Differentiation of dys- and demyelination using diffusional anisotropy

Ono, Jiro; Harada, K.; Mano, Toshiyuki; Sakurai, Kosuke; Okada, Shintaro

doi:10.1016/s0887-8994(96)00249-4

Cited by 60 publications

(25 citation statements)

References 9 publications

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“…Animal studies have shown that an increment of axial diffusivity ( 2 and 3 ) is related to myelin deficiency, whereas a decrease of parallel diffusivity ( 1 ) indicates axonal disturbance. [26][27][28] Our findings of higher values for 2 and 3 indicate that diffusion perpendicular to the white matter structure is higher. Because we did not find lower values for 1 in NF-1 regions with UBOs than in NF-1 regions without UBOs, we hypothesize that the observed changes of the brain tissue in NF-1 are not caused by damage to the axon, but relate to myelin deficiency.…”

Section: Discussionmentioning

confidence: 52%

Quantitative Differentiation Between Healthy and Disordered Brain Matter in Patients with Neurofibromatosis Type I Using Diffusion Tensor Imaging

Engelen¹,

Krab²,

Moll³

et al. 2008

AJNR Am J Neuroradiol

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Section: Discussionmentioning

confidence: 52%

Quantitative Differentiation Between Healthy and Disordered Brain Matter in Patients with Neurofibromatosis Type I Using Diffusion Tensor Imaging

Engelen¹,

Krab²,

Moll³

et al. 2008

AJNR Am J Neuroradiol

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“…Medially, the border was defined by a straight line joining the deepest point of the inferior frontal sulci with the deepest point of the lateral orbital sulci. These definitions closely followed surface sulci demarcated by Duvernoy and Bourgouin 27 and Ono et al 28 …”

Section: Inferior Frontal Gyrusmentioning

confidence: 68%

Functional brain imaging study of mathematical reasoning abilities in velocardiofacial syndrome (del22q11.2)

Eliez

Blasey

Menon

et al. 2001

Genetics in Medicine

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Purpose: Children with velocardiofacial syndrome (VCFS) often have deficits in mathematical reasoning. Previous research has suggested that structural abnormalities in the parietal lobe region might underlie these deficits. The present study utilized functional magnetic resonance imaging (fMRI) to explore the relationship between brain function and mathematical performance in VCFS. Methods: Eight children with VCFS and eight comparison subjects underwent fMRI scanning and completed an arithmetic computation task. Results: In the VCFS group, increased activation was observed in the left supramarginal gyrus (LSMG) as the task difficulty increased. Conclusion: Persons with velocardiofacial syndrome (VCFS) have cognitive deficits and typically score in the borderline to mildly mentally retarded range on standardized tests of general cognitive ability. [1][2][3][4][5] In addition to general cognitive disability, children with VCFS also show more specific deficiencies in the area of mathematics ability.The first descriptive study of the cognitive phenotype associated with VCFS 2 showed that children with this condition scored disproportionately lower on math and reading comprehension tests relative to tests of language. For example, an early study demonstrated that math scores from the Wide Range Achievement Test (WRAT) among 6 -11 year olds with VCFS ranged from 81 to 90 (population mean ϭ 100, SD ϭ 10) and from 74 to 86 among affected adolescents. 2 More recent investigations have yielded similar results. 3,6,7 General weaknesses in problem solving and manipulation of numbers have been observed among school-age children with VCFS, as well as particular difficulties in converting language into number sentences, solving problems with decimals and fractions, telling time, and converting money. 6 When examining standardized test scores in clinical samples of 33 subjects with VCFS, Moss et al. 3 reported lower composite math achievement scores relative to composite scores of reading and spelling. In accordance with these findings, Swillen et al. 7 recently reported that children with VCFS had significant decrements in arithmetic performance alongside relatively preserved abilities in reading and spelling.Although the neural substrates that underlie deficiencies in arithmetic reasoning in VCFS are currently unknown, research focused on individuals with neurological dysfunction from other causes has begun to define the specific brain regions that are involved in mathematical performance. For example, human brain lesion studies have demonstrated acalculia among patients with lesions to the parietal cortex. Further, the parietal area is thought to underlie the acalculia component of Gerstmann's syndrome. 8 -13 Functional magnetic resonance imaging (fMRI) studies with "normal" subjects also have implicated several brain regions as being associated with arithmetic performance. 14,15 During "approximate" computation, brain activation has been observed in the bilateral inferior parietal lobule, right precuneus, bilateral prece...

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“…This effect, diffusional anisotropy, is thought to be due to restriction of the random motion of water molecules by the myelin sheath. Diffusional anisotropy increases with myelination during neonatal brain maturation [17] and decreases in demyelinating disorders [18]. ADCavg is diminished in the acute stage of ischemic stroke, which is thought to be related to intracellular water accumulation caused by rapid failure of energy metabolism [19,20].…”

Section: Discussionmentioning

confidence: 99%

Diffusion-Weighted Magnetic Resonance Imaging in Alzheimer’s Disease

Sandson

Félician

Edelman

et al. 1999

Dement Geriatr Cogn Disord

101

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Diffusion-weighted imaging (DWI) is a powerful new magnetic resonance imaging technique for evaluating tissue pathophysiology in vivo. We performed DWI in three orthogonal spatial directions in 10 patients with mild to moderate Alzheimer’s disease (AD) and 11 control subjects. Average apparent diffusion coefficients (ADCavg) were calculated for gray matter regions, and anisotropy indexes were calculated for white matter regions. Global measures of atrophy and white matter hyperintensities (WMH) were obtained on T₂-weighted images to control for their potential confounding effects on ADCavg and anisotropy. The measures of atrophy and WMH differed between the groups and were used as covariates in the subsequent statistical analyses. Patients with AD demonstrated diminished anisotropy in the posterior white matter (p < 0.0001) and increased ADCavg in the hippocampus (p < 0.05) when compared to the control group. Diffusion measures did not correlate with the severity of dementia. DWI provides a unique, quantitative parameter that may be sensitive to the pathophysiological and/or microstructural abnormalities that occur in AD.

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Differentiation of dys- and demyelination using diffusional anisotropy

Cited by 60 publications

References 9 publications

Quantitative Differentiation Between Healthy and Disordered Brain Matter in Patients with Neurofibromatosis Type I Using Diffusion Tensor Imaging

Quantitative Differentiation Between Healthy and Disordered Brain Matter in Patients with Neurofibromatosis Type I Using Diffusion Tensor Imaging

Functional brain imaging study of mathematical reasoning abilities in velocardiofacial syndrome (del22q11.2)

Diffusion-Weighted Magnetic Resonance Imaging in Alzheimer’s Disease

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