Background

Whole-heart magnetic resonance angiography (MRA) requires sophisticated methods accounting for respiratory motion. Our purpose was to evaluate the image quality of compressed sensing-based respiratory motion-resolved three-dimensional (3D) whole-heart MRA compared with self-navigated motion-corrected whole-heart MRA in patients with known thoracic aorta dilation.

Methods

Twenty-five patients were prospectively enrolled in this ethically approved study. Whole-heart 1.5-T MRA was acquired using a prototype 3D radial steady-state free-precession free-breathing sequence. The same data were reconstructed with a one-dimensional motion-correction algorithm (1D-MCA) and an extradimensional golden-angle radial sparse parallel reconstruction (XD-GRASP). Subjective image quality was scored and objective image quality was quantified (signal intensity ratio, SIR; vessel sharpness). Wilcoxon, McNemar, and paired t tests were used.

Results

Subjective image quality was significantly higher using XD-GRASP compared to 1D-MCA (median 4.5, interquartile range 4.5–5.0 versus 4.0 [2.25–4.75]; p < 0.001), as well as signal homogeneity (3.0 [3.0–3.0] versus 2.0 [2.0–3.0]; p = 0.003), and image sharpness (3.0 [2.0–3.0] vs 2.0 [1.25–3.0]; p < 0.001). SIR with the 1D-MCA and XD-GRASP was 6.1 ± 3.9 versus 7.4 ± 2.5, respectively (p < 0.001); while signal homogeneity was 274.2 ± 265.0 versus 199.8 ± 67.2 (p = 0.129). XD-GRASP provided a higher vessel sharpness (45.3 ± 10.7 versus 40.6 ± 101, p = 0.025).

Conclusions

XD-GRASP-based motion-resolved reconstruction of free-breathing 3D whole-heart MRA datasets provides improved image contrast, sharpness, and signal homogeneity and seems to be a promising technique that overcomes some of the limitations of motion correction or respiratory navigator gating.

中文翻译：

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纠正与解决自由呼吸全心MRA中的呼吸运动：胸主动脉疾病患者的比较。

背景

全心磁共振血管造影（MRA）需要考虑呼吸运动的复杂方法。我们的目的是评估已知主动脉扩张的患者基于压缩感知的呼吸运动分辨三维（3D）全心MRA与自导航运动校正全心MRA的图像质量。

方法

前瞻性地招募了25名患者参加了这项获得伦理学认可的研究。使用原型3D径向稳态自由进动自由呼吸序列获得了全心1.5-T MRA。使用一维运动校正算法（1D-MCA）和超维金角径向稀疏并行重建（XD-GRASP）重建了相同的数据。对主观图像质量进行评分，并对客观图像质量进行量化（信号强度比，SIR；血管清晰度）。使用Wilcoxon，McNemar和配对t检验。

结果

与1D-MCA相比，使用XD-GRASP的主观图像质量显着更高（中位数4.5，四分位间距4.5-5.0与4.0 [2.25-4.75]；p <0.001），以及信号同质性（3.0 [3.0-3.0]与2.0 [2.0-3.0]；p = 0.003）和图像清晰度（3.0 [2.0-3.0] vs 2.0 [1.25-3.0]；p <0.001）。一维MCA和XD-GRASP的SIR分别为6.1±3.9和7.4±2.5（p <0.001）; 而信号均匀度则为274.2±265.0，而信号均质度为199.8±67.2（p = 0.129）。XD-GRASP提供了更高的血管清晰度（45.3±10.7对40.6±101，p = 0.025）。

结论

基于XD-GRASP的自由呼吸3D全心MRA数据集的运动分辨重建可提供改善的图像对比度，清晰度和信号均匀性，并且似乎是克服运动校正或呼吸导航门控的某些局限性的有前途的技术。