T-1 EFFECTS IN SEQUENTIAL DYNAMIC SUSCEPTIBILITY CONTRAST EXPERIMENTS

Residual effects of an initial bolus of gadolinium contrast agent have been previously demonstrated in sequential dynamic susceptibility con trast MR experiments. While these residual effects quickly reach a sat uration steady state, their etiology is uncertain, and they can lead t o spurious estimates of hemodynamic parameters in activation experimen ts. The possible influence of T-1 effects is now investigated with exp eriments in which T-1 weighting is varied as well as with serial regio nal T-1 measurements. Little evidence for significant residual T-1 eff ects is found, suggesting instead that susceptibility effects underlie these observations. An initial saturation dose of contrast agent mini mizes this effect. (C) 1998 Academic Press.