No abstract available.
Diffusion Tensor Imaging* ; Diffusion*

Diffusion Tensor Imaging (DTI) is an advanced magnetic resonance imaging (MRI) technique. DTI provides quantitative information at microstuructural level via its parameter indices e.g. mean diffusivity (MD) and fractional anisotropy (FA). It also allows for visualization of neuron fibres through a specific technique called fibre tractography. Leukoaraiosis is an asymptomatic pathological condition of the brain white matter which appears hyperintense on T2-weighted MRI images. Association of leukoaraiosis with age and ischemic heart disease have been previously reported. The objective of this study is to compare MD and FA values measured in various areas of the brain white matter (WM), grey matter (GM), and cerebrospinal fluid (CSF) in humans using DTI. 30 subjects with leukoaraiosis and 12 subjects without leukoaraiosis underwent brain scan using GE 1.5 Tesla MRI system. Region of interests were located in the CSF and various WM and GM areas. Comparison of MD and FA values was made between leukoaraiosis tissue (LA) and normal appearing brain tissue (NABT) measured within the same leukoaraiosis subjects, and with normal brain tissue (CONTROL) of healthy control subjects. LA demonstrated a significantly higher MD and lower FA compared to NABT and CONTROL in frontal and occipital WM areas. No differences were observed in MD in any brain region between NABT and CONTROL. Whereas no differences were observed in FA between NABT and CONTROL except in the occipital WM. Fibre tractography showed 31.7% to 56.1% lesser fibre tracts in LA subjects compared to CONTROL subjects. Significant differences were found between pathological tissue compared to normal appearing brain tissue and normal brain tissue. Fibre tractography exposed reduced number of neural fibres in leukoaraiosis subjects as compared to normal subjects.
Diffusion Tensor Imaging

Internal capsular genu infarcts infrequently cause cognitive impairment and behavioral changes, and little is known about the underlying mechanism. Using diffusion-tensor imaging (DTI) and the fractional anisotropy (FA) index in the region of interest (ROI) and ipsilesional frontal cortex, we evaluated two patients with internal capsular genu infarction who presented with frontal dysfunction and cognitive impairment. The reported findings help to elucidate the mechanism underlying cognitive deterioration in internal capsular genu infarction.
Anisotropy ; Diffusion ; Diffusion Tensor Imaging ; Humans ; Infarction

PURPOSE: Diffusion tensor imaging (DTI) data must be analyzed by an analyzer after data processing. Hence, the analyzed data of DTI might depend on the analyzer, making it a major limitation. This paper reviewed previous DTI studies reporting the repeatability and reproducibility of data from the corticospinal tract (CST), one of the most actively researched neural tracts on this topic. MATERIALS AND METHODS: Relevant studies published between January 1990 and December 2018 were identified by searching PubMed, Google Scholar, and MEDLINE electronic databases using the following keywords: DTI, diffusion tensor tractography, reliability, repeatability, reproducibility, and CST. As a result, 15 studies were selected. RESULTS: Measurements of the CSTs using region of interest methods on 2-dimensional DTI images generally showed excellent repeatability and reproducibility of more than 0.8 but high variability (0.29 to 1.00) between studies. In contrast, measurements of the CST using the 3-dimensional DTT method not only revealed excellent repeatability and reproducibility of more than 0.9 but also low variability (repeatability, 0.88 to 1.00; reproducibility, 0.82 to 0.99) between studies. CONCLUSION: Both 2-dimensional DTI and 3-dimensional DTT methods appeared to be reliable for measuring the CST but the 3-dimensional DTT method appeared to be more reliable.
Diffusion Tensor Imaging ; Diffusion ; Methods ; Pyramidal Tracts

No abstract available.
Diffusion Tensor Imaging ; Diffusion ; Hemiplegia ; Humans

Neuroimaging studies in schizophrenia have remarkably increased and provided some clues to understand its pathophysiology. Here, we reviewed the neuroimaging, studies including volume analysis, functional magnetic resonance imaging (MRI) and diffusion tensor imaging, and findings in both early stage schizophrenia and high-risk group. The reviewed studies suggested that the brain with schizophrenia showed both regional deficits and dysconnectivity of neural circuit in the first episode, even high-risk group as well as chronic schizophrenia. Multimodal neuroimaging or combined approach with genetic, electro- or magneto-encephalographic data could provide promising results to understand schizophrenia in the near future.
Brain ; Diffusion Tensor Imaging ; Magnetic Resonance Imaging ; Neuroimaging ; Schizophrenia

Diffusion tensor imaging (DTI) is being used more and more widely in the diagnosis of central nervous system. Based on DTI, track density imaging (TDI) is an emerging technique applied to clinical use. This article introduced the principle and clinical application, analyzed pros and cons, and made conclusion and prospect of these two techniques.
Diffusion Tensor Imaging ; Humans ; Nervous System ; diagnostic imaging

Neuroimaging in psychiatry encompasses the powerful tools available for the in vivo study of brain structure and function. MRI including the volumetry, voxel-base morphometry(VBM) and diffusion tensor imaging (DTI) are useful for assessing brain structure, whereas function MRI, positron emission tomography(PET) and magnetoencephalography(MEG) are well established for probing brain function. These tools are well tolerated by the vast majority of psychiatric patients because they provide a powerful but noninvasive means to directly evaluate the brain. Although neuroimaging technology is currently used only to rule in or rule out general medical conditions as opposed to diagnosing primary mental disorders, it may be used to confirm or make psychiatric diagnoses in the future. In addition, neuroimaging may be valuable for predicting the natural course of psychiatric illness as well as treatment response.
Brain ; Diffusion Tensor Imaging ; Electrons ; Humans ; Mental Disorders ; Neuroimaging

We report a case of bilateral perisylvian polymicrogyria, which was evaluated using diffusion tensor imaging (DTI) and tractography. On DTI tractography, fibers of the arcuate fasciculus (AF), which connects the posterior inferior frontal region and superior temporal gyrus were absent. It indicates that in cases of bilateral perisylvian polymicrogyria, compromised language skills might be associated with the absence of AF.
Child* ; Diffusion Tensor Imaging ; Humans ; Polymicrogyria* ; Temporal Lobe

To explore the mechanism for changes in brain microstructure in long-term abstinent from methamphetamine-dependence by using the diffusion tensor imaging (DTI).
 Methods: A total of 26 patients with long-term abstinent methamphetamine-dependence, whose abstinence time more than 14 months, and 26 normal controls all underwent cognitive executive function tests and DTI scans. We used voxel-based analysis to compare the fractional anisotropy (FA) and mean diffusivity (MD) to obtain the abnormal brain regions of DTI parameters between the two groups. Spearman correlation analysis was used to explore the correlation between FA, MD of the brain regions with abnormal parameters and cognitive executive function tests.
 Results: There were no statistical differences in the cognitive executive function tests between the two groups (P>0.05). Compared with the normal control group, the long-term abstinent from methamphetamine-dependence group showed the decreased FA in the right precuneus, right superior frontal gyrus, right calcarine, left inferior temporal gyrus and the increased MD in the right triangular part of inferior frontal gyrus, right precuneus, right posterior cingulate, right middle temporal gyrus, bilateral middle occipital gyrus, left superior parietal lobule, and lobule VIII of cerebellar hemisphere. The MD values of the right middle temporal gyrus in the long-term abstinent group were negatively correlated with the number of completions within 60 seconds (r=-0.504) and within 120 seconds (r=-0.464) .
 Conclusion: The DTI parameters in multiple brain regions from the methamphetamine-dependence patients are still abnormal after a long-term abstinence. DTI can provide imaging evidence for brain microstructural abnormalities in long-term abstinent from methamphetamine-dependence.
Amphetamine-Related Disorders ; Anisotropy ; Brain ; Diffusion Tensor Imaging ; Humans ; Methamphetamine