Seifalian A M, Hawkes D J, Hardingham C R, Colchester A C, Reidy J F
Academic Department of Surgery, Royal Free Hospital School of Medicine, London, UK.
J Biomed Eng. 1991 May;13(3):225-33. doi: 10.1016/0141-5425(91)90132-q.
We have validated a new radiographic technique for determining pulsatile volume flow in arteries following an intraarterial injection of contrast material. Instantaneous blood velocities were estimated by generating a parametric image from dynamic angiographic images in which the image grey level represents contrast material concentration as a function of time and distance along a vessel segment. Adjacent concentration--distance profiles in the parametric image were shifted with respect to distance until a match occurred. A match was defined as the point where the sum of squares of the differences in the two profiles was a minimum. The distance translated per frame interval gives the instantaneous contrast material bolus velocity. We have validated the technique using an experimental phantom of blood circulation, consisting of a pump, flexible plastic tubing, the tubular probe of an electromagnetic flowmeter (EMF) and a solenoid, to simulate a pulsatile flow waveform, which includes reverse flow. Small boluses of contrast material can be injected at various positions in the circuit. Measurements of pulsatile velocity flow were taken at 40 ms intervals, using a tube of 6.6 mm internal diameter and an imaged tube length of 200 mm. The shape of the flow velocity waveform was faithfully reproduced but there was an overestimation of peak velocity of 40% at low velocities (peak velocity of 540 mm s-1), reducing to 19% at peak velocities of 964 mm s-1 with an underestimation of 16% at the peak velocities of 1899 mm s-1. The validation was repeated for distances ranging from 130 to 230 mm between injection and measurement sites and for imaged tube lengths varying from 200 to 20 mm.(ABSTRACT TRUNCATED AT 250 WORDS)
我们验证了一种新的影像学技术，用于在动脉内注射造影剂后测定动脉中的搏动性容积流量。通过从动态血管造影图像生成参数图像来估计瞬时血流速度，其中图像灰度级表示造影剂浓度随时间和沿血管段距离的函数。参数图像中相邻的浓度-距离剖面相对于距离进行移位，直到出现匹配。匹配定义为两个剖面差异平方和最小的点。每帧间隔平移的距离给出瞬时造影剂团块速度。我们使用血液循环实验模型验证了该技术，该模型由泵、柔性塑料管、电磁流量计（EMF）的管状探头和螺线管组成，以模拟包括逆流的搏动血流波形。可以在回路中的不同位置注射小剂量的造影剂。使用内径为6.6 mm的管子和成像管长度为200 mm，以40 ms的间隔进行搏动速度流量测量。流速波形的形状得到了如实再现，但在低流速（峰值流速为540 mm s-1）时峰值流速高估了40%，在峰值流速为964 mm s-1时降至19%，在峰值流速为1899 mm s-1时低估了16%。在注射和测量部位之间的距离范围为130至230 mm以及成像管长度从200至20 mm变化的情况下重复进行了验证。（摘要截断于250字）
