Journal of magnetic resonance imaging : JMRI
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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.
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J Magn Reson Imaging · May 2014
Fractal analysis of spontaneous fluctuations of the BOLD signal in the human brain networks.
To investigate what extent brain regions are continuously interacting during resting-state, independent component analyses (ICA) was applied to analyze resting-state functional MRI (RS-fMRI) data. According to the analyzed results, it was surprisingly found that low frequency fluctuations (LFFs), which belong to the 1/f signal (a signal with power spectrum whose power spectral density is inversely proportional to the frequency), have been classified into groups using ICA; furthermore, the spatial distributions of these groups within the brain were found to resemble the spatial distributions of different networks, which manifests that the signal characteristics of RS LFFs are distinct across networks. In our work, we applied the 1/f model in the fractal analyses to further investigate this distinction. ⋯ Our results support that the origin of RS-fMRI signals contains arterial fluctuations. Hence, in addition to the commonly used method such as synchrony analysis and power spectral analysis, another approach, the fractal analysis, is suggested for acquiring the information of hemodynamic responses by means of RS-fMRI data.