title: Avidin and 111In-labelled biotin scan: a new radioisotopic method for localising vascular graft infection.
abstract: OBJECTIVE
  To evaluate a new imaging technique, for diagnosis of prosthetic vascular graft infection. Avidin is a protein which accumulates nonspecifically at sites of inflammation or infection. Due to its extremely low dissociation constant with biotin sites of infection can be imaged, using avidin as a pre-target, followed by injection of 111In-labelled biotin. This technique is much simpler than the common scintigraphic methods which employ labelling of blood components and its target-to-background ratio is greater than the methods employing radiolabelled proteins.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  A single department of vascular surgery and one of nuclear medicine of a Northern Italian hospital.
  
  
  METHODS
  Between May 1993 and May 1994, 31 grafts in 26 patients were studied; the series included 23 men and three women with a mean age of 65.5 years (range 54-76 years). The prosthetic graft (Dacron -16, ePTFE -15) were: aortoaortic 5, aortobifemoral 15, aortoiliac 1, and femoropopliteal 10. Sixteen patients were suspected of having a vascular graft infection (Group A), the other 10 patients served as controls (Group B). 20 mg of Avidin were injected iv, followed 24 h later by i.v. injection of 500 micrograms of Biotin labelled with 74 MBq of 111In.
  
  
  METHODS
  Whole-body imaging was performed at 10 min and 2 h post-injection, along with SPECT imaging when indicated. Scan results were correlated with the traditional imaging modalities and the clinical outcome of the patients.
  
  
  RESULTS
  In Group A: two patients (three grafts) were excluded from the study, there were six true-positives, one false-positive and 11 true-negatives. Results in Group B: 10 true-negatives. The overall sensitivity was 100%, the specificity 95%, the accuracy 96%, the positive predictive value 86% and the negative predictive value 100%.
  
  
  CONCLUSIONS
  These data suggest that Avidin/111In-labelled Biotin scintigraphy is a useful non invasive diagnostic method for early diagnosis of suspected prosthetic vascular graft infection.
mesh_terms: D000368:Aged; D001011:Aorta / Q000601:surgery; D001360:Avidin; D001710:Biotin; D001807:Blood Vessel Prosthesis / Q000009:adverse effects*; D005260:Female; D005263:Femoral Artery / Q000601:surgery; D005500:Follow-Up Studies; D006801:Humans; D007083:Iliac Artery / Q000601:surgery; D007205:Indium Radioisotopes; D008297:Male; D008875:Middle Aged; D011093:Polyethylene Terephthalates; D011138:Polytetrafluoroethylene; D011150:Popliteal Artery / Q000601:surgery; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011474:Prosthesis Design; D016459:Prosthesis-Related Infections / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon; D016896:Treatment Outcome
chemical_list: D007205:Indium Radioisotopes; D011093:Polyethylene Terephthalates; D001360:Avidin; D001710:Biotin; D011138:Polytetrafluoroethylene