RT Journal Article SR Electronic T1 Reproducibilty of Magnetization Transfer Ratio Histogram–Derived Measures of the Brainin Healthy Volunteers JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology SP 133 OP 136 VO 21 IS 1 A1 Maria P. Sormani A1 Giuseppe Iannucci A1 Maria A. Rocca A1 Giovanna Mastronardo A1 Mara Cercignani A1 Luca Minicucci A1 Massimo Filippi YR 2000 UL http://www.ajnr.org/content/21/1/133.abstract AB Summary: Using two MR scanners, we evaluated the intraobserver, interobserver, image-reimage, and interimager variabilities in the assessment of magnetization transfer ratio (MTR) histograms obtained monthly on four occasions from five healthy volunteers. With multiple observers, the mean coefficients of variations ranged from 2.2% to 8.2% for “pure” image-reimage variability, from 1.2% to 4.9% for interobserver variability, and from 2.1% to 4.9% for image-reimage variability. The mean intraobserver coefficients of variations were always lower than 1%. The mean coefficients of variations ranged from 10.2% to 14.6% for pure interimager variability and from 8.6% to 14.3% for interimager variability with multiple observers. Interimager variability accounted for 96.0% of the overall variability of average MTR, for 96.7% of peak location, and for 41.1% of the peak height. The use of different MR scanners is the main source of variability when obtaining MTR histograms.