Non-doppler Three Dimensional Flow Images Obtained vi Reconstruction from 2D Vector Velocity Maps

We describe method for producing three dimensional images of flow magnitude and direction. The method involves the use of an ultrasonic vector velocity speckle tracking system which computes 2D flow velocity maps in real time. This system, unlike current Doppler instrumentation, quantifies both the axial and lateral components of flow velocity vectors and thereby requires no angle correction. Numerous velocity maps are obtained for successive, closely spaced parallel planes by translating the ultrasound transducer across the flow region of interest. These 2D velocity maps are processed vi commercial graphics software to yield three dimensional images showing the magnitudes and directions of flow throughout the interrogated volume. We present images from in vitro experiments with jet phantom and 4 mm vessel surrounded by tissue mimicking material. Constant-velocity surfaces obtained from the jet phantom allow visualization of the characteristic high velocity central core, surrounded by cones of lower velocities farther from the jet centerline. Directional arrows superimposed on images of the 4 mm vessel allow visualization of the three dimensional flow velocity profile. Results indicate the promise of this technique for improved visualization and absolute quantification of cardiac flow in an angle independent fashion.