MR relaxometry on a whole-body imager: Quality control

Long-term monitoring of the average proton relaxation time T-2 of phantoms measured on a Siemens MR whole-body imager showed very good repeatability a nd reproducibility. The repeatability (short-term precision) and reproducib ility (long-term precision) of the average values of a relaxation time T-2 congruent to 81 ms, obtained by a standard 16-echo CPMG pulse sequence, wer e 2.6% and 9.7%, respectively. The Siemens Vision imager proved to be a sui table tool for T-2 evaluation in vivo. Quality control was performed using the techniques of control diagrams developed by Shewhart, which proved to b e an appropriate method for continuous quality control of relaxation time d etermination. (C) 1999 Elsevier Science Inc.