T1Effects in Sequential Dynamic Susceptibility Contrast Experiments

✍ Scribed by Jonathan M. Levin; Lawrence L. Wald; Marc J. Kaufman; Marjorie H. Ross; Luis C. Maas; Perry F. Renshaw

• Book ID: 102594570
• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 97 KB
• Volume: 130
• Category: Article
• ISSN: 1090-7807
• DOI: 10.1006/jmre.1997.1317

✦ Synopsis

Residual effects of an initial bolus of gadolinium contrast agent T 1 and T 2 weighing, distinguishing a residual susceptibility have been previously demonstrated in sequential dynamic suscepeffect from a T 1 effect is difficult. Yet, determining the etioltibility contrast MR experiments. While these residual effects ogy of such effects has important implications for activation quickly reach a saturation steady state, their etiology is uncertain, studies utilizing sequential DSC experiments. Not only does and they can lead to spurious estimates of hemodynamic paramethis lead to a better understanding of the DSC experiment, ters in activation experiments. The possible influence of T 1 effects but it aids in determining the best strategy for reducing the is now investigated with experiments in which T 1 weighting is influence of these residual effects, be it using a presaturation varied as well as with serial regional T 1 measurements. Little evidose or a data correction method after the fact.

dence for significant residual T 1 effects is found, suggesting instead

In order to investigate the influence of T 1 effects on these that susceptibility effects underlie these observations. An initial data, we have conducted a series of spin-echo EPI multibolus saturation dose of contrast agent minimizes this effect. ᭧ 1998 Academic Press DSC experiments under conditions with different T 1 Key Words: f MRI; contrast agents; susceptibility contrast; relaxweighting, by varying the flip angle (u) and the repetition ation time; cerebral blood volume.

time (TR). T 1 effects are proportional to the degree of T 1 weighting; therefore, reducing T 1 weighting should reduce these effects in the resulting images which are spin density and T 2 weighted. In addition, we have mapped brain T 1