T₁ mapping performance and measurement repeatability: results from the multi-national T₁ mapping standardization...

Area of Science:

• Magnetic Resonance Imaging
• Medical Physics
• Quality Assurance

Background:

• The T1MES (T1 Mapping and Extracellular volume Standardization) program utilized a CE/FDA-cleared phantom for T1 mapping quality assurance.
• This study aimed to assess T1 measurement repeatability across different centers, evaluating sequence, magnet, and vendor performance.

Purpose of the Study:

• To evaluate the repeatability of T1 mapping measurements across multiple centers using a standardized phantom.
• To identify factors influencing T1 measurement variability, including field strength, scanner type, and sequence parameters.

Main Methods:

• Utilized batch-manufactured phantoms over two years for structural imaging, B0 and B1 testing, and reference T1 measurements.
• Assessed center-specific T1 mapping repeatability on 1.5T and 3T magnets using various T1 mapping sequences over extended periods.
• Analyzed image and temperature data, evaluating repeatability using coefficient of variation (CoV) and constructing linear mixed models.

Main Results:

• Phantom integrity and reference T1 values remained stable over two years.
• T1 measurements showed temperature dependency, with varying effects based on field strength and sequence.
• High repeatability (mean CoV < 1-2%) was observed for many sequences/magnets, with narrower ranges for 1.5T compared to 3T.
• T1 mapping sequence and scanner software version were significant factors influencing T1 variation across centers.

Conclusions:

• The T1MES phantom is a reliable tool for multi-center T1 mapping quality assurance.
• While performance differences exist across field strengths, sequences, and manufacturers, specific combinations demonstrate high repeatability.
• Standardized T1 assessment for clinical use is feasible with certain scanner/sequence combinations, though temperature correction is necessary.