Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
J Cardiovasc Magn Reson. 2010 Feb 12;12(1):9. doi: 10.1186/1532-429X-12-9.
The beating heart is the generator of blood flow through the cardiovascular system. Within the heart's own chambers, normal complex blood flow patterns can be disturbed by diseases. Methods for the quantification of intra-cardiac blood flow, with its 4D (3D+time) nature, are lacking. We sought to develop and validate a novel semi-automatic analysis approach that integrates flow and morphological data.
In six healthy subjects and three patients with dilated cardiomyopathy, three-directional, three-dimensional cine phase-contrast cardiovascular magnetic resonance (CMR) velocity data and balanced steady-state free-precession long- and short-axis images were acquired. The LV endocardium was segmented from the short-axis images at the times of isovolumetric contraction (IVC) and isovolumetric relaxation (IVR). At the time of IVC, pathlines were emitted from the IVC LV blood volume and traced forwards and backwards in time until IVR, thus including the entire cardiac cycle. The IVR volume was used to determine if and where the pathlines left the LV. This information was used to automatically separate the pathlines into four different components of flow: Direct Flow, Retained Inflow, Delayed Ejection Flow and Residual Volume. Blood volumes were calculated for every component by multiplying the number of pathlines with the blood volume represented by each pathline. The accuracy and inter- and intra-observer reproducibility of the approach were evaluated by analyzing volumes of LV inflow and outflow, the four flow components, and the end-diastolic volume.
The volume and distribution of the LV flow components were determined in all subjects. The calculated LV outflow volumes [ml] (67 +/- 13) appeared to fall in between those obtained by through-plane phase-contrast CMR (77 +/- 16) and Doppler ultrasound (58 +/- 10), respectively. Calculated volumes of LV inflow (68 +/- 11) and outflow (67 +/- 13) were well matched (NS). Low inter- and intra-observer variability for the assessment of the volumes of the flow components was obtained.
This semi-automatic analysis approach for the quantification of 4D blood flow resulted in accurate LV inflow and outflow volumes and a high reproducibility for the assessment of LV flow components.
跳动的心脏是心血管系统中血流的发生器。在心脏自身的腔室内，正常的复杂血流模式可能会被疾病扰乱。缺乏用于量化具有 4D（3D+时间）性质的心脏内血流的方法。我们试图开发和验证一种新的半自动分析方法，该方法集成了流量和形态数据。
在六名健康受试者和三名扩张型心肌病患者中，采集了三个方向的三维电影相位对比心血管磁共振（CMR）速度数据和平衡稳态自由进动长轴和短轴图像。在等容收缩（IVC）和等容舒张（IVR）时，从短轴图像上分割 LV 心内膜。在 IVC 时，从 IVC LV 血容量发出轨迹线，并在时间上向前和向后追踪，直到 IVR，从而包括整个心动周期。使用 IVR 体积来确定轨迹线是否以及在何处离开 LV。此信息用于自动将轨迹线分为四种不同的流动成分：直接流动、保留流入、延迟射流和残留体积。通过将轨迹线的数量乘以每条轨迹线所代表的血容量，计算每个成分的血容量。通过分析 LV 流入和流出量、四个流动成分以及舒张末期容积，评估该方法的准确性和观察者内和观察者间的可重复性。
在所有受试者中确定了 LV 流动成分的体积和分布。计算出的 LV 流出量[ml]（67 +/- 13）似乎介于平面相位对比 CMR（77 +/- 16）和多普勒超声（58 +/- 10）获得的值之间。计算出的 LV 流入量（68 +/- 11）和流出量（67 +/- 13）非常匹配（NS）。评估流量成分体积的观察者内和观察者间的变异性较低。
这种用于量化 4D 血流的半自动分析方法可准确测量 LV 流入和流出量，并高度重现性地评估 LV 流量成分。
