Quantification of breathing-induced B0 field variations along the human spinal cord at 3T

Motivation: Breathing-induced B0 field variations cause artefacts in spinal cord MRI. Characterizing the variations is useful for optimizing correction strategies, but has not yet been done below the thoracic region. Goal(s): To quantify breathing-induced fields in the cervical, thoracic, and lumbar spinal cord, and to investigate their effect on image quality in multi-echo GRE. Approach: Field measurements were obtained from navigator projection lines in 2D slices, and were quantified by taking their standard deviation over time. Results: Breathing-induced field variations were detected in every subject, with a similar profile across vertebral levels. Levels with more intense field variations showed higher artifact load. Impact: Breathing-induced B0 fields impact image quality and exhibit a consistent pattern of variation along the spinal cord that is highly similar between subjects. Characterizing these variations lays the foundation for future optimized corrections to achieve consistently high image quality.