Magnetic resonance water-fat image separation method and apparatus, imaging system and storage medium

A magnetic resonance imaging (MRI) water-fat image separation apparatus, comprising:

• a data acquisition module configured to, within an echo period:
• acquire a first echo set corresponding to a Dixon water-fat separation calculation under a first readout gradient polarity, and acquire a second echo set corresponding to the Dixon water-fat separation calculation under a second readout gradient polarity, wherein the first readout gradient polarity and the second readout gradient polarity are opposite, echoes in the second echo set being located at positions that are positionally symmetric to echoes in the first echo set with respect to an echo center of the echo period;
• an image extraction module configured to:
• obtain a first echo image set based on first echo set data acquired in each echo period, and obtain a second echo image set based on second echo set data acquired in each echo period, wherein the first echo set and the second echo set each comprise:
• one nearly-in-phase echo meeting a set in-phase requirement and one nearly-out-of-phase echo meeting a set out-of-phase requirement, the Dixon water-fat separation calculation being a two-point Dixon water-fat separation calculation;
• or
• two nearly-in-phase echoes meeting a set in-phase requirement and one nearly-out-of-phase echo meeting a set out-of-phase requirement, the Dixon water-fat separation calculation being a three-point Dixon water-fat separation calculation;
• and
• a water-fat separation module configured to perform Dixon water-fat separation calculation, based on the first echo image set and the second echo image set, to obtain a water image and a fat image.

A magnetic resonance imaging (MRI) water-fat image separation method, comprising:

• within an echo period, acquiring a first echo set corresponding to a Dixon water-fat separation calculation under a first readout gradient polarity, and acquiring a second echo set corresponding to the Dixon water-fat separation calculation under a second readout gradient polarity, wherein the first readout gradient polarity and the second readout gradient polarity are opposite, echoes in the second echo set being located at positions that are positionally symmetric to echoes in the first echo set with respect to an echo center of the echo period;
• obtaining a first echo image set based on first echo set data acquired in each echo period;
• obtaining a second echo image set based on second echo set data acquired in each echo period;
• and
• performing a Dixon water-fat separation calculation, based on the first echo image set and the second echo image set, to obtain a water image and a fat image, wherein performing the Dixon water-fat separation calculation to obtain the water image and the fat image comprises:
• (i) separately subjecting each pair of echo images with symmetrical echo positions in the first echo image set and the second echo image set to phase difference correction, separately subjecting each pair of echo images resulting from phase difference correction to complex averaging to obtain a corresponding echo averaged image set, and using images in the echo averaged image set obtained to perform the Dixon water-fat separation calculation to obtain the water image and the fat image;
• or
• (ii) performing a Dixon water-fat separation calculation based on the first echo image set to obtain a first water image and a first fat image, performing a Dixon water-fat separation calculation based on the second echo image set to obtain a second water image and a second fat image, subjecting the first water image and the second water image to modulus averaging to obtain a water image, and subjecting the first fat image and the second fat image to modulus averaging to obtain a fat image.