Cross-sectional area changes in peripheral vein grafts monitored by three-dimensional ultrasound imaging

Abstract

Vein grafts are placed to bypass diseased arteries in the lower limb when symptoms such as pain during walking, rest pain, and tissue necrosis occur. Frequent surveillance of these grafts is recommended since early detection and revision of stenoses improves the likelihood of long-term patency. We are using three-dimensional (3D) ultrasound imaging to measure progressive changes in vein graft geometry. Cross-sectional area measurements in planes normal to the vessel center axis are calculated from 3D surface reconstructions. Data sets from serial studies are registered in a common coordinate system using anatomical reference points and cross-sectional area measurements are compared at matched sites. Extended studies have tracked patients requiring surgical revision to enlarge the vessel lumen in stenotic regions of their grafts. Follow-up periods on 5 cases range from 30 to 79 weeks to date. Each revised graft segment demonstrated a decrease in cross-sectional area over time, ranging from 25% to 77%, averaged over the length of the revision. The sequential area measurements, combined with 3D surface displays, provide a record of remodeling patterns and rates at specific sites within the grafts.