Single breath-hold MR T1 mapping in the heart: Hybrid MOLLI combining saturation and inversion recovery

Chun-Yang Yu; Teng-Yi Huang; Hsiao-Wen Chung

doi:10.1016/j.mri.2022.12.001

Single breath-hold MR T1 mapping in the heart: Hybrid MOLLI combining saturation and inversion recovery

Magn Reson Imaging. 2023 Feb:96:85-92. doi: 10.1016/j.mri.2022.12.001. Epub 2022 Dec 5.

Authors

Chun-Yang Yu¹, Teng-Yi Huang², Hsiao-Wen Chung¹

Affiliations

¹ Graduate Institute of Biomedical Electronics and Bioinformatics, Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan.
² Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan. Electronic address: tyhuang@mail.ntust.edu.tw.

PMID: 36470451
DOI: 10.1016/j.mri.2022.12.001

Abstract

The native T1 values of the myocardium provide valuable information for tissue characterization and assessment of cardiomyopathies. In this study, we proposed a novel hybrid MOLLI sequence for myocardial T1 mapping. Unlike the two groups of inversion-recovery sampling of the conventional MOLLI5(3 s)3 sequence, the hybrid MOLLI sequence consisted of an inversion-recovery block followed by a saturation-recovery block. Since the second block employed a saturation pulse to spoil the longitudinal magnetization, it did not require a waiting period as MOLLI5(3 s)3 did. As a result, the hybrid MOLLI required less acquisition time leading to a practical application for patients with breath-hold difficulties. Phantom and healthy subject experiments were performed to evaluate the proposed sequence against the MOLLI5(3 s)3 sequence. The phantom study showed that the heart-rate dependency of one variant of the hybrid MOLLI sequences, hbMOLLI4, was comparable to that of MOLLI5(3 s)3. In addition, both hbMOLLI4 and MOLLI53 derived T1 values under 2% variations with simulated heart rates from 50 to 90 beats-per-minute within the range of T1 values for myocardium and blood before contrast administration. Simulation results suggested slightly reduced T1 fitting precision in hbMOLLI4 compared with MOLLI5(3 s)3, but prominently better than saturation recovery. Bland-Altman analysis on accuracy assessment revealed that hbMOLLI4 partially reduced the T1 underestimation of MOLLI5(3 s)3. In the human study, The T1 values of both methods were consistent (hbMOLLI4 vs. MOLLI5(3 s)3, slope = 1.14, R² > 0.97), with equal reproducibility. The results supported that hybrid MOLLI produced comparable T1 mapping results in terms of accuracy, reproducibility, and heart-rate dependency, at the expense of slightly reduced precision. We concluded that the hybrid MOLLI sequence presents a competitive alternative to the MOLLI5(3 s)3 sequence when a speedy acquisition is required.

Keywords: Cardiac magnetic resonance imaging, MOLLI; T1 mapping.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cardiomyopathies*
Heart / diagnostic imaging
Humans
Magnetic Resonance Imaging* / methods
Myocardium
Phantoms, Imaging
Reproducibility of Results