Fetal descending aorta detailed velocity profiles in real-time using a novel global acquisition & signal processing (G.A.S.P.) software for the multigate spectral doppler analysis

Abstract

A NOVEL GLOBAL ACQUISITION & SIGNAL PROCESSING (G.A.S.P.) SOFTWARE FOR THE MULTIGATE SPECTRAL DOPPLER ANALYSIS GABRIELE URBAN, PASQUALE PATRIZIO, PIERO TORTOLI, STEFANO RICCI, FABIO SANGUINETI, PATRIZIA VERGANI, MICHAEL PAIDAS, Yale University, Obstetrics & Gynecology, New Haven, Connecticut, University of Florence, Electronic Engineering, Florence, Italy, University of Milano-Bicocca, Monza, Milano, Italy OBJECTIVE: To study velocity profiles, relative wall distension rate (rWDR) of fetal descending aorta (FDA) and shear rate (WSR) in uncomplicated singleton pregnancy. STUDY DESIGN: Eighty Two uncomplicated singleton fetuses were studied at different gestational ages using Multigate Spectral Doppler Analysis (MSDA) working with GASP software. This consists of a PC add-on board including a single high-speed digital signal processor. The analysis of echosignals backscattered from 256 range cells located along the axis of the interrogating ultrasound (US) beam. Post-processing were done using GASP software. Statistical analysis consisted of Spearman correlation and chi-square test. RESULTS: Velocity profiles, wall distension, wall shear rate were obtained from fetal descending aorta at different gestational age. Comparables results from conventional Doppler masks different velocity profiles, turbulent flow (4 cases), downstream (5 cases), partial reverse in diastole (3 cases). WDR[%] is highly correlated with gestational age and fetal growth (2.7G1.8 , rs=0.471 p!0.01) with linear regression with standardized coefficient of 0.4 (p!0.01). Otherwise WSR (432G191) is not significantly variable (P=0.7) from first , second and third trimester. CONCLUSION: This novel technology is more sensitive than conventional Doppler in detecting patterns other than pseudo-laminar flow. The progressive linear increase of wall distansibility detected could be explained by the accumulation of elastin that contributes most to developmental change. The mean WSR for the study group was independent and constant throughout the gestation. This suggest that unless the increase of aortal size adapts to the flow demands and maintain constant the hemodynamic characteristics. The relative WDR changes during gestation, in normal growth, may be secondary to adaptive vascular and autonomic responses and the evolving composition of the vessel wall, particularly with respect to elastin.