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

Area of Science:

• Medical Imaging
• Biophysics
• Radiology

Background:

• Abdominal effective transverse relaxation rate (R(2)*) mapping is essential for various clinical applications.
• Respiratory motion significantly degrades image quality and causes R(2)* overestimation in abdominal scans.
• Breath-holding techniques are often required but can be challenging for some patients.

Purpose of the Study:

• To investigate the feasibility of combining respiratory self-gating with a multiple gradient-recalled echo (MGRE) sequence for free-breathing abdominal R(2)* measurements.
• To assess the effectiveness of this technique in mitigating motion artifacts and ensuring quantitative accuracy.
• To evaluate the potential of this method as an alternative to breath-holding for abdominal R(2)* mapping.

Main Methods:

• Exploration of a novel approach integrating respiratory self-gating with an MGRE sequence.
• Application of the developed method in a cohort of eight healthy volunteers.
• Comparison of R(2)* measurements obtained during free-breathing with those acquired during breath-holding.

Main Results:

• Respiratory self-gated MGRE effectively eliminated motion artifacts in abdominal R(2)* mapping.
• Quantitative R(2)* measurements in the liver, spleen, and kidneys were comparable between free-breathing and breath-holding acquisitions.
• The technique demonstrated high feasibility and accuracy in normal volunteers.

Conclusions:

• Respiratory self-gated MGRE is a promising technique for accurate free-breathing abdominal R(2)* mapping.
• This method offers a viable solution for patients who cannot perform adequate breath-holds.
• The findings support the clinical utility of this approach for improving abdominal R(2)* measurements.