[Scintigraphy with 99MTc-HMPAO labeled leukocytes and computed tomography in the diagnosis of vascular graft...

The purpose of this work was to compare the results obtained with a scitigraphy using 99mTc-HMPAO labeled leukocyte and a computed tomography (CT) in the diagnosis of vascular graft infection (VGI). We carried out 22 studies with both scintigraphy and CT in 20 patients with vascular grafts with VGI suspicion. One patient had two grafts, thus a total of 23 grafts were analyzed. In addition, 6 control studies were performed. The persistent increase in leukocyte uptake in the graft area was considered as evidence of VGI and the scintigraphy with HMPAO-99mTc labeled leukocytes. For the CT, the presence of perigraft fluid and/or gas collection in the graft bed was also considered to be evidence of VGI. The total number of VGI was 12. The VGI diagnosis was confirmed by culture in all cases. The sensitivity and specificity of the scintigraphy in the diagnosis of VGI was 100%, while the CT has a sensitivity of 58% and specificity of 91%. Five grafts presented pseudoaneurysm in distal aorto-bifemoral graft anastomosis. All theses cases were detected with CT and only one patient with pseudoaneurysms showed scintigraphic evidence of VGI. In addition, both techniques detected two soft tissue infections associated with cutaneous fistulae, one case of abdominal abscess and another of acute diverticulitis. The scintigraphy was also pathologic in one infection of the surgical wound while that the CT was negative. In conclusion, although both techniques are useful to evaluate patients with suspicion of VGI, the scintigraphy with 99m-Tc-HMPAO labeled leukocytes has been shown to be more sensitive than the CT in the assessment of patients with VGI suspicion.