New isotopic technique for detecting prosthetic arterial graft infection: 99mTc-hexametazime-labelled leucocyte imaging. Early and accurate detection of prosthetic arterial graft infection is important because this serious complication of vascular surgery carries high morbidity and mortality rates. This report describes the use of a new method of isotopic imaging to detect graft infection using 99mTc-hexametazime-labelled leucocytes. Seventeen patients with potentially infected arterial grafts were imaged in addition to routine investigations but were managed according to our normal surgical practice. 99mTc-imaging was positive in eight patients with proven graft infection and falsely positive in one patient with a groin haematoma (89 per cent specificity). There were no false negatives (100 per cent sensitivity) after an average follow-up of 6 months (range 3-9 months). This technique has proved a reliable and rapid method of confirming graft infection. 