Initial experience comparing B-mode imaging and venography of the saphenous vein before in situ bypass.

Preoperative saphenous vein assessment was performed using both venography and B-mode scanning. Fifty patients underwent preoperative assessment, and the results were compared with the intraoperative findings. Both venography and B-mode imaging were equally accurate at determining the dominant saphenous system, but B-mode imaging missed five thigh double systems that were shown on venography. Neither venography nor B-mode imaging were good predictors of actual vein size at most sites in the leg, with the exception of B-mode assessment below the knee, where there was a positive correlation with intraoperative vein size (r = 0.80; p less than 0.01). In our study, B-mode scanning was consistently more reliable in determining vein presence and continuity than venography, which gave nine false-negative results. Finally, B-mode imaging allows the marking of a saphenous vein map on the patient's leg preoperatively as a guide to bypass surgery.