Learn More
PURPOSE To quantify measurement uncertainties of fractional anisotropy, mean diffusivity, and principal eigenvector orientations in human diffusion tensor imaging (DTI) data acquired with common clinical protocols using a wild bootstrap analysis, and to establish optimal scan protocols for clinical DTI acquisitions. MATERIALS AND METHODS A group of 13(More)
BACKGROUND Alzheimer's disease (AD) is associated with changes in cerebral white matter (WM), but the functional significance of such findings is not yet established. We hypothesized that diffusion tensor imaging (DTI) might reveal links between regional WM changes and specific neuropsychologically and psychophysically defined impairments in early AD. (More)
OBJECTIVE Alzheimer's disease (AD) is a serious neurodegenerative disorder characterized by deficits of working memory, attention, language and many other cognitive functions. Although different stages of the disease are relatively well characterized by clinical criteria, stage-specific pathological changes in the brain remain relatively poorly understood,(More)
To explore the changes of glutamate-glutamine (Glx) and gamma-aminobutyric acid (GABA) in the brain in normal old age and cognitive impairment using magnetic resonance spectroscopy (MRS). Seventeen normal young controls (NYC), 15 normal elderly controls (NEC), 21 patients with mild cognitive impairment (MCI) and 17 with Alzheimer disease (AD) patients were(More)
Diffusion kurtosis imaging (DKI) is a new diffusion magnetic resonance imaging (MRI) technique to go beyond the shortages of conventional diffusion tensor imaging (DTI) from the assumption that water diffuse in biological tissue is Gaussian. Kurtosis is used to measure the deviation of water diffusion from Gaussian model, which is called non-Gaussian, in(More)
OBJECTIVE To evaluate non-Gaussian diffusion changes of the whole-brain and its correlation with cognitive performance in patients with early Alzheimer's disease (AD), using diffusion kurtosis imaging (DKI). METHODS Twenty-six patients with early AD and twenty-six normal controls underwent diffusion imaging. Seven parametric maps were calculated from(More)
We have used MR DTI to identify relevant brain structures involved in visuospatial processing, in an attempt to link perceptual and attentional impairments to WM changes in Alzheimer’s disease (AD) patients. Correlation of DTI measured parameters with results of several neuropsychological tests will be reported here. Several issues related to quantitation(More)
Diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) are important diffusion MRI techniques for detecting microstructure abnormities in diseases such as Alzheimer's. The advantages of DKI over DTI have been reported generally; however, the indistinct relationship between diffusivity and kurtosis has not been clearly revealed in clinical(More)
Normal aging is typically characterized by abnormal resting-state functional connectivity (FC), including decreasing connectivity within networks and increasing connectivity between networks, under the assumption that the FC over the scan time was stationary. In fact, the resting-state FC has been shown in recent years to vary over time even within minutes,(More)