Respiratory self-gated multiple gradient recalled echo sequence for free-breathing abdominal R₂* mapping

Abdominal effective transverse relaxation rate (R₂*) mapping is critical for a wide range of applications. However, respiratory motion can lead to significant image quality deterioration and R ₂* overestimation. For this work, we explored the feasibility of combining respiratory self-gating techniques with a multiple gradient-recalled echo sequence for free-breathing abdominal R ₂* measurements. In a series of eight normal volunteers, respiratory self-gated-multiple gradient-recalled echo methods effectively avoided motion artifacts to produce quantitative R₂* measurements in liver, spleen, and kidneys that were comparable to R ₂* measurements produced while breath-holding. Respiratory self-gated-multiple gradient-recalled echo methods demonstrated the potential to avoid the need for breath-holding during abdominal R₂* mapping. For clinical application, respiratory self-gated-multiple gradient-recalled echo approaches could be particularly useful for R ₂* measurements in those patients unable or unwilling to sustain sufficiently long breath-holds to avoid motion artifacts. Magn Reson Med, 2011. © 2011 Wiley-Liss, Inc.