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Functional recovery after stroke has been associated with brain plasticity; however, the exact relationship is unknown. We performed behavioral tests, functional MRI, and histology in a rat stroke model to assess the correlation between temporal changes in sensorimotor function, brain activation patterns, cerebral ischemic damage, and cerebrovascular(More)
The precise characterization of cortical connectivity is important for the understanding of brain morphological and functional organization. Such connectivity is conveyed by specific pathways or tracts in the white matter. Diffusion-weighted magnetic resonance imaging detects the diffusivity of water molecules in three dimensions. Diffusivity is anisotropic(More)
BACKGROUND AND PURPOSE Multiple biomarkers are used to quantify the severity of traumatic brain injury (TBI) and to predict outcome. Few are satisfactory. CT and conventional MR imaging underestimate injury and correlate poorly with outcome. New MR imaging techniques, including diffusion tensor imaging (DTI), can provide information about brain(More)
The pattern and role of brain plasticity in stroke recovery has been incompletely characterized. Both ipsilesional and contralesional changes have been described, but it remains unclear how these relate to functional recovery. Our goal was to correlate brain activation patterns with tissue damage, hemodynamics, and neurologic status after temporary stroke,(More)
The ascending reticular activating system (ARAS) mediates arousal, an essential component of human consciousness. Lesions of the ARAS cause coma, the most severe disorder of consciousness. Because of current methodological limitations, including of postmortem tissue analysis, the neuroanatomic connectivity of the human ARAS is poorly understood. We applied(More)
Relative cerebral blood flow (CBF) and tissue mean transit time (MTT) estimates from bolus-tracking MR perfusion-weighted imaging (PWI) have been shown to be sensitive to delay and dispersion when using singular value decomposition (SVD) with a single measured arterial input function. This study proposes a technique that is made time-shift insensitive by(More)
BACKGROUND AND PURPOSE Tissue signatures from acute MR imaging of the brain may be able to categorize physiological status and thereby assist clinical decision making. We designed and analyzed statistical algorithms to evaluate the risk of infarction for each voxel of tissue using acute human functional MRI. METHODS Diffusion-weighted MR images (DWI) and(More)
BACKGROUND AND PURPOSE Hyperintense vessels (HVs) have been observed in fluid-attenuated inversion recovery imaging of patients with acute ischemic stroke and been linked to slow flow in collateral arterial circulation. Given the potential importance of HV, we used a large, multicenter data set of patients with stroke to clarify which clinical and imaging(More)
BACKGROUND Many patients with stroke are precluded from thrombolysis treatment because the time from onset of their symptoms is unknown. We aimed to test whether a mismatch in visibility of an acute ischaemic lesion between diffusion-weighted MRI (DWI) and fluid-attenuated inversion recovery (FLAIR) MRI (DWI-FLAIR mismatch) can be used to detect patients(More)