Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Jul 2009
Time-resolved three-dimensional magnetic resonance digital subtraction angiography without contrast material in the brain: Initial investigation.
To evaluate a novel magnetic resonance (MR) angiography (MRA) of three-dimensional (3D) MR digital subtraction angiography (MRDSA) without contrast material, which is essentially 3D true steady-state free precession (SSFP) with selected inversion recovery (IR) pulse using multiple cardiac phase acquisitions with a short increment delay in the assessment of normal cranial arteries, as a feasibility study before clinical use. ⋯ Time-SLIP 3D MRDSA is a simple method for obtaining hemodynamic information. Although more MR sequence improvement is needed, it can play an important role in assessing cranial arteries without contrast material.
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J Magn Reson Imaging · Jul 2009
Automated assessment of whole-body adipose tissue depots from continuously moving bed MRI: a feasibility study.
To present an automated algorithm for segmentation of visceral, subcutaneous, and total volumes of adipose tissue depots (VAT, SAT, TAT) from whole-body MRI data sets and to investigate the VAT segmentation accuracy and the reproducibility of all depot assessments. ⋯ Automated and manual VAT results correlated strongly. The assessments of all depots were highly reproducible. The acquisition and postprocessing techniques presented are likely useful in obesity related studies.
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J Magn Reson Imaging · Jul 2009
Pilot study of improved lesion characterization in breast MRI using a 3D radial balanced SSFP technique with isotropic resolution and efficient fat-water separation.
To assess a 3D radial balanced steady-state free precession (SSFP) technique that provides submillimeter isotropic resolution and inherently registered fat and water image volumes in comparison to conventional T2-weighted RARE imaging for lesion characterization in breast magnetic resonance imaging (MRI). ⋯ 3DPR-SSFP has the potential to improve the lesion characterization information available in breast MRI, particularly in comparison to conventional FSE. A larger study is warranted to quantify the effect of 3DPR-SSFP on specificity.
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J Magn Reson Imaging · Jul 2009
Quantitative contrast-enhanced perfusion measurements of the human lung using the prebolus approach.
To investigate dynamic contrast-enhanced MRI (DCE-MRI) for quantification of pulmonary blood flow (PBF) and blood volume (PBV) using the prebolus approach and to compare the results to the global lung perfusion (GLP). ⋯ The prebolus approach enables independent determination of appropriate doses for AIF and tissue signal. Using this technique, the signal-to-noise ratio (SNR) from lung parenchyma can be increased, resulting in improved PBF and PBV quantification, which is especially useful for the generation of parameter maps.
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J Magn Reson Imaging · Jul 2009
SAR and power implications of different RF shimming strategies in the pelvis for 7T MRI.
To determine the best radiofrequency (RF) shimming method for 7 T body imaging that provides sufficient B(1)(+) excitation inside the target region while energy deposition (SAR) and power demands are as low as possible and that does not incorporate anatomy specific electric field information inside the patient models, as this information is not available in practice. ⋯ RF shimming can reduce the SAR and improve power efficiency in an accurate patient model without knowing the electric field. However, choosing the right method is critical to prevent unexpected behavior in local SAR deposition.