Laboratory of Computing, Medical Informatics and Biomedical-Imaging Technologies, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Department of Clinical Sciences Lund, Clinical Physiology, Lund University, Skåne University Hospital, Lund, Sweden.
J Magn Reson Imaging. 2020 Jan;51(1):260-272. doi: 10.1002/jmri.26842. Epub 2019 Jun 22.
Fetal cardiovascular MRI complements ultrasound to assess fetal cardiovascular pathophysiology.
To develop a free-breathing method for retrospective fetal cine MRI using Doppler ultrasound (DUS) cardiac gating and tiny golden angle radial sampling (tyGRASP) for accelerated acquisition capable of detecting fetal movements for motion compensation.
Feasibility study.
Nine volunteers (gestational week 34-40). Short-axis and four-chamber views were acquired during maternal free-breathing and breath-hold.
FIELD STRENGTH/SEQUENCE: 1.5T cine balanced steady-state free precession.
A self-gated reconstruction method was improved for clinical application by using 1) retrospective DUS gating, and 2) motion detection and rejection/correction algorithms for compensating for fetal motion. The free-breathing reconstructions were qualitatively and quantitatively assessed, and DUS-gating was compared with self-gating in breath-hold reconstructions. A scoring of 1-4 for overall image quality, cardiac, and extracardiac diagnostic quality was used.
Friedman's test was used to assess differences in qualitative scoring between observers. A Wilcoxon matched-pairs signed rank test was used to assess differences between breath-hold and free-breathing acquisitions and between observers' quantitative measurements.
In all cases, 111 free-breathing and 145 breath-hold acquisitions, the automatically calculated DUS-based cardiac gating signal provided reconstructions of diagnostic quality (median score 4, range 1-4). Free-breathing did not affect the DUS-based cardiac gated retrospective radial reconstruction with respect to image or diagnostic quality (all P > 0.06). Motion detection with rejection/correction in k-space produced high-quality free-breathing DUS-based reconstructions [median 3, range (2-4)], whereas free-breathing self-gated methods failed in 80 out of 88 cases to produce a stable gating signal.
Free-breathing fetal cine cardiac MRI based on DUS gating and tyGRASP with motion compensation yields diagnostic images. This simplifies acquisition for the pregnant woman and thus could help increase fetal cardiac MRI acceptance in the clinic.
2 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2020;51:260-272.
胎儿心血管磁共振成像可补充超声检查，以评估胎儿心血管病理生理学。
使用多普勒超声（DUS）心脏门控和微小金角径向采样（tyGRASP）开发一种用于回顾性胎儿电影磁共振成像的自由呼吸方法，用于加速采集，能够检测胎儿运动以进行运动补偿。
可行性研究。
9 名志愿者（妊娠 34-40 周）。在孕妇自由呼吸和屏气期间采集短轴和四腔心视图。
磁场强度/序列：1.5T 电影平衡稳态自由进动。
通过使用 1）回顾性 DUS 门控和 2）用于补偿胎儿运动的运动检测和拒绝/校正算法，改进了一种用于临床应用的自门控重建方法。对自由呼吸重建进行定性和定量评估，并将 DUS 门控与屏气重建中的自门控进行比较。使用整体图像质量、心脏和心脏外诊断质量的 1-4 分评分。
采用 Friedman 检验评估观察者之间定性评分的差异。采用 Wilcoxon 配对符号秩检验评估屏气和自由呼吸采集以及观察者定量测量之间的差异。
在所有情况下，111 次自由呼吸和 145 次屏气采集，自动计算的基于 DUS 的心脏门控信号提供了具有诊断质量的重建（中位数评分为 4，范围为 1-4）。自由呼吸不会影响基于 DUS 的心脏门控回顾性径向重建的图像或诊断质量（所有 P > 0.06）。在 k 空间中使用拒绝/校正进行运动检测产生了高质量的自由呼吸基于 DUS 的重建[中位数 3，范围（2-4）]，而 88 例中有 80 例自由呼吸自门控方法未能产生稳定的门控信号。
基于 DUS 门控和 tyGRASP 运动补偿的自由呼吸胎儿电影心脏磁共振成像可获得诊断图像。这简化了孕妇的采集过程，因此有助于提高胎儿心脏磁共振成像在临床中的接受度。
2 技术功效阶段：1 J. Magn. Reson. Imaging 2020;51:260-272.
