Vector‐Doppler ultrasound for the detection of internal bleeding

A vector Doppler (VDop) ultrasound system uses a transmitter and a spatially separated pair of receivers to measure bistatic scattering from blood. VDop has two principal advantages over color‐flow Doppler in identifying internal bleeding: (1) measures flow direction, and thus absolute magnitude of flow velocity (2) does not require special orientation to detect and measure flow, thus can measure flows perpendicular to the transmitter. Our hypothesis is that real‐time flow direction and magnitude can be used to detect and characterize internal bleeding. A real‐time vector Doppler system has been built and tested in vitro. The system is capable of measuring flow magnitude and direction up to 145 cm/s at a depth of 3.6 cm at a processing rate of 10 Hz. Accuracy was measured using a calibrated moving string phantom and the system performs well within a useful range. A blood flow phantom was developed to mimic arterial flow into an open cavity as well as into tissue and replicate both pulsatile flow as well as the energy storage due to vascular elasticity. Flow signature data is gathered under conditions of normal branching flow, and vessel breach. The talk will describe the VDop system and the flow phantom and summarize results.