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Updated: Mar 30, 2026
Assessment of Cardiac Function and Myocardial Morphology Using Small Animal Look-locker Inversion Recovery SALLI MRI in Rats
Published on: July 19, 2013
Simultaneous myocardial T1, T2, T1ρ and fat fraction mapping with hybrid dual-echo cartesian acquisition and
Zhenfeng Lyu1, Hongzhang Huang1, HaoTian Hong1
1School of Biomedical Engineering & State Key Laboratory of Advanced Medical Materials and Devices, ShanghaiTech University, Shanghai, China.
Background:
T1, T2, T1ρ and fat fraction (FF) are important parameters for diagnosing various pathological changes in the myocardium. However, existing methods either require repeated breath-holds to quantify multiple parameters, or rely on complex image reconstruction to remove artifacts arising from highly undersampled acquisition. To address this technical gap, a free-breathing Dixon-MultiMap technique is proposed to allow for simultaneous myocardial T1, T2, T1ρ and FF mapping in a single scan with conventional single-shot Cartesian acquisition.
Methods:
Dixon-MultiMap employs electrocardiogram-triggered, single-shot dual-echo Cartesian acquisition over 14 consecutive cardiac cycles. A hybrid dual-echo acquisition scheme is designed to acquire four-echo images within a short cardiac acquisition window in the first two cardiac cycles, which are used to obtain FF and B0 field maps with water-fat separation. The derived B0 map is used as prior information for dual-echo water-fat separation of the multi-contrast images acquired in the following cardiac cycles. Subsequently, dictionary matching is performed on the water images for multi-parameter mapping, accounting for spin-history B1+ inhomogeneities. Dixon-MultiMap was optimized through simulations and validated in phantoms, 13 healthy volunteers, and three patients with suspected hypertrophic cardiomyopathy.
Results:
In phantoms, Dixon-MultiMap showed strong correlation with reference methods for measuring T1, T2, T1ρ and FF (R² > 0.96). In healthy subjects, Dixon-MultiMap achieved robust water-fat separation, yielding FF comparable to the conventional multi-echo method. Compared with separate breath-hold mapping techniques, Dixon-MultiMap yielded significantly higher T1 values (1348 ± 33 ms vs. 1159 ± 28 ms, p < 0.001), comparable T2 values (46.4 ± 1.7 ms vs. 45.4 ± 1.5 ms, p = 0.96), and a small but statistically significant increase in T1ρ values (55.8 ± 2.6 ms vs. 53.0 ± 1.8 ms, p = 0.01). Pathological changes detected by Dixon-MultiMap were consistent with those identified using conventional mapping techniques in the three patients.
Conclusion:
The proposed Dixon-MultiMap allows for simultaneous myocardial T1, T2, T1ρ and FF mapping in a free-breathing acquisition of 14 cardiac cycles. Water-fat partial volume was resolved by water-fat separation in Dixon-MultiMap, which improved the accuracy of multi-parameter estimation.
