title: Accuracy of radiography, computed tomography and magnetic resonance imaging in diagnosing foreign bodies in the foot.
abstract: OBJECTIVE
  The purpose of this study was to determine the accuracy of conventional radiography, computed tomography (CT) and magnetic resonance imaging (MRI) in detecting foreign bodies by using cadaver feet.
  
  
  METHODS
  One hundred and sixty foreign bodies consisting of 5 × 2-mm fresh wood, dry wood, glass, porcelain and plastic fragments were randomly placed in the plantar soft tissue of the forefoot and sole. An additional 160 incisions were made without the insertion of foreign bodies. Radiographs, CT and MRI scans were assessed in a blinded fashion for the presence of a foreign body.
  
  
  RESULTS
  Overall sensitivity and specificity for foreign body detection was 29% and 100% for radiographs, 63% and 98% for CT and 58% and 100% for MRI. The sensitivity of radiography was lower in the forefoot. CT and MRI detection rates depended on the attenuation values of the foreign bodies and on the susceptibility artefact, respectively. CT was superior to MRI in identifying water-rich fresh wood.
  
  
  CONCLUSIONS
  Radiography, CT and MRI are highly specific in detecting foreign bodies but sensitivity is poor. The detection rate depends on the type of foreign body for all techniques and on location for radiography. To identify foreign bodies with MRI, pulse sequences should be used to enhance the susceptibility artefact. In water-rich wood, as in chronically retained wood, CT is more accurate than MRI.
authors: Department of Radiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
authors: N
authors: N
authors: Pattamapaspong
authors: T
authors: T
authors: Srisuwan
authors: C
authors: C
authors: Sivasomboon
authors: M
authors: M
authors: Nasuto
authors: P
authors: P
authors: Suwannahoy
authors: J
authors: J
authors: Settakorn
authors: J
authors: J
authors: Kraisarin
authors: G
authors: G
authors: Guglielmi
mesh_terms: D016477:Artifacts; D002102:Cadaver; D003937:Diagnosis, Differential; D005534:Foot Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging; D005547:Foreign Bodies / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*