Abstract
Radiologic investigation of malfunctioning central venous catheters is conventionally performed using a bolus injection of either radiographic contrast material or a radionuclide solution. An alternative scintigraphic technique employing a slow radionuclide infusion is described. The association between retrograde flow in an obstructing fibrin sleeve and leakage from a central venous catheter is better demonstrated using this technique than with imaging after a bolus injection.