Radiology, Vol 153, 473-478, Copyright © 1984 by Radiological Society of North America
Magnetic resonance imaging systems: optimization in clinical use
JB Kneeland, RJ Knowles and PT Cahill
Magnetic resonance (MR) imaging confronts the user with a large number of
options that can critically affect image quality. Among the most important
parameters over which the user may exercise control are receiver frequency,
tip angles, imaging and compensatory gradient strengths, the number of
signals averaged, the number of phase encoding gradient steps, and the
repetition times. All of these parameters were systematically varied and
optimal values determined for a 0.5T Teslacon system, a task which employed
both phantoms and normal volunteers. Under the normal conditions of tuning,
the z-compensatory gradient presents the most critical adjustment. The
compromise between image quality and time of study was also carefully
examined, with the following determined as best: 192 gradient steps plus
two signal averages for the head coil, or 192 gradient steps plus four
signal averages for the body coil.
