To develop a method for T1 mapping at high spatial resolution and for multiple slices.
The proposed method emerges as a single-shot inversion-recovery experiment which covers the entire spinlattice
relaxation process by serial acquisitions of highly undersampled radial FLASH images, either in single-slice or
multi-slice mode. Serial image reconstructions are performed in time-reversed order and first involve regularized nonlinear
inversion (NLINV) to estimate optimum coil sensitivity profiles. Subsequently, the coil profiles are fixed for the calculation
of differently T1-weighted frames and the resulting linear inverse problem is solved by a conjugate gradient (CG)
technique. T1 values are obtained by pixelwise fitting with a Deichmann correction modified for multi-slice applications.
T1 accuracy was validated for a reference phantom. For human brain, T1 maps were obtained at 0.5 mm resolution
for single-slice acquisitions and at 0.75 mm resolution for up to 5 simultaneous slices (5 mm thickness). Corresponding
T1 maps of the liver were acquired at 1 mm and 1.5 mm resolution, respectively. All T1 values were in agreement
with literature data.
Inversion-recovery sequences with highly undersampled radial FLASH images and NLINV/CG reconstruction
allow for fast, robust and accurate T1 mapping at high spatial resolution and for multiple slices.