Arm vein uptake of thallium-201 during exercise: incidence and clinical significance.

We prospectively analyzed several clinical and technical variables that might be associated with arm vein uptake of 201Tl during stress thallium scintigraphy in 63 patients. The influence of site (medial antecubital vs. other vein) and technique (with or without a 15-cc saline flush) were examined. Arm vein uptake was not seen after medial antecubital injections except in one case injected through a 24-hr-old indwelling catheter. Arm vein uptake was seen in 24/45 (53%) of cases injected into veins other than the medial antecubital. A saline flush did not reduce the incidence of arm uptake. In patients with normal myocardial studies, those with positive arm uptake had 33% lower net myocardial counts on the postexercise images (p = 0.00008) and 20% lower net myocardial counts on the delayed images (p = 0.04). Myocardial washout of thallium was significantly (p = 0.009) slower in those with arm uptake.