What is the clinical evidence from this study?

Study design: Other. Population: Healthy volunteers (n=10). Intervention: Simultaneous Multi-Slice (SMS) Cardiac MR Multitasking vs. Reference mapping methods (MOLLI and T2-prep FLASH). Primary outcome: Myocardial T1 value (ms) (p=0.347).

What does this research mean for the field?

Simultaneous multi-slice cardiac MR multitasking yields similar myocardial T1 and T2 values compared to standard reference methods while allowing for a 3-minute, free-breathing, non-ECG scan. Novelty: ClaimNovelty.METHODOLOGICAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

March 4, 2022Open Access

Simultaneous Multi-Slice Cardiac MR Multitasking for Motion-Resolved, Non-ECG, Free-Breathing T1–T2 Mapping

Resultado clave

Simultaneous multi-slice cardiac MR multitasking yielded similar myocardial T1 (1215 vs 1239 ms, P=0.347) and T2 (41.5 vs 42.7 ms, P=0.296) values compared to reference methods in a 3-minute scan.

PICO estructurado

Does simultaneous multi-slice cardiac MR Multitasking provide accurate and repeatable T1 and T2 mapping compared to reference methods in healthy volunteers?

Población

10 healthy volunteers (mean age 36.7 years, 70% female) underwent cardiac MRI to validate a novel free-breathing, non-ECG simultaneous multi-slice T1-T2 mapping technique.

Intervención

Simultaneous multi-slice (SMS) cardiac MR Multitasking (T2prep-IR FLASH sequence with two flip angles) for motion-resolved, non-ECG, free-breathing T1-T2 mapping

Comparador

Reference methods (MOLLI for T1, T2-prep FLASH for T2)

Resultado

T1 and T2 measurements and scan-rescan repeatabilitysurrogate

Multitasking-SMS is a feasible method for free-breathing, non-ECG myocardial T1/T2 quantification across 3 short-axis slices in 3 minutes, showing good agreement with reference methods.

Resultado numérico

Tasa de eventos absoluta: 1215% vs 1239%

valor p: p=0.347

Limitaciones

T1 and T2 maps show some blurring, which may be due to unresolved motion or over-regularization during the reconstruction.
The reconstruction time was 2-3 hours for each data acquisition, which is too long for online reconstruction in the clinic.
The study only evaluated Multitasking-SMS in a small number of healthy volunteers, warranting larger studies in patients.

Resumen

The aim of this study is to simultaneously quantify T1/T2 across three slices of the left-ventricular myocardium without breath-holds or ECG monitoring, all within a 3 min scan. Radial simultaneous multi-slice (SMS) encoding, self-gating, and image reconstruction was incorporated into the cardiovascular magnetic resonance (CMR) Multitasking framework to simultaneously image three short-axis slices. A T2prep-IR FLASH sequence with two flip angles was designed and implemented to allow B1+-robust T1 and T2 mapping. The proposed Multitasking-SMS method was validated in a standardized phantom and 10 healthy volunteers, comparing T1 and T2 measurements and scan-rescan repeatability against corresponding reference methods in one layer of phantom vials and in 16 American Heart Association (AHA) myocardial segments. In phantom, Multitasking-SMS T1/T2 measurements showed substantial correlation ( R 2 0.996) and excellent agreement intraclass correlation coefficients (ICC) ≥ 0.999) with reference measurements. In healthy volunteers, Multitasking-SMS T1/T2 maps reported similar myocardial T1/T2 values (1,215 ± 91.0/41.5 ± 6.3 ms) to the reference myocardial T1/T2 values (1,239 ± 67.5/42.7 ± 4.1 ms), with P = 0.347 and P = 0.296, respectively. Bland–Altman analyses also demonstrated good in vivo repeatability in both the multitasking and references, with segment-wise coefficients of variation of 4.7% (multitasking T1), 8.9% (multitasking T2), 2.4% modified look-locker inversion recovery (MOLLI), and 4.6% (T2-prep FLASH), respectively. In summary, multitasking-SMS is feasible for free-breathing, non-ECG, myocardial T1/T2 quantification in 16 AHA segments over 3 short-axis slices in 3 min. The method shows the great potential for reducing exam time for quantitative CMR without ECG or breath-holds.

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