Comparing the test-retest reproducibility of quantitative T1 and T2 mapping: DESPOT and 3D-QALAS

Motivation: Measuring T1 and T2 relaxation times accurately is vital for understanding tissue properties. The choice of mapping method, including pulse sequence, parameters, hardware, and reconstruction, affects accuracy Goal(s): This study evaluates and compares test-retest reproducibility of two MRI relaxometry techniques, DESPOT and QALAS, for T1 and T2 mapping in healthy volunteers. Approach: Ten volunteers were scanned test-retest using DESPOT and QALAS. Reproducibility was analyzed using Bland-Altman plots, coefficient of variation, and intraclass correlation Results: QALAS showed better reproducibility for T1 and was more time-efficient, while DESPOT showed slightly higher reproducibility for T2. Impact: Establishing the reproducibility and accuracy of T1 and T2 mapping is crucial for their adoption in clinical practice and longitudinal studies, particularly for 'hybrid' methods, like DESPOT and QALAS, that map T1 and T2 from a set of mixed-contrast images.