PROBLEM TO BE SOLVED: To provide a water/fat separation technique in which is calculated with a higher degree of accuracy a phase image reflected with nonuniformity in static magnetic field in a 2-Point Dixon method, and which therefore prevents a water image from being exchanged with a fat image, thereby separating water and fat without placing a burden of determination on an operator.SOLUTION: The possibility is increased that a phase distribution showing phase changes due to nonuniformity in static magnetic field is calculated accurately. Further, water and fat are separated using signal values from which the effect of the nonuniformity in static magnetic field is eliminated. For implementation of this, start point candidates are determined so that in a calculation of the phase distribution, a pixel constituted mainly of a water signal is selected with a higher probability as the start point of phase unwrapping processing which uses a region expanding method. In addition, the correctness of the calculated phase distribution is determined with a high degree of accuracy, using the characteristics of the start point candidates.COPYRIGHT: (C)2014,JPO&INPIT【課題】2-Point Dixon法において、静磁場不均一が反映された位相画像を正しく算出する確度を高めることで、水画像と脂肪画像とが入れ替わることを防ぎ、操作者に判断する負担を負わせることなく、水と脂肪とを分離する技術を提供する。【解決手段】静磁場不均一に起因した位相変化である位相分布を、正しく算出する可能性を高める。そして、その影響を取り除いた信号値を用いて、水と脂肪とを分離する。これを実現するため、位相分布の算出において、領域拡大法を用いた位相アンラップ処理の開始点として、水信号が主となる画素が選択される確率が高まるよう、開始点候補を特定する。さらに、算出した位相分布の正誤を、開始点候補の特性を用いて高い確度で判別する。【選択図】 図3
