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Evaluations of magnetic resonance imaging parameters with simple phantoms
Author(s) -
Brateman Libby,
Jennings Linda W.,
Nunnally Ray L.,
Vaughan J. Thomas
Publication year - 1986
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.595894
Subject(s) - magnetic resonance imaging , reproducibility , point spread function , imaging phantom , physics , nuclear magnetic resonance , medical imaging , spin echo , optics , computational physics , computer science , mathematics , artificial intelligence , radiology , statistics , medicine
Imaging parameters associated with a clinical magnetic resonance imaging (MRI) system, evaluated with the use of simple and inexpensive phantoms, are described in evaluation of a clinical MRI system. Images, obtained with a Diasonics 0.35‐T MRI system using an elliptical whole‐body radio frequency coil, are presented which demonstrate geometric distortion, inaccuracy of image dimensions, and artifacts. Measurements of reproducibility and uniformity of both signal intensity and spin‐lattice relaxation times are presented for uniform phantoms. Replicate measurements are analyzed by two‐way analyses of variance to determine the significance of variations as a function of position and slice. Apparent T 1 's are not significantly different among the slices for the images analyzed, but there is a significant effect due to position in the field. Direct measurement of the radio frequency field for the center slice follows a pattern which is similar. Spin‐lattice relaxation times are compared among two‐point calculations and nonlinear four‐point calculations, and the effects of pooling data are found to increase the precision of T 1 measurements.