NAWM of MyD patients ( P<0.05). There was no significant correlation of mean FA or MD values in NAWM with patient age, age at onset, or duration of illness ( P>0.1). Conclusion: Diffusion tensor imaging analysis suggests the presence of diffuse microstructural changes in NAWM of MyD patients that may play an important role in the development of disability.

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.

Diffusion Tensor Imaging in Patients With Adult Chronic Idiopathic Hydrocephalus

Neurosurgery ◽  
2010 ◽  
Vol 66 (5) ◽  
pp. 917-924 ◽  
Author(s):  
Elke Hattingen ◽  
Alina Jurcoane ◽  
Julia Melber ◽  
Stella Blasel ◽  
Friedhelm E. Zanella ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Normal Pressure ◽  
Clinical Findings ◽  
Control Group ◽  
Microstructural Changes ◽  
Automated Method ◽  
Definition Of ◽  
Lumbar Cerebrospinal Fluid

Abstract OBJECTIVE Diffusion tensor imaging (DTI) parameters were investigated in patients with chronic idiopathic hydrocephalus to evaluate microstructural changes of brain tissue caused by chronic ventricular dilatation. METHODS Eleven patients fulfilling the criteria for possible or probable idiopathic normal pressure hydrocephalus and 10 healthy control subjects underwent MRI at 3 Tesla, including DTI with 12 gradient directions. Patients were scanned before lumbar cerebrospinal fluid (CSF) withdrawal tests. Differences in fractional anisotropy (FA) and mean diffusivity (MD) between patients and controls were assessed using 2 different methods: manual definition of regions of interest and a fully automated method, TBSS (Tract-Based Spatial Statistics). DTI parameters were correlated with clinical findings. RESULTS Compared with the control group, patients with chronic idiopathic hydrocephalus had significantly higher MD values in both the periventricular corticospinal tract (CST) and the corpus callosum (CC), whereas FA values were significantly higher in the CST but lower in the CC. DTI parameters of the CST correlated with the severity of gait disturbances. CONCLUSION Microstructural changes in periventricular functionally relevant white matter structures (CSF, CC) in chronic idiopathic hydrocephalus can be visualized using DTI. Further studies should investigate the change of DTI parameters after CSF shunting and its relation to neurologic outcome.

scholarly journals Diffusion tensor imaging in differentiation metastatic from reactive axillary lymph nodes in patients with breast cancer

2021 ◽  
Author(s):  
Ahmed Abdel Razek ◽  
Waleed Elnahas ◽  
Mahmoud Abd El-Latif
Keyword(s):  
Breast Cancer ◽  
Diffusion Tensor Imaging ◽  
Lymph Nodes ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Final Diagnosis ◽  
Axillary Lymph Nodes ◽  
Axillary Lymph ◽  
Reactive N ◽  
Diffusion Tensor Imaging Dti

Purpose: To determine if diffusion tensor imaging (DTI) parameters can differentiate metastatic from reactive axillary lymph nodes (ALNs) in patients with breast cancer. Methods: Prospective study was done on 48 patients with breast cancer that were examined by DTI of the breast. The mean diffusivity (MD) and fractional anisotropy (FA) of ALNs were calculated by 2 observers. The final diagnosis was obtained by biopsy. Results: Metastatic nodes (n=50) had significantly lower MD (p = 0.001, 0.001) and higher FA (p = 0.002, 0.01) than reactive (n=20) nodes for both observers respectively. When threshed of MD (0.875, 0.815 X10-3 mm2/s) was used for differentiation of both entities revealed accuracy (80 %, 81.4 %) and had AUC of 0.920 and 0.918 by both observers respectively. When threshold FA (0.565, 0.645) was used for differentiation revealed an accuracy of 87.1%, 81.4% and had AUC of 0.860 and 0.870 by both observers respectively. Combined FA and MD had AUC 0.940, 0.950) with an accuracy of 91.4%, 92.9% for both observers respectively. Conclusion: Combined analysis DTI parameters FA may play a role in differentiation of metastatic from reactive ALNs in patients with breast cancer.

scholarly journals Diffusion tensor imaging and arterial tissue: establishing the influence of arterial tissue microstructure on fractional anisotropy, mean diffusivity and tractography

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
B. Tornifoglio ◽  
A. J. Stone ◽  
R. D. Johnston ◽  
S. S. Shahid ◽  
C. Kerskens ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Fractional Anisotropy ◽  
Diffusion Tensor ◽  
Ex Vivo ◽  
Mean Diffusivity ◽  
Tissue Microstructure ◽  
Highly Sensitive ◽  
Arterial Tissue ◽  
Porcine Carotid Artery ◽  
Diffusion Tensor Imaging Dti

AbstractThis study investigates diffusion tensor imaging (DTI) for providing microstructural insight into changes in arterial tissue by exploring how cell, collagen and elastin content effect fractional anisotropy (FA), mean diffusivity (MD) and tractography. Five ex vivo porcine carotid artery models (n = 6 each) were compared—native, fixed native, collagen degraded, elastin degraded and decellularised. Vessels were imaged at 7 T using a DTI protocol with b = 0 and 800 s/mm2 and 10 isotopically distributed directions. FA and MD were evaluated in the vessel media and compared across models. FA values measured in native (p < 0.0001), fixed native (p < 0.0001) and collagen degraded (p = 0.0018, p = 0.0016, respectively) were significantly higher than those in elastin degraded and decellularised arteries. Native and fixed native had significantly lower MD values than elastin degraded (p < 0.0001) and decellularised tissue (p = 0.0032, p = 0.0003, respectively). Significantly lower MD was measured in collagen degraded compared with the elastin degraded model (p = 0.0001). Tractography yielded helically arranged tracts for native and collagen degraded vessels only. FA, MD and tractography were found to be highly sensitive to changes in the microstructural composition of arterial tissue, specifically pointing to cell, not collagen, content as the dominant source of the measured anisotropy in the vessel wall.

Abstract WP71: Gradient of Tissue Injury on Diffusion Tensor Imaging After Stroke: Rethinking the Infarct vs Non-infarcted Dichotomy

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Felix Ng ◽  
Vijay Venkatraman ◽  
Mark Parsons ◽  
Andrew Bivard ◽  
Gagan Sharma ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Diffusion Tensor ◽  
Tissue Injury ◽  
Ct Perfusion ◽  
Mean Diffusivity ◽  
Brain Regions ◽  
Homologous Region ◽  
Fluid Attenuated Inversion Recovery ◽  
Infarcted Tissue ◽  
Diffusion Tensor Imaging Dti

Objective: To evaluate the degree of variability in microstructural injury within and adjacent to regions identified as infarcted tissue using Diffusion Tensor Imaging (DTI). Methods: Perfusion CT was performed in 18 patients within 12 hours of ischemic stroke onset followed by Fluid-attenuated Inversion recovery (FLAIR) and DTI one month after stroke. Four regions of interest (ROIs) corresponding to the severity of hypoperfusion on CT perfusion within and beyond the radiological infarct lesion defined on FLAIR were segmented. Fractional anisotropy (FA) and mean diffusivity (MD) were quantified for each ROI and compared to a mirror homologue in the contralateral hemisphere. Ipsilateral to contralateral FA and MD ratios were compared across ROIs. Results: Lower FA and higher MD values were observed within both the infarct lesion and the peri-infarct tissue compared with their homologous contralateral brain regions (all comparisons p≤0.01). No difference was observed in FA and MD between remote non-hypoperfused tissue and its contralateral homologous region (FA p=0.42, MD p≥0.99). The magnitude of asymmetry (ipsilateral/contralateral ratios) of FA and MD was greater with increasing severity of hypoperfusion in a dose-response pattern. Asymmetry greatest in the area of infarction with severe hypoperfusion, followed by infarction with moderate hypoperfusion, the peri-infarct hypoperfused tissue and lastly the remote non-hypoperfused normal tissue (median on clustered quantile regression p≤0.01). Conclusion: A gradient of microstructural injury corresponding to the severity of ischemic insult is present within and beyond conventionally-defined infarct boundaries. The traditional dichotomized notion of infarcted versus non-infarcted tissue widely adopted in clinical research and in practice warrants re-examination.

Quantitative Diffusion Tensor Imaging (DTI) Analysis Reveals Different Infiltrative Patterns of Oligodendrogliomas and Astrocytomas in Peri-Tumour White Matter

Neurosurgery ◽  
2019 ◽  
Vol 84 (5) ◽  
pp. E273-E273
Author(s):  
Christopher Murphy ◽  
Erjon Agushi ◽  
Zhangjie Su ◽  
Rainer Hinz ◽  
Federico Roncaroli ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Control Group ◽  
Control Data ◽  
Primary Brain Tumours ◽  
Diffusion Parameters ◽  
Grade Ii ◽  
Diffusion Tensor Imaging Dti

Abstract INTRODUCTION Gliomas are highly infiltrative primary brain tumours. Glioma infiltration is difficult to identify clinically using conventional diagnostic imaging. We used diffusion tensor imaging (DTI) to identify glioma infiltration in peritumour white matter (WM) and characterized differences between histological subtypes. METHODS We recruited 8 patients with a histological diagnosis of grade II or III glioma and 10 healthy controls. We compared fractional anisotropy (FA) maps of each patient against the control group using SPM8 (Matlab 2014a) to identify regions of glioma infiltration. The FA and mean diffusivity (MD) of formerly WM matter tumour regions, infiltrated WM and normal appearing WM were compared with a 2-sample t-test and characterized with respect to normal control data. RESULTS Our results have identified radiological evidence of infiltration in the peri-tumour WM of glioma patients. The infiltrated region of oligodendrogliomas extended further than that of astrocytomas. Oligodendrogliomas preferentially infiltrated larger WM tracts, whereas astrocytomas infiltrated more peripheral WM. In all grades, the 3 regions had significantly different diffusion parameters and there were significant differences between oligodendrogliomas and astrocytomas. CONCLUSION We identified previously unrecognized study wide significant changes in the peri-tumour WM of gliomas. Despite the known propensity of these tumours to infiltrate WM we found no significant DTI changes distant to the tumour. Our DTI results suggest oligodendrogliomas and astrocytomas demonstrate different infiltrative patterns, which highlights the need for astrocytomas and oligodendrogliomas to be studied separately.

scholarly journals Free-water diffusion tensor imaging improves the accuracy and sensitivity of white matter analysis in Alzheimer’s disease

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maurizio Bergamino ◽  
Ryan R. Walsh ◽  
Ashley M. Stokes
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Diffusion Tensor ◽  
Free Water ◽  
Potential Impact ◽  
Magnetic Resonance Imaging Mri ◽  
Underlying Pathology ◽  
Diffusion Tensor Imaging Dti

AbstractMagnetic resonance imaging (MRI) based diffusion tensor imaging (DTI) can assess white matter (WM) integrity through several metrics, such as fractional anisotropy (FA), axial/radial diffusivities (AxD/RD), and mode of anisotropy (MA). Standard DTI is susceptible to the effects of extracellular free water (FW), which can be removed using an advanced free-water DTI (FW-DTI) model. The purpose of this study was to compare standard and FW-DTI metrics in the context of Alzheimer’s disease (AD). Data were obtained from the Open Access Series of Imaging Studies (OASIS-3) database and included both healthy controls (HC) and mild-to-moderate AD. With both standard and FW-DTI, decreased FA was found in AD, mainly in the corpus callosum and fornix, consistent with neurodegenerative mechanisms. Widespread higher AxD and RD were observed with standard DTI; however, the FW index, indicative of AD-associated neurodegeneration, was significantly elevated in these regions in AD, highlighting the potential impact of free water contributions on standard DTI in neurodegenerative pathologies. Using FW-DTI, improved consistency was observed in FA, AxD, and RD, and the complementary FW index was higher in the AD group as expected. With both standard and FW-DTI, higher values of MA coupled with higher values of FA in AD were found in the anterior thalamic radiation and cortico-spinal tract, most likely arising from a loss of crossing fibers. In conclusion, FW-DTI better reflects the underlying pathology of AD and improves the accuracy of DTI metrics related to WM integrity in Alzheimer’s disease.

scholarly journals Gry wideo a zmiany strukturalne mózgu

Kosmos ◽  
2020 ◽  
Vol 69 (1) ◽  
pp. 233-241
Author(s):  
Natalia Kowalczyk ◽  
Aneta Brzezicka
Keyword(s):  
Magnetic Resonance Imaging ◽  
Diffusion Tensor Imaging ◽  
Magnetic Resonance ◽  
Diffusion Tensor ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri ◽  
Diffusion Tensor Imaging Dti

Mimo iż gry wideo, zwane również grami komputerowymi, nie powstały, aby uczyć to stanowią płaszczyznę do badania neuroplastyczności czyli zdolności mózgu do ,,przeprogramowywania się?? w wyniku specyficznego doświadczenia. Badania donoszą, iż regularne granie w gry komputerowe, w szczególności gry akcji, poprawia głównie podstawowe zdolności poznawcze, takie jak szybkość reagowania, wrażliwość na kontrast czy selektywność i podzielność uwagi. Pojedyncze badania pokazują poprawę funkcji wykonawczych. Mniej wiadomo natomiast nt. neuronalnych podstaw tego rodzaju poprawy. W niniejszym artykule podsumowujemy wyniki badań, w których przeprowadzano pomiary strukturalnych zmian mózgu w wyniku doświadczenia z grami komputerowymi. Zestawione zostały badania wykorzystujące głównie dwie metody badania plastyczności mózgu - morfometrii bazującej na wokselach (ang. based morphometry, VBM) istoty szarej oraz obrazowanie tensora dyfuzji (ang. diffusion tensor imaging, DTI) w istocie białej. Badania zmian strukturalnych mózgu z użyciem rezonansu magnetycznego (magnetic resonance imaging, MRI) dostarczają kolejnych przykładów na potencjalne korzyści płynące z grania w gry komputerowe.

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