Significant Fractional Anisotropy Reductions Research Articles

Detection of White Matter Ultrastructural Changes for Amyotrophic Lateral Sclerosis Characterization: A Diagnostic Study from Dti-Derived Data.

In amyotrophic lateral sclerosis (ALS), magnetic resonance imaging (MRI) allows investigation at the microstructural level, employing techniques able to reveal white matter changes. In the current study, a diffusion tensor imaging (DTI) analysis, with a collection of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) indexes, was performed in ALS patients to correlate geno- and phenotype features with MRI data, to investigate an in-vivo correlation of different neuropathological patterns. All patients who underwent the MR-DTI analysis were retrospectively recruited. MRI scan was collected within three months from diagnosis. FA and ADC values were collected in corpus callosum (CC), corona radiata (CR), cerebral peduncle (CR), cerebellar peduncle (CbP) and corticospinal tract at posterior limb of internal capsule (CST). DTI analysis performed in the whole ALS cohort revealed significant FA reduction and ADC increase in all selected regions, as widespread changes. Moreover, we observed a higher value of FA in rCR in bulbar patients. A positive correlation between ALS Functional Rating Scale-Revised and FA in rCP was evident. In consideration of the non-invasiveness, the reliability and the easy reproducibility of the method, we believe that brain MRI with DTI analyses may represent a valid tool usable as a diagnostic marker in ALS.

Microstructural white matter abnormalities in obsessive-compulsive disorder: A coordinate-based meta-analysis of diffusion tensor imaging studies.

There are no conclusive diffusion tensor imaging (DTI) findings on obsessive-compulsive disorder (OCD) for now. We conducted a comprehensive meta-analysis of DTI studies to identify white matter (WM) microarchitecture changes in OCD, and also to compare the results differences between the two most frequently used methods (voxel-based analysis, VBA versus tract-based spatial statistics, TBSS) for DTI data. A systematic search was performed on relevant studies that reported fractional anisotropy (FA) alterations between patients with OCD and healthy controls (HC). Seed-based d mapping (SDM) was applied to analyze microstructural WM abnormalities in OCD patients. Subgroup meta-analysis was subsequently performed to explore methodological differences between VBA and TBSS approaches. A total of 30 studies (with 31 datasets) that comprised 855 patients and 875 HC were identified. OCD patients exhibited significantly decreased FA in the right cerebellar hemispheric lobule, corpus callosum (CC), left superior frontal gyrus (orbital part), right gyrus rectus, left superior longitudinal fasciculus and right lenticular nucleus in the pooled meta-analysis. The VBA subgroup showed lower FA in several brain regions while the TBSS subgroup only exhibited significant FA reductions in the CC. According to the pooled meta-analysis, OCD patients presented microstructural abnormalities in distributed WM tracts. However, heterogeneous results were found between VBA and TBSS studies.

Corpus callosum integrity loss predicts cognitive impairment in Leukoaraiosis.

ObjectiveTo investigate regional white matter fibers loss in Leukoaraiosis (LA) and its relationship with cognitive impairments.MethodsFifty‐six participants with LA and 38 healthy controls underwent clinical evaluations and MR scans. Participants with LA were classified as cognitively normal (LA‐NC, n = 18), vascular cognitive impairment of none dementia (LA‐VCIND, n = 24), and vascular dementia (LA‐VaD, n = 14) by Mini‐Mental State Examination and Clinical Dementia Rating. Cognitive domains including visual‐spatial, naming, attention, language, abstraction, memory, and orientation were assessed. With the use of Tract‐based spatial statistics, mean fractional anisotropy (FA) of major white matter fiber tracts were compared between LA and controls and among LA groups with varying levels of cognitive impairments. Regression analyses were performed to evaluate relationships between FA values and cognitive performance.ResultsParticipants showed significant FA reduction in the corpus callosum (CC), bilateral corona radiata, anterior limb of the internal capsule, external capsule, posterior thalamic radiation, and superior longitudinal fasciculus compared to controls and across LA groups. The LA‐VaD group showed consistent damage in the body and genu of CC compared to the LA‐NC and LA‐VCIND groups. A positive correlation between visual‐spatial and FA reduction in right anterior corona radiates in LA‐VCIND and body of CC in LA‐ VaD.InterpretationWe found regional fiber loss in the CC across the cognitive spectrum in patients with LA and correlations between FA and visuospatial impairment in the anterior corona radiata in patients with LA‐VCIND and in the body of CC in patients with LA‐VaD.

FROM THE SPINAL CORD TO THE MUSCLE: O.09 Spinal cord MRI for early detection of presymptomatic pathology in c9orf72 mutation carriers: A longitudinal neuroimaging study

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative conditions with shared genetic susceptibility and a large portion of familial cases due to c9orf72 gene mutations. Brain imaging studies in asymptomatic c9orf72 carriers have demonstrated white (WM) and grey matter (GM) degeneration before the age of 40. The aim of this study was to investigate whether cervical spinal cord (SC) degeneration can be detected in asymptomatic c9orf72 hexanucleotide carriers using multimodal quantitative imaging. 72 asymptomatic individuals were enrolled in a prospective observational study of first-degree relatives of ALS and FTD patients carrying the c9orf72 mutation. 40 (C9+) carried the pathogenic repeat expansion. Each subject underwent a 3T cervical SC MRI. Quantitative measures of GM and WM atrophy and DTI parameters were evaluated at baseline, after 18 and after 36 months. Data were analysed on the total population and in two subgroups composed by subjects younger and older than 40 years of age. No significant difference was observed between C9+ and C9- subjects younger than 40 years of age regarding morphometric and DTI parameters at each time point. At baseline, significant WM atrophy was detected at each cervical vertebral level in C9+ compared to C9- subjects older than 40 years of age (p-value < 0.05) without associated changes in GM and DTI parameters. At 18 and 36-month follow-up, WM atrophy in C9+ subjects older than 40 years was accompanied by significant and progressive corticospinal tract fractional anisotropy (FA) reduction compared to C9- subjects (p-value = 0.031). Intriguingly, asymptomatic C9+ subjects older than 40 years with a family history of ALS exhibited significant global CSA and CST FA reduction on their baseline scans. Cervical SC imaging of c9orf72 hexanucleotide carriers does not detect degeneration in subjects younger than 40 years, but WM atrophy is observed in C9+ subjects older than 40 years of age. While WM atrophy remains stable, progressive pyramidal tract FA reduction can be detected on follow-up acquisitions. SC MRI in c9orf 72 related conditions is a powerful tool to characterise presymptomatic pathological changes and it may also have a role to predict phenotypic conversion.

Microstructural Integrity of Peripheral Nerves in Charcot-Marie-Tooth Disease: An MRI Evaluation Study.

Charcot-Marie-Tooth (CMT) disease is diagnosed through clinical findings and genetic testing. While there are neurophysiological tools and clinical functional scales in CMT, objective disease biomarkers that can facilitate in monitoring disease progression are limited. To investigate the utility of diffusion tensor imaging (DTI) in determining the microstructural integrity of sciatic and peroneal nerves and its correlation with the MRI grading of muscle atrophy severity and clinical function in CMT as determined by the CMT neuropathy score (CMTNS). Prospective case-control. Nine CMT patients and nine age-matched controls. 3 T T1 -weighted in-/out-of phase spoiled gradient recalled echo (SPGR) and DTI sequences. Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD) values for sciatic and peroneal nerves were obtained from DTI. Muscle atrophy was graded according to the Goutallier classification using in-/out-of phase SPGRs. DTI parameters and muscle atrophy grades were compared between CMT and controls, and the relationship between DTI parameters, muscle atrophy grades, and CMTNS were assessed. The Wilcoxon Signed Ranks test was used to compare DTI parameters between CMT and controls. The relationship between DTI parameters, muscle atrophy grades, and CMTNS were analyzed using the Spearman correlation. Receiver operating characteristic (ROC) analyses of DTI parameters that can differentiate CMT from healthy controls were done. There was a significant reduction in FA and increase in RD of both nerves (P < 0.05) in CMT, with significant correlations between FA (negative; P < 0.05) and RD (positive; P < 0.05) with muscle atrophy grade. In the sciatic nerve, there was significant correlation between FA and CMTNS (r = -0.795; P < 0.05). FA and RD could discriminate CMT from controls with high sensitivity (77.8-100%) and specificity (88.9-100%). There were significant differences of DTI parameters between CMT and controls, with significant correlations between DTI parameters, muscle atrophy grade, and CMTNS. Level of Evidence 2 Technical Efficacy Stage 2 J. MAGN. RESON. IMAGING 2021;53:437-444.

Diffusion tensor imaging in renal artery stenosis: a preliminary report.

To investigate the diffusion properties in the kidneys affected by renal artery stenosis (RAS) using diffusion tensor imaging (DTI). In this prospective study, 35 patients with RAS and 15 patients without renal abnormalities were enrolled and examined using DTI. Cortical and medullary regions of interest (ROIs) were located to obtain the corresponding values of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA). The cortical and medullary ADC and FA were compared in the kidney affected by variable degrees of stenosis (RAS 50-75% and >75%) vs controls, using the one-way ANOVA and Student's t-test. The Spearman correlation test was used to correlate the mean ADC and FA values in the cortex and medulla with the estimate glomerular filtration rate (eGFR). For the controls, the ADC value was significantly (p = 0.03) higher in the cortex than in the medulla; the FA value was significantly (p = 0.001) higher in the medulla than in the cortex. Compared with the controls, a significant reduction in the cortical ADC was present with a RAS of 50-75% and >75% (p = 0.001 and 0.041, respectively); a significant reduction in the medullary FA was verified only for RAS >75% (p = 0.023). The Spearman correlation test did not show a statistically significant correlation between the cortical and medullary ADC and FA, and the eGFR. The alterations of the diffusional parameters caused by RAS can be detected by DTI and could be useful in the diagnostic evaluation of these patients. 1. Magnetic resonance DTI could provide useful information about renal involvement in RAS.2. Magnetic resonance DTI allows non-invasive repeatable evaluation of the renal parenchyma, without contrast media.

Is treatment-resistant schizophrenia associated with distinct neurobiological callosal connectivity abnormalities?

Resistance to antipsychotic treatment affects up to 30% of patients with schizophrenia. Although the time course of development of treatment-resistant schizophrenia (TRS) varies from patient to patient, the reasons for these variations remain unknown. Growing evidence suggests brain dysconnectivity as a significant feature of schizophrenia. In this study, we compared fractional anisotropy (FA) of brain white matter between TRS and non-treatment-resistant schizophrenia (non-TRS) patients. Our central hypothesis was that TRS is associated with reduced FA values. TRS was defined as the persistence of moderate to severe symptoms after adequate treatment with at least two antipsychotics from different classes. Diffusion-tensor brain MRI obtained images from 34 TRS participants and 51 non-TRS. Whole-brain analysis of FA and axial, radial, and mean diffusivity were performed using Tract-Based Spatial Statistics (TBSS) and FMRIB's Software Library (FSL), yielding a contrast between TRS and non-TRS patients, corrected for multiple comparisons using family-wise error (FWE)<0.05. We found a significant reduction in FA in the splenium of corpus callosum (CC) in TRS when compared to non-TRS. The antipsychotic dose did not relate to the splenium CC. Our results suggest that the focal abnormality of CC may be a potential biomarker of TRS.

State-Independent Microstructural White Matter Abnormalities in Major Depressive Disorder.

BackgroundEven with continuous antidepressant treatment, residual symptoms and the risk of relapse can persist in remitted major depressive disorder (MDD) patients. Hence, having a clear recognition of the persistent abnormalities of the underlying neural substrate in MDD through a longitudinal investigation is of great importance.MethodsA total of 127 adult medication-free MDD patients with an acute depressive episode and 118 matched healthy controls (HCs) underwent diffusion tensor imaging. Over a 6-month treatment course, 62 remitted patients underwent a second scan. Remission was defined as a 24-item Hamilton Depression Rating Scale (HAMD24) score ≤7 for at least two weeks. Diffusion tensor imaging was performed with a 3.0 T scanner. Differences in whole-brain fractional anisotropy (FA) between MDD patients and HCs were assessed by an independent t-test using gender, age, and education as covariates.ResultsSignificant FA reductions in the left insula, left middle occipital gyrus, right thalamus, left pallidum and left precuneus were observed in current MDD (cMDD) patients compared with HCs. Moreover, significant FA reductions in the left insula were observed in remitted (rMDD) patients compared to HCs. However, no significant differences in FA values were found when comparing cMDD and rMDD patients.ConclusionsThe abnormalities in the insula showed state-independent characteristics, while the abnormalities in the middle occipital gyrus, thalamus, pallidum and precuneus seemed to be state-dependent impairments in MDD patients.

Disrupted Functional and Structural Connectivity in Angelman Syndrome.

This work investigated alterations in functional connectivity (FC) and associated structures in patients with Angelman syndrome (AS) by using integrated quantitative imaging analysis and connectivity measures. We obtained 3T brain MR imaging, including resting-state functional MR imaging, diffusion tensor imaging, and 3D T1-weighted imaging from children with AS (n = 14) and age- and sex-matched controls (n = 28). The brains of patients with AS were analyzed by measuring FC, white matter microstructural analysis, cortical thickness, and brain volumes; these were compared with brains of controls. Interregional FC analysis revealed significantly reduced intra- and interhemispheric FC, especially in the basal ganglia and thalamus, in patients with AS. Significant reductions in fractional anisotropy were found in the corpus callosum, cingulum, posterior limb of the internal capsules, and arcuate fasciculus in patients with AS. Quantitative structural analysis also showed gray matter volume loss of the basal ganglia and diffuse WM volume reduction in AS compared with the control group. This integrated quantitative MR imaging analysis demonstrated poor functional and structural connectivity, as well as brain volume reduction, in children with AS, which may explain the motor and language dysfunction observed in this well-characterized neurobehavioral phenotype.

Functional and Structural Brain Alterations in Encephalitis With LGI1 Antibodies.

Objective: The purpose of this study was to examine the neural substrates and mechanisms that generate memory deficits, seizures and neuropsychiatric abnormalities in encephalitis with LGI1 antibodies using a data-driven, multimodal magnetic resonance imaging (MRI) approach.Methods: Functional MRI data were acquired from 14 anti-LGI1 encephalitis patients and 14 age and gender matched normal controls. Independent component analysis with hierarchical partner matching (HPM-ICA) was used to assess the whole-brain intrinsic functional connectivity. Granger causality (GC) was applied to investigate the effective connectivity among the brain regions that identified by HPM-ICA. Diffusion tensor imaging (DTI) was utilized to investigate white matter microstructural changes of the patients.Results: Participants with LGI1 antibodies encephalitis presented reduced functional connectivity in the brain areas associated with memory, cognition and motion circuits, while increased functional connectivity in putamen and caudate in comparison to the normal controls. Moreover, the effective connectivity in patients was decreased from the frontal cortex to supplementary motor area. Finally, patients had significant reductions in fractional anisotropy (FA) for the corpus callosum, internal capsule, corona radiata and superior longitudinal fasciculus, accompanied by increases in mean diffusivity (MD) for these regions as compared to controls.Conclusion: Our findings suggest that the neural disorder and behavioral deficits of anti-LGI1 encephalitis may be associated with extensive changes in brain connectivity and microstructure. These pathological alterations affect the basal ganglia and limbic system besides the temporal and frontal lobe.

Altered integrity of corpus callosum in generalized epilepsy in relation to seizure lateralization after corpus callosotomy.

Generalized-onset seizures are usually conceptualized as engaging bilaterally distributed networks with no clear focus. However, the authors previously reported a case series demonstrating that in some patients with generalized-onset seizures, focal seizure onset could be discovered after corpus callosotomy. The corpus callosum is considered to be a major pathway for seizure generalization in this group of patients. The authors hypothesized that, in patients with generalized-onset seizures, the structure of the corpus callosum could be different between patients who have lateralized seizures and those who have nonlateralized seizures after corpus callosotomy. The authors aimed to evaluate the structural difference through statistical analysis of diffusion tensor imaging (DTI) scalars between these two groups of patients. Thirty-two patients diagnosed with generalized-onset motor seizures and without an MRI lesion were included in this study. Among them, 16 patients developed lateralized epileptic activities after corpus callosotomy, and the remaining 16 patients continued to have nonlateralized seizures after corpus callosotomy. Presurgical DTI studies were acquired to quantify the structural integrity of the corpus callosum. The DTI analysis showed significant reduction of fractional anisotropy (FA) and increase in radial diffusivity (RD) in the body of the corpus callosum in the lateralized group compared with the nonlateralized group. The authors' findings indicate the existence of different configurations of bilateral epileptic networks in generalized epilepsy. Generalized seizures with focal onset relying on rapid spread through the corpus callosum might cause more structural damage related to demyelination in the corpus callosum, showing reduced FA and increased RD. This study suggests that presurgical DTI analysis of the corpus callosum might predict the seizure lateralization after corpus callosotomy.

White and Gray Matter Abnormalities in Manifest Huntington's Disease: Cross-Sectional and Longitudinal Analysis.

Early white matter (WM) changes and cortical atrophy in Huntington's disease (HD) are often evident before disease onset and extend through the brain during manifest stages. The trajectory of these brain abnormalities in symptomatic stages remains relatively unexplored. The aim of this study is to investigate how the pattern of WM and gray matter (GM) alterations progress over time. We investigated alterations in brain WM, cortical thickness, and subcortical structures using diffusion and structural magnetic resonance imaging, in manifest HD patients (n = 13) compared to age-matched healthy controls (n = 11). Imaging and clinical data for the HD group were collected at follow-up (7 months) to explore possible longitudinal changes. Cross-sectional analyses identified significant posterior cortical thinning (P<.05) and symmetric fractional anisotropy (FA) reduction (P<.01) in brain WM of HD group compared to HC. These changes were strongly correlated with impairment in motor symptoms and processing speed. Subcortical atrophy was significant in caudate, putamen, globus pallidus, and thalamus (P<.001). Regions of interest analysis revealed a significant reduction in FA of the corpus callosum (CC) (-2.19%, P<.05) upon follow-up, whereas no significant cortical thinning and subcortical atrophy was found. This study showed broad GM and WM abnormalities in manifest HD patients. Reductions in FA and cortical thinning correlated significantly with the disturbances of motor and cognitive processing that describe HD. Follow-up assessment showed that the CC is compromised in the absence of detectable GM changes or motor decline, suggesting it plays an important role in disease progression.

Cortical Thickness and Diffusion Properties in the Injured Brain: The Influence of Chronic Health Complaints.

Cortical thickness and diffusion properties can be served as an indicator of aging and other brain changes such as those related to brain injury. It can additionally provide another platform by which we can characterize the injury and its associated symptoms, especially in the chronic condition. We examined the changes in cortical thickness and diffusion properties in white matter tracts in 51 patients with and without traumatic brain injury (TBI) and/or self-report chronic symptoms. Significant cortical thinning was observed in the frontal lobe and temporal lobe for TBI patients with chronic symptoms, but not for TBI patients without chronic symptoms, compared with control group. Significant reduction in fractional anisotropy occurred on average across left and right major fiber tracts for TBI patients with chronic symptoms. No mean diffusivity changes were found in any individual white matter tract for TBI patients with or without chronic symptoms. Traumatic brain injury patients with chronic symptoms have more significant cortical thinning or degeneration of diffusion properties than the mild to severe TBI patients without chronic symptoms. This finding suggests that symptom reporting should be assessed in line with objective measures in clinical practice.

Re-emergent tremor in patients with Parkinson’s disease: an imaging study

BACKGROUND AND PURPOSE: Re-emergent tremor (ReT) is the tremor that reappears after a variable period of latency while maintaining posture. Little is known about the mechanisms that contribute to the origin of this silent period (SP). Our aim was to compare the imaging characteristics of patients with and without ReT and find the structural correlate of SP if any. MATERIALS AND METHODS: Fifteen patients with ReT (Group 1) and eighteen patients without ReT (patients with rest tremor and postural tremor, but no latency) were evaluated clinically, electrophysiologically, with diffusion tensor imaging (DTI) and voxel-based morphometry (VBM). DTI parameters of different regions of interest were analyzed and compared with that of 37 healthy age- and gender-matched controls. RESULTS: No statistically significant difference was observed between the two groups in terms of age, duration of disease, levodopa equivalent dose, or severity of the disease. However, in the left supplementary motor area (SMA), there was a significant reduction of fractional anisotropy and an increase of radial diffusivity and mean diffusivity in patients with ReT (Group 1) as compared to patients without ReT (Group 2) and healthy controls. The results of the VBM analysis were not significant. CONCLUSION: The presence of abnormality of SMA suggests that patients with ReT have a different pathophysiological mechanism as compared to patients without ReT. This is a novel finding implicating a possible contribution of the frontal lobe to the genesis of SP in ReT. ReT could be a distinct clinical entity within the tremor dominant subtype.

Severe white matter damage in SHANK3 deficiency: a human and translational study

ObjectiveHeterozygous SHANK3 mutations or partial deletions of the long arm of chromosome 22, also known as Phelan–McDermid syndrome, result in a syndromic form of the autism spectrum as well as in global developmental delay, intellectual disability, and several neuropsychiatric comorbidities. The exact pathophysiological mechanisms underlying the disease are still far from being deciphered but studies of SHANK3 models have contributed to the understanding of how the loss of the synaptic protein SHANK3 affects neuronal function.Methods and resultsDiffusion tensor imaging‐based and automatic volumetric brain mapping were performed in 12 SHANK3‐deficient participants (mean age 19 ± 15 years) versus 14 age‐ and gender‐matched controls (mean age 29 ± 5 years). Using whole brain–based spatial statistics, we observed a highly significant pattern of white matter alterations in participants with SHANK3 mutations with focus on the long association fiber tracts, particularly the uncinate tract and the inferior fronto‐occipital fasciculus. In contrast, only subtle gray matter volumetric abnormalities were detectable. In a back‐translational approach, we observed similar white matter alterations in heterozygous isoform–specific Shank3 knockout (KO) mice. Here, in the baseline data sets, the comparison of Shank3 heterozygous KO vs wildtype showed significant fractional anisotropy reduction of the long fiber tract systems in the KO model. The multiparametric Magnetic Resonance Imaging (MRI) analysis by DTI and volumetry demonstrated a pathology pattern with severe white matter alterations and only subtle gray matter changes in the animal model.InterpretationIn summary, these translational data provide strong evidence that the SHANK3‐deficiency–associated pathomechanism presents predominantly with a white matter disease. Further studies should concentrate on the role of SHANK3 during early axonal pathfinding/wiring and in myelin formation.

Differentiation of Early Alzheimer's Disease, Mild Cognitive Impairment, and Cognitively Healthy Elderly Samples Using Multimodal Neuroimaging Indices

Brain resting-state functional connectivity (rsFC), white matter (WM) integrity, and cortical morphometry, as well as neuropsychological performance, have seldom been studied together to differentiate Alzheimer's disease (AD), mild cognitive impairment (MCI), and elderly cognitively healthy comparison (eCHC) samples in the context of the same study. We examined brain rsFC in samples of patients with mild AD (n = 50) and MCI (n = 49) in comparison with eCHC samples (n = 48) and then explored whether rsFC abnormalities can be linked to underlying gray matter (GM) volumetric and/or WM microstructural abnormalities. The mild AD sample showed significantly increased rsFC in the executive control network (ECN) and dorsal attention network (DAN) compared with the eCHC sample, and increased rsFC in ECN compared with MCI. Brain regions corresponding to both these resting-state networks (RSNs) showed significant reduction in fractional anisotropy in mild AD in comparison with eCHC. Significant GM volumetric reductions were observed in brain regions corresponding to both RSNs in the mild AD sample compared with MCI as well as eCHC samples. The association of default mode network-DAN anticorrelation with cognitive performances differentiated mild AD and MCI from eCHC sample. These findings highlight the association between brain structural and functional abnormalities as well as cognitive impairment that enables differentiation between early AD, MCI, and eCHC samples.

Measurement of structural integrity of the spinal cord in patients with amyotrophic lateral sclerosis using diffusion tensor magnetic resonance imaging.

BackgroundThe value of conventional magnetic resonance imaging (MRI) for amyotrophic lateral sclerosis (ALS) is low. Functional and quantitative MRI could be more accurate. We aimed to examine the value of diffusion tensor imaging (DTI) with fractional anisotropy (FA) measurements of the cervical and upper thoracic spinal cord in patients with ALS.Patients and methodsFourteen patients with ALS and 15 sex- and age-matched controls were examined with DTI at a 3T MRI scanner. Region-of-interest (ROI) based fractional anisotropy measurements were performed at the levels C2-C4, C5-C7 and Th1-Th3. ROIs were placed at different anatomical locations of the axial cross sections of the spinal cord.ResultsFA was significantly reduced in ALS patients in anterolateral ROIs and the whole cross section at the C2-C4 level and the cross section of the Th1-Th3 level. There was a trend towards a statistically significant FA reduction in the anterolateral ROIs at the C5-C7 level in ALS patients. No significant differences between patients and controls were found in posterior ROIs.ConclusionFA was reduced in ROIs representing the motor tracts in ALS patients. DTI with FA measurements is a promising method in this circumstance. However, for DTI to become a valuable and established method in the diagnostic workup of ALS, larger studies and further standardisation are warranted.

Diffuse Tract Damage in CADASIL Is Correlated with Global Cognitive Impairment

Introduction: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy ­(CADASIL) is the most common familial cerebral small vessel disease caused by notch homolog protein 3 gene mutations and is strongly associated with ischemic stroke and dementia. Patients are characterized by cognitive impairment and widespread white matter (WM) lesions. However, the relationship between WM lesions and cognitive impairment is not very clear. The aim of this study was to investigate WM microstructural abnormalities by diffusion tensor imaging (DTI) and the relationship between WM alterations and cognitive impairment in patients with CADASIL. Methods: In the present study, we evaluated WM degeneration in 18 patients with CADASIL and 18 controls by fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD) based on DTI. Results: Compared with healthy controls, patients with CADASIL showed extensive and significant reductions in FA and increased RD, AD, and MD. These alterations were distributed throughout the entire brain (mainly the inferior and superior longitudinal fasciculus, inferior fronto-occipital fasciculus, corpus callosum, internal capsule, external capsule, corona radiata, thalamic radiation, and cingulum). Furthermore, these WM microstructural alterations were significantly correlated with cognitive scores and stroke scale scores. Conclusion: Patients with ­CADASIL showed widespread WM abnormalities, and WM microstructural integrity and cognitive impairment were significantly correlated. Our results indicated that damage to WM tracts plays an important role in cognitive impairment in CADASIL.

Brain white matter abnormalities and correlation with severity in amyotrophic lateral sclerosis: An atlas-based diffusion tensor imaging study

ObjectivesTo assess microstructural alterations in white matter (WM) in amyotrophic lateral sclerosis (ALS) using diffusion tensor imaging (DTI). MethodsDTI data were collected from 34 subjects (18 patients with ALS and 16 healthy controls). The atlas-based region of interest (ROI) analysis was conducted to assess WM microstructure in ALS by combining intra-voxel metrics, which included fractional anisotropy (FA) and mean diffusivity (MD), and an inter-voxel metric, i.e., local diffusion homogeneity (LDH). Correlation analysis of diffusion values and clinical factors was also performed. ResultsALS group showed a significant FA reduction in bilateral corticospinal tract (CST) as well as right uncinate fasciculus (RUF). The areas with higher MD were situated in right corticospinal tract (RCST), left cingulum hippocampus (LCH), RUF, and right superior longitudinal fasciculus (RSLF). Additionally, ALS patients showed decreased LDH in bilateral anterior thalamic radiation (ATR), bilateral CST and left inferior frontal-occipital fasciculus (LIFOF). Significant correlations were observed between ALSFRS-R (revised ALS Functional Rating Scale) scores or progression rate and FA in bilateral CST, as well as between disease duration and LDH in right CST. Receiver operating characteristic (ROC) analysis revealed the feasibility of employing diffusion metrics along the CST to distinguish two groups (AUC = 0.792–0.868, p < .005 for all). ConclusionsWM microstructural alteration is a common pathology in ALS, which can be detected by both intra- and inter-voxel diffusion metrics. The extent of abnormalities in several WM tracts such as ATR and LIFOF may be better assessed through the inter-voxel diffusion measurement.

Reduced Fractional Anisotropy of Superior Cerebellar Peduncle is Associated With Persistent Ataxia in Children Undergoing Resection of Posterior Fossa Tumors

Abstract INTRODUCTION Persistent neurological deficits are seen in over 60% of children after resection of posterior fossa tumors. The goal of this study was to determine if these deficits are associated with persistent structural injury to white matter tracts. METHODS Demographic, clinical, and imaging data were reviewed for children undergoing resection of posterior fossa tumors at a tertiary care pediatric hospital. Preoperative, early postoperative (within 48 h of injury) and follow-up diffusion tensor imaging (DTI) were analyzed. Fractional anisotropy (FA) of the middle and superior cerebellar peduncles (SCP) were measured using manual regions of interest. Mean FA values before and after surgery were compared using paired sample T-test. Preoperative, postoperative and follow-up FA values were compared between patients with and without persistent neurological deficits. Statistical significance was set at P &lt; .05. RESULTS A toal of 20 patients (12 male, mean age 6.1 ± 4.1 yr) were included in this study. A total of Twelve patients (60%) underwent a trans-vermian approach and 15 patients (75%) underwent gross total resection. All patients had preoperative DTI scans, and follow-up DTI scans were available for 18 patients at a median duration of 19.7 mo (range 4-57.9 mo). Compared to preoperative DTI, FA of the left SCP was significantly reduced on early postoperative DTI scans (0.44 ± 0.07 vs 0.53 ± 0.1, P = .003). Significant reduction in left SCP FA on follow-up DTI was seen in patients with persistent ataxia at follow-up (0.43 ± 0.1 vs 0.55 ± 0.1, P = .016). Patients with persistent ataxia at follow-up (n = 10) had significantly lower FA of the left SCP at follow-up compared to patients who recovered from early postoperative ataxia (n = 4) (0.43 ± 0.1 vs 0.55 ± 0.04, P = .04). CONCLUSION Reduced FA of the SCP is associated with persistent ataxia at follow-up in children undergoing resection of posterior fossa tumors.