Potential Pitfalls of Including Reference Data in Parallel Imaging Reconstructions at High Acceleration
Griswold M, Huo D, Wilson D, Blaimer M
Case Western Reserve University
In GRAPPA, the ACS (Auto Calibration Signal) lines are used to determine coil-weighting factors and can be included directly in the. Park et al. proposed shifting the calibration region to higher frequency in the PE direction. This modification can improve overall image quality, but at high acceleration factors, it can create shading and blurring of the image. Adding center reference data can reduce these artifacts, but the residual artifact is still a big issue in clinical applications requiring fine details. One should be careful when incorporating reference data in a GRAPPA reconstruction, in particular at high acceleration factors.