Josephine Nancy Rini MD, Presenter: Nothing to Disclose

Charito Love MD, Abstract Co-Author: Nothing to Disclose

Nadeem Zia MD, Abstract Co-Author: Nothing to Disclose

Gene G Tronco MD, Abstract Co-Author: Nothing to Disclose

Maria Bernadette Tomas MD, Abstract Co-Author: Nothing to Disclose

Christopher J. Palestro MD, Abstract Co-Author: Nothing to Disclose

Tc99m-fanolesomab (AGA), a radiolabeled murine monoclonal IgM antigranulocyte antibody, binds to CD15 antigens expressed on circulating neutrophils, neutrophils located at sites of infection, and neutrophil debris. This agent, approved by the FDA in July 2004 for scintigraphic imaging of patients with equivocal signs and symptoms of appendicitis, labels human leukocytes in vivo. The goal of this investigation was to review our initial clinical experience with AGA and to determine its accuracy for identifying extraappendiceal sites of infection.

AGA imaging was performed in 26 patients for whom a final institutional diagnosis subsequently was available. Indications for imaging included: suspected osteomyelitis (23 patients) and graft infection (3 patients). Images were obtained 1-7 h (mean 2.4 h) following injection of 75-125 ug fanolesomab labeled with 555-740 MBq (15-20 mCi) Tc99m. Delayed images at 24 h were obtained in 9 patients. Images consisted of whole body and/or 10 minute static views of the area of concern. All studies were prospectively read in consensus by at least 2 experienced nuclear physicians who classified studies as positive or negative for osteomyelitis or graft infection. Imaging results were compared to final institutional diagnoses. Sensitivity, specificity and accuracy were determined.

Final diagnoses were: osteomyelitis (21); graft infection (3); and no infection (2), including 22/26 patients with histopathologic and/or microbiologic confirmation and 4/26 patients with clinical confirmation. AGA scans were interpreted as: 21 positive and 5 negative. AGA studies were correct in 3/3 patients with graft infections. Sensitivity, specificity and accuracy for all patients combined were 83% (20/24), 50% (1/2) and 81% (21/26).

Sensitivity of AGA was similar to previously reported results of clinical trials in patients with suspected osteomyelitis, and comparable to results obtained with In-111 labeled leukocytes. Specificity cannot be accurately assessed in this study population due to the high prevalence of infection. Further investigation in a larger population, with a lower prevalence of infection, is warranted.

C.J.P.: Speaking honoraria from Mallinckrodt, Inc.

Rini, J, Love, C, Zia, N, Tronco, G, Tomas, M, Palestro, C, Initial Clinical Experience with Tc99m-Fanolesomab in Patients with Suspected Infection.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4408578.html