Serial measurement of cross-sectional area in peripheral vein grafts using three-dimensional ultrasound.

Frequent surveillance of bypass grafts placed in the lower limbs can provide early detection of stenoses. A three-dimensional (3-D) ultrasound (US) imaging system has been used to produce serial surface reconstructions of regions of interest in vein grafts in the lower extremities. Using anatomical reference points, data sets from serial studies are registered in a common 3-D coordinate system. Cross-sectional area measurements are extracted from the surface reconstructions in planes normal to the vessel center axis. These measurements are compared at matched sites over time to track changes in the vessel configuration. The quantitative measurements are paired with surface displays of the vessels for a complete depiction of the changing geometry. Example studies from three patients are shown, for time periods up to 38 weeks. The cross-sectional area measurements highlight regions of remodeling and developing stenoses within the grafts.