Ma Liliana, Yerly Jérôme, Di Sopra Lorenzo, Piccini Davide, Lee Jeesoo, DiCarlo Amanda, Passman Rod, Greenland Philip, Kim Daniel, Stuber Matthias, Markl Michael
Department of Radiology, Feinberg School of Medicine, Chicago, Illinois, USA.
Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA.
Magn Reson Med. 2021 Jun;85(6):3125-3139. doi: 10.1002/mrm.28642. Epub 2021 Jan 5.
This study used a 5D flow framework to explore the influence of arrhythmia on thrombogenic hemodynamic parameters in patients with atrial fibrillation (AF).
A fully self-gated, 3D radial, highly accelerated free-running 5D flow sequence with interleaved four-point velocity-encoding was acquired using an in vitro arrhythmic flow phantom and in 25 patients with a history of AF (68 ± 8 y, 6 female). Self-gating signals were used to calculate AF burden, bin data, and tag each k-space line with its RR . Data were binned as an RR-resolved dataset with four RR-interval bins (RR1-RR4, short-to-long) for compressed sensing reconstruction. AF burden was calculated as interquartile range of all intrascan RR-intervals divided by median RR-interval, and left atrial (LA) stasis as the percent of the cardiac cycle where the velocity was <0.1 m/s.
In vitro results demonstrated successful recovery of RR-binned flow curves using RR-resolved 5D flow compared to a real-time PC reference standard. In vivo, 5D flow was acquired in 8:48 minutes. AF burden was significantly correlated with 5D flow-derived peak (PV) and mean (MV) velocity and stasis (|ρ| = 0.54-0.75, P < .001). Sensitivity analyses determined a threshold for low versus high AF burden at 9.7%. High burden patients had increased LA mean stasis (up to +42%, P < .01), and lower MV and PV (-30%, -40.6%, respectively, P < .01). RR4 deviated furthest from respiratory-resolved reconstruction (end-expiration) with increased mean stasis (7.6% ± 14.0%, P = .10) and decreased PV (-12.7 ± 14.2%, P = .09).
RR-resolved 5D flow can capture temporal and RR-resolved 3D hemodynamics in <10 minutes and offers a novel approach to investigate arrhythmias.
本研究采用5D血流框架，探讨心律失常对心房颤动（AF）患者血栓形成血流动力学参数的影响。
使用体外心律失常血流模型以及25例有AF病史的患者（68±8岁，6名女性），采用具有交错四点速度编码的全自门控、3D径向、高度加速自由运行5D血流序列。自门控信号用于计算AF负荷、分箱数据，并为每个k空间线标记其RR间期。数据被分箱为具有四个RR间期箱（RR1-RR4，从短到长）的RR分辨数据集，用于压缩感知重建。AF负荷计算为所有扫描内RR间期的四分位数间距除以RR间期中位数，左心房（LA）血流淤滞计算为速度<0.1 m/s的心动周期百分比。
体外结果表明，与实时PC参考标准相比，使用RR分辨的5D血流成功恢复了RR分箱血流曲线。在体内，5D血流采集用时8分48秒。AF负荷与5D血流衍生的峰值（PV）和平均（MV）速度以及血流淤滞显著相关（|ρ| = 0.54 - 0.75，P <.001）。敏感性分析确定低AF负荷与高AF负荷的阈值为9.7%。高负荷患者的LA平均血流淤滞增加（高达+42%，P <.01），MV和PV降低（分别为-30%、-40.6%，P <.01）。RR4与呼吸分辨重建（呼气末）偏差最大，平均血流淤滞增加（7.6%±14.0%，P =.10），PV降低（-12.7±14.2%，P =.09）。
RR分辨的5D血流可在10分钟内捕获时间和RR分辨的3D血流动力学，并为研究心律失常提供了一种新方法。
