Panel Disdussion

3rd International Congress of of Nuclear Medicine & & 15th 15th Iranian Annual Annual Congress of
Congress of Nuclear Medicine
Shahid Beheshti Shahid Beheshti University University of Medical of Medical Sciences Sciences 19-21 19-21 May May 2011
The role of nuclear medicine in the diagnosis of infected joint
prostheses
K. Aryana
Nuclear Medicine Department, Mashhad University of Medical Sciences
Some complications of joint replacement surgery are easily
diagnosed; however, differentiating infection from aseptic loosening
is difficult because these entities are remarkably similar at clinical
and histopathologic examination. Clinical signs and symptoms,
laboratory tests, radiography, and joint aspiration are insensitive,
nonspecic, or both. Cross-sectional imaging modalities are
hampered by artifacts produced by the prosthetic devices
themselves. Radionuclide imaging is not affected by the presence of
metallic hardware and is therefore useful for evaluating the painful
prosthesis. Bone scintigraphy is useful as a screening test, despite an
accuracy of only 50%–70%, because normal results essentially
exclude a prosthetic complication. The addition of gallium-67, a
nonspecic inammation-imaging agent, improves the accuracy of
bone scintigraphy to 70%– 80%. The accuracy of combined
leukocyte-marrow imaging, 90%, is the highest among available
radionuclide studies. Its success is due to the fact that leukocyte
imaging is most sensitive for detection of neutrophil-mediated
inammation . The success of leukocyte-marrow imaging is tempered
by the limitations of in vitro labeling. In vivo labeling has been
investigated, and a murine monoclonal antigranulocyte antibody
appears promising. Ubiquicidin (UBI) 29–41 is a small synthetic
antimicrobial cationic peptide that binds preferentially to the anionic
present on microbial cell membrane at the site of infection is highly
sensitive and specific for differentiating of infected prosthesis from
loosening. Tc99m-ciprofloxacin (Infecton) has recently been
established as a new radiopharmaceutical for infection imaging.
Infecton has a sensitivity of 85%, specificity of 92%, and accuracy of
88% in detecting orthopaedic infections compared with 78%, 100%,
and 90% respectively for combined bone and gallium imaging. Some
investigations have focused on uorodeoxyglucose imaging. Although
this method is sensitive, specicity is a concern
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