Accuracy and reproducibility of image derived relaxation times on a clinical 1.5 T magnetic resonance scanner

A methodology for evaluating the accuracy and reproducibility of calculated T1's and T2's has been developed and applied to a General Electric 1.5 T Signa System. Specifically studied were absolute accuracy and temporal stability of image derived T1's and T2's as well as the dependence of calculated relaxation times on position in the scan plane, position along the axis of the magnet bore, the scan plane orientation (axial, sagittal, coronal), and the center frequency. The results of this study of the accuracy and reproducibility of image relaxation times have direct bearing on the design of clinical investigations assessing the diagnostic usefulness of these values.