法洛四联症患者腔静脉血流分布：应用 4D 流磁共振成像示踪粒子对其进行定量分析。
Caval blood flow distribution in patients with Fontan circulation: quantification by using particle traces from 4D flow MR imaging.
机构信息
Department of Radiology, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 367, Santiago 8330024, Chile.
出版信息
Radiology. 2013 Apr;267(1):67-75. doi: 10.1148/radiol.12120778. Epub 2013 Jan 7.
PURPOSE
To validate the use of particle traces derived from four-dimensional (4D) flow magnetic resonance (MR) imaging to quantify in vivo the caval flow contribution to the pulmonary arteries (PAs) in patients who had been treated with the Fontan procedure.
MATERIALS AND METHODS
The institutional review boards approved this study, and informed consent was obtained. Twelve healthy volunteers and 10 patients with Fontan circulation were evaluated. The particle trace method consists of creating a region of interest (ROI) on a blood vessel, which is used to emit particles with a temporal resolution of approximately 40 msec. The flow distribution, as a percentage, is then estimated by counting the particles arriving to different ROIs. To validate this method, two independent observers used particle traces to calculate the flow contribution of the PA to its branches in volunteers and compared it with the contribution estimated by measuring net forward flow volume (reference method). After the method was validated, caval flow contributions were quantified in patients. Statistical analysis was performed with nonparametric tests and Bland-Altman plots. P < .05 was considered to indicate a significant difference.
RESULTS
Estimation of flow contributions by using particle traces was equivalent to estimation by using the reference method. Mean flow contribution of the PA to the right PA in volunteers was 54% ± 3 (standard deviation) with the reference method versus 54% ± 3 with the particle trace method for observer 1 (P = .4) and 54% ± 4 versus 54% ± 4 for observer 2 (P = .6). In patients with Fontan circulation, 87% ± 13 of the superior vena cava blood flowed to the right PA (range, 63%-100%), whereas 55% ± 19 of the inferior vena cava blood flowed to the left PA (range, 22%-82%).
CONCLUSION
Particle traces derived from 4D flow MR imaging enable in vivo quantification of the caval flow distribution to the PAs in patients with Fontan circulation. This method might allow the identification of patients at risk of developing complications secondary to uneven flow distribution.
SUPPLEMENTAL MATERIAL
http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120778/-/DC1.
目的
验证利用四维（4D）血流磁共振成像（MR）技术获得的示踪粒子来量化接受 Fontan 手术治疗的患者体内腔静脉血流对肺动脉（PA）的贡献。
材料与方法
本研究经机构审查委员会批准，并获得了知情同意。共评估了 12 名健康志愿者和 10 名 Fontan 循环患者。粒子示踪法包括在血管上创建一个感兴趣区（ROI），用大约 40 毫秒的时间分辨率发射粒子。然后，通过计数到达不同 ROI 的粒子来估计血流分布百分比。为了验证该方法，两位独立观察者使用粒子示踪法计算志愿者 PA 分支的血流贡献，并将其与通过测量净前向血流体积（参考方法）估计的贡献进行比较。方法验证后，量化了患者的腔静脉血流贡献。采用非参数检验和 Bland-Altman 图进行统计学分析。P<0.05 表示差异有统计学意义。
结果
使用粒子示踪法估计血流贡献与参考方法相当。志愿者 PA 对右 PA 的平均血流贡献，观察者 1 用参考方法为 54%±3（标准差），用粒子示踪法为 54%±3（P=0.4），观察者 2 为 54%±4 与 54%±4（P=0.6）。Fontan 循环患者中，上腔静脉 87%±13的血流流入右 PA（范围为 63%-100%），而下腔静脉 55%±19的血流流入左 PA（范围为 22%-82%）。
结论
4D 血流 MR 成像生成的示踪粒子可在活体量化 Fontan 循环患者腔静脉血流对 PA 的分布。该方法可能有助于识别因血流分布不均而导致发生并发症风险较高的患者。
补充材料
http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120778/-/DC1.
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