Magnetic resonance imaging apparatus, and an image processing method

PROBLEM TO BE SOLVED: To provide a method of calculating a higher-SNR local frequency distribution in a shorter calculation time when a local magnetic field distribution resulting from magnetic susceptibility differences between living tissues is calculated using MRI.SOLUTION: Multiecho complex images measured at at least two or more different echo times using MRI are converted into low-resolution images. Global frequency distribution resulting from global magnetic field changes and offset phase distribution including reception and transmission phases are separated from a phase distribution of a low-resolution multiecho complex image. The calculated global frequency distribution and offset phase distribution are provided with higher resolution. A local frequency distribution of each echo is calculated from the measured multiecho complex image, high-resolution global frequency distribution, and high-resolution offset phase distribution. The local frequency distributions of the echoes are averaged on a weighted basis to calculate the final local frequency distribution.SELECTED DRAWING: Figure 6