Objective

To develop a three-dimensional (3D) high-resolution free-breathing magnetization transfer ratio (MTR) sequence for contrast-free assessment of myocardial infarct and coronary vein anatomy.

Materials and methods

Two datasets with and without off-resonance magnetization transfer preparation were sequentially acquired to compute MTR. 2D image navigators enabled beat-to-beat translational and bin-to-bin non-rigid motion correction. Two different imaging sequences were explored. MTR scar localization was compared against 3D late gadolinium enhancement (LGE) in a porcine model of myocardial infarction. MTR variability across the left ventricle and vessel sharpness in the coronary veins were evaluated in healthy human subjects.

Results

A decrease in MTR was observed in areas with LGE in all pigs (non-infarct: 25.1 ± 1.7% vs infarct: 16.8 ± 1.9%). The average infarct volume overlap on MTR and LGE was 62.5 ± 19.2%. In humans, mean MTR in myocardium was between 37 and 40%. Spatial variability was between 15 and 20% of the mean value. 3D whole heart MT-prepared datasets enabled coronary vein visualization with up to 8% improved vessel sharpness for non-rigid compared to translational motion correction.

Discussion

MTR and LGE showed agreement in infarct detection and localization in a swine model. Free-breathing 3D MTR maps are feasible in humans but high spatial variability was observed. Further clinical studies are warranted.

中文翻译：

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无对比高分辨率 3D 磁化转移成像可同时实现心肌疤痕和心脏静脉可视化。

客观的

开发三维 (3D) 高分辨率自由呼吸磁化传递比 (MTR) 序列，用于心肌梗塞和冠状静脉解剖结构的无造影评估。

材料和方法

依次获取有和没有非共振磁化转移准备的两个数据集来计算 MTR。2D 图像导航器可实现节拍平移和箱到箱非刚性运动校正。探索了两种不同的成像序列。在猪心肌梗塞模型中将 MTR 疤痕定位与 3D 晚期钆增强 (LGE) 进行比较。在健康人类受试者中评估了左心室的 MTR 变异性和冠状静脉的血管清晰度。

结果

在所有猪的 LGE 区域中均观察到 MTR 降低（非梗塞：25.1 ± 1.7% 与梗塞：16.8 ± 1.9%）。MTR 和 LGE 上的平均梗塞体积重叠为 62.5 ± 19.2%。在人类中，心肌的平均 MTR 介于 37% 至 40% 之间。空间变异性在平均值的 15% 到 20% 之间。3D 全心 MT 准备的数据集可实现冠状静脉可视化，与平移运动校正相比，非刚性血管清晰度提高了 8%。

讨论

MTR 和 LGE 在猪模型中的梗死检测和定位方面表现出一致。自由呼吸 3D MTR 地图在人类中是可行的，但观察到较高的空间变异性。需要进一步的临床研究。