Mean FA Research Articles

DTI analysis of the peritumoral zone of diffuse low-grade gliomas in progressing patients

DLGGs are rare brain tumors transforming to higher grade even with surgery, chemotherapy and radiotherapy. Their preferential infiltration of WM tracts, beyond tumor boundaries on FLAIR, make difficult to plan focal treatment such as surgery, radiotherapy and monitor response to chemotherapy. DTI might reflect this infiltration of WM tracts. The aim of our study is to assess how DTI signal in the peritumoral zone might be modified before FLAIR tumor progression appears at one-year follow-up. The study retrospectively enrolled five patients who met inclusion criteria: DTI with 25 directions, T1 and FLAIR at initial imaging; FLAIR at one-year follow-up. Patients with surgery, radiotherapy and chemotherapy completed less than 2 years before initial imaging were excluded. FLAIR tumor progression, named progression mask, was assessed by subtracting tumor masks between initial imaging and one-year follow-up. Initial DTI signal was analyzed within this progression mask and compared with the healthy contralateral side. Tumor progression was confirmed for the five patients at one year. All patients showed pre-existing DTI signal abnormalities within the progression mask. Mean FA (p = 0.03) was lower in the progression mask, whereas MD, AD and RD mean (p = 0.03) was higher in the progression mask, compared to healthy side. This study shows pre-existing DTI signal abnormalities in regions with tumor progression at one year. Such abnormalities could correspond to a tumor infiltration not yet visible on FLAIR. This might be helpful to predict tumor progression and allow to adapt the therapeutic strategy.

Assessing Visual Pathway White Matter Degeneration in Primary Open‐Angle Glaucoma Using Multiple MRI Morphology and Diffusion Metrics

BackgroundPrimary open‐angle glaucoma (POAG), a leading cause of irreversible blindness, is associated with neurodegeneration in the visual pathway, but the underlying pathophysiology remains incompletely resolved.PurposeTo characterize macro‐ and microstructural white matter abnormalities in optic tract (OT) and optic radiation (OR) of POAG.Study typeProspective.PopulationsA total of 34 POAG patients (21 males, 13 females) and 25 healthy controls (HCs) (16 males, nine females).Field Strength/Sequence3 T; multiband spin‐echo echo planar diffusion spectrum imaging (DSI).AssessmentWe compared multiple morphology metrics, including volume, area, length, and shape metrics, as well as diffusion metrics such as diffusion tensor imaging (fractional anisotropy [FA], mean diffusivity, radial diffusivity, and axial diffusivity), mean apparent propagator (mean squared displacement, q‐space inverse variance, return‐to‐origin probability, return‐to‐axis probabilities [RTAP] and return‐to‐plane probabilities, non‐Gaussianity, perpendicular non‐Gaussianity, parallel non‐Gaussianity), and neurite orientation dispersion and density imaging (intracellular volume fraction, orientation dispersion index [ODI], and isotropic volume fraction of the OT and OR).Statistical TestsStatistical comparisons and classifications employed linear mixed model and logistic regression. Diagnostic performance was assessed using area under the receiver operating characteristic curve (AUC). P‐value <0.05 was statistically significant.ResultsMorphology analysis in POAG revealed a lower span in the OR (29.43 ± 2.30 vs. 30.59 ± 2.01, 3.8%) and OT (19.73 ± 2.21 vs. 20.68 ± 1.37, 4.6%), and a higher curl (3.03 ± 0.22 vs. 2.90 ± 0.16, 4.5%) in OT. Diffusion metrics revealed lower mean FA (OR: 0.328 ± 0.03 vs. 0.340 ± 0.018, 3.5%; OT: 0.255 ± 0.022 vs. 0.268 ± 0.018, 4.9%) and lower mean RTAP (OR: 5.919 ± 0.529 vs. 6.216 ± 0.489, 4.8%; OT: 4.089 ± 0.402 vs. 4.280 ± 0.353, 4.5%), with higher mean ODI in the OT (0.448 ± 0.029 vs. 0.433 ± 0.025, 3.5%). Combined models, incorporating these MRI metrics, effectively discriminated POAG from HCs, achieving AUCs of 0.84 for OR and 0.83 for OT.Data ConclusionsDSI‐derived morphology and diffusion metrics demonstrated macro‐ and micro abnormalities in the visual pathway, providing insights into POAG‐related neurodegeneration.Level of Evidence2Technical EfficacyStage 3

Estimation of Formaldehyde Levels in Indoor Air of Gross Anatomy Laboratory

Introduction: Medical students spend majority of their times in Anatomy lab during their first year MBBS. Formalin has attracted attention as a health hazard for students and instructors as formalin concentrations in air of gross anatomy laboratories are often higher than permissible limits. Despite the known toxicity of formaldehyde and its potential health effects, laboratory workers and others have little enthusiasm for reducing or replacing the formaldehyde working solution Materials and Methods: The FA concentration (in ppm) of indoor air in Anatomy laboratory was measured using a SMILEDRIVE Portable air quality pollution meter. The mean FA concentration was measured after 1 hour after the cadavers were shifted to dissection table at three different levels a. At the level of floor b. At the level of roof c. 2 feets above the table (Breathing Zone of medical students) Three air samples from the breathing zones were tested and mean concentration of FA was taken with exhaust fan on at the level of roof and recorded as a. S1R- First immediately before the dissection (Zero hour), b. S2R- Second sample was collected after one hour after first sample was taken (First hour) and c. S3R- Third sample after two hours after first sample was taken (Second hour). Three air samples from the breathing zones were tested and mean concentration of FA was taken with exhaust fan on at the level of floor and recorded as a. S1F- First immediately before the dissection (Zero hour), b. S2F- Second sample was collected after one hour after first sample was taken (First hour) and c. S3F- Third sample after two hours after first sample was taken (Second hour). Results: The vertical distribution of FA was measured by taking the mean air samples at the level of floor, at roof level and about 2 feet above dissection table immediately after the cadavers were shifted to tables. It was found to be about 0.54ppm at the level of floor, 0.52 at the breathing zone and 0.51 ppm at roof level. The FA concentration was highest at the level of floor and least at the level of roof. On comparing S2F and S2R the p value was 1.335. Thus, it was not statistically significant. On comparing S3F and S3R the p value was 0.411. Thus, it was not statistically significant. Conclusion: The mean FA at the level of floor was 0.54 ppm. At the breathing zone the mean FA concentration was 0.51 ppm before the dissection was started. Exhaust fans at the level of roof were switched on and the second sample was taken after 1 hour. The FA concentration was 0.23 ppm. Third sample was taken at 2nd hour and FA concentration was 0.11 ppm. The exhaust fans at the level of floor were switched on. The air samples were measured at 0, 1st and 2nd hour at breathing zones. It was 0.51, 0.31 and 0,15 ppm respectively.

Diffusion tensor imaging in differentiation of spinal cord lesions

Background Spinal lesions sometimes remain insufficiently visualized by ‘conventional’ magnetic resonance imaging techniques; indeed very often the lesions seen on T2 weighted images do not completely display the effects of pathology on the long tracts. Diffusion imaging, which enables the imaging of molecular water motion, has been applied recently to spinal cord diseases Aim The purpose of this study was to assess the role of Diffusion tensor imaging in in differentiation between different spinal cord lesions Patients & methods This prospective study included 30 patients with myelopathy symptoms. All patients were subjected to full history taking, clinical examination, magnetic resonance imaging and diffusion tensor imaging MRI. Results The mean FA values at the site of the lesion was significantly lower than the normal appearing spinal cord in inflammation/demyelination, compressive myelopathy and traumatic spinal cord injury groups while the mean apparent diffusion coefficient values at the site of the lesions was significantly higher than the normal appearing spinal cord in inflammation/demyelination group. FA was sensitive than apparent diffusion coefficient in the detection of the spinal cord abnormalities with a sensitivity of 90% versus 60% respectively. Conclusion Diffusion tensor imaging with its quantitative indices is a non-invasive tool that is used in functional assessment of normal and pathologic spinal cord white matter, giving detailed information about different pathology and helping early management.

Role of MRI Diffusion Tensor Imaging in Early Diagnosis of Cervical Spondylotic Myelopathy (CSM)

Abstract Background and Purpose Cervical spondylotic myelopathy (CSM) is a common degenerative disorder of the cervical spine and is considered as the most common cause of spinal cord dysfunction in older individuals worldwide. Assessing the severity of the disease objectively remains a challenge and there is still remaining controversy in terms of the optimal timing and indications for surgical intervention. The conventional MRI is the gold standard for radiographic evaluation of the spinal cord; however, it cannot assess the underlying microstructural deficits of the spinal cord and it has a limited application in determining prognosis and recovery of the disease [1]. We sought to assess the utility of MR diffusion tensor imaging as an imaging technique in clinically suggested CSM patients by obtaining the microstructural parameters (Fractional anisotropy; FA and apparent diffusion coefficient; ADC) in the cervical spinal cord segments. Patient & methods our study was a prospective cross-sectional study including 40 patients with clinical manifestations of cervical spondylotic myelopathy. The patients were sorted according to the European myelopathy score into three categories as follows: grade 1 (with mild symptoms), grade 2 (with moderate symptoms) and grade 3 (with severe symptoms). All the patients were investigated with a 1.5 T MRI unit acquiring conventional MRI and DTI sequences. FA and ADC values at each spinal segment from C2/C3 to C6/C7 were generated and measured using manual drawing of multiple ROIs within the cervical cord in the sagittal and axial combined anatomical and color-coded images. For each of these cases, the patient’s age, gender, DTI parameters at each spinal segment level, maximum compression level, conventional T2WI characteristics and EMS score were recorded, analyzed and compared. Results The study included 23 females (57.5%) and 17 males (42.5%). Their age ranged from 30 to 72 years with a mean age of 47.3 ± 9.79 years. The study revealed a significant difference in the mean FA and ADC values between stenotic and non-stenotic segments of the cervical spinal cord. There was a significant correlation between the European myelopathy score and DTI parameters (FA and ADC). FA and ADC values performed better in recognizing myelopathic changes in patients who were classified as grade 1 according to EMS compared to conventional MRI T2WI which performed very poorly in recognizing myelopathy changes in the same patients, therefore DTI indices were more sensitive in the detection of CSM patients compared to conventional MRI especially in early myelopathic stages. T2 weighted images were highly significant in recognizing myelopathy changes in patients who were classified as grade 3 according to EMS. The CSM patients had significant FA decrease and ADC increase at the most compressed part of the cervical spinal cord and there was a significant correlation between the number of patients who had myelopathic changes by DTI parameters and the severity of disease. The FA sensitivity and specificity in recognition of myelopathic changes were 73.5% and 83.3% respectively and the ADC sensitivity and specificity were 100% and 70.6% respectively. Conclusion In conclusion, diffusion tensor imaging enhances the efficacy and accuracy of MRI in the diagnosis of cervical spondylotic myelopathy. Therefore, it can be used as a non-invasive modality for detection of the spondylotic myelopathy changes in the early stages helping to decide the appropriate timing of decompression surgery before attaining the irreversible chronic changes. Abbreviations ADC: Apparent diffusion coefficient; CSM: Cervical spondylotic myelopathy; DTI: Diffusion tensor imaging; FA: Fractional Anisotropy; EMS: European myelopathy score

An attempt to improve the traditional olive (Olea europaea) oil eco-extraction as applied in the Bouzeguène municipality (Northern Algeria)

This work is an attempt to improve the traditional olive (Olea europaea L.) oil (OO) eco-extraction (TOOEE) as applied in the Bouzeguène municipality (extreme south-east of Tizi-Ouzou, chief town of the region of the same name located 100 km east of Algiers). The improvement concerns the possible replacement of the direct solar drying (DSD), habitually applied before OO extraction, by indirect solar drying (ISD). For comparison purpose, oven drying (OD) was also considered. The drying kinetics of fresh olives (FOs), OO yield (OOY, % w/w in relation to the FO weight), rate of released olive vegetation water (OVW, % w/w in relation to the FO weight), and OO physicochemical quality parameters (free acidity (FA, % w/w oleic acid), specific extinction coefficient at 230 (K230) and 270 nm (K270), etc.) were investigated. For the three drying procedures tested, the quadratic equation was found to correctly describe the whole drying curves, with R2 and mean absolute percentage error (MAPE) varying from 0.995 (case of ISD) to 0.999 (case of DSD) and from 5 (case of DSD) to 21.33 % (case of ISD), respectively. The DSD-dried olives and ISD-dried olives gave the OOY of 11 % on average with a release of only 0.20 % OVW. For physicochemical parameters, the results were contradictory. For example, the mean FA value for OO from DSD-dried olives (DSD-OO) was ∼ 2.86 % (against ∼ 4.57 % for OO from ISD-dried olives (ISD-OO)) while the mean radical scavenging activity (RSA) for ISD-OO was ∼ 34 % (against ∼ 18 % for DSD-OO). This study confirms the ecological character of the TOOEE and the possibilities of its improvement, which could make it inspiring for all the actors of the field.

Diffusion-weighted and diffusion kurtosis imaging analysis of microstructural differences in clear cell renal cell carcinoma: a comparative study.

To quantitatively compare the diagnostic values of conventional diffusion-weighted imaging (DWI) and diffusion kurtosis imaging (DKI) analysis of microstructural differences for clear cell renal cell carcinoma (CRCC). A total of 108 patients with pathologically confirmed CRCC, including 38 Grade I, 37 Grade II, 18 Grade III and 15 Grade IV, were enrolled and divided into groups according to tumor grade [low grade (Ⅰ+Ⅱ, n = 75) and high grade (Ⅲ+Ⅳ, n = 33)]. Apparent diffusion coefficient (ADC), mean diffusivity (MD), mean kurtosis (MK), kurtosis anisotropy (KA) and radial kurtosis (RK) were performed. Both the ADC (r = -0.803) and MD (-0.867) values showed a negative correlation with tumor grading (p < 0.05) and MK (r = 0.812), KA (0.816) and RK (0.853) values a positive correlation with tumor grading (p < 0.05). Mean FA values showed no significant differences among CRCC grades (p > 0.05). ROC curve analyses showed that MD values had the highest diagnostic efficacy in differentiating low/high and Ⅱ/Ⅲ tumor grading. MD values gave AUC: 0.937 (0.896); sensitivity: 92.0% (86.5%); specificity: 78.8% (77.8%) and accuracy: 90.7% (87.3%). ADC performed worse than MD, MK, KA or RK (all p < 0.05) during pair-wise comparisons of ROC curves to show diagnostic efficacy. DKI analysis performs better than ADC in differentiating CRCC grading. Both the ADC and MD values correlated negatively with CRCC grading.The MK, KA and RK values correlated positively with CRCC grading.MD values had the highest diagnostic efficacy in differentiating low/high and Ⅱ/Ⅲ CRCC grading.

Brain volumetric and white matter structural connectivity alterations in autistic children: case–control study

BackgroundAutism spectrum disorder (ASD) is a neurodevelopmental disorder that includes a large heterogeneous constellation of disorders with overlapping symptoms and clinical features. The diagnosis is based mainly on clinical symptoms meeting DSM-5 criteria with no radiologic or laboratory diagnostic investigations available yet. The specific neuropathologic aberrations occurring in ASD are still under investigation. This study aimed at providing a preliminary database for better understanding of the neuropathologic aspects of ASD, regarding both macrostructure and microstructure of the brain using magnetic resonance imaging. This case–control study included total of 40 children, 20 cases (diagnosed with ASD) and 20 control (Typically Developing Children, TDC) aged 2–18 years. 3D-T1 and Diffusion Tensor Images (DTI) were acquired. 3D-T1 images were uploaded to Volbrain and brain segmentation was done using Volbrain 2.0 pipeline. DTI data were analyzed using FSL where Tract-Based Spatial Statistics analysis was carried out and mean fractional anisotropy values obtained. Independent samples t test was used to compare means of both groups.ResultsASD group displayed statistically significant larger intracranial cavity, brain, white matter, grey matter and cerebrospinal fluid volumes (p < 0.001 for all except CSF volume p = 0.01) with the white matter occupying higher percentage of intracranial volume in ASD compared to TDC group (p < 0.001). The cortical thickness showed statistically significant larger volume in entorhinal cortex in ASD group compared to TDC group at both sides (p < 0.001 at right side, p = 0.003 at left side). Widespread statistically significant (p < 0.001) higher mean FA value was observed at multiple white matter tracts.ConclusionThese findings suggest that the main pathology of ASD is within the white matter. It also supports the hypothesis that autistic brain undergoes period of precocious growth in early years of life. Further studies with age and clinical severity stratification are needed to investigate temporal changes and severity related macrostructure and microstructure changes in autistic brains.

Automation and standardization of subject-specific region-of-interest segmentation for investigation of diffusion imaging in clinical populations.

Diffusion weighted imaging (DWI) is key in clinical neuroimaging studies. In recent years, DWI has undergone rapid evolution and increasing applications. Diffusion magnetic resonance imaging (dMRI) is widely used to analyse group-level differences in white matter (WM), but suffers from limitations that can be particularly impactful in clinical groups where 1) structural abnormalities may increase erroneous inter-subject registration and 2) subtle differences in WM microstructure between individuals can be missed. It also lacks standardization protocols for analyses at the subject level. Region of Interest (ROI) analyses in native diffusion space can help overcome these challenges, with manual segmentation still used as the gold standard. However, robust automated approaches for the analysis of ROI-extracted native diffusion characteristics are limited. Subject-Specific Diffusion Segmentation (SSDS) is an automated pipeline that uses pre-existing imaging analysis methods to carry out WM investigations in native diffusion space, while overcoming the need to interpolate diffusion images and using an intermediate T1 image to limit registration errors and guide segmentation. SSDS is validated in a cohort of healthy subjects scanned three times to derive test-retest reliability measures and compared to other methods, namely manual segmentation and tract-based spatial statistics as an example of group-level method. The performance of the pipeline is further tested in a clinical population of patients with traumatic brain injury and structural abnormalities. Mean FA values obtained from SSDS showed high test-retest and were similar to FA values estimated from the manual segmentation of the same ROIs (p-value > 0.1). The average dice similarity coefficients (DSCs) comparing results from SSDS and manual segmentations was 0.8 ± 0.1. Case studies of TBI patients showed robustness to the presence of significant structural abnormalities, indicating its potential clinical application in the identification and diagnosis of WM abnormalities. Further recommendation is given regarding the tracts used with SSDS.

Microstructural changes in the white matter tracts of the brain due to mild cognitive impairment

AbstractBackgroundMild cognitive impairment (MCI) is an early stage of memory loss or cognitive decline and progresses to Alzheimer’s disease at a rate of about 15% per year. It is important to study the effects of MCI on the brain. Here we present a novel along‐tract analysis of microstructural brain metrics computed from diffusion MRI. We extract, map, and visualize the profile of microstructural abnormalities on 3D models of fiber tracts, yielding fine‐scale maps of the effects of MCI.MethodsWe analyzed multi‐shell diffusion‐weighted MRI data with 127 volumes from 131 ADNI3 participants (age: 55‐91years, 74F,57M). Participants included 44 with MCI and 87 cognitively normal controls (CN). Pre‐processed using the ADNI3 dMRI protocol. We applied multi‐shell‐multi‐tissue CSD and a probabilistic particle‐filtering‐tracking to generate whole‐brain tractograms. We applied DIPY’s BUAN tractometry pipeline to extract 30 white matter tracts from all subjects and evaluate the effects of MCI on 4 DTI measures (FA, MD, RD, and AD) along the length of the tracts. BUAN applies Linear‐Mixed‐Models with DTI measures set as the response variable, group mean modeled as fixed effects term, and subject‐specific mean as random effects term.ResultsWe report significant group differences between MCI and CN in 6 bundles with p‐values&lt;0.01 and &lt;0.001 (Fig.1). In Fig.1 and Fig2, the columns and rows show results from six bundles for four DTI measures (see Fig.2 for keywords). Fig.2 highlights areas with significant differences on the tracts with black color where for MD, p‐values&lt;0.001 and for the rest of the 3 measures, p‐values&lt;0.01. Fig.3 reports significant effects of MCI on the rest of the tracts and measures with p‐values&lt;0.001. We find lower mean FA and higher mean MD, AD, and RD in the MCI, compared to the control group.ConclusionWe applied the BUAN tractometry pipeline to map and visualize the effects of MCI on the white matter tracts of the brain. We found significant microstructural group differences in tracts where FA decreases and diffusivity measures increase in MCI participants.

The long-range white matter microstructural alterations in drug-naive children with ADHD: A tract-based spatial statistics study

BackgroundTo investigate WM alterations, particularly the changes in long-range fibers, in drug-naive children with attention deficit hyperactivity disorder (ADHD), we conducted tract-based spatial statistics (TBSS) analysis on diffusion tensor imaging (DTI) data. Materials and methodsIn this study, 57 children with ADHD and 41 healthy controls (HCs) were enrolled. None of the enrolled ADHD children received any medication before data collection. WM changes were then correlated with clinical symptoms, including the hyperactivity index score and the impulsivity score. ResultsADHD children demonstrated decreased FA in the right forceps major, left inferior fronto-occipital fasciculus, and left genu Internal capsule. Moreover, higher RD was observed in the right forceps major, superior longitudinal fasciculus, and forceps major. The results of linear regression analysis including learning problem score, hyperactivity index score and impulsivity score showed that higher earning problem and hyperactivity/impulsivity symptom scores were negatively correlated with the mean FA value in the right forceps major, left IFOF and left genu Internal capsule. ConclusionOur results demonstrate that microstructural WM alterations and changes in the long-range WM connections are present in children with ADHD. We speculate that these changes may relate to the symptoms of hyperactivity and impulsivity.

Diffusion Tensor Imaging Shows More Extensive White Matter Changes in Frontal than in Temporal Lobe Epilepsy

Introduction: FLE is known to have a poorer prognosis than TLE. We compared the extent of white matter changes in these groups using diffusion tensor imaging-based tractography. Methods: 20 tracts each were made in five TLE and six FLE patients (bilateral FORX, CGC, PH, UF, SLF, ILF, IFOF, ATR, CST; FMajor and FMinor) and their FA values compared. Results: The TLE group had decreased FA of all ipsilateral fibres except IFOF, with a statistically significant decrease in FORX and UF. The FLE group had a significant decrease (p&lt; 0.05) in the FA values of contralateral ATR and CST. A few contralateral tracts (PH, UF, SLF, IFOF) and ipsilateral FORX and ILF also showed (statistically nonsignificant) decreased mean FA. Mann-Whitney U test comparing ipsilateral nine fibre pairs of FLE vs. TLE was non-significant and significant (p&lt;0.05) only for CST in contralateral fibre comparison. However, a generalised decrease in all fibre FA in FLE vs. TLE was noticed, except for the ‘intimate’ temporal fibres, viz., FORX and PH. The mean FA of all tracts was 0.4982 and 0.5201 for FLE and TLE, respectively (p&lt;0.05). The mean FMajor and FMinor FA were 0.6146 vs. 0.6702 and 0.5598 vs. 0.5917 in FLE vs. TLE, respectively. Conclusion: Tractography based FA value comparison reveals more extensive and severe white matter changes in FLE than in TLE.

0645 Associations of Objective Sleep Parameters and Gray Matter Microstructure in community dwelling cognitive normal older adults

Abstract Introduction Disturbed sleep measures differentially alter white-matter microstructure. We examined whether obstructive sleep apnea (OSA)-severity, sleep fragmentation and duration measures were associated with gray-matter diffusion tensor-imaging metrics (DTI) (i.e., fractional anisotropy [FA], mean diffusivities [MD] and kurtoses [MK]) in community-dwelling cognitive-normal older-adults. Methods Gray-matter DTI metrics from MRI including mean FA, MD and MK measures of the hippocampus, thalamus, medial prefrontal-cortex (mPC) and Alzheimer’s Disease (AD) vulnerable regions (temporal [inferior, middle, and superior], parietal [inferior and superior], entorhinal cortex, and precuneus) were determined from 85 subjects. OSA-severity measures included AHI3a and AHI4%. Other sleep measures included sleep efficiency (SE), non-rapid eye movement (NREM) slow wave sleep (SWS) duration, percent time spent in SWS (%SWS), slow wave activity (SWA), total sleep time (TST), and wake after sleep onset (WASO). To analyze the data, first, we utilized factor analysis using varimax rotation to account for the DTI metrics as multivariate outcomes. Using factor loadings, we anticipated a two or three-factor model was sufficient to explain the variance of the DTI metrics. Second, we investigated predictive associations between the sleep parameters and the loaded DTI factors, and explored age, sex, BMI, education and APOE4 as covariates underlying any differences. Results Of the 85 participants, 60 (70.6%) were women, 67 (78.8%) were non-Hispanic Whites. Mean (SD) age, BMI and education was 66.7 (5.3) years, 27.9 (6.1) kg/m2 and 16.8 (2.4) years respectively. We selected the two primary loadings’ factor model based on AIC criteria. FA metrics of the investigated brain regions except thalamus, loaded on one factor, conceptualized as manifest indicators for FA. MD and MK metrics of all the investigated brain regions loaded on the second factor, conceptualized as manifest indicators for MD/MK. SWS, %SWS, TST were predictors of FA (P ≤0.01 for all). AHI3a, AHI4%, and SWA were predictors of MD/MK (P ≤0.05 for all). Additionally, sex, age, APOE4 and education were predictors of FA (P ≤0.01 for all). Conclusion In this limited sample of cognitively-normal older-adults, sleep duration measures predicted gray-matter FA, OSA-severity measures predicted gray matter MD and MK. Demographic, genetic and SES factors explained the differences in these relationships. Support (If Any) AASM 231-BS-20, AARGD-21-8488397, NIH/NIA/NHLBI (K23AG068534, L30-AG064670, CIRAD P30AG059303 Pilot, NYU ADRC P30AG066512 Developmental Grant, R25HL105444, SRG, R01AG12101, R01AG022374, R01AG13616, RF1AG057570, R01HL118624, R01AG056031)

Physicochemical and antioxidant properties of Coffea arabica honey from Western Oromia, Ethiopia

Coffea arabica is one of the most widely consumed and marketed commodities in the world. The study was designed to characterize C.arabica honey for botanical composition, physicochemical parameters, and antioxidant properties of honey. Twelve honey samples of C. arabica honey were collected during the flowering period of coffee flowers from the Zander hive. The physicochemical properties of honey and the Botanical origin of honey were determined based on Harmonized methods of the International Honey Commission. The antioxidant power of the coffee monofloral honey samples was determined by dissolving 1.5 gm of honey with 25 ml distilled water and mixing it with 25ml methanol and placed at 25◦C for sixty minutes of maceration using a temperature shaker. The pollen count percentage from honey indicated that all honey samples collected from Gera, Gomma, Yayu, and Manna districts were identified as coffee monofloral honey representing 84%, 93%, 75%, and 73 % of pollen count respectively. The mean moisture, ash, HMF, EC, FA, pH, fructose, glucose and sucrose content of Coffea arabica honey were 22.48%, 0.21%, 11.88, 0.49 mS/cm, 13.44 meq/Kg, 3.32, 32.77%, 32.9%, and 3.57% respectively. The total phenol and flavonoid content range from 42.1-82.1 and 21.7-59.7 mg/100 g of GAE/g respectively while the radical scavenging activity ranges from 60.2- 66.3%. The pollen analysis of honey from the area is coffee monofloral honey since its pollen count exceeds more than 45% and the honey quality also meets the Ethiopian and International standards. The antioxidant power of Coffee honey has a considerable amount of polyphenolics which have relevant antiradical activity.

Role of MRI special diffusion weighted imaging/diffusion tensor imaging techniques in the assessment of perianal fistula activity

BackgroundPre-operative MRI examination is currently considered as an evolving tool for assessment of perianal fistula types, extensions, and complications to achieve proper treatment plan. Proper assessment of fistula activity can also have a major contributing role to the treatment plan, through deciding the type of prescribed medications, proper surgical approach as well as the proper operative intervention timing. Reviewing literature, only few studies have mentioned the importance of diffusion tensor imaging (DTI) sequences in diagnosing perianal fistula activity, yet many studies have discussed the perianal fistula activity assessment using other diffusion weighted imaging (DWI) sequences. In the present study, the main objective was to prove the MRI quantitative DTI sequences’ ability of diagnosing perianal fistulae inflammatory activity.ResultsThis study was a prospective analysis in which fistular activity was confirmed by intra-operative findings (considered as the standard reference). The cases included in the study were divided into two groups, based on their surgical findings, positive inflammatory and negative inflammatory groups. Both groups were pre-operatively assessed using MRI imaging and additionally used diffusion weighted and tensor imaging (DWI and DTI) sequences by special post-processing quantitative assessment of DTI FA and ADC values. There was significant statistical difference between the mean ADC value of the PIA and NIA groups in the track, edema, ipsilateral and contralateral sphincter areas with P values (P = 0.000, 0.000, 0.002 and 0.000 respectively). There was also significant difference between the mean FA value of the PIA and NIA groups in the track, edema, ipsilateral and contralateral sphincter areas with P values (P = 0.000, 0.000, 0.000 and 0.008 respectively).ConclusionThis study results revealed that FA are relatively lower in positive inflammatory activity lesions than in negative inflammatory activity lesions while the ADC values were relatively higher in positive inflammatory activity lesions than in negative inflammatory activity lesions and the differences were statistically significant having a fundamental role in the assessment of perianal fistula activity especially at the track area being of highest sensitivity and specificity. Unlike conventional MRI sequences which revealed only high specificity being a good negative modality.

Abstract WMP14: White Matter Free Water Drives Diffusion Abnormalities And Correlates With Conventional MRI Markers Of Small Vessel Disease In Cerebral Amyloid Angiopathy

Introduction: Increased extracellular fluid, measured by the free water (FW) diffusion model, was found to be the main contributor to diffusion tensor imaging (DTI) alterations in monogenic and sporadic non-amyloid cerebral small vessel diseases (SVD). We investigated whether the FW component also drives DTI changes in cerebral amyloid angiopathy (CAA) and to what extent it correlates with conventional MRI markers of SVD. Methods: Non-demented probable CAA patients, without symptomatic intracerebral haemorrhage, were recruited from a memory-clinic cohort and underwent structural MRI, including diffusion-weighted imaging. Primary DTI metrics (mean diffusivity [MD] and fractional anisotropy [FA]), FW maps and tissue compartment tensors (tMD, tFA) were computed using a freely available script (https://markvcid.partners.org/). To reduce contamination by cerebrospinal fluid, diffusion metrics were analyzed within the white matter skeleton, using tract-based spatial statics. White matter hyperintensities (WMH) and total brain volume (TBV) were normalized by total intracranial volume. Images were rated for lobar microbleeds count (CMB), perivascular spaces scored in the centrum semiovale (CSO-PVS), and presence of cortical superficial siderosis. Results: Thirty-eight subjects (mean age 72.5 ± 7.4 years; 47.4% female) were included in the analysis. In simple linear regression models, conventional mean MD and FA were more strongly associated with the FW component (β=0.999, p&lt;.001; β=-0.907, p&lt;.001, respectively) than with their respective tissue compartment tensors (β=0.263, p=.111; β=0.659, p&lt;.001, respectively). In multivariable regression analyses, adjusted for age, WMH (β=0.395, p=.002), CMB (β=0.346, p=.003) and CSO-PVS (β=0.496, p&lt;.001) were independently associated with mean FW, whereas TBV was the only independent predictor for tissue compartment metrics (tMD and tFA) (β=0.506, p=.033; β=0.505, p=.040, respectively). Conclusion: FW imaging findings suggest that DTI changes in CAA are mainly driven by increased extracellular fluid rather than disruption of fiber structure. FW content was strongly associated with core SVD MRI markers, which could imply similar underlying pathogenesis.

White matter diffusivity and its correlations to state measures of psychopathology in male refugees with posttraumatic stress disorder

Post-traumatic stress disorder (PTSD) is a heterogenous condition and the underlying neurobiology is still poorly understood. In this study, we tested the hypothesis that PTSD is associated with microstructural changes in white matter (WM) fibre tracts that connect regions involved in emotional processing, memory, attention, and language. Furthermore, we examined how different response patterns to individualized trauma-provoking stimuli related to underlying WM microstructure. Sixty-nine trauma-affected male refugees with PTSD (N = 38) or without PTSD (N = 31) underwent clinical assessments and diffusion-weighted magnetic resonance imaging (DWI) of the whole brain at 3 Tesla. Diffusion tensor metrics were computed from DWI data and used to characterize regional white-matter microstructure. An automated tract segmentation method was used to extract diffusion tensor metrics from subject-based reconstructions of tract segments (ROI), including uncinate fasciculus (UF), cingulum bundle (CB), superior longitudinal fasciculus (SLF) in three subdivisions (SLF I - III), and fibre bundles connecting orbito-frontal cortex to striatum (OF-ST). Outside the scanner we obtained measures of immediate (state) arousal, avoidance and dissociation symptoms assessed in response to auditory exposure to a personal traumatic memory. Using mean FA of the middle part of each ROI, mixed ANOVA revealed a significant interaction between group, ROI and hemisphere. Post-hoc comparisons showed that, relative to refugees without PTSD, refugees with PTSD had lower FA in right CB, left SLF-I, bilateral OF-ST and bilateral SLF-II. Mean FA scaled negatively with avoidance in right CB while mean FA in bilateral UF scaled positively with individual scores reflecting dissociation symptoms. The results support a pathophysiological model of PTSD that implicates limbic structures, prefrontal cortex and striatum. The results also emphasize the need to consider PTSD’s multifaceted manifestations when searching for functional-structural relationships.

Quantification of Similar Neurodegeneration Across Geriatric Concussions and Alzheimer’s Disease

Advancements in biomedical research have identified the genes influencing life spans, stress resistance and age-related diseases, including Alzheimer’s disease. Stress resistance includes resistance to multiple forms of stress, pathogens and toxic beta-amyloid which is tightly associated with Alzheimer’s disease. We have investigated 431 human genes that are associated with co-morbidities (Vahdati Nia et al, 2017; Le et al., 2020). Those genes are involved in lipid metabolism, hemostasis, hemostasis, neuroendocrine and immune functions. The genes are relevant to middle-life health. We explore a wide variety of co-morbidities that could happen in middle to late life. I will give a brief review of increased stress resistance, and genetic markers associated with co-morbidities. I will discuss how the studies may benefit to fight against COVID-19.

High-resolution microscopic diffusion anisotropy imaging in the human hippocampus at 3T.

Several neurological conditions are associated with microstructural changes in the hippocampus that can be observed using DWI. Imaging studies often use protocols with whole-brain coverage, imposing limits on image resolution and worsening partial-volume effects. Also, conventional single-diffusion-encoding methods confound microscopic diffusion anisotropy with size variance of microscopic diffusion environments. This study addresses these issues by implementing a multidimensional diffusion-encoding protocol for microstructural imaging of the hippocampus at high resolution. The hippocampus of 8 healthy volunteers was imaged at 1.5-mm isotropic resolution with a multidimensional diffusion-encoding sequence developed in house. Microscopic fractional anisotropy (µFA) and normalized size variance (CMD ) were estimated using q-space trajectory imaging, and their values were compared with DTI metrics. The overall scan time was 1 hour. The reproducibility of the protocol was confirmed with scan-rescan experiments, and a shorter protocol (14 minutes) was defined for situations with time constraints. Mean µFA (0.47) was greater than mean FA (0.20), indicating orientation dispersion in hippocampal tissue microstructure. Mean CMD was 0.17. The reproducibility of q-space trajectory imaging metrics was comparable to DTI, and microstructural metrics in the healthy hippocampus are reported. This work shows the feasibility of high-resolution microscopic anisotropy imaging in the human hippocampus at 3 T and provides reference values for microstructural metrics in a healthy hippocampus.

Examining the effects of prenatal alcohol exposure on corticothalamic connectivity: A multimodal neuroimaging study in children

Children with a fetal alcohol spectrum disorder (FASD) experience a range of cognitive and behavioral effects. Prior studies have demonstrated white matter changes in children with FASD relative to typically developing controls (TDC) and these changes relate to behavior. Our prior MEG study (Candelaria-Cook et al. 2020) demonstrated reduced alpha oscillations during rest in FASD relative to TDC and alpha power is correlated with behavior. However, little is known about how brain structure influences brain function. We hypothesized that alpha power was related to corticothalamic connectivity. Children 8–13 years of age (TDC: N = 25, FASD: N = 24) underwent rest MEG with eyes open or closed and MRI to collect structural and diffusion tensor imaging data. MEG spectral analysis was performed for sensor and source data. We estimated mean fractional anisotropy in regions of interest (ROIs) that included the corticothalamic tracts. The FASD group had reduced mean FA in three of the corticothalamic ROIs. FA in these tracts was significantly correlated with alpha power at the sensor and source level. The results support the hypothesis that integrity of the corticothalamic tracts influences cortical alpha power. Further research is needed to understand how brain structure and function influence behavior.