Decreased Fractional Anisotropy Values Research Articles

Diffusion tensor imaging findings of patients with parkinson's disease refractory to medical treatment

Aim: Diffusion Tensor Imaging (DTI) findings can be useful to detect and measure neurodegeneration that is seen in Parkinson’sdisease (PD). Microstructural changes in regions of the brain related with motor function are evaluated by using DTI measurementsof fractional anisotropy (FA) to find out the possible role of the technique in diagnosis in patients with PD.Materials and Methods: The study includes 18 PD patients who were candidates for deep brain stimulation surgery, and 19 controlgroup patients. DTI was performed in all cases. DTI characteristics of FA were measured in primary motor cortex (M1), supplementarymotor area (SMA), inferior parietal lobule, putamen (P), globus pallidus externus (GPe) and internus (GPi), ventrolateral nucleus ofthalamus (Th), substantia nigra (SN), cuneus, precuneus and cerebellar dentate nucleus (D) bilaterally. Additionally, we processed“raw” FA images and colored them according to fiber orientation to visualize STN and GPi nuclei.Results: Mean age of the control group was 59.2±13.2 (range: 31-79) years, while it was 56.7±16 (range: 42-77) years for the patientgroup. Mean duration of PD was 12.4±7.1 (range: 5-30) years. Study group FA values were significantly lower than the control groupin all areas bilaterally (p<0.05). Additionally, FA-M1, FA-GPi and FA-GPe values were significantly lower on left side compared to rightside (p<0.05).Conclusion: Decrease in FA values in all regions in the study group is thought to result from loss of nerve cells. Additionally, raw FAimages that are processed, and colored in relation to fiber orientation can be useful for a better identification of STN and GPi nuclei.This type of imaging will provide a more precise anatomy necessary for surgical targeting.

White matter alteration in adults with prelingual deafness: A TBSS and SBM analysis of fractional anisotropy data

A loss of hearing in early life leads to diversifications of important white matter networks. Previous studies related to WM alterations in adult deaf individuals mainly involved univariate analysis of fractional anisotropy (FA) data and volumetric analysis, which yielded inconsistent results. To address this issue, we investigated the FA value alterations in 38 prelingual adult deaf individuals and compared the results with those obtained from the same number of adults with normal hearing by using univariate (tract-based spatial statistics) and multivariate (source-based morphometry) methods. The findings from tract-based spatial statistics suggested an increased FA value in regions such as the left cingulate gyrus, left inferior frontal occipital fasciculus, left inferior longitudinal fasciculus and superior corona radiata; however, the results indicated a decreased FA value in the left planum temporale of adult deaf individuals. While source-based morphometry analysis outlined higher FA values in regions such as bilateral lingual gyrus, bilateral cerebellum, bilateral putamen and bilateral caudate, a considerable decrease was observed in the bilateral superior temporal region of the deaf group. These alterations in multiple neural regions might be linked to the compensatory cross-modal reorganizations attributed to early hearing loss.

Structural MRI and tract-based spatial statistical analysis of diffusion tensor imaging in children with hemimegalencephaly.

To investigate the gross white matter abnormalities in the structural brain MR imaging as well as white matter microstructural alterations using tract-based spatial statistics (TBSS) analysis of diffusion tensor imaging (DTI) in both affected and contralateral cerebral hemispheres of children with hemimegalencephaly (HMEG). From 2003 to 2019, we retrospectively reviewed brain MR images in 20 children (11 boys, 2days-16.5years) with HMEG, focusing on gross white matter abnormalities. DTI was evaluated in 12 patients (8 boys, 3months-16.5years) with HMEG and 12 age-, sex-, and magnetic field strength-matched control subjects. TBSS analysis was performed to analyze main white matter tracts. Regions of significant differences in fractional anisotropy (FA) were determined between HMEG and control subjects and between affected and contralateral hemispheres of HMEG. Gross white matter abnormalities were noted in both affected (n = 20, 100%) and contralateral hemisphere (n = 4, 20%) of HMEG. FA values were significantly decreased in both hemispheres of HMEG, compared with control subjects (P < 0.05). Contralateral hemispheres of HMEG showed regions with significantly decreased FA values compared with affected hemispheres (P < 0.05). In addition to gross white matter abnormalities particularly evident in affected hemispheres, DTI analysis detected widespread microstructural alterations in both affected and contralateral hemispheres in HMEG suggesting HMEG may involve broader abnormalities in neuronal networks.

Insight Into Myocardial Microstructure of Athletes and Hypertrophic Cardiomyopathy Patients Using Diffusion Tensor Imaging.

Hypertrophic cardiomyopathy (HCM) remains the commonest cause of sudden cardiac death among young athletes. Differentiating between physiologically adaptive left ventricular (LV) hypertrophy observed in athletes' hearts and pathological HCM remains challenging. By quantifying the diffusion of water molecules, diffusion tensor imaging (DTI) MRI allows voxelwise characterization of myocardial microstructure. To explore microstructural differences between healthy volunteers, athletes, and HCM patients using DTI. Prospective cohort. Twenty healthy volunteers, 20 athletes, and 20 HCM patients. 3T/DTI spin echo. In-house MatLab software was used to derive mean diffusivity (MD) and fractional anisotropy (FA) as markers of amplitude and anisotropy of the diffusion of water molecules, and secondary eigenvector angles (E2A)-reflecting the orientations of laminar sheetlets. Independent samples t-tests were used to detect statistical significance between any two cohorts. Analysis of variance was utilized for detecting the statistical difference between the three cohorts. Statistical tests were two-tailed. A result was considered statistically significant at P ≤ 0.05. DTI markers were significantly different between HCM, athletes, and volunteers. HCM patients had significantly higher global MD and E2A, and significantly lower FA than athletes and volunteers. (MDHCM = 1.52 ± 0.06 × 10-3 mm2 /s, MDAthletes = 1.49 ± 0.03 × 10-3 mm2 /s, MDvolunteers = 1.47 ± 0.02 × 10-3 mm2 /s, P < 0.05; E2AHCM = 58.8 ± 4°, E2Aathletes = 47 ± 5°, E2Avolunteers = 38.5 ± 7°, P < 0.05; FAHCM = 0.30 ± 0.02, FAAthletes = 0.35 ± 0.02, FAvolunteers = 0.36 ± 0.03, P < 0.05). HCM patients had significantly higher E2A in their thickest segments compared to the remote (E2Athickest = 66.8 ± 7, E2Aremote = 51.2 ± 9, P < 0.05). DTI depicts an increase in amplitude and isotropy of diffusion in the myocardium of HCM compared to athletes and volunteers as reflected by increased MD and decreased FA values. While significantly higher E2A values in HCM and athletes reflect steeper configurations of the myocardial sheetlets than in volunteers, HCM patients demonstrated an eccentric rise in E2A in their thickest segments, while athletes demonstrated a concentric rise. Further studies are required to determine the diagnostic capabilities of DTI. 1 TECHNICAL EFFICACY STAGE: 2.

T48. DEVIATIONS IN MICRO AND MACRO WHITE MATTER STRUCTURES IN PSYCHOSIS PRONENESS

BackgroundPsychotic disorders are characterized by neurobiological deviations, including in the macro and microstructure of white matter. White matter alterations are also seen in psychosis-proneness and in individuals who have a high risk of psychosis. For example, studies have indicated decreases in white matter integrity in the genu/forceps minor of corpus callosum (CC) in the latter populations. Anterior corona radiata (ACR) is one crucial white-matter tract connecting the anterior cingulate cortex to the striatum. Indeed, reductions in the white matter structure of anterior genu of CC significantly predict the transition from ultra-high risk to psychosis. However, there is a gap in the literature related to observing the psychosis-proneness by applying both micro and macrostructural brain analyses, and most of the microstructural white matter studies in psychosis focus on fractional anisotropy (FA) and not include mean diffusivity (MD). Thus, the current study aims to assess whether white matter deviations in CG, ACR, and CC, are associated with psychosis proneness by combining both tract-based spatial statistics (TBSS) and voxel-based morphometry (VBM) analyses in a sample of participants with psychosis proneness (PP) and without psychosis proneness (NPP).MethodsThe study included 53 participants (29 PP vs. 24 NPP) whose ages were between 17 and 24 years. Participants were split into two groups based on their scores on Structured Interview for Schizotypy assessment, a well-validated instrument of psychosis proneness. White matter integrity was analyzed via diffusion tensor imaging (DTI) and white matter volume (WMV) via VBM. Two sample t-test was used in GLM for both DTI and VBM analyses. FA, MD, and VMV were compared between two groups to observe micro and macro white matter structure alterations in the region of interest.ResultsDTI analysis revealed decreased FA values in the right ACR and right genu of the CC in the psychosis-proneness group (F(1,52)= 7.37, p= 0.009). Moreover, VBM showed a significant WMV decreases in the right CG, Brodmann areas 8, 9, and 32 in the PP group (F(1,52)= 50.85, uncorrected p<0.01). However, MD did not differ between the two groups (F(1,51)= 3.65, p=0.06)DiscussionThese findings suggest that PP associated with decreased white matter integrity in ACR, genu of CC, and also reduced white matter volumes in the right CG, Brodmann areas 8, 9, and 32. Significant FA decreases might result from alterations in radial or axial diffusivity since we did not observe significant MD differences between two groups. The current findings suggested that participants with PP had both macro and micro white matter structure disruptions, mostly in frontal parts of the right cerebrum, compared to no PP group.

Age-Related Alterations of White Matter Integrity in Adolescents and Young Adults With Bipolar Disorder.

BackgroundAlterations of white matter integrity during adolescence/young adulthood may contribute to the neurodevelopmental pathophysiology of bipolar disorder (BD), but it remains unknown how white matter integrity changes in BD patients during this critical period of brain development. In the present study, we aimed to identify possible age-associated alterations of white matter integrity in adolescents and young adults with BD across the age range of 13–30 years.MethodsWe divided the participants into two groups by age as follows: adolescent group involving individuals of 13–21 years old (39 patients with BD and 39 healthy controls) and young adult group involving individuals of 22–30 years old (47 patients with BD and 47 healthy controls). Diffusion tensor imaging (DTI) was performed in all participants to assess white matter integrity.ResultsIn the adolescent group, compared to those of healthy controls, fractional anisotropy (FA) values were significantly lower in BD patients in the left inferior longitudinal fasciculus, splenium of the corpus callosum and posterior thalamic radiation. In the young adult group, BD patients showed significantly decreased FA values in the bilateral uncinate fasciculus, genu of the corpus callosum, right anterior limb of internal capsule and fornix compared to healthy controls. White matter impairments changed from the posterior brain to the anterior brain representing a back-to-front spatiotemporal directionality in an age-related pattern.ConclusionsOur findings provide neuroimaging evidence supporting a back-to-front spatiotemporal directionality of the altered development of white matter integrity associated with age in BD patients during adolescence/young adulthood.

Study on the white matter neuronal integrity in amnestic mild cognitive impairment based on automating fiber-tract quantification

Objective: To analyze the pattern of the change in cerebral white matter tract in amnestic mild cognitive impairment (aMCI) patients based on the automating fiber-tract quantification (AFQ). Methods: A total of 20 aMCI patients,9 males,11 females, the mean age was (67±9) years, and 22 patients with naMCI, 8 males,14 females, the mean age was (64±10) years, and 23 normal control subjects, 10 males, 13 females, with a mean age of (65±9) years were enrolled from the Affiliated Drum Tower Hospital of Nanjing University Medical School from January 2018 to March 2019. All of them underwent 3.0 T MRI scan, which include DTI and 3D T(1)WI sequence.Two tract profiles, fractional anisotropy (FA) and mean diffusivity (MD), were extracted to evaluate the white matter integrity at 100 locations along each of 20 fiber tracts based on the AFQ. Results: In a pointwise comparison of FA profiles,the aMCI patients showed FA reduction in the middle part of right corticospinal tract (t=-4.023, P<0.01, FWE corrected) relative to the naMCI patients. There was a positive correlation between the decreased FA value and the auditory verbal learning test score (P=0.039). In a pointwise comparison of MD profiles, the aMCI patients showed extensive MD elevation in the middle part of the left cingulum hippocampus (t=2.408,P=0.037,FWE corrected) relative to the naMCI patients. The aMCI patients showed MD elevation in the posterior part of the left inferior longitudinal fasciculus (t=-2.919, P=0.006, FWE corrected) and the middle part of the left cingulum hippocampus (t=-3.878, P=0.002, FWE corrected) relative to the NC subjects. And the elevated MD in left inferior longitudinal fasciculus showed negative correlation with MoCA (P=0.039) and auditory verbal learning test score (P=0.015). There was also a negative correlation between the elevated MD value in the left cingulum hippocampus and the auditory verbal learning test score (P=0.033). Conclusions: Disruption is found in specific part along the white matter tract in the aMCI group. Furthermore, the pattern of white matter abnormalities is different across neuronal fiber tracts. These findings will have an impact on the further specific study of the white matter tract in aMCI patients.

Effectiveness of Diffusion Tensor Imaging in Determining Cervical Spondylotic Myelopathy.

To determine the effectiveness of diffusion tensor imaging (DTI) in diagnosing cervical spondylotic myelopathy (CSM) in patients with no findings detected in conventional magnetic resonance imaging (MRI). Fifty-four patients who presented for cervical MRI between January 2016 and June 2016, with symptoms such as neck pain, paresis, and numbness in hands, were included in the study. The patients were split into four groups based on their degrees of spinal stenosis. The obtained data were examined using special software and color-coded fractional anisotropy (FA), and apparent diffusion coefficient (ADC) maps were formed. Through these maps, using regions of interest (ROIs), FA and ADC values were calculated and the contribution of these values to the diagnosis was evaluated statistically. When all grades of cervical spinal canal stenosis were compared, a statistically significant negative correlation between spinal canal stenosis degree and FA values, and a positive correlation between stenosis degree and ADC values were noted (p < 0.001). In the comparison of stenotic levels and non-stenotic levels for the grade 2 patient group, there was a statistically significant decrease in FA values and an increase in ADC values in stenotic levels compared with prestenotic and poststenotic levels (p < 0.05). DTI and quantitative FA and ADC measurements are candidate imaging techniques for the diagnosis of early-stage CSM, which shows no findings in conventional MRI, and determining the degree of spinal cord injury.

Microstructure and functional connectivity-based evidence for memory-related regional impairments in the brains of pilocarpine-treated rats

Patients with temporal lobe epilepsy (TLE) frequently suffer from memory disorders, and the pathological changes show widespread regional impairments in the brain. In lithium-pilocarpine (LIP)-treated rats with TLE, an abnormal hippocampal microstructure and functional connectivity have been observed. However, changes in other brain regions are still unclear. In the present study, diffusion tensor imaging and functional magnetic resonance imaging (MRI) signals were collected in LIP-TLE rats and controls using a 7.0 T MRI. Microstructural parameters and functional connectivity were calculated among regions of interest (ROIs), including the bilateral prefrontal cortex, amygdala, hippocampus and entorhinal cortex. A correlation analysis was further performed between the neuroimaging results and the behavioral performance in the novel object and novel location memory tests. In our results, TLE rats showed increased fractional anisotropy (FA) values in the hippocampus and decreased FA values in the amygdala and entorhinal cortex. In addition, decreased functional connectivity between the amygdala and the CA3, and increased connectivity between the prefrontal cortex and the CA1 were observed in the TLE rats compared to control rats. Moreover, FA values in the amygdala, the hippocampus and the entorhinal cortex, as well as the amygdala-CA3 and the prefrontal-CA1 connectivity correlated with the memory performance. Based on our results, both the microstructure and functional connections were impaired in memory-related brain regions of LIP-TLE rats. Furthermore, the abnormal changes in the microstructure and functional connectivity were related to behavioral deficits in object and location memory.

Multiple sclerosis and depressive manifestations: can diffusion tensor MR imaging help in the detection of microstructural white matter changes?

BackgroundMultiple sclerosis is one of the commonest causes of neurological disability in middle-aged and young adults. Depression in MS patients can compromise cognitive functions, lead to suicide attempts, impair relationships and reduce compliance with disease-modifying treatments. The aim of this study was to investigate and compare the microstructural changes in the white matter tracts of the limbic system in MS patients with and those without depressive manifestations using a diffusion tensor imaging (DTI) technique.MethodsThis study included 40 patients who were divided into three groups. Group 1 comprised of 20 patients with relapsing-remitting MS with depressive symptoms and group 2 comprised 10 MS patients without symptoms of depression. The third group is a control group that included 10 age-matched healthy individuals. All patients underwent conventional MRI examinations and DTI to compare the fractional anisotropy (FA) values in the white matter tracts of the limbic system.ResultsWe compared the DTI findings in MS patients with and those without depressive symptoms. It was found that patients with depression and MS exhibited a significant reduction in the FA values of the cingulum (P < 0.0111 on the right and P < 0.0142 on the left), uncinate fasciculus (P < 0.0001 on the right and P < 0.0076 on the left) and the fornix (P < 0.0001 on both sides). No significant difference was found between the FA values of the anterior thalamic radiations in both groups.ConclusionPatients with depression and MS showed more pronounced microstructural damage in the major white matter connections of the limbic pathway, namely, the uncinate fasciculus, cingulum and fornix. These changes can be detected by DTI as decreased FA values in depressed MS patients compared to those in non-depressed patients.

Localizing deficits in white matter tracts of patients with narcolepsy with cataplexy: tract-specific statistical analysis.

White matter alterations related to hypocretin pathway have been less evaluated in patients who have narcolepsy with cataplexy (NC), as compared to the identified exploration of gray matter and have varied among structural brain magnetic resonance imaging studies. The aim of this study was to investigate the disruption of specific white matter tracts in drug-naïve patients with NC, by using a tract-specific statistical analysis (TSSA). Forty drug-naïve NC patients with cataplexy and 42 heathy controls were enrolled in the study. All participants completed diffusion weighted imaging, polysomnography, and neuropsychological testing. At that time, we automatically identified fourteen major fiber tracts using diffusion tensor imaging techniques and analyzed the group comparison of fractional anisotropy (FA) values for each tract between the NC and controls, controlling for the participant's age and gender. The mean age of the NC patients was 26.9years and the onset age of daytime sleepiness and cataplexy was 16.7years and 19.9years, respectively. Relative to the controls, the NC patients showed that there were identified decreased FA values in the bilateral inferior fronto-occipital fasciculus (IFO). The Epworth sleepiness scale was positively correlated with FA values for the left IFO and right cingulate. The REM sleep latency was positively correlated with FA values for the left IFO, cingulate, and uncinate fasciculus in patients. This TSSA study revealed disintegration of the IFO in the NC patients and suggested that disintegration of WM tracts connected to the frontal cortex contributes to clinical manifestations of narcolepsy.

Altered brain diffusion tensor imaging indices in adolescents with the Fontan palliation.

Single ventricle heart disease (SVHD) patients show injury in brain sites that regulate autonomic, mood, and cognitive functions. However, the nature (acute or chronic changes) and extent of brain injury in SVHD are unclear. Our aim was to examine regional brain tissue damage in SVHD over controls using DTI-based mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), and fractional anisotropy (FA) procedures. We collected two DTI series (3.0-T MRI), mood and cognitive data, from 27 SVHD and 35 control adolescents. Whole-brain MD, AD, RD, and FA maps were calculated from each series, realigned and averaged, normalized to a common space, smoothed, and compared between groups using ANCOVA (covariates, age and sex; false discovery rate, p < 0.05). Region-of-interest analyses were performed to calculate MD, AD, RD, and FA values for magnitude assessment between groups. SVHD patients showed impaired mood and cognitive functions over healthy adolescents. Multiple brain sites in SVHD showed increased MD values, including the insula, caudate, cingulate, hypothalamus, thalamus, medial prefrontal and frontal cortices, parahippocampal gyrus, hippocampus, precentral gyrus, amygdala, cerebellum, corpus callosum, basal forebrain, mammillary bodies, internal capsule, midbrain, fornix, and occipital, parietal, and temporal cortices, indicating chronic tissue changes. Similar areas showed either increased AD or RD values, with RD changes more enhanced over AD in SVHD compared to controls. Few brain regions emerged with increased or decreased FA values in SVHD patients over controls. SVHD adolescents, more than a decade from their last surgical procedure, show widespread brain abnormalities in autonomic, mood, and cognitive regulatory areas. These findings indicate that brain injury is in a chronic stage in SVHD with predominantly myelin changes that may result from previous hypoxia/ischemia- or developmental-induced processes.

Brain white matter changes in asymptomatic carriers of Leber's hereditary optic neuropathy.

Subclinical abnormalities, including microangiopathy, swelling of nerve fibers, visual field abnormalities and visual functional impairments had been reported in Leber's hereditary optic neuropathy (LHON) carriers. The purpose of this study was to investigate microstructural changes of brain white matter in asymptomatic LHON carriers using DTI and tract-based spatial statistics (TBSS). DTI and neuro-ophthalmologic measurements were acquired in 14 LHON carriers and 15 gender- and age-matched healthy controls, and diffusion metrics, including fractional anisotropy (FA), axial (AD), radial diffusion (RD) and mean diffusion (MD) were calculated. Intergroup differences in diffusion metrics were compared regressing out potential nuisance covariates of age and gender. A correlation analysis was performed to test associations between abnormal neuro-ophthalmologic measures and diffusion metrics while controlling the effects of age and gender. Compared to healthy controls, LHON carriers showed a weak increase of thickness of the retinal nerve fiber layer (RNFL) of the right inferior quadrant (F = 5.22, p = 0.032, before multiple comparison correction). LHON carriers exhibited widespread decreased FA value (bilateral anterior thalamic radiations, bilateral corticospinal tracts, major and minor forceps, bilateral inferior fronto-occipital fasciculi and left superior longitudinal fasciculus), increased RD value (bilateral anterior thalamic radiations, bilateral corticospinal tracts, major and minor forceps, bilateral inferior fronto-occipital fasciculi, bilateral inferior longitudinal fasciculi, bilateral superior longitudinal fasciculi and bilateral uncinate fasciculi) and increased MD value (bilateral anterior thalamic radiations, bilateral corticospinal tracts, minor forceps, bilateral inferior fronto-occipital fasciculi, bilateral inferior longitudinal fasciculi, left superior longitudinal fasciculus and bilateral uncinate fasciculi). Moreover, these changed diffusion metrics were not correlated with age, gender, LHON mutations and retinal measures in LHON carriers. Our results show microstructural alterations in brain white matter in asymptomatic LHON carriers, indicating that LHON-related genetic mutations themselves might result in occult white matter alterations in the brain.

Relationship between auditory pathway fractional anisotropy and audibility in patients with cerebellopontine angle tumors on diffusion tensor imaging

ObjectiveRecent reports demonstrated that acoustic nerve disorders affect the auditory pathway on diffusion tensor imaging (DTI). The aim was to investigate whether auditory pathway fractional anisotropy (FA) values are associated with audibility in patients with cerebellopontine angle tumors. Patients and methodsPatients with cerebellopontine angle tumors were included in this retrospective study. Preoperatively, all patients underwent magnetic resonance imaging (MRI) including DTI. Two regions of interest on the lateral lemniscus (LL) and inferior colliculus (IC) were set bilaterally on DTI. FA values were calculated using software. Correlations between FA values and audibility were evaluated using Spearman’s rank correlation coefficient. Statistical significance was defined as p < 0.05. ResultsSeventeen patients with cerebellopontine angle tumors were included in this study. FA values in the bilateral LL showed a significant negative correlation with hearing impairment severity (r = −0.758, −0.600, p < 0.05). FA values on the ipsilateral side of the IC showed a significant negative correlation with hearing impairment severity (r = -0.477, p < 0.05). FA values on the contralateral side of the IC did not correlate with hearing impairment severity (r = -0.201, p > 0.05). One patient with a low FA value on the contralateral side of the IC had postoperative hearing impairment despite good preoperative hearing ability. ConclusionsFA values in the bilateral LL and on the ipsilateral side of the IC reflected hearing impairment severity. Decreased FA values on the contralateral side of the IC might predict hearing impairment postoperatively.

White matter impairment in type 2 diabetes mellitus with and without microvascular disease

Background and objectiveType 2 diabetes mellitus (T2DM) is a serious public health problem, and the phenomenon of T2DM occurring in younger people has directed more attention to functional changes in the brain. In this study, the microstructural integrity of white matter (WM) was evaluated in three groups of middle-aged subjects: healthy controls (HCs) and T2DM patients with and without peripheral microvascular complications (T2DM-C and T2DM-NC patients, respectively).MethodsDiffusion tensor imaging (DTI) and related clinical examinations were performed in 66 subjects, including 20 T2DM-C patients, 20 T2DM-NC patients, 26 age- and sex-matched HCs. Magnetic resonance imaging (MRI) at 3 T was used to perform DTI; then, FSL and tract-based spatial statistics (TBSS) software were used to assess differences in the fractional anisotropy (FA) and mean diffusivity (MD) among the groups. The use of the FA and MD as parameters was evaluated by receiver operating characteristic (ROC) curve analysis.ResultsThere were no significant differences in sex or age among the groups, and the clinical data of the groups met the experimental requirements. There was no significant difference in the FA values between the HCs and T2DM-NC groups. Compared with the HCs, the T2DM-C patients showed decreased FA values and increased MD values in the corpus callosum, bilateral anterior limb of the internal capsule, right retrolenticular part of the internal capsule, bilateral posterior thalamic radiation, right superior longitudinal fasciculus, bilateral superior corona radiata and left middle frontal gyrus (P < .01). Compared with the T2DM-NC patients, the T2DM-C patients showed decreased FA values and increased MD values in the corpus callosum, bilateral fornix, right retrolenticular part of the internal capsule, middle cerebral peduncle, right superior longitudinal fasciculus, right posterior thalamic radiation, and left middle frontal gyrus (P < .01).ConclusionsThis study indicates that WM impairment is present in T2DM patients and may be related to microvascular complications. More importantly, this study also shows that such impairment may be diagnosed using the DTI mode of functional MRI before it can be diagnosed clinically.

Cognition-related white matter integrity dysfunction in Alzheimer's disease with diffusion tensor image

Alzheimer’s disease (AD) is a worldwide progressive neurodegenerative disorder in the elderly. Previous research has indicated that Alzheimer’s disease impairs white matter (WM) tracts. Anatomical and neuroimaging studies have indicated that WM tracts are associated with cognitive function. Whether the abnormal WM integrity in AD is associated with cognitive impairments and the clinical symptoms is still not clear. To this end, we investigated the relationship between the impairments in WM tracts and the decline of cognitive ability in AD. Diffusion tensor imaging (DTI) data were collected from 38 AD patients and 30 normal, cognitively healthy volunteers. The tract-based spatial statistics (TBSS) approach was used to compare the fractional anisotropy (FA) and mean diffusivity (MD) values between the two groups. WM tracts (cingulum, superior longitudinal fasciculus (SLF), uncinate fasciculus (UF), and inferior longitudinal fasciculus (ILF)) associated with cognition function were extracted for region of interest (ROI)-based analysis. Significantly decreased FA values and increased MD values of the cognition-related WM tracts were observed in the AD group compared with the normal cognition (NC) group. In addition, we further demonstrated that the decreased FA values and increased MD values of the cognition-related WM tracts were significantly correlated with MMSE scores. These results indicated that abnormal changes in WM integrity are observed following AD. Finally, we used support vector machine (SVM) with a repeated, stratified 10-fold cross-validated classifier to evaluate the ability of FA and MD values to discriminate disease. The accuracy of the SVM using cognition-related WM as classified features was higher than that using non-cognition-related tracts. Most importantly, our results showed the relationship between abnormal WM tracts and cognitive ability in AD. These findings further suggested that AD-related impairments in cognition-related WM tracts may influence the cognitive ability of AD patients.

Abnormal white matter integrity in Chinese young adults with first-episode medication-free anxious depression: a possible neurological biomarker of subtype major depressive disorder.

BackgroundAlmost half of patients with major depressive disorder (MDD) also have clinically meaningful levels of anxiety. Anxious depression is a distinct clinical subtype of MDD, which has poor response to pharmacotherapy; however, the neural mechanisms behind are largely unknown. In the present study, we explored the white matter (WM) integrity traits of anxious depression in first-episode and medication-free (medication-naïve and medication washout) Chinese young adult patients by detecting differences in diffusion tensor imaging (DTI) with the tract-based spatial statistics (TBSS) method.Subjects and methodsDTI was obtained from 39 first-episode, medication-free anxious depressive patients, 45 nonanxious depressive patients, and 50 demographically similar healthy controls. All subjects underwent clinical assessments. TBSS was carried out to investigate the difference in WM integrity among three groups within DTI parameter maps. WM integrity was measured using fractional anisotropy (FA), mean diffusivity, axial diffusivity, and radial diffusivity (RD). The correlations between WM integrity and clinical features were also computed.ResultsWhen compared with nonanxious patients, lower FA values in anxious depressive patients were found in multiple regions of the brain, mainly involving left uncinate fasciculus (UF), superior longitudinal fasciculus (SLF), and forceps major and minor. Higher RD in forceps major and minor and SLF were also detected. The decreased FA values and increased RD values correlated with both anxiety level and depression level in the pooled depressive group.ConclusionThe anxious depressive patients had more abnormalities in WM integrity at the early phase than the nonanxious group. Alternations in WM integrity in fiber pathways, including SLF, UF, and forceps major and minor, may play a critical role in the neuropathology of anxious depression and might help to identify anxious MDD from nonanxious MDD. Further study with larger sample size, larger age range, and longitudinal design is needed to confer a robust inference to better understand the dynamic neurological change and neuropathology of WM integrity in anxious MDD.

Corpus callosal involvement is correlated with cognitive impairment in multiple system atrophy.

We examined the anatomical involvement related to cognitive impairment in patients with multiple system atrophy (MSA). We examined 30 patients with probable MSA and 15 healthy controls. All MSA patients were assessed by the Unified MSA-Rating scale and Addenbrooke's Cognitive Examination-Revised (ACE-R). We classified 15 MSA patients with ACE-R scores > 88 as having normal cognition (MSA-NC) and 15 with scores ≤ 88 as having cognitive impairment (MSA-CI). All subjects underwent 3T MRI scanning and were investigated using voxel-based morphometry and diffusion tensor imaging. Both the MSA-NC and MSA-CI patients exhibited cerebellar but not cerebral atrophy in voxel-based morphometry compared to controls. In contrast, tract-based spatial statistics revealed widespread and significantly decreased fractional anisotropy (FA) values, as well as increased mean diffusivity, radial diffusivity, and axial diffusivity in both the cerebrum and cerebellum in MSA-CI patients compared to controls. MSA-NC patients also exhibited similar involvement of the cerebellum but less extensive involvement of the cerebrum compared with the MSA-CI patients. In particular, FA values in MSA-CI patients were significantly decreased in the anterior part of the left corpus callosum compared with those in MSA-NC patients. The mean FA values in the left anterior part of the corpus callosum were significantly correlated with total ACE-R scores and subscores (memory, fluency, and language) in MSA patients. Decreased FA values in the anterior corpus callosum showed a significant correlation with cognitive impairment in MSA.

Cortical thickness and white matter integrity abnormalities in obsessive-compulsive disorder: A combined multimodal surface-based morphometry and tract-based spatial statistics study.

Cerebral morphological abnormalities may play a key role in pathogenesis of obsessive-compulsive disorder (OCD). However, few studies have used multimodal imaging strategies to investigate alterations of cortical morphometry and white matter (WM) integrity. This study aimed to evaluate cortical thickness, cortical and subcortical volume, and WM integrity characteristics in OCD patients comprehensively. We acquired magnetic resonance imaging (MRI) scans from 52 OCD patients and 46 well-matched healthy controls (HCs). Cortical thickness and cortical and subcortical volume were measured using the surface-based morphometry (SBM) approach. We also evaluated fractional anisotropy (FA) and mean diffusivity (MD) derived from diffusion tensor imaging (DTI) using tract-based spatial statistics (TBSS). The disease severity was evaluated by score of the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). For those brain regions exhibiting altered structure, correlations between alterations and clinical symptoms severity were analyzed in all patients and medication-naïve patients, respectively. Compared with controls, OCD patients exhibited cortical thinning in right posterior cingulate cortex (PCC), as well as significantly decreased FA values in the genu and body of corpus callosum (CC). In medication-naïve patients group, the total Y-BOCS score and obsession score were significantly negative correlated with right PCC cortical thickness. OCD patients demonstrated symptom-related reduced cortical thickness structural alteration of the right PCC, and altered WM integrity in the genu and body of CC. Medication seems could alleviate the alteration of cortical thickness but not WM integrity. Combined multimodal neuroimaging methods may provide a more comprehensive perspective to clarify the pathological mechanism of OCD.

Analysis of radiological parameters associated with decreased fractional anisotropy values on diffusion tensor imaging in patients with lumbar spinal stenosis

Previous studies have indicated that decreased fractional anisotropy (FA) values on diffusion tensor imaging (DTI) are well correlated with the symptoms of nerve root compression. The aim of our study is to determine primary radiological parameters associated with decreased FA values in patients with lumbar spinal stenosis involving single L5 nerve root. Patients confirmed with single L5 nerve root compression by transforaminal nerve root blocks were included in this study. FA values of L5 nerve roots on both symptomatic and asymptomatic side were obtained. Conventional radiological parameters, such as disc height, degenerative scoliosis, dural sac cross-sectional area (DSCSA), foraminal height (FH), hypertrophic facet joint degeneration (HFJD), sagittal rotation (SR), sedimentation sign, sagittal translation and traction spur were measured. Correlation and regression analyses were performed between the radiological parameters and FA values of the symptomatic L5 nerve roots. A predictive regression equation was established. Twenty-one patients were included in this study. FA values were significantly lower at the symptomatic side comparing to the asymptomatic side (0.263 ± 0.069 vs. 0.334 ± 0.080, P = 0.038). DSCSA, FH, HFJD, and SR were significantly correlated with the decreased FA values, with r = 0.518, 0.443, 0.472 and - 0.910, respectively (P < 0.05). DSCSA and SR were found to be the primary radiological parameters related to the decreased FA values, and the regression equation is FA = - 0.012 × SR + 0.002 × DSCSA. DSCSA and SR were primary contributors to decreased FA values in LSS patients involving single L5 nerve root, indicating that central canal decompression and segmental stability should be the first considerations in preoperative planning of these patients. These slides can be retrieved under Electronic Supplementary Material.