Non-contrast free-running high-resolution volumetric multi-slab cardiac cine MRI at 3 T

Free-running self-gated 3D cardiac cine imaging is highly desirable for volumetric, high-resolution, breath-hold-free assessment of left ventricular (LV) function. However, its implementation at 3 T remains challenging due to specific absorption rate (SAR) constraints and reduced myocardium-blood contrast. In this study, we propose a novel non-contrast, free-running, self-gated 3D gradient-echo (GRE) cine sequence for 3 T imaging, which acquires multi-slab data using a pseudo-radial Cartesian trajectory with a 1.5 mm slice thickness. To address respiratory motion, a locally low-rank motion-corrected image reconstruction algorithm was developed. Fifteen participants underwent imaging with the proposed multi-slab 3D cine sequence and conventional 2D cine sequences. Additionally, single-slab 3D cine data were acquired in 10 participants. Various image quality metrics (signal-to-noise ratio, contrast-to-noise ratio, myocardial sharpness, and residual artefact) and LV volumetric parameters (end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF)) were compared between the different methods. Results demonstrated that the proposed multi-slab 3D cine method provided significantly superior image quality compared to the single-slab 3D approach (myocardial sharpness: 2.82 ± 0.42 vs. 1.58 ± 0.46, P = 0.005; residual artefact: 2.58 ± 0.26 vs. 1.13 ± 0.21, P = 0.005) due to the improvement of image contrast. Furthermore, the multi-slab 3D cine sequence exhibited good agreement and correlation with the reference 2D cine method in terms of volumetric measures (EDV: 140.3 ± 19.9 mL vs. 139.3 ± 20.0 mL, P = 0.357, r = 0.976; ESV: 56.7 ± 11.8 mL vs. 57.7 ± 10.2 mL, P = 0.259, r = 0.964; EF: 59.8 % ± 4.9 % vs. 58.7 % ± 3.7 %, P = 0.073, r = 0.907). In conclusion, the proposed multi-slab 3D cine framework enables free-running 3 T cine imaging with whole-heart coverage and high through-plane resolution. Although myocardium-blood contrast is reduced compared to 2D breath-hold cine, the retained contrast is sufficient to evaluate LV function.