Weingärtner Sebastian, Akçakaya Mehmet, Roujol Sébastien, Basha Tamer, Tschabrunn Cory, Berg Sophie, Anter Elad, Nezafat Reza
Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
Computer Assisted Clinical Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany.
Magn Reson Med. 2015 Oct;74(4):1032-41. doi: 10.1002/mrm.25495. Epub 2014 Oct 16.
To develop a novel MR sequence for combined three-dimensional (3D) phase-sensitive (PS) late gadolinium enhancement (LGE) and T1 mapping to allow for simultaneous assessment of focal and diffuse myocardial fibrosis.
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 with 2D multislice Modified Look-Locker inversion recovery (MOLLI) T1 maps. Exemplary images in a patient with focal scar were compared with conventional LGE imaging.
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 versus 310 ± 49 ms, blood-pools: 191 ± 75 ms versus 182.0 ± 33). The LGE images showed proper nulling of the healthy myocardium in all subjects and clear depiction of scar in the patient.
The proposed sequence enables simultaneous acquisition of 3D PS-LGE images and spatially registered 3D T1 maps in a single scan.
开发一种新型磁共振序列，用于联合三维（3D）相敏（PS）延迟钆增强（LGE）和T1映射，以便同时评估局灶性和弥漫性心肌纤维化。
在所提出的序列中，在注射钆对比剂后，使用饱和与反转准备相结合的方法，采集四个具有不同T1加权的3D成像容积。一幅图像以完全采样的方式采集，选择反转时间以使健康心肌信号归零（LGE图像）。另外三幅图像进行三倍欠采样，并使用压缩感知进行重建。一种具有两个交错成像周期以及这些周期的联合导航门控的采集方案可确保成像容积的空间配准。使用所有四个成像容积生成T1映射。利用来自T1拟合的补充信息恢复LGE图像中的信号极性，以生成PS-LGE图像。相对于反转恢复自旋回波序列评估了所提出方法的准确性。使用所提出的序列采集体内T1映射和LGE图像，并与二维多层改良Look-Locker反转恢复（MOLLI）T1映射进行定量比较。将一名局灶性瘢痕患者的示例图像与传统LGE成像进行比较。
对于250至600 ms之间的T1时间，在所提出的方法与自旋回波参考之间，体模中的偏差小于11 ms，与LGE图像中选择的反转时间无关。所提出序列与二维MOLLI技术的体内T1时间无显著差异（心肌：292±75 ms对310±49 ms，血池：191±75 ms对182.0±33）。LGE图像在所有受试者中均显示健康心肌的适当归零，并清晰描绘了患者的瘢痕。
所提出的序列能够在单次扫描中同时采集3D PS-LGE图像和空间配准的3D T1映射。
