Simultaneous Multi-Slice Acceleration for Free-Breathing Motion Corrected Late Gadolinium Enhancement Imaging

The objective of this study was to develop and evaluate an accelerated free-breathing motion corrected and averaged late gadolinium enhancement MRI (FB PSIR-MoCo LGE) protocols.

Simultaneous multi-slice (SMS) bSSFP imaging with GC-LOLA correction and a multiband factor of two was implemented into a FB PSIR-MoCo LGE sequence with phase sensitive inversion recovery (PSIR) reconstruction. Two FB PSIR-MoCo LGE protocols were acquired in 26 patients referred for clinical cardiac MRI: (1) SMS-accelerated, and (2) non-SMS reference. Myocardial sharpness, scar-to-blood CNR estimate (CNRe), scar-to-healthy myocardium CNRe, blood-to-healthy myocardium CNRe, and scar volume were assessed. Scar assessment was conducted in all LGE-positive patients (N = 10). Image quality (4-point scale: 1-poor/non diagnostic, 4-excellent/diagnostic) was assessed by consensus of two readers.

SMS resulted in a twofold reduction of acquisition time (reference: 3.7 ± 0.9 min, proposed: 1.9 ± 0.6 min, p < 0.001). Although both approaches resulted in good to excellent image quality, the proposed approach resulted in slightly reduced image quality scores (reference: 3.64 ± 0.36 vs. proposed: 3.46 ± 0.36, p = 0.001) and modest (∼20%) reduction in CNRe. Myocardial sharpness measures showed no statistically significant differences between the two approaches (0.37 ± 0.06 vs. 0.37 ± 0.05 mm^-1, p = 0.84). Importantly, both approaches were in excellent agreement for scar volume assessment (bias = 0.48 ± 0.86 mL, R² = 0.996).

The proposed SMS FB PSIR-MoCo LGE protocol reduced scan time by a factor of 2 when 16 slices were obtained, with minimal impact on image quality and CNRe, and no differences in myocardial sharpness. Importantly, it provided excellent agreement for myocardial scar assessment, in comparison to the reference FB PSIR-MoCo LGE.