k-space off center and zero values

[Phillistan16]

Hi Dr. Lyu and Team,

Thank you for your efforts in releasing this valuable dataset.

I loaded the dataset with the suggested approach from M4Raw_tutorial.ipynb, and noticed the k-space center (location with largest absolute value) does not lie on the center of the matrix [128,128]. Instead, for T1 images they consistently appear near [136, 128], and for T2 and FLAIR images they appear near [125,128]. In addition, some k-space values within the readout were zero. Attached is a visualization of the log(abs(kspace)), note that zero values also appear white because they equal to -Inf.

I'm wondering if these were on purpose or if I loaded the dataset incorrectly. I appreciate your time looking into this!