Cardiac MR Fingerprinting at 0.55T Using a Deep Image Prior for Joint T<sub>1</sub>, T<sub>2</sub>, and M<sub>0</sub> Mapping.
Authors
Affiliations (6)
Affiliations (6)
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan, USA.
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA.
- School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.
- Harrington Heart and Vascular Institute, University Hospitals, Cleveland, Ohio, USA.
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA.
- Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Abstract
0.55T systems offer unique advantages and may support expanded access to cardiac MRI. To assess the feasibility of 0.55T cardiac MR Fingerprinting (MRF), leveraging a deep image prior reconstruction to mitigate noise. Phantom and prospective in vivo assessment. ISMRM/NIST MRI system phantom and 18 healthy subjects (11 female; ages 28 ± 8 years). MRF, modified Look-Locker inversion recovery (MOLLI), and T<sub>2</sub>-prepared balanced steady state free precession (T<sub>2</sub>-bSSFP) at 0.55T. MRF T<sub>1</sub> and T<sub>2</sub> 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 T<sub>1</sub> and T<sub>2</sub> values were compared among methods and image quality scored by three readers (2, 3, and 4 years of experience) on a 5-point scale. Linear regression, Bland-Altman, intraclass correlation coefficient, and one-way ANOVA with p < 0.05 considered significant. Mean measurements in the left ventricular septum were 671 ± 31 ms (MOLLI), 761 ± 147 ms (SLLR-MRF), and 686 ± 39 ms (DIP-MRF) for T<sub>1</sub>, and 63.5 ± 5.7 ms (T<sub>2</sub>-bSSFP), 47.5 ± 12.7 ms (SLLR-MRF), and 45.2 ± 4.5 ms (DIP-MRF) for T<sub>2</sub>. Compared to conventional mapping, DIP-MRF exhibited significantly lower T<sub>2</sub> but no differences in T<sub>1</sub> (p > 0.99). Standard deviations within the myocardium were significantly lower with DIP-MRF compared to SLLR-MRF (39 vs. 147 ms for T<sub>1</sub> and 4.5 vs. 12.7 ms for T<sub>2</sub>). Overall image quality ratings were significantly lower for SLLR-MRF (T<sub>1</sub>: 2.3, T<sub>2</sub>: 2.9), which were significantly lower compared to conventional mapping methods (T<sub>1</sub>: 3.4, T<sub>2</sub>: 3.9), and DIP-MRF (T<sub>1</sub>: 3.8, T<sub>2</sub>: 4.1) received higher scores. This study demonstrated the feasibility of cardiac MRF on a commercial 0.55T system, enabled by a deep image prior reconstruction for denoising. 2. 1.