NeuroImage. Clinical
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NeuroImage. Clinical · Jan 2014
Accurate GM atrophy quantification in MS using lesion-filling with co-registered 2D lesion masks.
In multiple sclerosis (MS), brain atrophy quantification is affected by white matter lesions. LEAP and FSL-lesion_filling, replace lesion voxels with white matter intensities; however, they require precise lesion identification on 3DT1-images. ⋯ These results demonstrate that for global GM volumetry, precise lesion masks on 3DT1 images can be replaced by co-registered 2DT2 lesion masks. This makes lesion-filling a feasible method for GM atrophy measurements in MS.
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NeuroImage. Clinical · Jan 2014
Anatomical and diffusion MRI of deep gray matter in pediatric spina bifida.
Individuals with spina bifida myelomeningocele (SBM) exhibit brain abnormalities in cortical thickness, white matter integrity, and cerebellar structure. Little is known about deep gray matter macro- and microstructure in this population. The current study utilized volumetric and diffusion-weighted MRI techniques to examine gray matter volume and microstructure in several subcortical structures: basal ganglia nuclei, thalamus, hippocampus, and amygdala. ⋯ These results provide further support that SBM differentially disrupts brain regions whereby some structures are volumetrically normal whereas others are reduced or enlarged. In the hippocampus, volumetric reduction coupled with increased MD may imply reduced cellular density and aberrant organization. Alternatively, the enlarged volume and significantly reduced MD in the putamen suggest increased density.
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NeuroImage. Clinical · Jan 2014
Deficits in episodic memory retrieval reveal impaired default mode network connectivity in amnestic mild cognitive impairment.
Amnestic mild cognitive impairment (aMCI) is believed to represent a transitional stage between normal healthy ageing and the development of dementia. In particular, aMCI patients have been shown to have higher annual transition rates to Alzheimer's Disease (AD) than individuals without cognitive impairment. Despite intensifying interest investigating the neuroanatomical basis of this transition, there remain a number of questions regarding the pathophysiological process underlying aMCI itself. ⋯ The two groups showed no statistical difference in their DMN intra-connectivity. However when connectivity was analysed according to performance on measures of episodic memory retrieval, the two groups were separable, with aMCI patients demonstrating impaired functional connectivity between the hippocampal formation and the posterior cingulate cortex. We provide evidence that this lack of connectivity is driven by impaired communication from the posterior cingulate hub and does not simply represent hippocampal atrophy, suggesting that posterior cingulate degeneration is the driving force behind impaired DMN connectivity in aMCI.
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NeuroImage. Clinical · Jan 2014
Voxel-based clustered imaging by multiparameter diffusion tensor images for glioma grading.
Gliomas are the most common intra-axial primary brain tumour; therefore, predicting glioma grade would influence therapeutic strategies. Although several methods based on single or multiple parameters from diagnostic images exist, a definitive method for pre-operatively determining glioma grade remains unknown. We aimed to develop an unsupervised method using multiple parameters from pre-operative diffusion tensor images for obtaining a clustered image that could enable visual grading of gliomas. ⋯ Furthermore, the log-ratio value of each class of the 16-class diffusion tensor-based clustered images was compared between low- and high-grade gliomas, and the log-ratio values of classes 14, 15 and 16 in the high-grade gliomas were significantly higher than those in the low-grade gliomas (p < 0.005, p < 0.001 and p < 0.001, respectively). These classes comprised different patterns of the seven diffusion tensor imaging-based parameters. The results suggest that the multiple diffusion tensor imaging-based parameters from the voxel-based diffusion tensor-based clustered images can help differentiate between low- and high-grade gliomas.
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Alterations in cortical development and impaired neurodevelopmental outcomes have been described following very preterm (VPT) birth in childhood and adolescence, but only a few studies to date have investigated grey matter (GM) and white matter (WM) maturation in VPT samples in early adult life. Using voxel-based morphometry (VBM) we studied regional GM and WM volumes in 68 VPT-born individuals (mean gestational age 30 weeks) and 43 term-born controls aged 19-20 years, and their association with cognitive outcomes (Hayling Sentence Completion Test, Controlled Oral Word Association Test, Visual Reproduction test of the Wechsler Memory Scale-Revised) and gestational age. Structural MRI data were obtained with a 1.5 Tesla system and analysed using the VBM8 toolbox in SPM8 with a customized study-specific template. ⋯ WM volume in posterior corpus callosum/thalamus/fornix and GM volume in temporal gyri bilaterally, accounted for 21% of the variance of executive function (F = 9.9, p < 0.0001) and WM in the posterior corpus callosum/thalamus/fornix alone accounted for 17% of the variance of total non-verbal memory scores (F = 9.9, p < 0.0001). These results reveal that VPT birth continues to be associated with altered structural brain anatomy in early adult life, although it remains to be ascertained whether these changes reflect neurodevelopmental delays or long lasting structural alterations due to prematurity. GM and WM alterations correlate with length of gestation and mediate cognitive outcome.