Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Apr 2006
Upper cervical cord area in early relapsing-remitting multiple sclerosis: cross-sectional study of factors influencing cord size.
To determine whether the upper cervical cord area (UCCA) is influenced by disease effect in early relapsing-remitting multiple sclerosis (MS), using statistical modeling to account for potential covariates. ⋯ Atrophy of the upper cervical cord is not readily apparent in most patients early in the course of relapsing-remitting MS. In evaluations of disease-related changes in the UCCA in cross-sectional studies, TICV and gender should be considered as potentially confounding covariates.
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J Magn Reson Imaging · Apr 2006
Focal liver lesions: breathhold gradient- and spin-echo T2-weighted imaging for detection and characterization.
To evaluate breathhold gradient- and spin-echo (GRASE) T2-weighted imaging for the detection and characterization of focal liver lesions. ⋯ T2-weighted breathhold GRASE has the potential to provide faster liver imaging.
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J Magn Reson Imaging · Apr 2006
EPI distortion correction from a simultaneously acquired distortion map using TRAIL.
To develop a method for shot-by-shot distortion correction of single-shot echo-planar imaging (EPI) that is capable of correcting each image individually using a distortion measurement performed during acquisition of the image itself. ⋯ Shot-by-shot distortion correction may be performed for EPI images acquired using an extension of the TRAIL technique, ensuring that the correction reflects the actual distortion pattern and not merely a previously measured, but possibly no longer valid, distortion field. This avoids errors due to changes in the distortion field or misregistration of a previously measured distortion map resulting from subject motion.
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J Magn Reson Imaging · Apr 2006
Effect of contrast enhancement on the measurement of carotid arterial lumen and wall volume using MRI.
To investigate whether gadolinium (Gd)-based contrast enhancement (CE) affects high-resolution magnetic resonance imaging (MRI) measurements of carotid arterial wall volume. ⋯ Gd CE causes a significant increase in the apparent volume of the carotid wall throughout multiple carotid artery locations, which may be associated with improved visibility or neovascularization.
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J Magn Reson Imaging · Apr 2006
Calculation of cerebral perfusion parameters using regional arterial input functions identified by factor analysis.
To calculate regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and regional mean transit time (rMTT) accurately, an arterial input function (AIF) is required. In this study we identified a number of AIFs using factor analysis of dynamic studies (FADS), and performed the cerebral perfusion calculation pixel by pixel using the AIF that was located geometrically closest to a certain voxel. ⋯ This study indicates that the use of FADS and the nearest-AIF method is preferable to manual selection of one single AIF.