title: Sensitivity and specificity of CT scanning for determining the number of internally concealed packages in 'body-packers'.
abstract: BACKGROUND
  If package counts on abdominal CTs of body-packers were known to be accurate, follow-up CTs could be avoided. The objective was to determine the accuracy of CT for the number of concealed packages in body-packers, and the reliability of package counts reported by body-packers who admit to concealing drugs.
  
  
  METHODS
  Suspected body-packers were identified from the emergency departments (ED) database. The medical record and radiology reports were reviewed for package counts determined by CT, patient-reported and physically retrieved. The last method was used as the reference standard. Sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) were calculated for CT package count accuracy. Reliability of patient-reported package counts was assessed using Pearson's correlation coefficient.
  
  
  RESULTS
  There were 50 confirmed body-packers on whom 104 CT scans were performed. Data for the index and reference tests were available for 84 scans. The sensitivity, specificity, PPV and NPV for CT package count were 63% (95% CI 46% to 77%), 82% (95% CI 67% to 92%), 76% (95% CI 58% to 89%) and 71% (95% CI 56% to 83%) respectively. For CTs with a package count<15, the sensitivity, specificity, PPV and NPV for CT package count were 96% (95% CI 80% to 99%), 95% (95% CI 82% to 99%), 93% (95% CI 76% to 99%) and 97% (95% CI 86% to 100%), respectively. Correlation between patient-reported package counts and the number of packages retrieved was high (r=0.90, p<0.001, R2=81%).
  
  
  CONCLUSIONS
  The accuracy of CT for determining the number of concealed packages is poor, although when applied to patients with few concealed packages accuracy is high and is useful as a rule-out test. Among patients who have admitted to drug concealment, the number of packages reported to be concealed is reliable.
authors.affiliation: Emergency Department, St George Hospital, Sydney, New South Wales, Australia Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Stephen Edward
authors.initials: SE
authors.lastname: Asha
authors.affiliation: Emergency Department, St George Hospital, Sydney, New South Wales, Australia.
authors.forename: Matthew
authors.initials: M
authors.lastname: Higham
authors.affiliation: Radiology Department, St George Hospital, Sydney, New South Wales, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Child
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D064423:Drug Trafficking; D005260:Female; D005547:Foreign Bodies / Q000000981:diagnostic imaging*; D006801:Humans; D013287:Illicit Drugs; D021621:Imaging, Three-Dimensional; D008297:Male; D061330:Multidetector Computed Tomography; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D013287:Illicit Drugs
keywords: Diagnosis; Drug Abuse; Forensic/Legal Medicine; Imaging, CT/MRI