What does this research mean for the field?

Employing z-scores for reporting myocardial T1 and T2 mapping values eliminates the variation across different MRI systems and field strengths, provided motion correction is applied. Novelty: ClaimNovelty.METHODOLOGICAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

January 1, 2024Journal of Cardiovascular Magnetic ResonanceOpen Access

Inter-scanner comparability of Z-scores for native myocardial T1 and T2 mapping

View Full Paper

Ask AI

Bookmark

Why the study?

Hardware- and software-specific variability limits the generalizability of CMR native T1 and T2 mapping data across platforms, prompting investigation into whether z-scores can improve comparability across scanners, field strengths, and sequences in the same participant.

Does z-score normalization improve the comparability of myocardial T1 and T2 mapping values across different CMR scanners in healthy volunteers?

Structured PICO

Does z-score normalization improve the comparability of myocardial T1 and T2 mapping values across different CMR scanners in healthy volunteers?

Population

51 healthy volunteers (26 men/25 women, mean age = 43 ± 13.51)

Intervention

Z-score normalization of myocardial T1 and T2 mapping values

Comparator

Raw (un-normalized) T1 and T2 mapping values across different scanners

Outcome

Inter-scanner comparability of T1 and T2 mapping valuessurrogate

Employing z-scores for reporting myocardial T1 and T2 mapping removes variation across different MRI systems and field strengths, improving comparability.

Implication

Motion correction may standardize T1 z-scores across scanners in volunteers; leaves open validation in patients and for T2.

Abstract

BACKGROUND: Cardiovascular Magnetic Resonance (CMR) native T1 and T2 mapping serve as robust, contrast-agent-free diagnostic tools, but hardware- and software-specific sources of variability limit the generalizability of data across CMR platforms, consequently limiting the interpretability of patient-specific parametric data. Z-scores are used to describe the relationship of observed values to the mean results as obtained in a sufficiently large normal sample. They have been successfully used to describe the severity of quantifiable abnormalities in medicine, specifically in children and adolescents. The objective of this study was to observe whether z-scores can improve the comparability of T1 and T2 mapping values across CMR scanners, field strengths, and sequences from different vendors in the same participant rather than different participants (as seen in previous studies). METHODS: Fifty-one healthy volunteers (26 men/25 women, mean age = 43 ± 13.51) underwent three CMR exams on three different scanners, using a Modified Look-Locker Inversion Recovery (MOLLI) 5-(3)- 3 sequence to quantify myocardial T1. For T2 mapping, a True Fast Imaging with steady-state free precession (TRUFI) sequence was used on a 3 T Skyra™ (Siemens), and a T2 Fast Spin Echo (FSE) sequence was used on 1.5 T Artist™ (GE) and 3.0 T Premier™ (GE) scanners. The averages of basal and mid-ventricular short axis slices were used to derive means and standard deviations of global mapping values. We used intra-class comparisons (ICC), repeated measures ANOVA, and paired Student's t-tests for statistical analyses. RESULTS: : p = 0.985). Furthermore, when images were not corrected for motion, T1 z-scores showed significant inter-scanner variability (p < 0.001), resolved by motion correction. CONCLUSION: Employing z-scores for reporting myocardial T1 and T2 removes the variation of quantitative mapping results across different MRI systems and field strengths, improving the clinical utility of myocardial tissue characterization in patients with suspected myocardial disease.