  Purpose: To implement and evaluate a sequential approach to obtain
semi-quantitative T1-weighted MPRAGE images, unbiased by B1 inhomogeneities at
7T.
  Methods: In the reference gradient echo used for normalization of the MPRAGE
image, flip angle (aGE) and acquisition voxel size (Vref) was varied to
optimize tissue contrast and acquisition time (Tacq). The finalized protocol
was implemented at three different resolutions and the reproducibility was
evaluated. Maps of T1 were derived based on the normalized MPRAGE through
forward signal modelling.
  Results: A good compromise between tissue contrast and SNR was reached at
aGE=3{\deg}. A reduction of the reference GE Tacq by a factor of 4, at the cost
of negligible bias, was obtained by increasing Vref with a factor of 8 relative
the MPRAGE resolution. The coefficient-of-variation in segmented WM was 9+/-5%
after normalization, compared to 24+/-12% before. The T1 maps showed no obvious
bias and had reasonable values with regard to literature, especially after
optional B1 correction through separate flip angle mapping.
  Conclusion: A non-interleaved acquisition for normalization of MPRAGE offers
a simple alternative to MP2RAGE to obtain semi-quantitative purely T1-weighted
images. These images can be converted to T1 maps analogously to the established
MP2RAGE approach. Scan time can be reduced by increasing Vref which has a
miniscule effect on image quality.
