Infected atrioventricular shunt: Importance of delayed (24-hour) Tc-99m HMPAO leukocyte imaging

The current recommendation for Tc-99m HMPAO-labeled leukocyte imaging is at 4-6 hours. This early imaging might not be long enough for localization of the labeled leukocytes at a site of infection and for further blood pool clearance. The scintigraphic findings of a patient with an infected ventriculoatrial shunt were negative at 4 hours, whereas at 24 hours there was intense uptake in the region of the right atrium. The case demonstrates that the 24-hour images were more sensitive to localize an infected catheter in the right atrium. If early images performed the same day as the administration of Tc-99m HMPAO-labeled leukocyte appear negative, delayed imaging the next day at 24 hours is recommended.