Estimation of the correlation amplitude of RF signals in small cutaneous vessels

作     者：Gens, F Remenieras, JP Diridollou, S Patat, F 

作者机构：GIP Ultrasons EA 2102 F-37032 Tours France IRPF Dept Rech Evaluat & Dermocosmet F-31400 Toulouse France 

出 版 物：《IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL》 (IEEE Trans Ultrason Ferroelectr Freq Control)

年 卷 期：2000年第47卷第6期

页      面：1455-1462页

核心收录：

学科分类：0808[工学-电气工程] 07[理学] 08[工学] 070206[理学-声学] 080402[工学-测试计量技术及仪器] 0804[工学-仪器科学与技术] 0802[工学-机械工程] 0702[理学-物理学] 

主　　题：biomedical ultrasonics blood flow measurement correlation methods time-domain analysis RF signals acoustical footprint blood flow velocity measurement correlation amplitude correlation peak amplitude estimator cross-correlation algorithm cutaneous vessel radio frequency signal Time domain analysis blood flow test correlation methods Cross correlation Blood Flow Amplitude biomedical ultrasonics Blood Circulation low SNR 

摘      要：Time domain correlation technique is a widely used method for blood flow velocity measurement. The time shift between a pair of windowed ultrasonic echoes is estimated by searching the temporal position of the maximum of the interpolated normalized correlation function. Between two consecutive echoes, the acoustical footprint of a group of scatterers, which are transported with the how, moves and is deformed. This implies a decreasing of the amplitude of the normalized correlation coefficient. In the case of microcirculation (low how rate, low SNR), the amplitude of the correlation peak can be used to detect the presence of blood flow and to discriminate false and true detections (reliability index). We have numerically evaluated the statistical performances of the cross-correlation algorithm used as a correlation peak amplitude estimator in severe conditions (short correlation window length, low SNR). These theoretical results have been compared with in vitro experimentation on a 100-mum-diameter microcirculatory phantom and with in vivo experimentation on a 180-mum-diameter vessel of a human leg carrying erysipelas.