scholarly journals Changes in Callosal Motor Fiber Integrity after Subcortical Stroke of the Pyramidal Tract

2012 ◽  
Vol 32 (8) ◽  
pp. 1515-1524 ◽  
Author(s):  
Basia A Radlinska ◽  
Yasmin Blunk ◽  
Ilana R Leppert ◽  
Jeffrey Minuk ◽  
G Bruce Pike ◽  
...  
Keyword(s):  
Primary Motor Cortex ◽  
Diffusion Tensor ◽  
Pyramidal Tract ◽  
Initial Time ◽  
Prospective Longitudinal Study ◽  
Fiber Tracts ◽  
Initial Time Point ◽  
Abnormal Pattern ◽  
Ischemic Attack ◽  
Prospective Longitudinal

In the healthy brain, there are close correlations between task-related activation of the primary motor cortex (M1), the magnitude of interhemispheric inhibition, and microstructural properties of transcallosal fiber tracts. After subcortical stroke affecting the pyramidal tract (PT), an abnormal pattern of bilateral activity develops in M1. With this prospective longitudinal study, we aimed to determine whether a morphological correlate of poststroke disinhibition could be measured within 20 days and 6 months of PT stroke. Using diffusion tensor imaging with tractography, we delineated transcallosal motor fibers (CMF) in nine PT stroke patients, six patients with subcortical infarct not affecting the PT (NonPT) and six transient ischemic attack patients. We compared changes in CMF fractional anisotropy ratios (rFA) with rFA in a distinct bundle of callosal occipital fibers (COF). At the initial time point, there were no significant differences in rFA between groups and fiber bundles. At follow-up, PT-group rFACMF was significantly lower than PT-group rFACOF and NonPT-group rFACMF. PT-group rFACMF decreased over time and correlated with rFA of the PT (rFAPT) retrograde to the infarct at 6 months. Our data suggest a progressive degenerative transsynaptic effect of PT stroke on CMF, which could be a morphological correlate of transcallosal disinhibition.

Gradient of Tissue Injury after Stroke: Rethinking the Infarct versus Noninfarcted Dichotomy

2020 ◽  
Vol 49 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Felix Ng ◽  
Vijay Venkatraman ◽  
Mark Parsons ◽  
Andrew Bivard ◽  
Gagan Sharma ◽  
...  
Keyword(s):  
Diffusion Tensor ◽  
Tissue Injury ◽  
Ct Perfusion ◽  
Mean Diffusivity ◽  
Brain Regions ◽  
Homologous Region ◽  
Anterior Circulation ◽  
Prospective Longitudinal Study ◽  
Fluid Attenuated Inversion Recovery ◽  
Prospective Longitudinal

Aim: To evaluate the degree of variability in microstructural injury within and adjacent to regions identified as infarcted tissue using diffusion tensor imaging (DTI). Methods: In this prospective longitudinal study, 18 patients presenting within 12 h of anterior circulation acute ischemic stroke who underwent CT perfusion (CTP) at baseline followed by fluid-attenuated inversion recovery (FLAIR) and DTI 1-month were analyzed. Four regions of interest (ROI) corresponding to the severity of hypoperfusion on CTP within and beyond the radiological infarct lesion defined on FLAIR were segmented. Fractional anisotropy (FA) and mean diffusivity (MD) were quantified for each ROI and compared to a mirror homologue in the contralateral hemisphere. Ipsilateral to contralateral FA and MD ratios were compared across ROIs. Results: Lower FA and higher MD values were observed within both the infarct lesion and the peri-infarct tissue compared with their homologous contralateral brain regions (all comparisons p ≤ 0.01). No difference was observed in FA and MD between remote nonhypoperfused tissue and its contralateral homologous region (FA p = 0.42, MD p ≥ 0.99). The magnitude of asymmetry (ipsilateral/contralateral ratios) of FA and MD was greater with increasing severity of hypoperfusion in a dose-response pattern. Asymmetry greatest in the area of infarction with severe hypoperfusion, followed by infarction with moderate hypoperfusion, the peri-infarct hypoperfused tissue, and lastly the remote nonhypoperfused normal tissue (median on clustered quantile regression p ≤ 0.01). Conclusion: A gradient of microstructural injury corresponding to the severity of ischemic insult is present within and beyond conventionally defined infarct boundaries. The traditional dichotomized notion of infarcted versus noninfarcted tissue widely adopted in clinical research and in practice warrants reexamination.

scholarly journals Multicentre longitudinal study of fluid and neuroimaging BIOmarkers of AXonal injury after traumatic brain injury: the BIO-AX-TBI study protocol

BMJ Open ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. e042093
Author(s):  
Neil Samuel Nyholm Graham ◽  
Karl A Zimmerman ◽  
Guido Bertolini ◽  
Sandra Magnoni ◽  
Mauro Oddo ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Longitudinal Study ◽  
Brain Injury ◽  
Diffusion Tensor ◽  
Axonal Injury ◽  
Ethics Committee ◽  
Cerebral Microdialysis ◽  
Prospective Longitudinal Study ◽  
Neuroimaging Biomarkers ◽  
Prospective Longitudinal

Introduction and aimsTraumatic brain injury (TBI) often results in persistent disability, due particularly to cognitive impairments. Outcomes remain difficult to predict but appear to relate to axonal injury. Several new approaches involving fluid and neuroimaging biomarkers show promise to sensitively quantify axonal injury. By assessing these longitudinally in a large cohort, we aim both to improve our understanding of the pathophysiology of TBI, and provide better tools to predict clinical outcome.Methods and analysisBIOmarkers of AXonal injury after TBI is a prospective longitudinal study of fluid and neuroimaging biomarkers of axonal injury after moderate-to-severe TBI, currently being conducted across multiple European centres. We will provide a detailed characterisation of axonal injury after TBI, using fluid (such as plasma/microdialysate neurofilament light) and neuroimaging biomarkers (including diffusion tensor MRI), which will then be related to detailed clinical, cognitive and functional outcome measures. We aim to recruit at least 250 patients, including 40 with cerebral microdialysis performed, with serial assessments performed twice in the first 10 days after injury, subacutely at 10 days to 6 weeks, at 6 and 12 months after injury.Ethics and disseminationThe relevant ethical approvals have been granted by the following ethics committees: in London, by the Camberwell St Giles Research Ethics Committee; in Policlinico (Milan), by the Comitato Etico Milano Area 2; in Niguarda (Milan), by the Comitato Etico Milano Area 3; in Careggi (Florence), by the Comitato Etico Regionale per la Sperimentazione Clinica della Regione Toscana, Sezione area vasta centro; in Trento, by the Trento Comitato Etico per le Sperimentazioni Cliniche, Azienda Provinciale per i Servizi Sanitari della Provincia autonoma di Trento; in Lausanne, by the Commission cantonale d’éthique de la recherche sur l’être humain; in Ljubljana, by the National Medical Ethics Committee at the Ministry of Health of the Republic of Slovenia. The study findings will be disseminated to patients, healthcare professionals, academics and policy-makers including through presentation at conferences and peer-reviewed publications. Data will be shared with approved researchers to provide further insights for patient benefit.Trial registration numberNCT03534154.

scholarly journals MRI in acute muscle tears in athletes: can quantitative T2 and DTI predict return to play better than visual assessment?

2020 ◽  
Vol 30 (12) ◽  
pp. 6603-6613
Author(s):  
J. D. Biglands ◽  
A. J. Grainger ◽  
P. Robinson ◽  
S. F. Tanner ◽  
A. L. Tan ◽  
...  
Keyword(s):  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Quantitative Mri ◽  
Return To Play ◽  
Prospective Longitudinal Study ◽  
Muscle Tear ◽  
Muscle Changes ◽  
Prospective Longitudinal ◽  
And Diffusion ◽  
Mri Measurements

Abstract Objectives To assess the ability of quantitative T2, diffusion tensor imaging (DTI) and radiologist’s scores to detect muscle changes following acute muscle tear in soccer and rugby players. To assess the ability of these parameters to predict return to play times. Methods In this prospective, longitudinal study, 13 male athletes (age 19 to 34 years; mean 25 years) underwent MRI within 1 week of suffering acute muscle tear. Imaging included measurements of T2 and DTI parameters. Images were also assessed using modified Peetrons and British athletics muscle injury classification (BAMIC) scores. Participants returned for a second scan within 1 week of being determined fit to return to play. MRI measurements were compared between visits. Pearson’s correlation between visit 1 measurements and return to play times was assessed. Results There were significant differences between visits in BAMIC scores (Z = − 2.088; p = 0.037), modified Peetrons (Z = − 2.530; p = 0.011) and quantitative MRI measurements; T2, 13.12 ms (95% CI, 4.82 ms, 21.42 ms; p = 0.01); mean diffusivity (0.22 (0.04, 0.39); p = 0.02) and fractional anisotropy (0.07 (0.01, 0.14); p = 0.03). BAMIC scores showed a significant correlation with return to play time (Rs = 0.64; p = 0.02), but modified Peetrons scores and quantitative parameters did not. Conclusions T2 and DTI measurements in muscle can detect changes due to healing following muscle tear. Although BAMIC scores correlated well with return to play times, in this small study, quantitative MRI values did not, suggesting that T2 and DTI measurements are inferior predictors of return to play time compared with visual scoring. Key Points • Muscle changes following acute muscle tear can be measured using T2 and diffusion measurements on MRI. • Measurements of T2 and diffusion using MRI are not as good as a radiologist’s visual report at predicting return to play time after acute muscle tear.

scholarly journals Neural systems predicting long-term outcome in dyslexia

2010 ◽  
Vol 108 (1) ◽  
pp. 361-366 ◽  
Author(s):  
Fumiko Hoeft ◽  
Bruce D. McCandliss ◽  
Jessica M. Black ◽  
Alexander Gantman ◽  
Nahal Zakerani ◽  
...  
Keyword(s):  
Reading Skills ◽  
Diffusion Tensor ◽  
Behavioral Measure ◽  
Support Vector ◽  
Behavioral Measures ◽  
Prospective Longitudinal Study ◽  
Long Term Outcome ◽  
Reading Gains ◽  
Prospective Longitudinal

Individuals with developmental dyslexia vary in their ability to improve reading skills, but the brain basis for improvement remains largely unknown. We performed a prospective, longitudinal study over 2.5 y in children with dyslexia (n = 25) or without dyslexia (n = 20) to discover whether initial behavioral or brain measures, including functional MRI (fMRI) and diffusion tensor imaging (DTI), can predict future long-term reading gains in dyslexia. No behavioral measure, including widely used and standardized reading and language tests, reliably predicted future reading gains in dyslexia. Greater right prefrontal activation during a reading task that demanded phonological awareness and right superior longitudinal fasciculus (including arcuate fasciculus) white-matter organization significantly predicted future reading gains in dyslexia. Multivariate pattern analysis (MVPA) of these two brain measures, using linear support vector machine (SVM) and cross-validation, predicted significantly above chance (72% accuracy) which particular child would or would not improve reading skills (behavioral measures were at chance). MVPA of whole-brain activation pattern during phonological processing predicted which children with dyslexia would improve reading skills 2.5 y later with >90% accuracy. These findings identify right prefrontal brain mechanisms that may be critical for reading improvement in dyslexia and that may differ from typical reading development. Brain measures that predict future behavioral outcomes (neuroprognosis) may be more accurate, in some cases, than available behavioral measures.

scholarly journals Longitudinal Structural and Functional Differences Between Proportional and Poor Motor Recovery After Stroke

2017 ◽  
Vol 31 (12) ◽  
pp. 1029-1041 ◽  
Author(s):  
Adrian G. Guggisberg ◽  
Pierre Nicolo ◽  
Leonardo G. Cohen ◽  
Armin Schnider ◽  
Ethan R. Buch
Keyword(s):  
White Matter ◽  
Structural Changes ◽  
Primary Motor Cortex ◽  
Diffusion Tensor ◽  
Motor Recovery ◽  
Brain Organization ◽  
Fiber Tracts ◽  
Functional Differences ◽  
Eeg Functional Connectivity ◽  
The Brain

Background. Evolution of motor function during the first months after stroke is stereotypically bifurcated, consisting of either recovery to about 70% of maximum possible improvement (“proportional recovery, PROP”) or in little to no improvement (“poor recovery, POOR”). There is currently no evidence that any rehabilitation treatment will prevent POOR and favor PROP. Objective. To perform a longitudinal and multimodal assessment of functional and structural changes in brain organization associated with PROP. Methods. Fugl-Meyer Assessments of the upper extremity and high-density electroencephalography (EEG) were obtained from 63 patients, diffusion tensor imaging from 46 patients, at 2 and 4 weeks (T0) and at 3 months (T1) after stroke onset. Results. We confirmed the presence of 2 distinct recovery patterns (PROP and POOR) in our sample. At T0, PROP patients had greater integrity of the corticospinal tract (CST) and greater EEG functional connectivity (FC) between the affected hemisphere and rest of the brain, in particular between the ventral premotor and the primary motor cortex. POOR patients suffered from degradation of corticocortical and corticofugal fiber tracts in the affected hemisphere between T0 and T1, which was not observed in PROP patients. Better initial CST integrity correlated with greater initial global FC, which was in turn associated with less white matter degradation between T0 and T1. Conclusions. These findings suggest links between initial CST integrity, systems-level cortical network plasticity, reduction of white matter atrophy, and clinical motor recovery after stroke. This identifies candidate treatment targets.

Neurofilament light chain in serum for the diagnosis of amyotrophic lateral sclerosis

2018 ◽  
Vol 90 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Federico Verde ◽  
Petra Steinacker ◽  
Jochen H Weishaupt ◽  
Jan Kassubek ◽  
Patrick Oeckl ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Neurodegenerative Diseases ◽  
Light Chain ◽  
Diffusion Tensor ◽  
Progression Rate ◽  
Neurofilament Light Chain ◽  
Neurofilament Light ◽  
Prospective Longitudinal Study ◽  
Prospective Longitudinal ◽  
Lateral Sclerosis

ObjectiveTo determine the diagnostic and prognostic performance of serum neurofilament light chain (NFL) in amyotrophic lateral sclerosis (ALS).MethodsThis single-centre, prospective, longitudinal study included the following patients: 124 patients with ALS; 50 patients without neurodegenerative diseases; 44 patients with conditions included in the differential diagnosis of ALS (disease controls); 65 patients with other neurodegenerative diseases (20 with frontotemporal dementia, 20 with Alzheimer’s disease, 19 with Parkinson’s disease, 6 with Creutzfeldt-Jakob disease (CJD)). Serum NFL levels were measured using the ultrasensitive single molecule array (Simoa) technology.ResultsSerum NFL levels were higher in ALS in comparison to all other categories except for CJD. A cut-off level of 62 pg/mL discriminated between ALS and all other conditions with 85.5% sensitivity (95% CI 78% to 91.2%) and 81.8% specificity (95% CI 74.9% to 87.4%). Among patients with ALS, serum NFL correlated positively with disease progression rate (rs=0.336, 95% CI 0.14 to 0.506, p=0.0008), and higher levels were associated with shorter survival (p=0.0054). Serum NFL did not differ among patients in different ALS pathological stages as evaluated by diffusion-tensor imaging, and in single patients NFL levels were stable over time.ConclusionsSerum NFL is increased in ALS in comparison to other conditions and can serve as diagnostic and prognostic biomarker. We established a cut-off level for the diagnosis of ALS.

scholarly journals Exposure to prenatal maternal distress and infant white matter neurodevelopment

2021 ◽  
Vol 33 (5) ◽  
pp. 1526-1538
Author(s):  
Catherine H. Demers ◽  
Maria M. Bagonis ◽  
Khalid Al-Ali ◽  
Sarah E. Garcia ◽  
Martin A. Styner ◽  
...  
Keyword(s):  
White Matter ◽  
Fractional Anisotropy ◽  
Diffusion Tensor ◽  
Critical Time ◽  
Anterior Cingulate ◽  
Maternal Distress ◽  
Prospective Longitudinal Study ◽  
Axial Diffusivity ◽  
Prenatal Distress ◽  
Prospective Longitudinal

AbstractThe prenatal period represents a critical time for brain growth and development. These rapid neurological advances render the fetus susceptible to various influences with life-long implications for mental health. Maternal distress signals are a dominant early life influence, contributing to birth outcomes and risk for offspring psychopathology. This prospective longitudinal study evaluated the association between prenatal maternal distress and infant white matter microstructure. Participants included a racially and socioeconomically diverse sample of 85 mother–infant dyads. Prenatal distress was assessed at 17 and 29 weeks’ gestational age (GA). Infant structural data were collected via diffusion tensor imaging (DTI) at 42–45 weeks’ postconceptional age. Findings demonstrated that higher prenatal maternal distress at 29 weeks’ GA was associated with increased fractional anisotropy, b = .283, t(64) = 2.319, p = .024, and with increased axial diffusivity, b = .254, t(64) = 2.067, p = .043, within the right anterior cingulate white matter tract. No other significant associations were found with prenatal distress exposure and tract fractional anisotropy or axial diffusivity at 29 weeks’ GA, or earlier in gestation.

144: A Prospective Longitudinal Study of Quality of Life Following Radical Perineal Prostatectomy

2004 ◽  
Vol 171 (4S) ◽  
pp. 38-38
Author(s):  
Benjamin K. Yang ◽  
Matthew D. Young ◽  
Brian Calingaert ◽  
Johannes Vieweg ◽  
Brian C. Murphy ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Longitudinal Study ◽  
Prospective Longitudinal Study ◽  
Perineal Prostatectomy ◽  
Prospective Longitudinal
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