Initial Experience on Hyperpolarized [1-¹³C]Pyruvate MRI Multicenter Reproducibility-Are Multicenter Trials Feasible?

Area of Science:

• Medical Imaging
• Metabolic Imaging
• Neuroimaging

Background:

• Hyperpolarized [1-¹³C]pyruvate MRI enables in vivo metabolic imaging.
• Comparability of hyperpolarized MRI across sites and protocols is currently unknown.

Purpose of the Study:

• Assess the agreement of hyperpolarized MRI between different sites and imaging protocols.
• Evaluate the repeatability of metabolic measurements in healthy volunteers.

Main Methods:

• Three healthy volunteers underwent repeated multicenter brain MRI using hyperpolarized [1-¹³C]pyruvate.
• Compared multisite agreement using identical and variable resolution echo-planar imaging protocols.
• Calculated metabolic conversion metrics (k_PL, lactate Z-score, lactate-to-pyruvate ratio) and assessed repeatability using intraclass correlation coefficients (ICC).

Main Results:

• The mean k_PL was 0.024 ± 0.0016 s^-1.
• Intraclass correlation coefficients (ICC) for k_PL were 0.83 between sites and 0.7 between examinations.
• Model-free metrics showed variable agreement, with lactate Z-score having similar ICC to k_PL, while lactate-to-pyruvate ratio had lower ICC.

Conclusions:

• Model-based metrics like k_PL demonstrate good agreement across sites and examinations for hyperpolarized [1-¹³C]pyruvate MRI.
• Results support the harmonization of protocols for multicenter studies.
• Findings inform the design of future multicenter clinical trials using this metabolic imaging technique.