Close R A, Duckwiler G R, Viñuela F
Department of Radiological Sciences, UCLA School of Medicine.
Invest Radiol. 1992 Jul;27(7):504-9. doi: 10.1097/00004424-199207000-00004.
Time-dependent fluid flow is computed from projection radiographs without bolus tracking by applying the fluid equations of continuity and incompressibility.
The fluid equations are combined and integrated to yield an equation that describes instantaneous mass conservation within a vessel segment. The technique is demonstrated using phantom images and patient data obtained using a digital subtraction angiography (DSA) system.
Instantaneous and mean flow rates are successfully computed with this algorithm, but the uncertainties are overestimated. In a 1.0-cm diameter tube, instantaneous and mean velocities corresponding to 7.3 cm per frame are computed within 13% uncertainty using a 4.0-cm segment length. Mean flow rates computed from standard diagnostic angiograms taken from three different projections agree within 16%.
This technique can successfully compute time-dependent flow rates from DSA image sequences with large fluid displacements between frames. The accuracy is strongly dependent on the magnitude of the contrast density gradient.
通过应用连续性和不可压缩性流体方程，在不进行团注追踪的情况下从投影射线照片计算随时间变化的流体流动。
将流体方程进行合并与积分，以得到一个描述血管段内瞬时质量守恒的方程。使用体模图像和通过数字减影血管造影（DSA）系统获得的患者数据对该技术进行了演示。
使用该算法成功计算出了瞬时和平均流速，但不确定性被高估。在直径为1.0厘米的管道中，使用4.0厘米的段长度，在13%的不确定性范围内计算出了对应于每帧7.3厘米的瞬时和平均速度。从三个不同投影获取的标准诊断血管造影计算出的平均流速在16%以内相符。
该技术能够成功地从DSA图像序列中计算出帧间有大流体位移情况下随时间变化的流速。准确性强烈依赖于对比剂密度梯度的大小。
