Water-fat Separation for the knee on a 50 mT Portable MRI Scanner

Motivation: Bright fat signals in MR images can obscure the underlying details and affect the physician's diagnosis. Especially in ultra-low-field MRI (B0 < 100 mT), lower SNR images are more important to discern fat and water signals. Goal(s): This study aims to achieve effective water-fat separation using the Dixon method at a 50 mT MR scanner. Approach: R2* effect and priori information have been added to the existing two-point Dixon method. Results: The images obtained on the 50 mT MRI scanner can clearly distinguish cartilage, muscle and fat compared to the water-fat separation images obtained on the 3T MRI scanner. Impact: Phase errors in the acquired MR images were significantly reduced after using priori phantom phase images. This work demonstrates the successful application of the Dixon method to ULF MRI. Future studies will focus on reducing imaging time.