Reproducibility of T1 relaxation times in diagnostic MRI: A phantom study

Abstract

T1 mapping is crucial for many quantitative magnetic resonance imaging (MRI) procedures. However, studies have reported wide T1 variations, both in vivo and in vitro. Since clinical decisions depend on T1 relaxation times, evaluating the factors affecting their reproducibility is necessary. Available studies are limited in that they do not provide a comparative perspective on the variation of T1 relaxation times as a function of relevant parameters, such as pulse sequence type, magnetic field strength and how their interplay with the scanner model affects the resulting T1 values. To address these gaps, we imaged two phantoms modelling T1 of different samples at 1.5 T and 3.0 T using fast and slow inversion recovery (IR) sequences. The results show that T1 relaxation times from 3.0 T scanners are accurate and reproducible in terms of the expected reference values and when compared between different scanner models. Similarly, T1 values measured with the two pulse sequences were similar for all 3.0 T scanners. On the contrary, 1.5 T scanners exhibited larger discrepancies in the measured T1 compared with the reference values. In addition, 1.5 T scanners displayed less reproducibility in T1 relaxation time measurements across different 1.5 T scanners, and pulse sequences.