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- In GeneRalized Autocalibrating Partially Parallel Acquisitions (GRAPPA), extra Nyquist-sampled k-space lines are acquired during the parallel imaging scan and are used to calculate the weighting factors that determine the missing k-space data.
- As in Figure 2, a GRAPPA weights is firstly estimated using the full-sampled ACS lines. According to the translation invariance property of the weighting matrix, we can compute the missing data using GRAPPA weights.
graph LR
Full[Fully-sampled k-space]
Full --> Sub["Sub-sampled k-space"]
Sub --> GRAPPA["GRAPPA reconstruction"]
GRAPPA --> Comb["Channel combination"]
Comb --> Final["Final image"]
Figure 3. Flow chart of GRAPPA reconstruction
- The program execution begins and ends in file
project2.m
. Functiongrappa_2d.m
realizes the GRAPPA algorithm.