3-D ultrasonic imaging of the structure and elasticity of the carotid bifurcation

The long-term goal of this work is to develop an ultrasound technique that produces a 3-D image of the structure and elasticity of the cervical common carotid artery and its bifurcation, allowing the quantitative measurement of the volume, structure and composition of atherosclerotic plaque at or near the bifurcation. An Acuson 128 imaging system was used to obtain time-gated B-mode images of the carotid in vivo. The motion of the vessel wall due to the changing blood pressure during a cardiac cycle was quantified and used to compute an estimate of the tissue elasticity distribution over each 2-D image plane. The tissue motion direction and amplitude was determined by a 2-D interframe block matching technique performed on a sequence of frames acquired at 18 frames per second. The transducer was moved linearly along the axis of the common carotid in 2 mm increments to collect the set of slices used to form the 3-D image. Volumetric images of the phantom have been made. Elasticity measurements indicate that the tissue motion appears to be an adequate measure for the determination of relative elasticity distributions.