The Journal of International Medical Research 2012; 40: 1335 – 1342 Intact versus Fragmented 99mTc-Monoclonal Antibody Imaging of Infection in Patients with Septically Loosened Total Knee Arthroplasty S GRATZ1,2, P REIZE3, A PFESTROFF1 AND H HÖFFKEN1 1Department of Nuclear Medicine, Philipps University, Marburg, Germany; 2Department of Nuclear Medicine, Centre Bad Cannstatt, Stuttgart, Germany; 3Department of Trauma, Reconstructive and Orthopaedic Surgery, Centre Bad Cannstatt, Stuttgart, Germany OBJECTIVE: This prospective study infection was shown in 18 patients. At 4 compared the diagnostic accuracy of and 24 h after intravenous injection, imaging using an intact murine absolute uptake of 99mTc-besilesomab was antigranulocyte antibody 99mTc- significantly higher than 99mTc-sulesomab besilesomab, and a murine antibody Fab′ in infected knee joints. Infected-to-healthy fragment 99mTc-sulesomab, in patients knee activity ratios were similar at 4 and with suspected septically loosened total 24 h for 99mTc-besilesomab and 99mTc- knee arthroplasty. METHODS: Images sulesomab. CONCLUSIONS: Both 99mTc- from 20 patients who underwent three- besilesomab and 99mTc-sulesomab had phase bone scintigraphy followed by similar diagnostic accuracy for the imaging using 99mTc-besilesomab (n = 10) detection of septic arthroplasty. If or 99mTc-sulesomab (n = 10) were evaluated repeated use of immunoscintigraphy is and compared. Final diagnosis was needed for follow-up, 99mTc-sulesomab determined by microbiological evaluation should be preferred over 99mTc- of aspirated synovial fluid, intraoperative besilesomab since it is known to be well samples through the clinical course, or by tolerated and without side effects or long-term follow-up. RESULTS: Prosthesis incompatibility reactions. KEY WORDS: TOTAL KNEE ARTHROPLASTY; RADIONUCLIDE IMAGING; 99MTC-ANTIGRANULOCYTE ANTIBODIES; BESILESOMAB; 99MTC-FAB′ FRAGMENTS; SULESOMAB; INFECTION Introduction scintigraphy, using monoclonal antibodies The increasing numbers of total joint or antibody Fab′ fragments, is a promising arthroplasty procedures performed and the diagnostic tool that is increasingly being need to diagnose complications, such as used to detect prosthesis infection after total loosening and infection, that can occur after knee arthroplasty (TKA).1,2 This approach the implantation of prosthetic components exploits the diapedesis and chemotaxis of have prompted the use of new noninvasive leucocytes by directly targeting leucocyte diagnostic methods.1,2 Antigranulocyte antigens or receptors in vivo via Downloaded from imr.sagepub.com1335 at RUTGERS UNIV on April 7, 2015 S Gratz, P Reize, A Pfestroff et al. Imaging infection in septically loosened total knee arthroplasty administration of radiolabelled for diagnosing knee prosthesis infection in antigranulocyte monoclonal antibodies.3 patients with septically loosened Several studies have evaluated the arthroplasty. efficacy of antigranulocyte scintigraphy with 99mTc-labelled monoclonal antibodies or Fab′ Patients and methods fragments for diagnosing infection in STUDY POPULATION different clinical settings, including Data from patients with suspected septically prosthesis infection after arthroplasty.1,2,4 loosened TKA, who underwent three-phase The agents most commonly used for imaging bone scintigraphy followed by imaging prosthesis infection have been using 99mTc-besilesomab or 99mTc-sulesomab immunoglobulin G (IgG) antibody directed at the Department of Nuclear Medicine, against normal cross-reactive antigen-95 Philipps University, Marburg, Germany, (99mTc-besilesomab)2 and the Fab′ fragment between June 2009 and November 2011, of IgG antibody directed against the were prospectively reviewed. Patients were glycoprotein cross-reactive antigen-90 (99mTc- selected either for 99mTc-besilesomab or 99mTc- sulesomab).4 In particular, 99mTc-sulesomab sulesomab scintigraphy at the discretion of has been increasingly used for the diagnosis the surgeon and nuclear medicine physician. of infection after arthroplasty, with a variety Surgery for TKA was performed in a variety of reported outcomes.5 – 7 of different orthopaedic departments at A disadvantage of using intact murine Philipps University. A detailed clinical monoclonal antibodies is the occurrence of examination was performed, blood samples allergic reactions in patients due to repeated were taken for routine haematological and antibody exposure and to the development biochemical analysis, and normal X-rays of of human antimouse antibodies (HAMA).8,9 the suspected area of prosthesis infection A multicentre study, assessing the image were obtained before carrying out quality of 99mTc-besilesomab in peripheral scintigraphic imaging. osteomyelitis, detected HAMA in 16 of 116 The study was approved by the Ethics (13.8%) patients. Antibody fragments, such Committee of the Department of Trauma, as 99mTc-sulesomab, rather than intact Reconstructive and Orthopaedic Surgery, antibodies are being used as an option to Centre Bad Cannstatt, Stuttgart, Germany. avoid the HAMA response. Research has All patients were fully informed about the shown that 99mTc-sulesomab is well tolerated study purpose and any potential risks, and and not associated with any patient side- gave their verbal informed consent prior to effects or the development of HAMA;10 Fab′ entry. fragment of IgG antibody lacks the Fc- terminal responsible for the immune DIAGNOSTIC STANDARD reactions. As previously already described4 definitive Several studies have been performed in diagnosis of prosthesis infection was patients with septically loosened established through culture of articular or arthroplasty using intact 99mTc-monoclonal intraoperative samples from patients antibodies2,7 or 99mTc-Fab′ fragments.4 The undergoing revision surgery. A lesion was present study aimed to carry out direct defined as infected when micro-organisms comparison of the accuracy of imaging with were found in cultures. Abscess formation 99mTc-besilesomab versus 99mTc-sulesomab and the presence of neutrophilic Downloaded from imr.sagepub.com1336 at RUTGERS UNIV on April 7, 2015 S Gratz, P Reize, A Pfestroff et al. Imaging infection in septically loosened total knee arthroplasty granulocytes were also considered as which were supplied in lyophilized form in indicating infection. For patients with ready-to-use vials: the 99mTc-besilesomab negative culture results and no clinical signs vials contained 1 mg of besilesomab; the of infection, a minimum of 1 year’s follow- 99mTc-sulesomab vials contained 0.31 mg of up was required involving detailed clinical sulesomab. Labelling was achieved by examinations and laboratory investigations, adding 1000 – 1500 MBq of freshly eluted including erythrocyte sedimentation rate 99mTc-pertechnetate in isotonic saline and C-reactive protein level and white blood solution directly into the vials. The cell count, to confirm the absence of radioactivity dose for 99mTc-besilesomab is prosthesis infection. normally 700 – 900 MBq (19 – 24 mCi) per injection (per patient) and for 99mTc- THREE-PHASE BONE SCINTIGRAPHY sulesomab it is normally 555 – 925 MBq, as Three-phase bone scintigraphy was proposed by the respective guidelines of the performed with 740 MBq of 99mTc-methylene European Association of Nuclear Medicine.11 diphosphonate (TECEOS®; CIS Bio, Berlin, The quantity of protein to be given to each Germany) injected intravenously (i.v.). patient was, therefore, estimated as 0.65 – Dynamic and planar images (in anterior 1.0 mg 99mTc-besilesomab and 0.10 – 0.31 and posterior views as per standard imaging mg 99mTc-sulesomab. protocol) were obtained with a large-field-of- Images were performed at least 48 h after view double-headed gamma camera (Prism bone imaging to avoid superimposition of 2000; Picker International, Cleveland, OH, the results. For 99mTc-besilesomab and 99mTc- USA), equipped with low-energy, high- sulesomab examination, 555 – 740 MBq resolution, parallel-hole collimators. Energy 99mTc-labelled antibodies per injection were discrimination was accomplished using a slowly administered i.v. Planar and single- 20% window centred on the 140 keV 99mTc photon emission computed tomography peak. Dynamic acquisitions were performed (SPECT) images were acquired 4 and 24 h using a 64 × 64 matrix at 5 s intervals for after the injection. Planar images with a 60 s during arterial inflow (phase 1). Blood minimum of 500000 counts/view (knee) pool planar static images were obtained were acquired in a 256 × 256 matrix using a using a 256 × 256 matrix 5 min after large-field-of-view double-headed continuous, injection and equilibration of the rotating gamma camera (Prism 2000) radionuclide (phase 2). Planar static equipped with low-energy, high-resolution imaging was performed 3 h after injection of collimators, with 18 min acquisition time at the radionuclide (phase 3). 3600 counts/pixel, 60 s/stop and 30 s/frame. Transverse sections were reconstructed using 99MTC-BESILESOMAB AND a filtered back-projection algorithm 99MTC-SULESOMAB IMAGING (Butterworth filter cut-off frequency of 0.45 Antigranulocyte antibody imaging was Nyquist and no attenuation compensation) performed with the murine 99mTc-labelled with subsequent computation of coronal and IgG antibody 99mTc-besilesomab (Scintimun®; sagittal slices. CIS Bio International, Saclay, France) and with the murine 99mTc-labelled Fab′ VISUAL IMAGE ANALYSES fragment 99mTc-sulesomab (LeukoScan®; Visual image analyses of 99mTc-besilesomab Immunomedics, Morris Plains, NJ, USA), and