title: Clinical usefulness of computed tomography study without contrast injection in the evaluation of acute pulmonary embolism.
abstract: OBJECTIVE
  To evaluate the percentage of cases in which emboli can be detected in unenhanced scans and to identify the cases in which they appear hyperattenuating or hypoattenuating in comparison to the circulating blood.
  
  
  METHODS
  An angio-computed tomography (CT) scan was performed before and after contrast injection in 140 consecutive patients after clinical suspicion of pulmonary embolism. A radiologist analyzed the examination results thus obtained. The enhanced scan was analyzed first, and after detecting the thrombus, the unenhanced scan was evaluated.
  
  
  RESULTS
  Fifty-one examinations were positive for a pulmonary embolism; in 21 cases, it was possible to identify the embolus even in the unenhanced scans. In 10 cases, the clots were hyperattenuating in comparison to the circulating blood; in 5 cases, they were hypoattenuating; and in 6 cases, they were mixed hyper-hypoattenuating.
  
  
  CONCLUSIONS
  In a relatively high percentage of cases, particularly those of central thromboembolism, it is possible to identify and characterize the clots even in unenhanced scans.
authors.affiliation: Department of Clinical Sciences, University of Parma, Parma, Italy. cobellirocco@hotmail.com
authors.forename: Rocco
authors.initials: R
authors.lastname: Cobelli
authors.forename: Maurizio
authors.initials: M
authors.lastname: Zompatori
authors.forename: Giovanni
authors.initials: G
authors.lastname: De Luca
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Chiari
authors.forename: Paolo
authors.initials: P
authors.lastname: Bresciani
authors.forename: Carla
authors.initials: C
authors.lastname: Marcato
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods; D001769:Blood; D003287:Contrast Media; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D011856:Radiographic Image Enhancement / Q000379:methods; D036542:Tomography, Spiral Computed / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media