SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Lätt J.) "

Sökning: WFRF:(Lätt J.)

  • Resultat 1-10 av 21
  • [1]23Nästa
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Mårtensson, J, et al. (författare)
  • Diffusion tensor imaging and tractography of the white matter in normal aging : The rate-of-change differs between segments within tracts
  • 2018
  • Ingår i: Magnetic Resonance Imaging. - Elsevier. - 0730-725X. ; 45, s. 113-119
  • Tidskriftsartikel (refereegranskat)abstract
    • Knowledge concerning the normal aging of cerebral white matter will improve our understanding of abnormal changes in neurodegenerative diseases. The microstructural basis of white matter maturation and aging can be investigated using diffusion tensor imaging (DTI). Generally, diffusion anisotropy increases during childhood and adolescence followed by a decline in middle age. However, this process is subject to spatial variations between tracts. The aim of this study was to investigate to what extent age-related variations also occur within tracts. DTI parameters were compared between segments of two white matter tracts, the cingulate bundle (CB) and the inferior fronto-occipital fasciculus (IFO), in 257 healthy individuals between 13 and 84years of age. Segments of the CB and the IFO were extracted and parameters for each segment were averaged across the hemispheres. The data was analysed as a function of age. Results show that age-related changes differ both between and within individual tracts. Different age trajectories were observed in all segments of the analysed tracts for all DTI parameters. In conclusion, aging does not affect white matter tracts uniformly but is regionally specific; both between and within white matter tracts.
  •  
2.
  •  
3.
  • Janhunen, P., et al. (författare)
  • Invited Article: Electric solar wind sail : Toward test missions
  • 2010
  • Ingår i: Review of Scientific Instruments. - 0034-6748 .- 1089-7623. ; 81:11, s. 111301
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>The electric solar wind sail (E-sail) is a space propulsion concept that uses the natural solar wind dynamic pressure for producing spacecraft thrust. In its baseline form, the E-sail consists of a number of long, thin, conducting, and centrifugally stretched tethers, which are kept in a high positive potential by an onboard electron gun. The concept gains its efficiency from the fact that the effective sail area, i.e., the potential structure of the tethers, can be millions of times larger than the physical area of the thin tethers wires, which offsets the fact that the dynamic pressure of the solar wind is very weak. Indeed, according to the most recent published estimates, an E-sail of 1 N thrust and 100 kg mass could be built in the rather near future, providing a revolutionary level of propulsive performance (specific acceleration) for travel in the solar system. Here we give a review of the ongoing technical development work of the E-sail, covering tether construction, overall mechanical design alternatives, guidance and navigation strategies, and dynamical and orbital simulations.</p>
  •  
4.
  • Cannerfelt, B., et al. (författare)
  • White matter lesions and brain atrophy in systemic lupus erythematosus patients : correlation to cognitive dysfunction in a cohort of systemic lupus erythematosus patients using different definition models for neuropsychiatric systemic lupus erythematosus
  • 2018
  • Ingår i: Lupus. - SAGE Publications. - 0961-2033. ; 27:7, s. 1140-1149
  • Tidskriftsartikel (refereegranskat)abstract
    • Aim: The aim of this study was to evaluate the extent of white matter lesions, atrophy of the hippocampus and corpus callosum, and their correlation with cognitive dysfunction (CD), in patients diagnosed with systemic lupus erythematosus (SLE). Methods: Seventy SLE patients and 25 healthy individuals (HIs) were included in the study. To evaluate the different SLE and neuropsychiatric SLE (NPSLE) definition schemes, patients were grouped both according to the American College of Rheumatology (ACR) definition, as well as the more stringent ACR-Systemic Lupus International Collaborating Clinics definition. Patients and HIs underwent a 3 Tesla brain MRI and a standardized neuropsychological test. MRI data were evaluated for number and volume of white matter lesions and atrophy of the hippocampus and corpus callosum. Differences between groups and subgroups were evaluated for significance. Number and volume of white matter lesions and atrophy of the hippocampus and corpus callosum were correlated to cognitive dysfunction. Results: The total volume of white matter lesions was significantly larger in SLE patients compared to HIs (p = 0.004). However, no significant differences were seen between the different SLE subgroups. Atrophy of the bilateral hippocampus was significantly more pronounced in patients with NPSLE compared to those with non-NPSLE (right: p = 0.010; left p = 0.023). Significant negative correlations between cognitive test scores on verbal memory and number and volume of white matter lesions were present. Conclusion: SLE patients have a significantly larger volume of white matter lesions on MRI compared to HIs and the degree of white matter lesion volume correlates to cognitive dysfunction, specifically to verbal memory. No significant differences in the number or volume of white matter lesions were identified between subgroups of SLE patients regardless of the definition model used.
5.
  • Delgado, Anna F, et al. (författare)
  • Preoperative Quantitative MR Tractography Compared with Visual Tract Evaluation in Patients with Neuropathologically Confirmed Gliomas Grades II and III : : A Prospective Cohort Study
  • 2016
  • Ingår i: Radiology research and practice. - Hindawi Publishing Corporation. - 2090-1941. ; 2016:1, s. 1-15
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and Purpose. Low-grade gliomas show infiltrative growth in white matter tracts. Diffusion tensor tractography can noninvasively assess white matter tracts. The aim was to preoperatively assess tumor growth in white matter tracts using quantitative MR tractography (3T). The hypothesis was that suspected infiltrated tracts would have altered diffusional properties in infiltrated tract segments compared to noninfiltrated tracts. Materials and Methods. Forty-eight patients with suspected low-grade glioma were included after written informed consent and underwent preoperative diffusion tensor imaging in this prospective review-board approved study. Major white matter tracts in both hemispheres were tracked, segmented, and visually assessed for tumor involvement in thirty-four patients with gliomas grade II or III (astrocytomas or oligodendrogliomas) on postoperative neuropathological evaluation. Relative fractional anisotropy (rFA) and mean diffusivity (rMD) in tract segments were calculated and compared with visual evaluation and neuropathological diagnosis. Results. Tract segment infiltration on visual evaluation was associated with a lower rFA and high rMD in a majority of evaluated tract segments (89% and 78%, resp.). Grade II and grade III gliomas had similar infiltrating behavior. Conclusion. Quantitative MR tractography corresponds to visual evaluation of suspected tract infiltration. It may be useful for an objective preoperative evaluation of tract segment involvement.
6.
  • Mårtensson, J, et al. (författare)
  • Diffusion tensor imaging and tractography of the white matter in normal aging : The rate-of-change differs between segments within tracts.
  • 2018
  • Ingår i: Magnetic Resonance Imaging. - Elsevier. - 0730-725X .- 1873-5894. ; 45, s. 113-119
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>Knowledge concerning the normal aging of cerebral white matter will improve our understanding of abnormal changes in neurodegenerative diseases. The microstructural basis of white matter maturation and aging can be investigated using diffusion tensor imaging (DTI). Generally, diffusion anisotropy increases during childhood and adolescence followed by a decline in middle age. However, this process is subject to spatial variations between tracts. The aim of this study was to investigate to what extent age-related variations also occur within tracts. DTI parameters were compared between segments of two white matter tracts, the cingulate bundle (CB) and the inferior fronto-occipital fasciculus (IFO), in 257 healthy individuals between 13 and 84years of age. Segments of the CB and the IFO were extracted and parameters for each segment were averaged across the hemispheres. The data was analysed as a function of age. Results show that age-related changes differ both between and within individual tracts. Different age trajectories were observed in all segments of the analysed tracts for all DTI parameters. In conclusion, aging does not affect white matter tracts uniformly but is regionally specific; both between and within white matter tracts.</p>
  •  
7.
  •  
8.
  • F., Durmo, et al. (författare)
  • Multivoxel 1H MR spectroscopy biometrics for preoprerative differentiation between brain tumors
  • 2018
  • Ingår i: Neuroradiology. - Springer. - 1432-1920. ; 60:S2, s. 444-444
  • Konferensbidrag (refereegranskat)abstract
    • Purpose To investigate multivoxel proton Magnetic Resonance Spectroscopy (1HMRS) biometrics for preoperative differentiation and prognosis of patients with brain metastases (MET), low-(LGG) and high grade glioma (HGG). Methods Thirty-five patients (15 HGG, 9 LGG and 11 MET) were included. Proton Magnetic Resonance Spectroscopy Imaging(1H-MRSI) data was assessed and neurochemical profiles for metabolites (NAA+NAAG, Cr+PCr, Glu+Gln (Glx), Lac, Ins, GPC+PCho) and total Lipids (tLip) and macromolecule (tMM) signals were estimated. Concentrations were reported as either absolute or ratios to total choline (tCho=GPC+PCho) and creatine (tCr=Cr+PCr) levels. Voxels of interest (VOIs) in a MRSI matrix were labelled accordingly to contrast-enhancing/nonenhancing lesional, edema, ipsi- or contralateral healthy appearing tissue and the metabolite averages were reported for each tissue type. Multi-biometric analysis with logistic regression, ROC- and Kaplan-Meier survival analysis was performed in SPSS v.24 and postprocessing with LC Model. Results Across HGG/LGG/MET; the average Ins/tCho was shown to be prognostic for overall survival (OS): with low values (≤1.29) in affected hemisphere predicting worse OS than high values (>1.29), (Log Rank
  •  
9.
  • Mårtensson, Johanna, et al. (författare)
  • Diffusion tensor imaging and tractography of the white matter in normal aging : The rate-of-change differs between segments within tracts
  • 2018
  • Ingår i: Magnetic Resonance Imaging. - 0730-725X .- 1873-5894. ; 45, s. 113-119
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>Knowledge concerning the normal aging of cerebral white matter will improve our understanding of abnormal changes in neurodegenerative diseases. The microstructural basis of white matter maturation and aging can be investigated using diffusion tensor imaging (DTI). Generally, diffusion anisotropy increases during childhood and adolescence followed by a decline in middle age. However, this process is subject to spatial variations between tracts. The aim of this study was to investigate to what extent age-related variations also occur within tracts. DTI parameters were compared between segments of two white matter tracts, the cingulate bundle (CB) and the inferior fronto-occipital fasciculus (IFO), in 257 healthy individuals between 13 and 84years of age. Segments of the CB and the IFO were extracted and parameters for each segment were averaged across the hemispheres. The data was analysed as a function of age. Results show that age-related changes differ both between and within individual tracts. Different age trajectories were observed in all segments of the analysed tracts for all DTI parameters. In conclusion, aging does not affect white matter tracts uniformly but is regionally specific; both between and within white matter tracts.</p>
  •  
10.
  • Santillo, Alexander Frizell, et al. (författare)
  • Diffusion Tensor Tractography versus Volumetric Imaging in the Diagnosis of Behavioral Variant Frontotemporal Dementia.
  • 2013
  • Ingår i: PLoS ONE. - Public Library of Science. - 1932-6203. ; 8:7
  • Tidskriftsartikel (refereegranskat)abstract
    • MRI diffusion tensor imaging (DTI) studies of white matter integrity in behavioral variant frontotemporal dementia have consistently shown involvement of frontal and temporal white matter, corresponding to regional loss of cortical volume. Volumetric imaging has a suboptimal sensitivity as a diagnostic tool and thus we wanted to explore if DTI is a better method to discriminate patients and controls than volumetric imaging. We examined the anterior cingulum bundle in 14 patients with behavioral variant frontotemporal dementia and 22 healthy controls using deterministic manual diffusion tensor tractography, and compared DTI parameters with two measures of cortical atrophy, VBM and cortical thickness, of the anterior cingulate cortex (ACC). Statistically significant changes between patients and controls were detected in all DTI parameters, with large effect sizes. ROC-AUC was for the best DTI parameters: 0.92 (fractional anisotropy) to 0.97 (radial diffusivity), 0.82 for the best cortical parameter, VBM of the ACC. Results from the AUC were confirmed with binary logistic regression analysis including demographic variables, but only for fractional anisotropy and mean diffusivity. Ability to classify patient/nonpatient status was significantly better for mean diffusivity vs. VBM (p=0.031), and borderline significant for fractional anisotropy vs. VBM (p=0.062). The results indicate that DTI could offer advantages in comparison with the assessment of cortical volume in differentiating patients with behavioral variant frontotemporal dementia and controls.
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 21
  • [1]23Nästa
 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy