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Conference Abstract: Phantom R1 Repeabililty
Accuracy, repeatability, and reproducibility of R1 in 12 small-animal MRI systems (Conference Abstract)
JC Waterton, CDG Hines, PD Hockings, I Laitinen, S Ziemian, S Campbell, M Gottschalk, C Green, M Haase, K Hoffmann, H-P Juretschke, S Koehler, W Lloyd, Y Luo, I Mahmutovic Persson, JPB O Connor, LE Olsson, GJM Parker, K Pindoriah, JE Schneider, D Steinmann, K Strobel, I Teh, A Veltien, X Zhang, G Schuetz
British Chapter ISMRM Annual Meeting 24th-26th September 2018, Oxford, UK Poster Abstract PO-19
Background: Many translational MR biomarkers derive from measurements of the longitudinal relaxation rate R1, but evidence for between-site reproducibility of R1 in small-animal MRI is lacking. Objective: To assess R1 repeatability and multi-site reproducibility in phantoms for preclinical MRI. Methods: R1 was measured by saturation recovery in 2% agarose phantoms with five nickel chloride concentrations in 12 magnets at 5 field strengths in 11 centres on two different occasions within 1-13 days. R1 was analysed in three different regions of interest, giving 360 measurements in total. Root-mean-square repeatability and reproducibility coefficients of variation were calculated. Relaxivities were calculated. Results: Day-to-day repeatability (N=180 regions of interest) was 2.3%. Between-centre reproducibility (N=9 centres) was 1.4%. The relaxivity of aqueous Ni2+ in 2% agarose varied between 0.66 s-1mM-1 at 3T and 0.94 s-1mM-1 at 11.7T.