Respiratory self-gated multiple gradient recalled echo sequence for free-breathing abdominal R 2 * mapping

Abdominal R2* mapping is critical for a wide range of applications. However, respiratory motion can lead to significant image quality deterioration and R2* overestimation. For this work, we explored the feasibility of combining respiratory self-gating (RSG) techniques with a multiple gradient-recalled echo (MGRE) sequence for free-breathing (FB) abdominal R2* measurements. In a series of 8 normal volunteers, RSG-MGRE methods effectively avoided motion artifacts to produce quantitative R2* measurements in the liver, spleen, and kidneys that were comparable to R2* measurements produced while breath-holding. RSG-MGRE methods demonstrated the potential to avoid the need for breath-holding during abdominal R2* mapping. For clinical application, RSG-MGRE approaches could be particularly useful for R2* measurements in those patients unable or unwilling to sustain sufficiently long breath-holds to avoid motion artifacts.