Hu Cheng1, John Kirsch2, Rebecca
Ward1, Thea Atwood1, Arian Ashourvan1, Yang
Wang3
1Indiana University, Bloomington, IN, United
States; 2Siemens Medical Solutions, United States; 3Indiana
University, Indianapolis, IN, United States
Temporal
characteristics of the noise in multi-run fMRI scans using GRAPPA are
examined with a gel phantom for acceleration factors 2-4 and various number
of ACS lines. It is demonstrated that the noise distribution can change
significantly from run to run. However, little change is observed from the
offline reconstruction if the same reference scans are used. The results
indicate that the variation is mainly caused by the noise fluctuation in the
reference scans.