Standardization of T1-mapping in cardiovascular magnetic resonance using clustered structuring for benchmarking normal ranges

BackgroundCardiovascular magnetic resonance T1-mapping is increasingly used for tissue characterization, commonly based on Modified Look-Locker Inversion recovery (MOLLI). However, there are numerous MOLLI variants with differing normal ranges. This lack of standardization presents confusion and difficulty in inter-center comparisons, hindering widespread adoption T1-mapping.MethodsTo address this, we performed a structured literature search native left ventricular myocardial healthy humans measured using at 1.5 3 Tesla, across scanner vendors. We then k-means clustering to structure MOLLI-T1 values according field strength, investigated correlations between common imaging parameters: repetition time (TR), echo (TE), flip angle (FA).ResultsWe analyzed data from 2207 controls 76 independent reports. Normal standard deviations varied by 11-fold, dependencies TE, TR, FA differed T T, thwarting meaningful T1 even within single including the use Z-score. divergent norms may be clustering. For two clusters emerged: Cluster11.5T: = 958 ± 16 ms (n 1280); Cluster21.5T: 1027 19 386). three Cluster13T: 1160 21 330); Cluster23T: 1067 18 178); Cluster33T: 1227 41). propose concept an online calculator assigning local known cluster, allowing benchmarking against published norms.ConclusionClustered structuring allows widely-divergent variants, (usually smaller samples) (larger samples). increase confidence quality control method implementation, facilitating wider clinical T1-mapping.