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Background: To evaluate the reliability of MRE using a spin-echo echo-planar imaging (SE-EPI) renal MRE technique in healthy volunteers., Methods: Institutional review board approved prospective study in which all participants provided written informed consent. Sixteen healthy volunteers comprising seven males and nine females with a median age of 35 years (age range: 23 to 59 years) were included. Coronal 90 Hz and 60 Hz MRE acquisitions were performed twice within a 30-min interval between examinations. Renal MRE reliability was assessed by (i) test-retest repeatability, and (ii) inter-rater agreement between two independent readers. The MRE-measured averaged renal stiffness values were evaluated using: intraclass correlation coefficient (ICC), Bland-Altman and the within-subject coefficient of variation (COV)., Results: For test-retest repeatability, Bland-Altman showed a mean stiffness difference between examinations of 0.07 kPa (95% limits of agreement: -1.41, 1.54) at 90 Hz and 0.01 kPa (95% limits of agreement: -0.51, 0.53) at 60 Hz. Coefficient of repeatability was 1.47 kPa and 0.52 kPa at 90 Hz and 60 Hz, respectively. The within-subject COV was 13.6% and 7.7% at 90 Hz and 60 Hz, respectively. ICC values were 0.922 and 0.907 for test-retest repeatability and 0.998 and 0.989 for inter-rater agreement, respectively (P < 0.001)., Conclusion: SE-EPI renal MRE is a reliable technique., (© 2014 Wiley Periodicals, Inc.)

Purpose: To assess the repeatability of measurement of lactate and other metabolites in tumors using magnetic resonance spectroscopy (MRS)., Materials and Methods: MRS with spectral editing for lactate was performed on 10 patients with astrocytoma (two Grade III, eight Grade IV) using an 8-channel receive coil at 3T. Lactate, lipid, choline, creatine, and N-acetyl aspartate (NAA) signals were measured in regions of tumor and contralateral white matter. Metabolites were quantified relative to unsuppressed water using LCModel fitting software., Results: The within-patient coefficients of variation were ≈16% (tumor lactate), 6%-8% (tumor choline and contralateral choline, creatine, and NAA), and 22% (tumor lipid). As expected due to their low concentration in normal tissue, lactate and lipid were not reliably detected in white matter but were found at high levels in most tumors. NAA and creatine were lower in tumors than in normal white matter, and choline varied between above- and below-normal values. No consistent short-term variation in metabolite levels was observed, despite differences in the time elapsed since administration of contrast agent., Conclusion: MRS appears repeatable enough to provide longitudinal measures of metabolite content in tumors and contralateral tissue in the brain in vivo., (Copyright © 2012 Wiley Periodicals, Inc.)

Purpose: To compare water and a polyethylene glycol (PEG) preparation as potential oral contrast media for magnetic resonance imaging (MRI) of the small bowel., Materials and Methods: Twenty-two healthy volunteers underwent separate MRI examinations after drinking up to two liters of water or PEG preparation. Small bowel images were obtained every 10 minutes for at least two hours using breath-hold single shot half-Fourier imaging, including both thick section projection and thin section images. Examinations were evaluated by two radiologists in consensus, blinded to the volunteer and contrast details, for arrival at the terminal ileum, transit time, and demonstration of small bowel segments., Results: The PEG preparation was significantly better than water at reaching the terminal ileum (PEG 21/22 volunteers [95.45%], water 14/22 volunteers [63.6%], P = 0.04). There was no significant difference in the mean transit time (water 51 +/- 48 minutes, PEG 37.7 +/- 22 minutes) or in the demonstration of the stomach, duodenum, and jejunum, but the PEG preparation was significantly better at demonstrating the ileum (P = 0.005) and terminal ileum (P = 0.002)., Conclusion: A PEG preparation is significantly better than water as an oral contrast medium for demonstrating the distal small bowel during breath-hold T2-weighted MRI., (Copyright 2002 Wiley-Liss, Inc.)