Journal of magnetic resonance imaging : JMRI
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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.
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J Magn Reson Imaging · Jul 2009
Automatic glioma characterization from dynamic susceptibility contrast imaging: brain tumor segmentation using knowledge-based fuzzy clustering.
To assess whether glioma volumes from knowledge-based fuzzy c-means (FCM) clustering of multiple MR image classes can provide similar diagnostic efficacy values as manually defined tumor volumes when characterizing gliomas from dynamic susceptibility contrast (DSC) imaging. ⋯ Our results suggest that knowledge-based FCM clustering of multiple MR image classes provides a completely automatic, user-independent approach to selecting the target region for presurgical glioma characterization.
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J Magn Reson Imaging · Jul 2009
Multicenter StudyMulticenter validation of the magnetic resonance T2* technique for segmental and global quantification of myocardial iron.
To assess the transferability of the magnetic resonance imaging (MRI) multislice multiecho T2(*) technique for global and segmental measurement of iron overload in thalassemia patients. ⋯ The multislice multiecho T2(*) technique is transferable among scanners with good reproducibility.
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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
A diffusion tensor imaging group study of the spinal cord in multiple sclerosis patients with and without T2 spinal cord lesions.
To examine the T(2)-normal appearing spinal cord of patients with multiple sclerosis (MS) using diffusion tensor imaging. ⋯ Our results suggest that the spinal cord may still be affected by MS, even when lesions are not detected on a conventional MR scan. In addition, we demonstrated that diffusion tensor tractography is a robust tool to analyze the spinal cord of MS patients.