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.