| 主权项 |
1. A method for acquiring magnetic resonance (MR) data comprising:
from a processor, operating an MR data acquisition scanner to execute an MR data acquisition pulse sequence to read out raw MR data from a subject, and to enter the raw MR data into a memory as k-space data; from said processor, operating said MR data acquisition scanner in said data acquisition pulse sequence to read out said raw MR data by actuating, in each of three orthogonal directions of a Cartesian coordinate system, a readout gradient magnetic field that comprises a first gradient portion in which a magnitude of said gradient magnetic field changes with respect to time followed by a second portion in which said magnitude of said gradient magnetic field is constant, and entering said raw MR data into said memory as said k-space data with respect to axes in said memory respectively corresponding to said orthogonal directions, along respective actual trajectories that fill actual data entry locations in said memory with said MR raw data; in said processor, dividing said data entry locations in said memory into a central region of said axes, filled with said raw MR data read out during said first portion of each readout gradient magnetic field, and a peripheral region of said axes, filled with said raw MR data read out during said second portion of each readout gradient magnetic field; in said processor, automatically calculating, for each of said actual trajectories, a deviation of said data entry locations only in said peripheral region from respective filling locations along predetermined ideal trajectories for filling said memory and, from said deviation, automatically calculating a delay time for activating said readout gradient magnetic fields, relative to respective times at which said readout gradient magnetic fields were activated in said MR data acquisition pulse sequence, that will conform each actual trajectory in said peripheral region to each ideal trajectory; from said processor, operating said MR data acquisition scanner to acquire further raw MR data with said readout gradient magnetic fields respectively activated with the calculated delay times, and thereby obtaining acquired corrected k-space data only in said peripheral region of said memory and re-acquired MR raw data in said central region of said memory; in said processor, executing a correction calculation algorithm only for said re-acquired raw MR data in said central region of said memory, thereby obtaining calculated corrected k-space data; and making said acquired corrected k-space data and said calculated corrected k-space data available from said processor in electronic form as a datafile. |
