Wellnhofer E, Finke W, Bernard L, Dänschel W, Fleck E
Department of Internal Medicine and Cardiology, Humboldt University, Germany.
Int J Card Imaging. 1997 Feb;13(1):25-34. doi: 10.1023/a:1005714629995.
Easy and safe in-vivo flow velocity studies in small coronary arteries have become feasible using a 0.014 'or 0.018' guidewire with an integrated Doppler probe in its tip (FloWire, Cardiometrics). Assessment of the flow velocity profile by the ratio of diastolic to systolic flow velocity (DSVR) is used as a diagnostic parameter. However, DSVR is a coarse quantifier of the flow velocity profile, and is subject to large physiologic variance and depends crucially on the quality of the Doppler signal. The aim of our study was to test parameters derived from statistical time series analysis for monitoring the quality of the instantaneous peak velocity (IPV) signal. Improvement of quantification of changes in quality and shape of flow velocity profiles by these parameters as compared to DSVR was a second goal. We investigated analog-digital converted IPV-signals and video registrations of corresponding greyscale spectra of intracoronary Doppler flow velocity signals. The signals were analyzed by using the autocorrelation function (ACF) in the time domain and a fast Fourier transform (FFT) in the frequency domain (standard time series statistics). The first minimum of autocorrelation function turned out to be very sensitive to signal quality, and Fisher's g of the periodogram was the parameter of choice for shape analysis. In 11 patients with coronary artery disease, pre and post PTCA, the sensitivity of DSVR and signal to noise ratio to changes in shape and quality of the flow velocity signals was compared to that of the new parameters. Nineteen Doppler flow velocity samples of good quality from measurements in nonstenotic vessels and 7 flow velocity tracings with visible artefacts were used to assess the value of these parameters in monitoring signal quality. By comparison with corresponding parameters in use (SNR and DSVR) a significantly improved performance of the new statistical parameters was observed with respect to sensitivity to changes in signal quality and flow profile. In view of these results and because of the short calculation time of these variables they should be used for on-line quality control and analysis of flow velocity profiles.
使用一种尖端集成了多普勒探头的0.014或0.018导丝（FloWire，Cardiometrics公司），在小型冠状动脉中进行简单且安全的体内血流速度研究已成为可能。通过舒张期与收缩期血流速度之比（DSVR）来评估血流速度剖面，将其用作诊断参数。然而，DSVR是血流速度剖面的粗略量化指标，存在较大的生理变异，并且关键取决于多普勒信号的质量。我们研究的目的是测试从统计时间序列分析得出的参数，以监测瞬时峰值速度（IPV）信号的质量。与DSVR相比，通过这些参数改善血流速度剖面质量和形状变化的量化是第二个目标。我们研究了模拟 - 数字转换后的IPV信号以及冠状动脉内多普勒血流速度信号相应灰度谱的视频记录。通过在时域中使用自相关函数（ACF）和在频域中使用快速傅里叶变换（FFT）（标准时间序列统计）对信号进行分析。结果表明，自相关函数的第一个最小值对信号质量非常敏感，而周期图的Fisher's g是形状分析的首选参数。在11例冠心病患者PTCA术前和术后，将DSVR和信噪比对于血流速度信号形状和质量变化的敏感性与新参数的敏感性进行了比较。使用来自非狭窄血管测量的19个高质量多普勒血流速度样本以及7个带有可见伪像的血流速度描记图来评估这些参数在监测信号质量方面的价值。与使用中的相应参数（SNR和DSVR）相比，新的统计参数在对信号质量和血流剖面变化的敏感性方面表现出显著改善。鉴于这些结果，并且由于这些变量的计算时间短，它们应用于血流速度剖面的在线质量控制和分析。
