Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · May 2014
Comparative StudyOptimized simultaneous ASL and BOLD functional imaging of the whole brain.
To compare a double-excitation combined arterial-spin labeling/blood-oxygenation level dependent (ASL/BOLD) functional imaging method to a double-echo method. ASL provides a useful complement to standard BOLD functional imaging, to map effects of cerebral hemodynamics. Whole-brain imaging is necessary to properly characterize large functional networks. A challenge of whole-brain ASL/BOLD is that images for ASL functional contrast must be acquired before significant longitudinal relaxation of the inverted spins occurs; however, a longer echo time (TE) is required for optimal BOLD functional contrast, lengthening the acquisition time. Thus, existing combined ASL/BOLD studies have only partial-brain coverage. ⋯ Our method simultaneously optimizes ASL and BOLD acquisitions for CNR while economizing acquisition time.
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J Magn Reson Imaging · May 2014
Therapy monitoring of skeletal metastases with whole-body diffusion MRI.
Current methods of assessing tumor response at skeletal sites with metastatic disease use a combination of imaging tests, serum and urine biochemical markers, and symptoms assessment. These methods do not always enable the positive assessment of therapeutic benefit to be made but instead provide an evaluation of progression, which then guides therapy decisions in the clinic. Functional imaging techniques such as whole-body diffusion magnetic resonance imaging (MRI) when combined with anatomic imaging and other emerging "wet" biomarkers can improve the classification of therapy response in patients with metastatic bone disease. ⋯ Rarer patterns of successful treatment include no changes in signal intensity accompanying increases in ADC values (T2 shine-through pattern) or reductions in signal intensity without ADC value changes. Progressive disease results in increases in extent/intensity of disease on high b-value images with variable ADC changes. Diffusion MRI therapy response criteria need to be developed and tested in prospective studies in order to address current, unmet clinical and pharmaceutical needs for reliable measures of tumor response in metastatic bone disease.
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J Magn Reson Imaging · May 2014
Comparative StudyVisualization of acute focal lesions in rats with experimental autoimmune encephalomyelitis by magnetic nanoparticles, comparing different MRI sequences including phase imaging.
To compare the sensitivity and specificity of phase imaging (PI) with other magnetic resonance imaging (MRI) methods in lesion detection in rats with experimental autoimmune encephalomyelitis (EAE), as an animal model for multiple sclerosis (MS). ⋯ The diagnostic use of PI without VSOP as contrast agent to detect lesions is not recommended at field strength of 4.7T or lower.
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J Magn Reson Imaging · May 2014
Functional magnetic resonance cholangiography enhanced with Gd-EOB-DTPA: effect of liver function on biliary system visualization.
To evaluate effect of liver function on biliary system visualization using gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance cholangiography (CE-MRC). ⋯ Different liver function according to Child-Pugh classification significantly affects biliary system visualization of Gd-EOB-DTPA CE-MRC.
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J Magn Reson Imaging · May 2014
Optimization of b-value distribution for biexponential diffusion-weighted MR imaging of normal prostate.
To determine the optimal b-value distribution for biexponential diffusion-weighted imaging (DWI) of normal prostate using both a computer modeling approach and in vivo measurements. ⋯ The optimal b-value distribution was found to be a clustered distribution with b-values concentrated in the low, mid, and high ranges and was shown to improve the estimation quality of biexponential DWI parameters of in vivo experiments.