Correction of phase errors in quantitative water-fat imaging using a monopolar time-interleaved multi-echo gradient...

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Physics
• Quantitative Imaging

Background:

• Accurate quantification of proton density fat fraction (PDFF) is crucial for diagnosing and monitoring various medical conditions.
• Existing water-fat imaging techniques can be susceptible to phase errors, compromising PDFF measurement accuracy.
• Time-interleaved multi-echo gradient echo sequences are sensitive to phase inconsistencies between echo trains.

Purpose of the Study:

• To develop and validate a phase error correction scheme for monopolar time-interleaved multi-echo gradient echo water-fat imaging.
• To enable accurate and robust complex-based quantification of PDFF.

Main Methods:

• A three-step phase correction strategy was proposed to address echo misalignments, concomitant gradient fields, and inter-echo train phase offsets.
• Simulations were used to evaluate PDFF bias from concomitant gradients and phase offset estimation.
• Phantom experiments and in vivo imaging (liver, thigh) were conducted to assess the correction scheme's impact on PDFF accuracy and robustness.

Main Results:

• Simulations, phantom, and in vivo results confirmed echo time-dependent PDFF bias caused by phase errors.
• The proposed phase correction scheme effectively mitigated these biases.
• Accurate PDFF estimation was achieved regardless of the echo time combinations used.

Conclusions:

• The developed phase error correction scheme significantly enhances the accuracy and robustness of complex-based time-interleaved water-fat imaging.
• This method provides reliable PDFF measurements, advancing quantitative MRI applications.