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The image contrast in magnetic resonance imaging (MRI) is highly sensitive to several mechanisms that are modulated by the properties of the tissue environment. The degree and type of contrast weighting may be viewed as image filters that accentuate specific tissue properties. Maps of quantitative measures of these mechanisms, akin to(More)
BACKGROUND The efficacy and safety of intracerebral gene therapy for brain disorders like Parkinson's disease depends on the appropriate distribution of gene expression. OBJECTIVES To assess whether the distribution of gene expression is affected by vector titer and protein type. METHODS Four adult macaque monkeys seronegative for adeno-associated virus(More)
A new time-efficient and accurate technique for simultaneous mapping of T(1) and B(1) is proposed based on a combination of the actual flip angle (FA) imaging and variable FA methods. Variable FA-actual FA imaging utilizes a single actual FA imaging and one or more spoiled gradient-echo acquisitions with a simultaneous nonlinear fitting procedure to yield(More)
OBJECTIVE To model inductive coupling of endovascular coils with transmit RF excitation for selecting coils for MRI-guided interventions. METHODS Independent and computationally efficient FEM models are developed for the endovascular coil, cable, transmit excitation, and imaging domain. Electromagnetic and circuit solvers are coupled to simulate net B1 +(More)
Importance The accumulation of aggregated β-amyloid and tau proteins into plaques and tangles is a central feature of Alzheimer disease (AD). While plaque and tangle accumulation likely contributes to neuron and synapse loss, disease-related changes to oligodendrocytes and myelin are also suspected of playing a role in development of AD dementia. Still, to(More)
PURPOSE Define criteria for selection of optimal flip angle sets for T1 estimation and evaluate effects on T1 mapping. THEORY AND METHODS Flip angle sets for spoiled gradient echo-based T1 mapping were selected by minimizing T1 estimate variance weighted by the joint density of M0 and T1 in an initial acquisition. The effect of optimized flip angle(More)
PURPOSE To introduce a new technique called MPnRAGE, which produces hundreds of images with different T1 contrasts and a B1 corrected T1 map. THEORY AND METHODS An interleaved three-dimensional radial k-space trajectory with a sliding window reconstruction is used in conjunction with magnetization preparation pulses. This work modifies the SNAPSHOT-FLASH(More)
Myelin is a critical component of the nervous system and a major contributor to contrast in Magnetic Resonance (MR) images. However, the precise contribution of myelination to multiple MR modalities is still under debate. The cuprizone mouse is a well-established model of demyelination that has been used in several MR studies, but these have often imaged(More)
PURPOSE To advance the best solutions to two important RF pulse design problems with an open head-to-head competition. METHODS Two sub-challenges were formulated in which contestants competed to design the shortest simultaneous multislice (SMS) refocusing pulses and slice-selective parallel transmission (pTx) excitation pulses, subject to realistic(More)
Intraoperative magnetic resonance imaging (MRI) has been proposed as a method to optimize intracerebral targeting and for tracking infusate distribution in gene therapy trials for nervous system disorders. We thus investigated possible effects of two MRI contrast agents, gadoteridol (Gd) and galbumin (Gab), on the distribution and levels of transgene(More)
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