Novel spin-lock time sampling strategies for improved reproducibility in quantitative T1ρ mapping

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Quantitative Imaging
• Biomedical Engineering

Background:

• Quantitative T1ρ mapping is essential for assessing tissue properties.
• Reproducibility in T1ρ measurements is critical for reliable clinical applications.
• Existing spin-lock time (TSL) sampling schemes may limit measurement accuracy.

Purpose of the Study:

• To develop and evaluate novel TSL sampling schemes for enhanced reproducibility in quantitative T1ρ mapping.
• To compare the performance of new schemes against existing methods under various conditions.

Main Methods:

• Proposed reproducibility-guided random sampling (RRS) and reproducibility-guided optimal sampling (ROS) schemes.
• Evaluated schemes using numerical simulations, phantom experiments, and volunteer studies.
• Assessed reproducibility via coefficient of variation (CoV) and investigated effects of field inhomogeneities.

Main Results:

• RRS and ROS demonstrated significantly lower mean CoVs compared to linear sampling (LS) and precision-guided sampling (PS) in simulations and phantom studies.
• Proposed schemes showed improved reproducibility under B1 field inhomogeneity (20% offset) and B0 field inhomogeneity (>50 Hz).
• Volunteer studies confirmed lower CoVs for RRS and ROS in thigh muscles.

Conclusions:

• The proposed RRS and ROS sampling schemes enhance the reproducibility of quantitative T1ρ mapping.
• Optimized TSL selection leads to more reliable measurements, beneficial for longitudinal studies tracking disease progression and treatment response.