MAGNETIC RESONANCE IMAGING APPARATUS

PROBLEM TO BE SOLVED: To realize a magnetic resonance imaging apparatus for determining a proper unwrap start point even in such a case that the non-uniformity of a static magnetic field is large and obtaining the non-uniform distribution chart of the static magnetic field free from offset. SOLUTION: The phase difference image 602 of mutual image data S1 and S2 is obtained from two different echo times TE1 and TE2. Positions where the non-uniformity value of the static magnetic field of the phase difference image 602 becomes zero are detected. A position where the phase of the image data S1 and that of the image data S2 together become zero is searched and the position where the phase of the image data S1 and that of the image data S2 together become zero among the positions where the non-uniformity value of the static magnetic field of the phase difference image 602 becomes zero is set to an unwrap processing start point. By this constitution, even in such a case that the non-uniformity of the static magnetic field is large, a proper unwrap start point is determined and the non-uniform distribution chart of the static magnetic field free from offset can be obtained.