Investigative radiology
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Investigative radiology · Sep 2013
Blood oxygen level-dependent magnetic resonance imaging of the kidneys: influence of spatial resolution on the apparent R2* transverse relaxation rate of renal tissue.
The aim of this study was to quantify the influence of image resolution on the apparent transverse relaxivity (R2*) of the magnetic resonance (MR) signal in human renal tissue in vivo and in phantom measurements. ⋯ The phantom experiments and in vivo acquisitions of healthy renal tissue documented a significant dependence of the apparent R2* relaxation rate on the spatial resolution of the MR imaging data. In clinical practice, the voxel volume for the quantification of renal R2* should be optimized in a compromise between minimizing the effects of macroscopic field inhomogeneity and maintaining a sufficiently high signal-to-noise ratio and goodness of fit. When comparing quantitative R2* among different publications, the influence of the spatial resolution should be taken into account.
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Investigative radiology · Aug 2013
Comparative StudyAutomated low-kilovoltage selection in pediatric computed tomography angiography: phantom study evaluating effects on radiation dose and image quality.
The purpose of this study was to compare the effects of combined automated tube voltage selection and automated tube current modulation on radiation dose and image quality in small-sized phantoms undergoing computed tomography angiography (CTA) with the use of automated current modulation alone. ⋯ Combined use of automated kilovoltage selection and automated tube current modulation is more effective for reducing radiation dose and maintaining image quality during simulated pediatric CTA than is automated tube current modulation in isolation.
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Investigative radiology · Aug 2013
Assessment of a model-based, iterative reconstruction algorithm (MBIR) regarding image quality and dose reduction in liver computed tomography.
The purpose of this study was to assess the image quality of half-dose (HD) liver computed tomography (CT) using a model-based iterative reconstruction algorithm (MBIR) compared with reference dose (RD) using filtered back projection (FBP) and the HD CT images using FBP and adaptive statistical iterative reconstruction (ASIR). ⋯ The HD MBIR images showed less noise, higher CNR, and better image quality than the HD ASIR and HD FBP images did; they also provided less image noise, higher CNR, and similar image quality compared with those of RD FBP images.
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Investigative radiology · Aug 2013
CAIPIRINHA-Dixon-TWIST (CDT)-volume-interpolated breath-hold examination (VIBE): a new technique for fast time-resolved dynamic 3-dimensional imaging of the abdomen with high spatial resolution.
The purpose of this study was to assess the feasibility and image quality of a novel, highly accelerated T1-weighted sequence for time-resolved imaging of the abdomen during the first pass of contrast media transit using controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) under sampling, view-sharing techniques, and Dixon water-fat separation (CAIPRINHA-Dixon-time-resolved imaging with interleaved stochastic trajectories-volumetric interpolated breath-hold examination [CDT-VIBE]). ⋯ The CDT-VIBE is a robust approach allowing, for the first time, dynamic imaging of the upper abdomen with high temporal resolution and preservation of high spatial resolution.
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Investigative radiology · Jul 2013
Nonenhanced magnetic resonance angiography of the lower extremity vessels at 7 tesla: initial experience.
The aim of this study was to investigate the feasibility of nonenhanced magnetic resonance angiography (MRA) of the lower extremities at 7 tesla (T). ⋯ The results of our study demonstrate the feasibility of non-contrast-agent-enhanced MRA of the lower extremity vessels at 7 T. Nonenhanced MRA of the lower extremities at this very high magnetic field can be considered to be in an early but promising stage. Further sequence optimization and the examination of a larger number of participants as well as comparison with contrast-enhanced MRA and nonenhanced techniques at lower field strengths should be pursued in future trials.