Fast myocardial T1 mapping using shortened inversion recovery based schemes

Background

Myocardial T₁ mapping shows promise for assessment of cardiomyopathies. Most myocardial T₁ mapping techniques, such as modified Look–Locker inversion recovery (MOLLI), generate one T₁ map per breath‐held acquisition (9–17 heartbeats), which prolongs multislice protocols and may be unsuitable for patients with breath‐holding difficulties.

Purpose

To develop and characterize novel shortened inversion recovery based T₁ mapping schemes of 2–5 heartbeats.

Study Type

Prospective.

Population/Phantom

Numerical simulations, agarose/NiCl₂ phantom, 16 healthy volunteers, and 24 patients.

Field Strength/Sequence

1.5T/MOLLI.

Assessment

All shortened T₁ mapping schemes were characterized and compared with a conventional MOLLI scheme (5‐(3)‐3) in terms of accuracy, precision, spatial variability, and repeatability.

Statistical Tests

Kruskal–Wallis, Wilcoxon rank sum tests, analysis of variance, Student's t‐tests, Bland–Altman analysis, and Pearson correlation analysis.

Results

All shortened schemes provided limited T₁ time variations (≤2% for T₁ times ≤1200 msec) and limited penalty of precision (by a factor of ~1.4–1.5) when compared with MOLLI in numerical simulations. In phantom, differences between all schemes in terms of accuracy, spatial variability, and repeatability did not reach statistical significance (P > 0.71). In healthy volunteers, there were no statistically significant differences between all schemes in terms of native T₁ times and repeatability for myocardium (P = 0.21 and P = 0.87, respectively) and blood (P = 0.79 and P = 0.41, respectively). All shortened schemes led to a limited increase of spatial variability for native myocardial T₁ mapping with respect to MOLLI (by a factor of 1.2) (P < 0.0001). In both healthy volunteers and patients, the two‐heartbeat scheme and MOLLI led to highly linearly correlated T₁ times (correlation coefficients ≥0.83).

Data Conclusion

The proposed two‐heartbeat T₁ mapping scheme yields a 5‐fold acceleration compared with MOLLI, with highly linearly correlated T₁ times, no significant difference of repeatability, and limited spatial variability penalty at 1.5T. This approach may enable myocardial T₁ mapping in patients with severe breath‐holding difficulties and reduce the examination time of multislice protocols.

Level of Evidence: 1

Technical Efficacy Stage: 3

J. Magn. Reson. Imaging 2019.

from #Head and Neck by Sfakianakis via simeraentaxei on Inoreader http://bit.ly/2UcZorw