NeuroImage. Clinical
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NeuroImage. Clinical · Jan 2016
Comparative StudyComparison of unsupervised classification methods for brain tumor segmentation using multi-parametric MRI.
Tumor segmentation is a particularly challenging task in high-grade gliomas (HGGs), as they are among the most heterogeneous tumors in oncology. An accurate delineation of the lesion and its main subcomponents contributes to optimal treatment planning, prognosis and follow-up. Conventional MRI (cMRI) is the imaging modality of choice for manual segmentation, and is also considered in the vast majority of automated segmentation studies. ⋯ In this paper, we compare the performance of several unsupervised classification methods for HGG segmentation based on MP-MRI data including cMRI, DWI, MRSI and PWI. Two independent MP-MRI datasets with a different acquisition protocol were available from different hospitals. We demonstrate that a hierarchical non-negative matrix factorization variant which was previously introduced for MP-MRI tumor segmentation gives the best performance in terms of mean Dice-scores for the pathologic tissue classes on both datasets.
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NeuroImage. Clinical · Jan 2016
Network analysis of functional brain connectivity in borderline personality disorder using resting-state fMRI.
Borderline personality disorder (BPD) is associated with symptoms such as affect dysregulation, impaired sense of self, and self-harm behaviors. Neuroimaging research on BPD has revealed structural and functional abnormalities in specific brain regions and connections. However, little is known about the topological organizations of brain networks in BPD. ⋯ Lastly, the key network measures showed high correlations with several clinical symptom scores, and classified BPD patients against healthy controls with high accuracy based on linear discriminant analysis. The abnormal topological properties and connectivity found in this study may add new knowledge to the current understanding of functional brain networks in BPD. However, due to limitation of small sample sizes, the results of the current study should be viewed as exploratory and need to be validated on large samples in future works.
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NeuroImage. Clinical · Jan 2016
Cerebral metabolism and perfusion in MR-negative individuals with refractory focal epilepsy assessed by simultaneous acquisition of (18)F-FDG PET and arterial spin labeling.
The major challenge in pre-surgical epileptic patient evaluation is the correct identification of the seizure onset area, especially in MR-negative patients. In this study, we aimed to: (1) assess the concordance between perfusion, from ASL, and metabolism, from (18)F-FDG, acquired simultaneously on PET/MR; (2) verify the utility of a statistical approach as supportive diagnostic tool for clinical readers. Secondarily, we compared (18)F-FDG PET data from the hybrid PET/MR system with those acquired with PET/CT, with the purpose of validate the reliability of (18)F-FDG PET/MR data. ⋯ High agreement between (18)F-FDG PET/MR and ASL was found, showing hypometabolism and hypoperfusion in the same hemisphere in 18/20 patients, while the remaining were normal. They were completely concordant in 14/18, concordant in at least one lobe in the remaining. zAI maps improved readers' confidence in 12/20 and 15/20 patients for (18)F-FDG PET/MR and ASL, respectively. (18)F-FDG PET/CT-PET/MR showed high agreement, especially when zAI was considered. The simultaneous metabolism-perfusion acquisition provides excellent concordance on focus lateralisation and good concordance on localisation, determining useful complementary information.
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NeuroImage. Clinical · Jan 2016
A brain stress test: Cerebral perfusion during memory encoding in mild cognitive impairment.
Arterial spin labeled perfusion magnetic resonance imaging (ASL MRI) provides non-invasive quantification of cerebral blood flow, which can be used as a biomarker of brain function due to the tight coupling between cerebral blood flow (CBF) and brain metabolism. A growing body of literature suggests that regional CBF is altered in neurodegenerative diseases. ⋯ Further, logistic regression analysis demonstrated that ASL MRI and concomitantly acquired structural MRI provide complementary information of disease status. The current findings support the potential utility of task-enhanced ASL MRI as a biomarker in early Alzheimer's disease.
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NeuroImage. Clinical · Jan 2016
Brain volume loss contributes to arousal and empathy dysregulation following severe traumatic brain injury.
Severe traumatic brain injury (TBI) often leads to deficits in physiological arousal and empathy, which are thought to be linked. This study examined whether injury-related brain volume loss in key limbic system structures is associated with these deficits. Twenty-four adults with TBI and 24 matched Controls underwent MRI scans to establish grey matter volumes in the amygdala, thalamus, and hippocampus. ⋯ Regional brain volumes were differentially correlated to arousal and self-report empathy. Importantly, lower volume in pertinent brain structures correlated with lower empathy, for participants with and without TBI. Overall we provide new insights into empathic processes after TBI and their relationship to brain volume loss.