Nikolaus
Weiskopf1, Antoine Lutti1, Gunther Helms2,
John Ashburner1, Chloe Hutton1
1Wellcome Trust Centre for
Neuroimaging, UCL Institute of Neurology, University College London, London,
United Kingdom; 2MR-Research in Neurology and Psychiatry,
University Medical Center, Gttingen, Germany
Quantitative
T1 mapping based on variable flip angle acquisitions requires precise
knowledge of the local flip angle and is therefore usually combined with RF
transmit mapping methods. RF transmit mapping is not readily available and
requires extra scan time. We propose a method to correct for RF
inhomogeneities that does not require measured RF maps. The method uses the
unified segmentation and bias correction approach implemented in SPM8 to
simultaneously estimate and correct for the RF inhomogeneities from the T1
maps. The model-based approach is shown to reduce the bias in T1 maps by more
than 50%.