Clinical validation of the avidin/indium-111 biotin approach for imaging infection inflammation in orthopaedic patients

We report here the results of a validation study of the avidin/indium-111 b iotin approach in patients with skeletal lesions. This study involved 54 pa tients with orthopaedic conditions: 20 patients with intermediate suspected osteomyelitis of the trunk, 19 patients with infection/inflammation of pro sthetic joint replacements, and 15 patients with suspected osteomyelitis of appendicular bones. Avidin (3 mg) was injected as an i.v. bolus, followed 4 h later by In-111-biotin; imaging was acquired 30 min and 16-18 h after a dministration of In-111-biotin. Technetium-99m hexamethylpropylene amine ox ime (Tc-99m-HMPAO)-labelled leucocyte scintigraphy was performed in 39/54 p atients. The overall sensitivity of the avidin/In-111-biotin scan was 97.7% (versus 88.9% for Tc-99m-HMPAO leucocyte scintigraphy). While the diagnost ic performance of avidin/(111)Inbiotin scintigraphy was similar to that of Tc-99m-HMPAO leucocyte scintigraphy in patients with prosthetic joint repla cements or osteomyelitis of appendicular bones, the avidin/In-111-biotin ap proach clearly performed better than 99mTc-HMPAO leucocyte scintigraphy in patients with suspected osteomyelieis of the trunk (100% sensitivity, speci ficity and accuracy Versus 50% sensitivity, 100% specificity and 66.7% accu racy for Tc-99m-HMPAO-leucocyte scintigraphy). These results demonstrate th e feasibility of the avidin/In-111-biotin approach for imaging sites of inf ection/inflammation in the clinical setting. Although no systematic advanta ges:of avidin/In-111-biotin scintigraphy were found versus Tc-99m-HMPAO leu cocyte scintigraphy, the newer scintigraphic method is more practicable and involves lower biological risk for the operators.