Minimizing Slice Profile Effects in T1W Perfusion Imaging
Mikkelsen I, Starck G, Ljungberg M, Sidaros K, Widmark M
T1 perfusion measurements during bolus passage may be performed using saturation-recovery TurboFLASH with a small flip angle, &[alpha]. The repeated use of &[alpha] with imperfect slice profile generates imperfect signal profiles. Using the sequence in baseline T1-measurement provides estimates of T1, and also M0 and &[alpha], which are fixed during the boluspassage. We show that fixating &[alpha] on the nominal value during parameter estimation may cause severe underestimation of T1 leading to erroneous perfusion estimates. If, however, &[alpha] is allowed to vary, T1 is accurately estimated. Based on this, a procedure for estimating T1 at realistic noise levels is proposed.