Simultaneous Spatial and Velocity Vector Mapping with Diffraction Tomography

Abstract

Current Doppler ultrasound technology privides only two-dimensional projections of vessels or velocity patterns, is highly operator-dependent and is unable to accomplish accurate maps of the vessel lumen and flow velocity at the same time. Doppler techniques are limited in their ability to detect or measure small or deep vessels especially in the presence of slow flow, although new contrast media may enhance sensitivity. Even in superficial vessels such as the corotid artery, a very small number of pixels defines the flow channel. The aim of this study was to explore a novel diffraction tomography technique for producing quantitative, high- resolution cross-sectional Doppler images. Using this approach, a flow channel or vessel may be mapped in sequential tomograms providing a unique representation of the three- dimensional patterns of complex, curvilinear, multi-phasic or turbulent flows. The method is based on instrumentation initially developed for breast imaging¹ where the value of Doppler flow data is proving valuable for breast cancer diagnosis.