Differences In Fractional Anisotropy Values Research Articles

Contribution of changes in the spinal cord and brain to the onset and progression of hand clumsiness symptoms in cervical spondylotic myelopathy.

Cervical spondylotic myelopathy (CSM) stands as the most prevalent form of spinal cord injury, frequently prompting various changes in both the brain and spinal cord. However, the precise nature of these changes within the brains and spinal cords of CSM patients experiencing hand clumsiness (HCL) symptoms has remained elusive. The authors aimed to scrutinize these alterations and explore potential links between these changes and the onset of HCL symptoms. Using the modified Japanese Orthopaedic Association (mJOA) scale, the authors classified CSM patients into two groups: those without HCL and those with HCL. The authors performed voxel-wise z-score transformation amplitude of low-frequency fluctuations (zALFF) and resting-state functional connectivity (FC) evaluations in the brain. Additionally, they used the Spinal Cord Toolbox to calculate the fractional anisotropy (FA) of spinal cord tracts. The analysis also encompassed an examination of the correlation of these measures with improvements in mJOA scores. Significant disparities in zALFF values surfaced in the right calcarine, right cuneus, right precuneus, right middle occipital gyrus (MOG), right superior occipital gyrus (SOG), and right superior parietal gyrus (SPG) between healthy controls (HC), patients without HCL, and patients with HCL, primarily within the visual cortex. In the patient group, patients with HCL displayed reduced FC between the right calcarine, right MOG, right SOG, right SPG, right SFG, bilateral MFG, and left median cingulate and paracingulate gyri when compared with patients without HCL. Moreover, significant differences in FA values of the corticospinal tract (CST) and reticulospinal tract (REST) at the C2 level emerged among HC, patients without HCL, and patients with HCL. Notably, zALFF, FC, and FA values in specific brain regions and spinal cord tracts exhibited correlations with mJOA upper-extremity scores. Additionally, FA values of the CST and REST correlated with zALFF values in the right calcarine, right MOG, right SOG, and right SPG. Alterations within brain regions associated with the visual cortex, the fronto-parietal-occipital attention network, and spinal cord pathways appear to play a substantial role in the emergence and progression of HCL symptoms. Furthermore, the existence of a potential connection between the spinal cord and the brain suggests that this link might be related to the clinical symptoms of CSM.

Impacts of dioxin exposure on brain connectivity estimated by DTI analysis of MRI images in men residing in contaminated areas of Vietnam.

Effects of dioxin exposure on gray matter volume have been reported in previous studies, but a few studies reported effects of dioxin exposure on white matter structure. Therefore, this study was undertaken to investigate the impact of dioxin exposure on white matter microstructure in men living in the most severely dioxin-contaminated areas in Vietnam. In 2019 brain MRI scans from 28 men living near Bien Hoa airbase were obtained at Dong Nai General Hospital, Vietnam, on a 3 T scanner using a conventional diffusion tensor imaging sequence. Two exposure markers were indicated by perinatal exposure estimated by assessment of maternal residency in a dioxin-contaminated area during pregnancy and by measurement of blood dioxin levels. A general linear model was used to compare fractional anisotropy (FA) values in 11 white matter tracts in both hemispheres between groups with and without perinatal dioxin exposure and groups with high and low blood dioxin levels after adjusting for covariates. The adjusted mean FA value in the left cingulum hippocampal part (CGH) was significantly lower in the perinatal dioxin exposure group compared with the group without perinatal dioxin exposure. The high blood TCDD group showed significantly reduced FA values in the left and right CGH and right uncinate fasciculus (UNC). Moreover, the high blood TEQ-PCDDs group showed significantly lower FA values in the left and right CGH and the left UNC. There were no significant differences in FA values between the groups with high and low TEQ-PCDFs levels or between the groups with high and low TEQ-PCDD/Fs levels. It was concluded that dioxin exposure during the perinatal period and adulthood may alter the microstructure of white matter tracts in individuals with neurodevelopmental disorders.

Clinical Value and Reliability of Quantitative Assessments of Lumbosacral Nerve Root Using Diffusion Tensor and Diffusion Weighted MR Imaging: A Systematic Review.

Lumbosacral radicular pain diagnosis remains challenging. Diffusion tensor imaging (DTI) and diffusion weighted imaging (DWI) have potential to quantitatively evaluate symptomatic nerve root, which may facilitate diagnosis. To determine the ability of DTI and DWI metrics, namely fractional anisotropy (FA) and apparent diffusion coefficient (ADC), to discriminate between healthy and symptomatic lumbosacral nerve roots, to evaluate the association between FA and ADC values and patient symptoms, and to determine FA and ADC reliability. Systematic review. Eight hundred twelve patients with radicular pain with or without radiculopathy caused by musculoskeletal-related compression or inflammation of a single, unilateral lumbosacral nerve root and 244 healthy controls from 29 studies. Diffusion weighted echo planar imaging sequence at 1.5 T or 3 T. An extensive systematic review of the literature was conducted in Embase, Scopus, and Medline databases. FA and ADC values in symptomatic and contralateral lumbosacral nerve roots were extracted and summarized, together with intra- and inter-rater agreements. Where available, associations between DWI or DTI parameters and patient symptoms or symptom duration were extracted. The main results of the included studies are summarized. No additional statistical analyses were performed. The DTI studies systematically found significant differences in FA values between the symptomatic and contralateral lumbosacral nerve root of patients suffering from radicular pain with or without radiculopathy. In contrast, identification of the symptomatic nerve root with ADC values was inconsistent for both DTI and DWI studies. FA values were moderately to strongly correlated with several symptoms (eg, disability, nerve dysfunction, and symptom duration). The inter- and intra-rater reliability of DTI parameters were moderate to excellent. The methodological quality of included studies was very heterogeneous. This systematic review showed that DTI was a reliable and discriminative imaging technique for the assessment of symptomatic lumbosacral nerve root, which more consistently identified the symptomatic nerve root than DWI. Further studies of high quality are needed to confirm these results. N/A TECHNICAL EFFICACY: Stage 2.

Diffusion tensor imaging in photosensitive and nonphotosensitive juvenile myoclonic epilepsy

Introduction/backgroundJuvenile myoclonic epilepsy (JME) syndrome is known to cause alterations in brain structure and white matter integrity. The study aimed to determine structural white matter changes in patients with JME and to reveal the differences between the photosensitive (PS) and nonphotosensitive (NPS) subgroups by diffusion tensor imaging (DTI) using the tract-based spatial statistics (TBSS) method. MethodsThis study included data from 16 PS, 15 NPS patients with JME, and 41 healthy participants. The mean fractional anisotropy (FA) values of these groups were calculated, and comparisons were made via the TBSS method over FA values in the whole-brain and 81 regions of interest (ROI) obtained from the John Hopkins University White Matter Atlas. ResultsIn the whole-brain TBSS analysis, no significant differences in FA values were observed in pairwise comparisons of JME patient group and subgroups with healthy controls (HCs) and in comparison between JME subgroups. In ROI-based TBSS analysis, an increase in FA values of right anterior corona radiata and left corticospinal pathways was found in JME patient group compared with HC group. When comparing JME-PS patients with HCs, an FA increase was observed in the bilateral anterior corona radiata region, whereas when comparing JME-NPS patients with HCs, an FA increase was observed in bilateral corticospinal pathway. Moreover, in subgroup comparison, an increase in FA values was noted in corpus callosum genu region in JME-PS compared with JME-NPS. ConclusionsOur results support the disruption in thalamofrontal white matter integrity in JME, and subgroups and highlight the importance of using different analysis methods to show the underlying microstructural changes.

Role of magnetic resonance diffusion tensor imaging in assessment of back muscles in young adults with chronic low back pain

BackgroundLow back pain (LBP) is one of the most common musculoskeletal complaints and considered as the most disabling condition among general population. Magnetic resonance imaging (MRI) is the preferred modality in imaging of LBP. Diffusion tensor imaging (DTI) is a version of MRI that can detect tissue microstructure changes occurring in different pathologies. The commonly used parameters are fractional anisotropy (FA) and mean diffusivity (MD). We aimed in this study to evaluate the role of DTI in the assessment of back muscles in young adults with chronic LBP with no major neurological or orthopedic disorders.ResultsThere was a statistically significant difference in MD values of back muscles between patients and control groups. At the ROC curve, for psoas muscle, the AUC was 0.906 with a cutoff point of 0.951. Sensitivity and specificity were 89.2% and 90.9% with accuracy 89.8%. For multifidus muscle, the AUC was 0.919 with a cutoff point of 1.29. Sensitivity and specificity were 91.9% and 90.9% with accuracy 91.4%. For erector spinae muscle, the AUC was 0.834 with a cutoff point of 1.224. Sensitivity and specificity were 81.1% and 72.7% with accuracy 77.9%. There was a statistically significant difference in FA values of back muscles between the patients and control groups. At the ROC curve, for psoas muscle, the AUC was 0.840 with a cutoff point of 0.546. Sensitivity and specificity were 81.1% and 72.7% with accuracy 77.97%. For multifidus muscle, the AUC was 0.875 with a cutoff point of 0.415. Sensitivity and specificity were 81.1% and 90.9% with accuracy 84.7%. For erector spinae muscle, the AUC was 0.805 with a cutoff point of 0.437. Sensitivity and specificity were 81.1% and 77.3% with accuracy 79.7%.ConclusionsDTI is a valuable promising noninvasive tool in the assessment of back muscles quality in patient with chronic low back pain, with no detected neurological or orthopedic pathologies. This is due to its sensitivity to microscopic intracellular changes that could not be detected on conventional imaging, allowing better tissue characterization.

Diffusion tensor imaging helps identify shunt-responsive normal pressure hydrocephalus patients among probable iNPH cohort

The aim of this study was to investigate whether white matter changes as measured by diffusion tensor imaging (DTI) can help differentiate shunt-responsive idiopathic normal pressure hydrocephalus (iNPH) patients from patients with other causes of gait disturbances and/or cognitive decline with ventriculomegaly whose clinical symptoms do not improve significantly after cerebrospinal fluid derivation (non-iNPH). Between 2017 and 2022, 85 patients with probable iNPH underwent prospective preoperative magnetic resonance imaging (MRI) and comprehensive clinical workup. Patients with clinical symptoms of iNPH, positive result on lumbar infusion test, and gait improvement after 120-h lumbar drainage were diagnosed with iNPH and underwent shunt-placement surgery. Fractional anisotropy (FA) and mean diffusivity (MD) values for individual regions of interest were extracted from preoperative MRI, using the TBSS pipeline of FSL toolkit. These FA and MD values were then compared to results of clinical workup and established diagnosis of iNPH. An identical MRI protocol was performed on 13 age- and sex-matched healthy volunteers. Statistically significant differences in FA values of several white matter structures were found not only between iNPH patients and healthy controls but also between iNPH and non-iNPH patients. ROI that showed best diagnostic ability when differentiating iNPH among probable iNPH cohort was uncinate fasciculus, with AUC of 0.74 (p < 0.001). DTI methods of white matter analysis using standardised methods of ROI extraction can help in differentiation of iNPH patients not only from healthy patients but also from patients with other causes of gait disturbances with cognitive decline and ventriculomegaly.

Visual alertness and brain diffusion tensor imaging at term age predict neurocognitive development at preschool age in extremely preterm-born children.

Cognitive development is characterized by the structural and functional maturation of the brain. Diffusion-weighted magnetic resonance imaging (dMRI) provides methods of investigating the brain structure and connectivity and their correlations with the neurocognitive outcome. Our aim was to examine the relationship between early visual abilities, brain white matter structures, and the later neurocognitive outcome. This study included 20 infants who were born before 28 gestational weeks and followed until the age of 6.5 years. At term age, visual alertness was evaluated and dMRI was used to investigate the brain white matter structure using fractional anisotropy (FA) in tract-based spatial statistics analysis. The JHU DTI white matter atlas was used to locate the findings. The neuropsychological assessment was used to assess neurocognitive performance at 6.5 years. Optimal visual alertness at term age was significantly associated with better visuospatial processing (p<.05), sensorimotor functioning (p<.05), and social perception (p<.05) at 6.5 years of age. Optimal visual alertness related to higher FA values, and further, the FA values positively correlated with the neurocognitive outcome. The tract-based spatial differences in FA values were detected between children with optimal and nonoptimal visual alertness according to performance at 6.5 years. We provide neurobiological evidence for the global and tract-based spatial differences in the white matter maturation between extremely preterm children with optimal and nonoptimal visual alertness at term age and a link between white matter maturation, visual alertness and the neurocognitive outcome at 6.5 years proposing that early visual function is a building block for the later neurocognitive development.

Diffusion tensor imaging discriminates focal cortical dysplasia from normal brain parenchyma and differentiates between focal cortical dysplasia types

ObjectivesAlthough diffusion tensor imaging (DTI) may facilitate the identification of cytoarchitectural changes associated with focal cortical dysplasia (FCD), the predominant aetiology of paediatric structural epilepsy, its potential has thus far remained unexplored in this population. Here, we investigated whether DTI indices can differentiate FCD from contralateral brain parenchyma (CBP) and whether clinical features affect these indices.MethodsIn this single-centre, retrospective study, we considered children and adolescents with FCD-associated epilepsy who underwent brain magnetic resonance (MRI), including DTI. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity, and radial diffusivity, were calculated in both FCD and CBP. The DTI indices best discriminating between FCD and CBP were subsequently used to assess the link between DTI and selected clinical and lesion-related parameters.ResultsWe enrolled 32 patients (20 male; median age at MRI 4 years), including 15 with histologically confirmed FCD. FA values were lower (p = 0.03), whereas MD values were higher in FCD than in CBP (p = 0.04). The difference in FA values between FCD and CBP was more pronounced for a positive vs. negative history of status epilepticus (p = 0.004). Among histologically confirmed cases, the difference in FA values between FCD and CBP was more pronounced for type IIb versus type I FCD (p = 0.03).ConclusionsFA and MD discriminate between FCD and CBP, while FA differentiates between FCD types. Status epilepticus increases differences in FA, potentially reflecting changes induced in the brain. Our findings support the potential of DTI to serve as a non-invasive biomarker to characterise FCD in the paediatric population.

Desynchronized white matter function and structure in drug-naive first-episode major depressive disorder patients.

Major depressive disorder (MDD) is a highly prevalent mental disease. Using magnetic resonance imaging (MRI), although numerous studies have revealed the alterations in structure and function of grey matter (GM), few studies focused on the synchronization of white matter (WM) structure and function in MDD. The aim of this study was to investigate whether functional and structural abnormalities of WM play an essential role in the neurobiological mechanisms of MDD. Gradient-echo imaging sequences at 3.0T were used to gather resting state functional MRI (rsfMRI) data, which were performed on 33 drug-naive first-episode MDD patients and 34 healthy controls (HCs). After data preprocessed, amplitude of low frequency fluctuation (ALFF) of WM was calculated. ALFF values in different frequency bands were analyzed, including typical (0.01-0.15 Hz) band, slow-4 (0.027-0.073 Hz) and slow-5 (0.01-0.027 Hz) bands. In addition, the fractional anisotropy (FA) values in WM in 23 patients and 26 HCs were examined using tract-based spatial statistics (TBSS) and tractography based on diffusion tensor imaging (DTI). Pearson correlation analysis was applied to analyze the relationships between ALFF values and Hamilton Depression Scale (HAMD) and Hamilton Anxiety Scale (HAMA). Compared with the HCs, MDD patients showed decreased ALFF values in posterior thalamic radiation (PTR) and superior longitudinal fasciculus (SLF) in slow-5 frequency band, no significant differences of ALFF values were found in typical and slow-4 frequency bands. In addition, there were no significant differences in FA values with TBSS analysis as well as the number of fibers in PTR and SLF with tractography analysis between two groups. Further correlation analysis showed that the ALFF value in SLF was negatively correlated with HAMA-2 score (r = -0.548, p FDR = 0.037) in patients. Our results indicated that WM dysfunction may be associated with the pathophysiological mechanism of depression. Our study also suggested that the functional damage of the WM may precedes the structural damage in first-episode MDD patients. Furthermore, for mental disorders, slow-5 frequency band may be a more sensitive functional indicator for early detection of abnormal spontaneous brain activity in WM.

Combined fractional anisotropy and subcortical volumetric deficits in patients with mild-to-moderate depression: Evidence from the treatment of antidepressant traditional Chinese medicine

Numerous neuroimaging studies have demonstrated that diverse brain structural plasticity could occur in a human brain during a depressive episode. However, there is a lack of knowledge regarding the underlying mechanisms of mild-to-moderate depression (MMD), especially the changes of brain structural characteristics after treatment with the Shuganjieyu capsule (SG), a kind of traditional Chinese medicine that has been recommended for the specialized treatment of MMD. In this study, we investigated the structural brain plasticity in MMD that have been undergoing 8 weeks of SG treatment compared with age- and sex-matched healthy controls (HCs) and assessed the relationship between these brain structural alternations and clinical symptoms in MMD. At the baseline, we found that: (1) fractional anisotropy (FA) values in patients with MMD were found to be significantly increased in the regions of anterior limb of internal capsule (ALIC) [MNI coordinates: Peak (x/y/z) = 102, 126, 77; MMD FApeak (Mean ± SD) = 0.621 ± 0.043; HCs FApeak (Mean ± SD) = 0.524 ± 0.052; MMD > HCs, t = 9.625, p < 0.001] and posterior limb of internal capsule (PLIC) [MNI coordinates: Peak (x/y/z) = 109, 117, 87; MMD FApeak (Mean ± SD) = 0.694 ± 0.042; HCs FApeak (Mean ± SD) = 0.581 ± 0.041; MMD > HCs, t = 12.90, p < 0.001], and FA values were significantly positively correlated with HAMD scores in patients with MMD. (2) Patients with MMD showed smaller gray matter volume (GMV) of the dorsolateral prefrontal cortex (DLPFC), frontal cortex, occipital cortex, and precuneus, and the GMV of DLPFC was negatively correlated with HAMD scores. After SG treatment, we found that (1) the HAMD scores decreased; (2) FA values were significantly decreased in the regions of the ALIC and PLIC compared to those at baseline and TBSS revealed no significant differences in FA values between patients with MMD and HCs. (3) The structural characteristics of DLPFC in patients with MMD obtained at the 8th week were improved, e.g., no significant differences in GMV of DLPFC between the two groups. Taken together, our results provided neuroimaging evidence suggesting that SG is an effective treatment for patients with MMD. Moreover, alterations of GMV after 8 weeks of SG treatment indicated a potential modulation mechanism in brain structural plasticity within the DLPFC in patients with MMD.

Utility of DTI (Diffusion Tensor Imaging) Metrics to Study Microstructural Changes of Trigeminal Nerve in Patients with Trigeminal Neuralgia (TN).

To study the trigeminal nerve tractography and assessment of diffusion tensor imaging (DTI) parameters by comparing the values of fractional anisotropy (FA) of trigeminal (V) nerve on the affected side with that of the unaffected opposite side. Prospective comparative study done for one year included 30 patients who presented with trigeminal neuralgia and 30 controls who did not have any present or past history of neurological or neurosurgical symptoms were enrolled in the study. Most common age of presentation of TN is >50 years, and the commonly involved branch is V2 (maxillary branch of the trigeminal nerve). Most of the patients were having symptoms for more than 1 year. The superior cerebellar artery was the most common vessel compressing the V nerve at the root entry zone (REZ), followed in the order by anterior inferior cerebellar artery and petrosal vein. Neurovascular compression (NVC) was more commonly seen in the study group when compared with the control group. In all the patients in the study group, fractional anisotropy (FA) was decreased on the affected side as compared to the unaffected side. In the study group, 10 patients were having NVC on both sides, but FA was significantly decreased only on the affected side. No significant difference in FA values at the REZ of bilateral V nerves in the control group. DTI metrics of the trigeminal nerve is a very helpful imaging technique in patients with trigeminal neuralgia. It not only helps in anatomical imaging but also reinforces the association between NVC and TN.

Evaluating the brainstem in children with breath-holding spells.

Breath-holding spells (BHSs) are a non-epileptic paroxysmal phenomenon characterized by frequent apnea episodes, loss of consciousness, and changes in skin tone and postural tone triggered by negative stimuli of childhood. The pathophysiology of the disease remains unclear; autonomic dysregulation caused by delayed myelination is believed to play a role. In this study, we aimed to evaluate the brainstems of children with BHS using diffusion tensor imaging (DTI) and investigate the etiology of this phenomenon. The study group consisted of 16 children with a history of severe breath-holding episodes (accompanied by loss of consciousness and tonic contraction due to prolonged anoxic response) and 18 age-, gender-, and handedness-matched controls. All children underwent systemic, neurologic, and cardiologic evaluation, including complete blood count, blood biochemistry, serum iron and ferritin level, serum vitamin B12 level, electrocardiogram, and electroencephalograms. Magnetic resonance imaging was performed using a 1.5-Tesla Siemens Aera scanner (Siemens, Germany). Evaluation of brainstem (midbrain, pons, and medulla oblongata) volumes revealed no statistically significant differences between the BHS patient and control groups. In a voxel-wise analysis of DTI data, the BHS patient group had significantly lower fractional anisotropy (FA) values than the control group in the bilateral midbrain and medulla, right corticospinal tract, bilateral corpus callosum body and splenium, and left corpus callosum genu. In contrast, there were no significant differences in FA values in the pons, cerebellum, left corticospinal tract, and right corpus callosum genu. Based on our findings, we think that patients with BHS should be treated with an approach similar to other neurodevelopmental diseases and that this study may help elucidate the pathophysiology and establish the groundwork for future studies on its treatment.

Diffusion tension imaging is a good tool for assessing patients with dementia and behavioral problems and discriminating them from other dementia patients.

BackgroundDementia is one of the leading public health concerns as the world’s population ages. Although Alzheimer’s disease (AD) is the most common dementia diagnosis among older patients, some patients have additional behavioral symptoms. It is therefore important to provide an exact diagnosis, both to provide the best possible treatment for patients and to facilitate better understanding.PurposeTo investigate whether magnetic resonance imaging (MRI) with fractional anisotropy (FA) can accurately find patients with behavioral symptoms within a group of AD patients.Material and MethodsForty-five patients from the geriatric outpatient clinic were recruited consecutively to form a group of patients with AD and behavioral symptoms (AD + BS) and a control group of 50 patients with established AD. All patients had a full assessment for dementia to establish the diagnosis according to ICD-10. MRI included 3D anatomical recordings for morphometric measurements, DTI for fiber tracking, and quantitative assessment of regional white matter integrity. The DTI analyses included computing of the diffusion tensor and its derived FA index.ResultsWe found a significant difference in FA values between the patient groups’ frontal lobes. The FA was greater in the study group in both left (0.39 vs 0.09, p < 0.05) and right (0.40 vs 0.16, p < 0.05) frontal lobes.ConclusionMRI with FA will find damage in frontal tracts and may be used as a diagnostic tool and be considered a robust tool for the recognizing different types of dementia in the future.

Evaluation of structural changes in orbitofrontal cortex in relation to medication overuse in migraine patients: a diffusion tensor imaging study.

Migraine is a prevalent neurological disease that leads to severe headaches. Moreover, it is the commonest among the primary headaches that cause medication overuse headache (MOH). The orbitofrontal cortex (OFC) is one of the structures most associated with medication overuse. To determine microstructural changes in the OFC among migraine patients who developed MOH, through the diffusion tensor imaging (DTI) technique. Fifty-eight patients who had been diagnosed with migraine based on the Classification of Headache Disorders (ICHD-III-B) were included in the study. Patients were sub-classified into two groups, with and without MOH, based on the MOH criteria of ICHD-III-B. DTI was applied to each patient. The OFC fractional anisotropy (FA), and apparent diffusion coefficient (ADC) values of the two groups were compared. The mean age of all the patients was 35.98±7.92 years (range: 18-65), and 84.5% (n=49) of them were female. The two groups, with MOH (n=25) and without (n=33), were alike in terms of age, gender, family history, migraine with or without aura and duration of illness. It was found that there was a significant difference in FA values of the left OFC between the two groups (0.32±0.01 versus 0.29±0.01; p=0.04). An association was found between MOH and changes to OFC microstructure. Determination of neuropathology and factors associated with medication overuse among migraine patients is crucial in terms of identifying the at-risk patient population and improving proper treatment strategies specific to these patients.

Correlation between DTI effect and white matter structural integrity, working memory in leukoaraiosis patients

Our objective was to study the correlation between Diffusion tensor MR imaging (DTI) effect and white matter structural integrity, working memory in leukoaraiosis patients. 100 leukoaraiosis patients referring to the First Affiliated Hospital of Beijing Medical University from December 2018 to December 2019, were selected as study subjects and divided into four groups according to disease severity: lesion-free group, mild lesion group, moderate lesion group, and severe lesion group. All patients underwent magnetic resonance diffusion tensor imaging to collect DWI images and analyze Fractional anisotropy (FA), mean diffusivity (MD), ReHo values of white matter area under different grading. The patients’ working memory was tested via auditory verb learning test and Stroop color word test, so that correlation between white matter structural integrity and working memory can be analyzed. Results: There are statistically significant differences in FA values of the right posterior thalamic radiation, the right sagittal layer and the right superior longitudinal fasciculus, MD values of the right sagittal layer, the right cingulum bundle, the left cingulum bundle, the right inferior fasciculus fronto-occipitalis and the left inferior fasciculus frontooccipitalis, as well as instant recall, delayed recall, delayed recognition, card A (dot), card B (character), card C (color word) and SIE value (P&lt;0.01). Correlation is shown between white matter structural integrity and working memory, gender, age, grading, disease course, recurrence interval, white matter area, and testing methods. There was a correlation between DTI effect and white matter structural integrity, working memory in leukoaraiosis patients, and leukoaraiosis patients have memory impairment.

The Utility and Efficiency of Diffusion Tensor Imaging Values to Determine Epidermal Growth Factor Receptor Gene Mutation Status in Brain Metastasis from Lung Adenocarcinoma; A Preliminary Study.

This study aims to investigate the existence of any Diffusion Tensor Imaging (DTI) value differences in Brain Metastases (BM) due to lung adenocarcinoma based on the Epidermal Growth Factor Receptor (EGFR) gene mutation status. 17 patients with 32 solid intracranial metastatic lesions from lung adenocarcinoma were included prospectively. Patients were divided according to the EGFR mutation status as EGFR (+) (group 1, n:8) and EGFR wild type (group 2, n:9). The Fractional Anisotropy (FA), apparent diffusion coefficient (ADC), normalized ADC (nADC), Axial Diffusivity (AD), and Radial Diffusivity (RD) values were measured from the solid component of the metastatic lesions and nADC values were calculated. DTI values were compared between group 1 and group 2. The receiver-operating characteristic analysis was used to obtain cut-off values for the parameters presenting a statistical difference between the EGFR gene mutation-positive and wild type group. There were statistically significant differences in measured ADC, nADC, AD, and RD values between group 1 and group 2. The ADC, nADC, AD, and RD values were significantly lower in group 1. There was no significant difference in FA values between the two groups. Analysis by the ROC curve method revealed a cut-off value of ≤721 x 10-6 mm2/s for ADC (Sensitivity= 72.7, Specificity=85.7); ≤0.820 for nADC (Sensitivity=72.7, Specificity=90.5), ≤ 886 for AD (Sensitivity=81.8, Specificity=81.0), and ≤588 for RD (Sensitivity=63.6, Specificity=90.5) in differentiating EGFR mutation (+) group from wild type group. A combination of the decreased ADC, nADC, AD, and RD values in BM due to lung adenocarcinoma can be important for predicting the EGFR gene mutation status. DTI features of the brain metastases from lung adenocarcinoma may be utilized to provide insight into the EGFR mutation status and guide the clinicians for the initiation of targeted therapy.

Evaluation of the relationship between corpus callosum and internal capsule and tuber load in patients with tuberous sclerosis complex by diffusion tensor imaging

Aim: To determine whether there are Diffusion Tensor Imaging (DTI) changes in the white matter pathways such as corpus callosum and internal capsule in patients with Tuberous sclerosis complex (TSC) and to investigate its relationship with tuber load. Materials and Methods: Our study included 17 children with TSC and 15 healthy controls. Total tuber load of the brain was calculated. Correlation between tuber load and ADC (Apparent diffusion coefficient) and FA (Fractional anisotropy) values at corpus callosum (CC) and internal capsule were investigated.Results: When patients with TSC were compared with control, there was a significant difference in ADC and FA values in the corpus callosum and internal capsule. There was a significant difference in FA values between the anterior and posterior limbs of the internal capsule on both sides. The ADC values of CC splenium were positively correlated with the total cerebral tuber load. Also, The FA values obtained from CC splenium were negatively correlated with the tuber load of the right cerebral hemisphere. Conclusion: Relationships between corpus callosum and internal capsule ADC and FA changes and tuber load show that microstructural damage develops in the white matter pathways. DTI parameters can be used as a more sensitive biomarker in the evaluation of the abnormal structure of white matter in patients with TSC. More comprehensive studies are needed to more clearly demonstrate the relationship between DTI properties of white matter and tuber load in TSC patients.

Pitfalls of Commonly Used Ischemic and Dementia Models Due to Early Seizure by Carotid Ligation.

While the bilateral common carotid artery (CCA) ligation model is widely used in cerebrovascular disease and dementia studies, it can frequently cause seizures. We examined the validity of seizure as an experimental model of ischemia. Eight-week-old male Wistar and Sprague-Dawley (SD) rats were implanted with electrocorticography (ECoG) electrodes and bilateral CCA ligation was performed and compared to the sham groups. ECoG monitoring was used to confirm the seizure discharge and count the number of spikes in the interictal phase 2 h after ligation, followed by power spectral analysis. Magnetic resonance imaging (MRI) was performed 6 h after bilateral CCA ligation to assess fractional anisotropy (FA), apparent diffusion coefficient (ADC), and cerebral blood flow (CBF) values. Magnetic resonance spectroscopy (MRS) was also performed and the ischemic parameters and electrophysiological changes were compared. The Wistar rat group had significantly higher mortality, frequency of seizures, incidence of non-convulsive seizures, and number of spikes in the interictal period compared to those in the SD rat group. Power spectral analysis showed increased power in the delta band in both Wistar and SD rat groups. MRI, after CCA ligation, showed significantly lower ADC values, lower glutamine and glutamate levels, and higher lactate values in Wistar rats, although there was no difference in FA values. Metabolic and electrophysiological changes after CCA ligation differed according to the rat strain. Wistar rats were prone to increased lactate and decreased glutamine and glutamate levels and the development of status epilepticus. Seizures can affect the results of ischemic experiments.

A diffusion tensor imaging study to compare normative fractional anisotropy values with patients suffering from Parkinson’s disease in the brain grey and white matter

Diffusion tensor imaging (DTI) appears as a sensitive method to study Parkinson’s disease (PD) pathophysiology and severity. Fractional anisotropy (FA) value is one of the scalar derivatives of DTI used to find out anisotropy within a voxel in a tissue and used for determining white matter integrity in aging and neurodegenerative diseases. We studied DTI derived FA in early PD subjects as their routine MRI scans were normal. 40 patients with early PD and 40 healthy controls were employed to evaluate changes in microstructural white and grey matter in the brain’s using DTI derived FA values. Comparison of FA values in the brain’s white and grey matter of patients with PD and age matched controls at the corpus callosum, centrum semiovale, pons, putamen, caudate nucleus, substantia nigra, cerebral peduncles and cerebellar peduncles, was done using a region of interest (ROI) technique, with b-value 1000s/mm2 and TE = 100 milliseconds using 1.5 T MRI system. PD patients showed differences in FA values in both the grey and white matter areas of the brain’s compared to healthy controls. Our study revealed the presence of damage in the substantia nigra, corpus callosum, putamen and cerebral peduncles mainly in the PD group. Our findings indicate that DTI and region of interest (ROI) methods can be used in patients with early PD to study microstructural alterations mainly in the substantia nigra, putamen and corpus callosum.

Characteristics of diffusion tensor imaging of central nervous system in children with tourette's disease.

To investigate the characteristics of diffusion tensor imaging (DTI) of the central nervous system in children with Tourette syndrome (TS).Fifteen children with TS (TS group) and 15 normal children (control group) were studied, and all of them underwent DTI. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) parameters were calculated using the DTIStudio software. The region of interest was delineated manually. The ADC and FA values of the bilateral caudate nucleus, bilateral globus pallidus, bilateral putamen, bilateral thalamus, and bilateral frontal lobe white matter were measured using the region of interest editor software. The differences of FA values and ADC values between the same brain areas were compared. The associations between ADC, FA values and Yale Global Tic Severity Scale (YGTSS) scores were evaluated by Pearson correlation analyses.The FA values of left globus pallidus and left thalamus were significantly lower in the TS group than in the control group (P < .05), while the ADC values of the right caudate nucleus and bilateral thalamus were significantly higher in the TS group than in the control group (P < .05). The decrease in FA in the left thalamus significantly correlated with the YGTSS score (r = 0.692; P < .05). No correlation was found between FA and ADC values in other brain regions and the YGTSS score (P > .05).After the DTI analyses, abnormalities were found in the left globus pallidus, right caudate nucleus, and bilateral thalamus in children with TS. Especially the changes in the left thalamus structure was crucial in the pathophysiological clock of TS.