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Updated: Jan 23, 2026

Cardiac Magnetic Resonance for the Evaluation of Suspected Cardiac Thrombus: Conventional and Emerging Techniques
Published on: June 11, 2019
Cardiac MR Fingerprinting at 0.55T Using a Deep Image Prior for Joint T1, T2, and M0 Mapping
Zhongnan Liu1, Zexuan Liu2, Imran Rashid3,4
1Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan, USA.
Background:
0.55T systems offer unique advantages and may support expanded access to cardiac MRI.
Purpose:
To assess the feasibility of 0.55T cardiac MR Fingerprinting (MRF), leveraging a deep image prior reconstruction to mitigate noise.
Study Type:
Phantom and prospective in vivo assessment.
Population:
ISMRM/NIST MRI system phantom and 18 healthy subjects (11 female; ages 28 ± 8 years).
Field Strength And Sequences:
MRF, modified Look-Locker inversion recovery (MOLLI), and T2-prepared balanced steady state free precession (T2-bSSFP) at 0.55T.
Assessment:
MRF T1 and T2 maps were reconstructed using (1) a low-rank technique with sparse and locally low-rank regularization (SLLR-MRF) and (2) a deep image prior (DIP-MRF). Accuracy and precision of MRF and conventional sequences were evaluated in a phantom. In vivo performance of MRF was evaluated in the 18 healthy subjects, with 7 subjects also undergoing conventional mapping. Myocardial T1 and T2 values were compared among methods and image quality scored by three readers (2, 3, and 4 years of experience) on a 5-point scale.
Statistical Tests:
Linear regression, Bland-Altman, intraclass correlation coefficient, and one-way ANOVA with p < 0.05 considered significant.
Results:
Mean measurements in the left ventricular septum were 671 ± 31 ms (MOLLI), 761 ± 147 ms (SLLR-MRF), and 686 ± 39 ms (DIP-MRF) for T1, and 63.5 ± 5.7 ms (T2-bSSFP), 47.5 ± 12.7 ms (SLLR-MRF), and 45.2 ± 4.5 ms (DIP-MRF) for T2. Compared to conventional mapping, DIP-MRF exhibited significantly lower T2 but no differences in T1 (p > 0.99). Standard deviations within the myocardium were significantly lower with DIP-MRF compared to SLLR-MRF (39 vs. 147 ms for T1 and 4.5 vs. 12.7 ms for T2). Overall image quality ratings were significantly lower for SLLR-MRF (T1: 2.3, T2: 2.9), which were significantly lower compared to conventional mapping methods (T1: 3.4, T2: 3.9), and DIP-MRF (T1: 3.8, T2: 4.1) received higher scores.
Data Conclusion:
This study demonstrated the feasibility of cardiac MRF on a commercial 0.55T system, enabled by a deep image prior reconstruction for denoising.
Evidence Level:
2.
Stage Of Technical Efficacy:
1.
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