Motion artifacts in quantitative magnetic resonance imaging.

Several investigators have emphasized the potential value of quantitative relaxation times in the assessment of diseases. In performing such measurements using the spin-echo technique, we have encountered several anomalous results, whereby the intensity of the organ parenchyma on second-echo images is greater than on first echo images. This is most likely a result of respiratory motion, and it occurs only rarely. Several volunteers were studied before and after exercise to see if respiratory motion could reproduce the anomalous intensity reverse; a reversal of intensities in renal parenchyma was observed in two of five individuals. We conclude that respiratory motion artifacts will seriously limit quantitative magnetic resonance imaging of the upper abdomen if respiratory gating during imaging is not used.