title: Unsuspected pulmonary embolism identified using multidetector computed tomography in hospital outpatients.
abstract: OBJECTIVE
  To evaluate the incidence of unsuspected pulmonary embolism (PE) in an unselected population of outpatients undergoing contrast-enhanced multidetector computed tomography (MDCT) for indications other than the investigation of PE.
  
  
  METHODS
  Outpatients undergoing CT of the chest over a 6-month period were retrospectively identified and images reviewed. Inpatients and patients undergoing unenhanced CT of the chest were excluded. Data, including referring specialty, patient age and sex, reasons for examination, level of embolism, image quality, and section thickness were recorded. Radiology reports were reviewed with respect to whether or not the embolism was noted at the time of initial reporting.
  
  
  RESULTS
  Following exclusions 440 patients were reviewed (195 women and 245 men). PE was identified in 10 of the 440 patients, an incidence of 2.23%. One pulmonary embolus was in the main pulmonary artery, three were in lobar arteries, three in segmental arteries, and three in subsegmental arteries. Patients over the age of 60 years were more likely to have an embolism (9/300, 2.9%) compared with those under 60 years (1/140, 0.7%). Seven of the 10 positive examinations were carried out in patients who were known or later shown to have malignancy. Seven of the 10 emboli were reported at the time of initial reporting.
  
  
  CONCLUSIONS
  The outpatient population has a significant incidence of unsuspected PE. PE should be actively sought when reporting examinations performed for alternative indications, particularly where cancer is a known or suspected diagnosis.
authors.affiliation: Department of Radiology, Royal Infirmary of Edinburgh, Edinburgh, UK.
authors.forename: C
authors.initials: C
authors.lastname: Farrell
authors.forename: M
authors.initials: M
authors.lastname: Jones
authors.forename: F
authors.initials: F
authors.lastname: Girvin
authors.forename: G
authors.initials: G
authors.lastname: Ritchie
authors.forename: J T
authors.initials: JT
authors.lastname: Murchison
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D010044:Outpatient Clinics, Hospital; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult