title: Helical computed tomography and alternative diagnosis in patients with excluded pulmonary embolism.
abstract: OBJECTIVE
  A clinical diagnosis of pulmonary embolism (PE) is confirmed objectively in 20-30% of patients. Helical computed tomography (CT) can allow an alternative diagnosis to be made. The frequency and validity of alternative diagnoses on helical CT in consecutive patients presenting with clinically suspected PE was assessed.
  
  
  METHODS
  In all 512 prospectively analyzed patients helical CT scan was performed, and apart from presence or absence of PE, pathologic changes in lung parenchyma, mediastinum, cardiovascular system, pleura and skeleton were recorded. When possible an alternative diagnosis was given and compared with the final diagnosis after 3 months follow-up.
  
  
  RESULTS
  In 130 patients (25.4%) PE was excluded and an alternative diagnosis considered likely. In 123 of the 130 patients (94.6%) this diagnosis was unchanged at 3 months follow-up. The diagnoses included pneumonia (n = 67), malignancy (n = 22), pleural fluid (n = 10), cardiac failure (n = 10), COPD (n = 6) and a variety of other causes (n = 15). The diagnosis changed at follow-up in seven patients (5.4%). An initial diagnosis of pneumonia changed to malignancy in two patients and to pleuritis and cardiac failure in one patient each. In two other patients malignancy and chronic obstructive pulmonary disease (COPD) were ruled out and the diagnosis changed to pneumonia. In one patient the final diagnosis remained unknown after an initial suspicion of malignancy.
  
  
  CONCLUSIONS
  In clinically suspected PE helical CT allows a reliable alternative diagnosis to be made in 25.4% of patients. This feature is an unique advantage in comparison with other diagnostic tests and supports the decision of taking helical CT as first line test in suspected PE.
authors.affiliation: Department of Radiology, Leyenburg Ziekenhuis, The Hague, The Netherlands. m.van.strijen@antonius.net
authors.forename: M J L
authors.initials: MJ
authors.lastname: van Strijen
authors.forename: J L
authors.initials: JL
authors.lastname: Bloem
authors.forename: W
authors.initials: W
authors.lastname: de Monyé
authors.forename: G J
authors.initials: GJ
authors.lastname: Kieft
authors.forename: P M T
authors.initials: PM
authors.lastname: Pattynama
authors.forename: A
authors.initials: A
authors.lastname: van den Berg-Huijsmans
authors.forename: M V
authors.initials: MV
authors.lastname: Huisman
mesh_terms: D000465:Algorithms; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000000981:diagnostic imaging; D017063:Outcome Assessment, Health Care; D010996:Pleural Effusion / Q000000981:diagnostic imaging; D011014:Pneumonia / Q000000981:diagnostic imaging; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D036542:Tomography, Spiral Computed