Free‐breathing combined three‐dimensional phase sensitive late gadolinium enhancement and T₁ mapping for myocardial tissue characterization

Abstract

Purpose To develop a novel MR sequence for combined 3D phase-sensitive (PS) late gadolinium enhancement (LGE) and T1 mapping to allow for simultaneous assessment of focal and diffuse myocardial fibrosis. Methods In the proposed sequence, four 3D imaging volumes are acquired with different T1 weightings using a combined saturation and inversion preparation, after administration of a gadolinium contrast agent. One image is acquired fully sampled with the inversion time selected to null the healthy myocardial signal (the LGE image). The other three images are three-fold under-sampled and reconstructed using compressed sensing. An acquisition scheme with two interleaved imaging cycles and joint navigator-gating of those cycles ensures spatial registration of the imaging volumes. T1 maps are generated using all four imaging volumes. The signal-polarity in the LGE image is restored using supplementary information from the T1 fit to generate PS-LGE images. The accuracy of the proposed method was assessed with respect to a inversion-recovery spin-echo sequence. In-vivo T1 maps and LGE images were acquired with the proposed sequence and quantitatively compared to 2D multi-slice Modified Look-Locker inversion recovery (MOLLI) T1 maps. Exemplary images in a patient with focal scar were compared to conventional LGE imaging. Results The deviation of the proposed method and the spin-echo reference was < 11 ms in phantom for T1 times between 250 and 600 ms, regardless of the inversion time selected in the LGE image. There was no significant difference in the in-vivo T1 times of the proposed sequence and the 2D MOLLI technique (myocardium: 292 ± 75 ms vs. 310 ± 49 ms, blood-pools: 191 ± 75 ms vs. 182.0 ± 33). The LGE images showed proper nulling of the healthy myocardium in all subjects and clear depiction of scar in the patient. Conclusion The proposed sequence enables simultaneous acquisition of 3D PS-LGE images and spatially registered 3D T1 maps in a single scan.

Sparse Reconstruction Techniques in Magnetic Resonance Imaging

“…However, questions remain regarding image quality compared to traditional exams 134 and whether CS-based methods suffer from worsened spatiotemporal blurring compared to parallel imaging-based acceleration 135,136 . Acceleration of late gadolinium enhancement (LGE) exams with sparse reconstructions for faster/free breathing acquisitions or greater anatomical coverage has also been explored 136–138 . An early study of 3D isotropic LGE imaging on 28 patients indicates that accelerated scans may be used to visualize left ventricular scar with a high spatial resolution, and potentially pulmonary vein and left atrial scar post ablation for atrial fibrillation 137 .…”

Motion-robust cardiac B1+ mapping at 3T using interleaved bloch-siegert shifts

“…The advent of quantitative tissue characterization of the myocardium, with its promise for prognostic and diagnostic value in a plethora of cardiomyopathies, has spiked great research interest and has triggered a large number of clinical studies . Available tools for MR‐based quantitative tissue characterization in the heart include perfusion ; T 1 , T 2 , and relaxation mapping techniques ; and a combination thereof .…”

Free‐running 3D whole heart myocardial T1 mapping with isotropic spatial resolution

“…2D myocardial mapping is typically performed with thick slices to avoid the influence of through‐plane motion and low SNR. 3D acquisitions can overcome these limitations and provide whole heart coverage for comprehensive characterization of diffuse diseases of myocardium . However, 3D T 1 mapping is technically challenging, because respiratory gating and ECG‐triggering together with the requirement of whole heart coverage, may lead to very long scan time.…”