BACKGROUND Three-dimensional time-resolved phase-contrast cardiovascular magnetic resonance (4D flow CMR) enables the quantification and visualisation of blood flow, but its clinical applicability remains hampered by its long scan time. The aim of this study was to evaluate the use of compressed sensing (CS) with on-line reconstruction to accelerate the acquisition and reconstruction of 4D flow CMR of the thoracic aorta. METHODS 4D flow CMR of the thoracic aorta was acquired in 20 healthy subjects using CS with acceleration factors ranging from 4 to 10. As a reference, conventional parallel imaging (SENSE) with acceleration factor 2 was used. Flow curves, net flows, peak flows and peak velocities were extracted from six contours along the aorta. To measure internal data consistency, a quantitative particle trace analysis was performed. Additionally, scan-rescan, inter- and intraobserver reproducibility were assessed. Subsequently, 4D flow CMR with CS factor 6 was acquired in 3 patients with differing aortopathies. The flow patterns resulting from particle trace visualisation were qualitatively analysed. RESULTS All collected data were successfully acquired and reconstructed on-line. The average acquisition time including respiratory navigator efficiency with CS factor 6 was 5:02 ± 2:23 min while reconstruction took approximately 9 min. For CS factors of 8 or less, mean differences in net flow, peak flow and peak velocity as compared to SENSE were below 2.2 ± 7.8 ml/cycle, 4.6 ± 25.2 ml/s and - 7.9 ± 13.0 cm/s, respectively. For a CS factor of 10 differences reached 5.4 ± 8.0 ml/cycle, 14.4 ± 28.3 ml/s and - 4.0 ± 12.2 cm/s. Scan-rescan analysis yielded mean differences in net flow of - 0.7 ± 4.9 ml/cycle for SENSE and - 0.2 ± 8.5 ml/cycle for CS factor of 6. CONCLUSIONS A six- to eightfold acceleration of 4D flow CMR using CS is feasible. Up to a CS acceleration rate of 6, no statistically significant differences in measured flow parameters could be observed with respect to the reference technique. Acquisitions in patients with aortopathies confirm the potential to integrate the proposed method in a clinical routine setting, whereby its main benefits are scan-time savings and direct on-line reconstruction.

中文翻译：

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使用压缩传感的加速主动脉 4D 血流心血管磁共振：适用性、验证和临床整合。


背景技术三维时间分辨相衬心血管磁共振（4D flow CMR）能够实现血流的量化和可视化，但其临床适用性仍然因其扫描时间长而受到阻碍。本研究的目的是评估压缩感知 (CS) 与在线重建的使用，以加速胸主动脉 4D 血流 CMR 的采集和重建。方法 使用加速因子为 4 至 10 的 CS 采集 20 名健康受试者的胸主动脉 4D 血流 CMR。作为参考，使用加速因子为 2 的传统并行成像 (SENSE)。从沿着主动脉的六个轮廓中提取流量曲线、净流量、峰值流量和峰值速度。为了测量内部数据的一致性，进行了定量颗粒痕量分析。此外，还评估了扫描-重扫描、观察者间和观察者内的再现性。随后，在 3 名患有不同主动脉病的患者中获得了具有 CS 因子 6 的 4D 血流 CMR。对颗粒痕迹可视化产生的流动模式进行了定性分析。结果所有收集的数据均成功在线获取和重建。平均采集时间（包括 CS 因子 6 的呼吸导航器效率）为 5:02 ± 2:23 分钟，而重建大约需要 9 分钟。对于 8 或更低的 CS 因子，与 SENSE 相比，净流量、峰值流量和峰值速度的平均差异分别低于 2.2 ± 7.8 ml/cycle、4.6 ± 25.2 ml/s 和 - 7.9 ± 13.0 cm/s。对于 10 的 CS 因子，差异达到 5.4 ± 8.0 ml/cycle、14.4 ± 28.3 ml/s 和 - 4.0 ± 12.2 cm/s。扫描-重新扫描分析得出，SENSE 的净流量平均差异为 - 0.7 ± 4.9 ml/周期，CS 因子为 6 的净流量平均差异为 - 0.2 ± 8.5 ml/周期。 结论 使用 CS 将 4D 流 CMR 加速六到八倍是可行的。 CS 加速度达到 6 时，相对于参考技术，测量的流量参数没有观察到统计学上的显着差异。主动脉病患者的采集证实了将所提出的方法整合到临床常规环境中的潜力，其主要好处是节省扫描时间和直接在线重建。