Water and fat separation in real-time MRI of joint movement with phase-sensitive bSSFP

Magn Reson Med. 2017 Jul;78(1):58-68. doi: 10.1002/mrm.26341. Epub 2016 Jul 15.


Purpose: To introduce a method for obtaining fat-suppressed images in real-time MRI of moving joints at 3 Tesla (T) using a bSSFP sequence with phase detection to enhance visualization of soft tissue structures during motion.

Methods: The wrist and knee of nine volunteers were imaged with a real-time bSSFP sequence while performing dynamic tasks. For appropriate choice of sequence timing parameters, water and fat pixels showed an out-of-phase behavior, which was exploited to reconstruct water and fat images. Additionally, a 2-point Dixon sequence was used for dynamic imaging of the joints, and resulting water and fat images were compared with our proposed method.

Results: The joints could be visualized with good water-fat separation and signal-to-noise ratio (SNR), while maintaining a relatively high temporal resolution (5 fps in knee imaging and 10 fps in wrist imaging). The proposed method produced images of moving joints with higher SNR and higher image quality when compared with the Dixon method.

Conclusions: Water-fat separation is feasible in real-time MRI of moving knee and wrist at 3 T. PS-bSSFP offers movies with higher SNR and higher diagnostic quality when compared with Dixon scans. Magn Reson Med 78:58-68, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Keywords: bSSFP; knee MRI; real-time MRI; water-fat separation; wrist MRI.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / diagnostic imaging*
  • Body Water / diagnostic imaging*
  • Computer Systems
  • Female
  • Humans
  • Image Enhancement / methods
  • Image Interpretation, Computer-Assisted / methods
  • Joints / diagnostic imaging*
  • Joints / physiology*
  • Magnetic Resonance Imaging / methods*
  • Male
  • Range of Motion, Articular / physiology*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Signal Processing, Computer-Assisted*
  • Subtraction Technique
  • Young Adult