M4Raw: A multi-contrast, multi-repetition, multi-channel MRI k-space dataset for low-field MRI research [V1.5]

V1.5 release notes: T1-w Gradient echo (GRE) data for all 183 subjects are released. Note that the phase encoding direction for GRE data is in the AP direction, different from other contrasts. These GRE data were not checked for motions. A few incorrect records of patient_id were corrected in the H5 files. Scans 2022062708 and 2022062709 were removed due to duplication. Two new scans were added to replace them. V1.1 release notes: Please refer to https://www.nature.com/articles/s41597-023-02181-4 for details.