Controlled saturation magnetization transfer for reproducible multivendor variable flip angle T₁ and T₂ mapping.

Area of Science:

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

Background:

• Clinical application of quantitative MRI is limited by poor reproducibility across sites and vendors.
• Previous efforts focused on B1 mapping and spoiling conditions, but magnetization transfer effects were overlooked.

Purpose of the Study:

• To validate the hypothesis that magnetization transfer effects contribute to MRI variability.
• To demonstrate reproducible multivendor single-pool relaxometry using the controlled saturation magnetization transfer (CSMT) framework.

Main Methods:

• Acquired T1 and T2 estimation data from three healthy volunteers on scanners from three different vendors.
• Applied vendor default RF pulses, harmonized RF spoiling, and harmonized RF spoiling with CSMT pulses.
• Estimated cross-protocol, cross-vendor, and test/retest variability.

Main Results:

• Harmonized RF spoiling alone was insufficient for cross-vendor reproducibility.
• CSMT reduced cross-protocol variability from 18.3% to 4.0%.
• Whole-brain variability decreased from 19% to 4.5% across sites with CSMT.

Conclusions:

• Magnetization transfer effects are a significant source of variability in T1 and T2 estimation.
• CSMT effectively stabilizes these effects, enhancing reproducibility.
• CSMT facilitates the use of single-pool T1 and T2 for reliable clinical diagnosis across different MRI systems.