Rebecca Ramb1,
Christian Binter2, Felix A. Breuer3, Gerrit Schultz1,
Maxim Zaitsev1, Sebastian Kozerke2, 4, Bernd
Jung1
1Dept.
of Radiology, Medical Physics, University Medical Center, Freiburg, Germany; 2Institute
for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 3MRB
Research Center, Wrzburg, Germany; 4Imaging Sciences and
Biomedical Engineering, King's College London, London, United Kingdom
The goal of this work is the analytical quantification of the noise enhancement in k-t-GRAPPA reconstructions from time-resolved k-t-accelerated acquisitions. Image reconstruction in x-f-space by transforming the three-dimensional convolution kernel is explained, the g-factor with respect to temporal frequencies is introduced and the method is validated in in-vivo-data by statistical noise estimation using the pseudo-replica method. In k-t-reconstruction temporal filtering is observed. The g-factor quantification in x-f-space for k-t-GRAPPA further reflects this and thus constitutes a measure for noise enhancement as well as the amount of temporal filtering introduced in the reconstruction process.