Vascular competence in the upper extremities of 44 patients was evaluated by three-phase bone scans consisting of rapid sequence dynamic radionuclide imaging (DRI), an immediate postinjection "blood pool" image, and a 3- to 4-hour delayed image. Findings were correlated with definitive anatomy determined by arteriography, operative findings, or both, in 50 extremities. DRI provided the correct diagnosis in all but four extremities (92%). Limited resolution precluded precise anatomic definition of aneurysms in three limbs and of digital artery occlusion, with adequate collateral circulation in the fourth limb. The greatest value of DRI was its provision of quantitative information about relative blood flow and preferential perfusion in every instance. We believe DRI to be a useful adjunct to preoperative and postoperative assessment of arterial perfusion.