In Vivo visualization of white matter fiber tracts in the brainstem using low flip angle double echo 3D gradient echo imaging at 3T.

BACKGROUND: White matter (WM) fiber tracts in the brainstem communicate with various regions in the cerebrum, cerebellum, and spinal cord. Clinically, small lesions, malformations, or histopathological changes in the brainstem can cause severe neurological disorders. A direct and non-invasive assessment approach could bring valuable information about the intricate anatomical variations of the white matter fiber tracts and nuclei. Although tractography from diffusion tensor imaging has been commonly used to map the WM fiber tracts connectivity, it is difficult to differentiate the complex WM tracts anatomically. Both high field MRI methods and ultrahigh-field MRI methods at 7T and 11.7 T have been used to enhance the contrast of WM fiber tracts. Despite their promising results, it is still challenging to achieve wide clinical adoption at 3T. In this study, we explored a clinically feasible method using a proton density weighted (PDW) 3D gradient echo (GRE) sequence to directly image the WM fiber tracts in the brainstem at 3T in vivo. METHODS: We optimized a 3D high resolution, double echo, short TR, PDW GRE sequence on 5 healthy volunteers using a clinical 3T scanner to visualize the complicated anatomy of WM fiber tracts in the brain stem. Tissue properties including T1, proton density and T2* from in vivo quantitative MRI data were used for simulations to determine the optimal flip angle for the sequence. The visualization of multiple WM fiber tracts in the brainstem was assessed qualitatively and quantitatively using relative contrast and contrast-to-noise ratio (CNR). To improve the CNR, the final images were created by averaging over all echoes from two consecutive scans at the optimal flip angle. The results were compared to anatomical atlases and histology sections to identify the major fiber tracts. All the identified major fiber tracts were labeled on axial, sagittal and coronal slices. RESULTS: The WM fiber tracts were found to have distinct hypointense signal throughout the brainstem and most of the major WM fiber tracts, such as the corticospinal tract, medial lemniscus, medial longitudinal fasciculus, and central tegmental tract, in the brainstem up to and including the thalamus were identified in all subjects. Both qualitative and quantitative evaluations showed that the 3° scan offered the best contrast for WM fiber tracts for a TR of 20 ms. The average over the first two echo times and two consecutive 3° scans gave a CNR of 47.8 ± 6.2 for the pyramidal tracts in particular and CNRs values greater than 6.5 ± 2.4 for the rest of the fiber tracts. CONCLUSIONS: All the major fiber tracts in the brainstem could be visualized. Given the reasonably short scan time of 10 min at 3T, double echo PDW GRE sequence is a very practical approach for clinical adoption.

Direct geniculo-extrastriate pathways: a review of the literature.

PURPOSE: The aim of this paper is to review the literature on direct geniculo-extrastriate pathways with special attention to 3D extrastriate visual areas. METHODS: A literature review was realized using PubMed and Google Scholar. "Lateral geniculate nucleus", "geniculo-extrastriate pathways" and "white matter fiber tracts" were among the keywords used. RESULTS: Existence of geniculo-extrastriate connections was first hypothesized by the clinical observations of Riddoch's syndrome in patients with striate cortex (primary visual area, V1) lesions. Robust histological proof of geniculo-extrastriate pathways exists in monkeys. In humans, these pathways were tested through functional magnetic resonance imaging (fMRI), electro- and magneto-physiological paradigms. Conversely, only indirect proof of the connection between lateral geniculate nucleus and V5 exists. To our knowledge there were not any anatomical studies of geniculo-extrastriate connections in humans. CONCLUSION: Few human studies take interest in geniculo-extrastriate pathways. Only indirect proof of geniculo-extrastriate pathways exists in humans.

Correspondence between white matter hyperintensities and regional grey matter volumes in Alzheimer's disease.

Objective: White matter hyperintensities (WMH) are the most common neuroimaging manifestation of cerebral small vessel disease, and is frequently observed in Alzheimer's disease (AD). This study aimed to investigate the relationship between WMH and cognition and to verify the mediation of grey matter atrophy in this relationship. Methods: The diffusion tensor imaging (DTI) technique analyses white matter fiber tract to assess white matter integrity. Voxel-based morphometry was applied to measure the grey matter volume (GMV). A linear regression model was applied to examine the associations between WMH and GMV, and mediation analyses was performed to determine the mediating role of regional GMV in the effect of WMH on cognitive function. Results: Compared to the HC group, AD group have 8 fiber tract fractional anisotropy (FA) decreased and 16 fiber tract mean diffusivity (MD) increased. Compared to AD without WMH, AD with high WMH had 9 fiber tracts FA decreased and 13 fiber tracts MD increased. High WMH volume was negatively correlated with GMV in the frontal-parietal region. Low WMH volume was also negatively correlated with GMV except for the three regions (right angular gyrus, right superior frontal gyrus and right middle/inferior parietal gyrus), where GMV was positively correlated. Mediation analysis showed that the association between WMH and executive function or episodic memory were mediated by GMV in the frontal-parietal region. Conclusion: Damage to white matter integrity was more severe in AD with WMH. Differential changes in DTI metrics may be caused by progressive myelin and axonal damage. There was a negative correlation between WMH and grey matter atrophy in frontal-parietal regions in a volume-dependent manner. This study indicates the correspondence between WMH volume and GMV in cognition, and GMV being a key modulator between WMH and cognition in AD. This result will contribute to understanding the progression of the disease process and applying targeted therapeutic intervention in the earlier stage to delay neurodegenerative changes in frontal-parietal regions to achieve better treatment outcomes and affordability.

Mapping Motor Pathways in Parkinson's Disease Patients with Subthalamic Deep Brain Stimulator: A Diffusion MRI Tractography Study.

INTRODUCTION: This study assessed the safety of postoperative diffusion tensor imaging (DTI) with on-state deep brain stimulation (DBS) and the feasibility of reconstruction of the white matter tracts in the vicinity of the stimulation site of the subthalamic nucleus (STN). The association between the impact of DBS on the nigrostriatal pathway (NSP) and the treatment effect on motor symptoms in Parkinson's disease (PD) was then evaluated. METHODS: Thirty-one PD patients implanted with STN-DBS (mean age: 66 years; 25 male) were scanned on a 1.5-T magnetic resonance imaging (MRI) scanner using the DTI sequence with DBS on. Twenty-three of them were scanned a second time with DBS off. The NSP, dentato-rubro-thalamic tract (DRTT), and hyperdirect pathway (HDP) were generated using both deterministic and probabilistic tractography methods. The DBS-on-state and off-state tractography results were validated and compared. Afterward, the relationships between the characteristics of the reconstructed white matter tracts and the clinical assessment of PD symptoms and the DBS effect were further examined. RESULTS: No adverse events related to DTI were identified in either the DBS-on-state or off-state. Overall, the NSP was best reconstructed, followed by the DRTT and HDP, using the probabilistic tractography method. The connection probability of the left NSP was significantly lower than that of the right side (p < 0.05), and a negative correlation (r = -0.39, p = 0.042) was identified between the preoperative symptom severity in the medication-on state and the connection probability of the left NSP in the DBS-on-state images. Furthermore, the distance from the estimated left-side volume of tissue activated (VTA) by STN-DBS to the ipsilateral NSP was significantly shorter in the DBS-responsive group compared to the DBS-non-responsive group (p = 0.046). CONCLUSIONS: DTI scanning is safe and delineation of white matter pathway is feasible for PD patients implanted with the DBS device. Postoperative DTI is a useful technique to strengthen our current understanding of the therapeutic effect of DBS for PD and has the potential to refine target selection strategies for brain stimulation.

For some more seriously affected Parkinson's disease (PD) patients, drugs are no longer effective in treating their symptoms. An alternate treatment is to use deep brain stimulation (DBS), a commonly used neurosurgical therapy for PD patients. For those DBS treatments targeting the subthalamic nucleus (STN), the electrical stimulation used may impact nearby white matter tracts and alter the effectiveness of the DBS treatment. The nigrostriatal pathway (NSP), dentato-rubro-thalamic tract, and hyperdirect pathway are three white matter tracts near the STN. They are all relevant to motor symptoms in PD. This study examined whether imaging these tracts using magnetic resonance imaging (MRI) is safe and feasible in the presence of DBS leads. The relationships between the fiber-tracking characteristics and distance to the DBS leads were then evaluated. For this purpose, 31 PD patients with stimulation-on were scanned on a 1.5 T MRI scanner using a diffusion tensor imaging sequence. A total of 23 subjects underwent another scan using the same sequence with stimulation-off. No adverse events related to diffusion tensor imaging were found. Among the white matter tracts near the STN, the NSP was best delineated, followed by the dentato-rubro-thalamic tract and the hyperdirect pathway. The connection probability of the left NSP was significantly lower than that of the right side as were the subject's motor symptoms. The closer the distance between the NSP and the stimulation location, the better the DBS outcome. These findings indicate that imaging white matter tracts with DBS on is safe and useful in mapping DBS outcomes.

Sensitivity of Diffusion MRI to White Matter Pathology: Influence of Diffusion Protocol, Magnetic Field Strength, and Processing Pipeline in Systemic Lupus Erythematosus.

There are many ways to acquire and process diffusion MRI (dMRI) data for group studies, but it is unknown which maximizes the sensitivity to white matter (WM) pathology. Inspired by this question, we analyzed data acquired for diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) at 3T (3T-DTI and 3T-DKI) and DTI at 7T in patients with systemic lupus erythematosus (SLE) and healthy controls (HC). Parameter estimates in 72 WM tracts were obtained using TractSeg. The impact on the sensitivity to WM pathology was evaluated for the diffusion protocol, the magnetic field strength, and the processing pipeline. Sensitivity was quantified in terms of Cohen's d for group comparison. Results showed that the choice of diffusion protocol had the largest impact on the effect size. The effect size in fractional anisotropy (FA) across all WM tracts was 0.26 higher when derived by DTI than by DKI and 0.20 higher in 3T compared with 7T. The difference due to the diffusion protocol was larger than the difference due to magnetic field strength for the majority of diffusion parameters. In contrast, the difference between including or excluding different processing steps was near negligible, except for the correction of distortions from eddy currents and motion which had a clearly positive impact. For example, effect sizes increased on average by 0.07 by including motion and eddy correction for FA derived from 3T-DTI. Effect sizes were slightly reduced by the incorporation of denoising and Gibbs-ringing removal (on average by 0.011 and 0.005, respectively). Smoothing prior to diffusion model fitting generally reduced effect sizes. In summary, 3T-DTI in combination with eddy current and motion correction yielded the highest sensitivity to WM pathology in patients with SLE. However, our results also indicated that the 3T-DKI and 7T-DTI protocols used here may be adjusted to increase effect sizes.

Evidence for exercise-related plasticity in functional and structural neural network connectivity.

The number of studies investigating exercise and cardiorespiratory fitness (CRF)-related changes in the functional and structural organization of brain networks continues to rise. Functional and structural connectivity are critical biomarkers for brain health and many exercise-related benefits on the brain are better represented by network dynamics. Here, we reviewed the neuroimaging literature to better understand how exercise or CRF may facilitate and maintain the efficiency and integrity of functional and structural aspects of brain networks in both younger and older adults. Converging evidence suggests that increased exercise performance and CRF modulate functional connectivity of the brain in a way that corresponds to behavioral changes such as cognitive and motor performance improvements. Similarly, greater physical activity levels and CRF are associated with better cognitive and motor function, which may be brought about by enhanced structural network integrity. This review will provide a comprehensive understanding of trends in exercise-network studies as well as future directions based on the gaps in knowledge that are currently present in the literature.

Tract Specific White Matter Lesion Load Affects White Matter Microstructure and Their Relationships With Functional Connectivity and Cognitive Decline.

White matter hyperintensities (WMHs) are associated with cognitive decline. Assessing the effect of WMH on WM microstructural changes and its relationships with structural and functional connectivity to multiple cognitive domains are helpful to better understand the pathophysiological processes of cognitive impairment. 65 participants (49 normal and 16 MCI subjects, age: 67.4 ± 8.3 years, 44 females) were studied at 3T. The WMHs and fifty fiber tracts were automatically segmented from the T1/T2-weighted images and diffusion-weighted images, respectively. Tract-profiles of WMH were compared with those of apparent fiber density (AFD). The relationship between AFD and tract connectivity (TC) was assessed. Functional connectivity (FC) between tract ends obtained from resting-state functional MRI was examined in relation to TC. Tract-specific relationships of WMH, TC and FC with a multi-domain neuropsychological test battery and Montreal Cognitive Assessment (MoCA) were also separately assessed by lasso linear regression. Indirect pathways of TC and FC between WMH and multiple cognitive measures were tested using the mediation analysis. Higher WMH loads in WM tracts were locally matched with the reduced AFD, which was related to decrease in TC. However, no direct relationship was found between TC and FC. Tract-specific changes on WMH, TC and FC for each cognitive performance may explain that macro- and microstructural and functional changes are associated differently with each cognitive domain in a fiber specific manner. In these identified tracts, the differences between normal and MCI for WMH and TC were increased, and the relationships of WMH, TC and FC with cognitive outcomes were more significant, compared to the results from all tracts. Indirect pathways of two-step (TC-FC) between WMH and all cognitive domains were significant (p < 0.0083 with Bonferroni correction), while the separated indirect pathways through TC and through FC were different depending on cognitive domain. Deterioration in specific cognitive domains may be affected by alterations in a set of different tracts that are differently associated with macrostructural, microstructural, and function changes. Thus, assessments of WMH and its associated changes on specific tracts help for better understanding of the interrelationships of multiple changes in cognitive impairment.

Tract-defined regional white matter hyperintensities and memory.

White matter hyperintensities (WMH) are common radiological findings among older adults and strong predictors of age-related cognitive decline. Recent work has implicated WMH in the pathogenesis and symptom presentation of Alzheimer's disease (AD), which is characterized clinically primarily by a deficit in memory. The severity of WMH volume is typically quantified globally or by lobe, whereas white matter itself is organized by tracts and fiber classes. We derived WMH volumes within white matter tract classes, including association, projection, and commissural tracts, in 519 older adults and tested whether WMH volume within specific fiber classes is related to memory performance. We found that increased association and projection tract defined WMH volumes were related to worse memory function but not to a global cognition summary score that excluded memory. We conclude that macrostructural damage to association and projection tracts, manifesting as WMH, may result in memory decline among older adults.

[Therapeutic effect of the combined treatment with acupuncture and venlafaxine hydrochloride on depression based on diffusion tensor imaging technology].

OBJECTIVE: To explore the effectiveness and safety of the combined treatment with acupuncture and venlafaxine hydrochloride on depression in terms of the microstructure change of white matter fiber tracts of brain based on diffusion tensor imaging technology (DTI). METHODS: The prospective study design was adopted. All of 60 patients with depression were randomized into an acupuncture-medication group and a medication group, 30 cases in each one. In the medication group, venlafaxine hydrochloride was used, 75 mg per day in the 1st week, 150 mg per day in the 2nd week and 225 mg per day from the 3rd to 6th week. In the acupuncture-medication group, on the base of the treatment in the medication group, acupuncture was combined. Baihui (GV 20) and Yintang (GV 29) were the main acupoints. The supplementary acupoints were selected according to the clinical symptoms of individuals. The needles were retained for 30 min. Acupuncture was provided once every 2 days, 3 times a week. The consecutive 12 weeks of treatment were required in the two groups. Additionally, a normal group was prepared with 30 healthy volunteers. Separately, before treatment, in 2, 8 and 12 weeks of treatment, Hamilton's depression scale (HAMD-17), Beck depression inventory scale (BDI) and the antidepressant side effect scale (SERS) were adopted to evaluate the effectiveness and safety of the two groups. Moreover, before and after 12 weeks of treatment, DTI was adopted to detect the fractional anisotropy score (FA) of each brain region in the patients. RESULTS: After treatment, the scores of HAMD-17 and BDI were all reduced in the two groups (P<0.05). In 8 and 12 weeks of treatment, the scores of HAMD-17 and BDI in the acupuncture-medication group were less than those in the medication group (P<0.05). The difference in SERS score was not significant statistically between the two groups (P>0.05). Compared with the healthy volunteers, FA scores in 6 brain regions changed obviously in the patients with depression, including the white matter of bilateral frontal lobes, splenium of corpus callosum, left cingulated gyrus, white matter of bilateral inferior temporal gyrus, white matter of bilateral inferior parietal lobe and white matter of bilateral deep temporal occipital region separately. Before treatment, the differences in FA scores of these 6 brain regions were not significant statistically between the two groups (P>0.05). After treatment, FA scores in the white matter of bilateral frontal lobes, white matter of bilateral inferior temporal gyrus and white matter of bilateral deep temporal occipital region in the acupuncture-medication group were all higher than those in the medication group (P<0.05). CONCLUSION: Acupuncture repairs the brain white matter fiber tracts in some brain regions to certain extent and the therapeutic effects are enhanced with the adjuvant medication of venlafaxine hydrochloride.

Microsurgical Anatomy of the Insular Region and Operculoinsular Association Fibers and its Neurosurgical Application.

OBJECTIVE: To analyze the three-dimensional relationships of the operculoinsular compartments, using standard hemispheric and white matter fiber dissection and review the anatomy of association fibers related to the operculoinsular compartments of the Sylvian fissure and the main white matter tracts located deep into the insula. The secondary aim of this study was to improve the knowledge on this complex region to safely address tumor, vascular, and epilepsy lesions with an integrated perspective of the topographic and white matter fiber anatomy using 2D and 3D photographs. METHODS: Six cadaveric hemispheres were dissected. Two were fixed with formalin and the arteries were injected with red latex dye; the remaining four were prepared using the Kingler method and white fiber dissections were performed. RESULTS: The insula is located entirely inside the Sylvian fissure. The topographic hemispheric anatomy, Sylvian fissure, opercula, surrounding sulci and gyri, as well as the M2, M3, and M4 segments were identified. The anatomy of the insula, with the sulci and gyri and the limiting sulci, were also identified and described. The main white matter fiber tracts of the operculoinsular compartments of the Sylvian fissure as well as the main association and commissural fibers located deep in the insula were dissected and demonstrated. CONCLUSIONS: Complementing topographic anatomy with detailed study of white matter fibers and their integration can help the neurosurgeon to safely approach lesions in the insular region, improving postoperative results in the microsurgical treatment of aneurysmal lesions, insular tumors, or epilepsy surgery.

The association of regional white matter lesions with cognition in a community-based cohort of older individuals.

Emerging evidence from lesion-symptom mapping (LSM) studies suggested that regional white matter lesions (WML) on strategic white matter (WM) fiber tracts are significantly associated with specific cognitive domains, independent of global WML burden. However, previous LSM investigations were mostly carried out in disease cohorts, with little evidence from community-based older individuals, making findings difficult to generalize. Moreover, most LSM studies applied a threshold to the probabilistic atlas, leading to the loss of information and threshold-dependent findings. Furthermore, it is still unclear whether associations between regional WML and cognition are independent of global grey matter (GM) and WM volumes, which have also been linked to cognition. In the current study, we undertook a region of interest (ROI) LSM study to examine the relationship between regional WML on strategic WM tracts and cognitive performance in a large community-based cohort of older individuals (N = 461; 70-90 years). WML were extracted using a publicly available pipeline, UBO Detector (https://cheba.unsw.edu.au/group/neuroimaging-pipeline). Mapping of WML to the Johns Hopkins University WM atlas was undertaken using an automated TOolbox for Probabilistic MApping of Lesions (TOPMAL), which we introduce here, and is implemented in UBO Detector. The results show that different patterns of brain structural volumes in the ageing brain were associated with different cognitive domains. Regional WML were associated with processing speed, executive function, and global cognition, independent of total GM, WM and WML volumes. Moreover, regional WML explained more variance in executive function, compared to total GM, WM and WML volumes. The current study highlights the importance of studying regional WML in age-related cognitive decline.

A Fiber Tractography Study of Social-Emotional Related Fiber Tracts in Children and Adolescents with Autism Spectrum Disorder.

The symptoms of autism spectrum disorder (ASD) have been hypothesized to be caused by changes in brain connectivity. From the clinical perspective, the "disconnectivity" hypothesis has been used to explain characteristic impairments in "socio-emotional" function. Therefore, in this study we compared the facial emotional recognition (FER) feature and the integrity of social-emotional-related white-matter tracts between children and adolescents with high-functioning ASD (HFA) and their typically developing (TD) counterparts. The correlation between the two factors was explored to find out if impairment of the white-matter tracts is the neural basis of social-emotional disorders. Compared with the TD group, FER was significantly impaired and the fractional anisotropy value of the right cingulate fasciculus was increased in the HFA group (P < 0.01). In conclusion, the FER function of children and adolescents with HFA was impaired and the microstructure of the cingulate fasciculus had abnormalities.

Therapeutic effect of the combined treatment with acupuncture and venlafaxine hydrochloride on depression based on diffusion tensor imaging technology / 中国针灸

OBJECTIVE@#To explore the effectiveness and safety of the combined treatment with acupuncture and venlafaxine hydrochloride on depression in terms of the microstructure change of white matter fiber tracts of brain based on diffusion tensor imaging technology (DTI).@*METHODS@#The prospective study design was adopted. All of 60 patients with depression were randomized into an acupuncture-medication group and a medication group, 30 cases in each one. In the medication group, venlafaxine hydrochloride was used, 75 mg per day in the 1st week, 150 mg per day in the 2nd week and 225 mg per day from the 3rd to 6th week. In the acupuncture-medication group, on the base of the treatment in the medication group, acupuncture was combined. Baihui (GV 20) and Yintang (GV 29) were the main acupoints. The supplementary acupoints were selected according to the clinical symptoms of individuals. The needles were retained for 30 min. Acupuncture was provided once every 2 days, 3 times a week. The consecutive 12 weeks of treatment were required in the two groups. Additionally, a normal group was prepared with 30 healthy volunteers. Separately, before treatment, in 2, 8 and 12 weeks of treatment, Hamilton's depression scale (HAMD-17), Beck depression inventory scale (BDI) and the antidepressant side effect scale (SERS) were adopted to evaluate the effectiveness and safety of the two groups. Moreover, before and after 12 weeks of treatment, DTI was adopted to detect the fractional anisotropy score (FA) of each brain region in the patients.@*RESULTS@#After treatment, the scores of HAMD-17 and BDI were all reduced in the two groups (0.05). Compared with the healthy volunteers, FA scores in 6 brain regions changed obviously in the patients with depression, including the white matter of bilateral frontal lobes, splenium of corpus callosum, left cingulated gyrus, white matter of bilateral inferior temporal gyrus, white matter of bilateral inferior parietal lobe and white matter of bilateral deep temporal occipital region separately. Before treatment, the differences in FA scores of these 6 brain regions were not significant statistically between the two groups (>0.05). After treatment, FA scores in the white matter of bilateral frontal lobes, white matter of bilateral inferior temporal gyrus and white matter of bilateral deep temporal occipital region in the acupuncture-medication group were all higher than those in the medication group (<0.05).@*CONCLUSION@#Acupuncture repairs the brain white matter fiber tracts in some brain regions to certain extent and the therapeutic effects are enhanced with the adjuvant medication of venlafaxine hydrochloride.

Correlation analysis between white matter fiber tracts and executive function in corticobasal syndrome / 中风与神经疾病杂志

@#To investigate the executive function impairment in CBS patients and its relationship with the microstructural integrity of white matter fiber tracts. MethodsEleven CBS patients and 17 cognitively normal subjects who visited our hospital from November 2018 to November 2019 were evaluated for executive function，including forward digit span，reverse digit span，correct line of TMT-A line，and correct line of TMT-B line. Diffusion tensor imaging（DTI）scans were performed in the CBS control group to compare the fractional anisotropy（FA）value，mean diffusivity（MD）value，axial diffusivity（AD）and radial diffusivity（RD）values of the fiber bundles with changed microstructure with executive function scores. ResultsExcept for CBS digit span forward score（P=0.446），reverse digit span（P<0.001），correct line of TMT-A line（P<0.001）and correct line of TMT-B line（P<0.001），the differences were statistically significant. Compared with the HC group，the FA values of the left corticospinal tract，anterior thalamic radiation，cingulate fasciculus，superior longitudinal fasciculus，inferior longitudinal fasciculus，and corpus callosum were reduced in the CBS group compared with the HC group，and the difference was not statistically significant（P>0.05）. The MD values，AD values，and RD values of the left corticospinal tract，anterior thalamic radiation，cingulate tract，superior longitudinal tract，inferior longitudinal tract，and corpus callosum were increased in the CBS group（lesion side）and the HC group compared with the HC group，and the differences were statistically significant（P<0.05）. The reverse digit span was negatively correlated with the RD value of the superior longitudinal fasciculus of the lesion（r=-0.741，P=0.036），and the reverse digit span was negatively correlated with the RD value of the superior longitudinal fasciculus of the lesion. ConclusionPatients with CBS have executive dysfunction and changes in the integrity of white matter fiber tracts；executive dysfunction in patients with CBS is related to changes in the integrity of white matter fiber tracts in addition to frontotemporal atrophy；abnormal structural connectivity of white matter fibers may be one of the causes of executive dysfunction in patients with CBS.

Advance in Diffusion Tensor Imaging in Assessment of White Matter Fiber Tracts Injury and Prognosis of Stroke(rerview) / 中国康复理论与实践

@# Diffusion tensor imaging (DTI) could not only reconstruct of the brain white matter neural connectivity, but also show clearly the brain white matter fiber morphology of lesions, either directly or indirectly, which imaged on white matter fiber tracts in the three-dimensional geometric structure by special software for image on the anisotropic thermal motion of water molecules. This paper reviewed the researches on DTI in the assessment of white matter fiber tracts injury and prognosis in patients with stroke.