title: Clinical impact of findings supporting an alternative diagnosis on CT pulmonary angiography in patients with suspected pulmonary embolism.
abstract: BACKGROUND
  CT pulmonary angiography (CTPA) is commonly used as the first imaging test in the diagnostic workup of patients with suspected pulmonary embolism (PE). Other CTPA findings may provide an alternative explanation for signs and symptoms in these patients, but the clinical impact is not clear.
  
  
  METHODS
  In 203 consecutive patients with suspected PE, we prospectively evaluated the clinical implication of abnormalities on CTPA. Alternative diagnoses were defined on clinical grounds before and after CTPA. Subsequent diagnostic tests and therapeutic consequences were assessed by criteria defined a priori.
  
  
  RESULTS
  Sixty-one of the 203 patients (30%) had no abnormality on CTPA. Thirty-nine patients (19%) were given a diagnosis of PE. Before CTPA, alternative diagnoses were suspected in 97 patients (48%). Findings supporting an alternative diagnosis were detected in 88 patients (43%). In 28 patients, this was a new finding; in 18, a conclusive and previously unknown alternative diagnosis was made on the basis of the CTPA results. Overall, the findings supporting alternative diagnoses had therapeutic consequences in 10 patients (4.9%). Incidental findings (nodules and enlarged lymph nodes) requiring diagnostic procedures were present in 17 patients (8.4%), with one (0.5%) having a therapeutic consequence.
  
  
  CONCLUSIONS
  In patients undergoing CTPA for suspected PE, findings supporting an alternative diagnosis were found in almost one-half of the patients. However, in only a few patients, the alternative diagnosis had therapeutic consequences. Hence, CTPA should principally be used to confirm or exclude PE in high-probability cases but not to establish an alternative diagnosis.
authors.affiliation: Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands. Electronic address: j.vanes@amc.uva.nl.
authors.forename: Josien
authors.initials: J
authors.lastname: van Es
authors.affiliation: Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Renée A
authors.initials: RA
authors.lastname: Douma
authors.affiliation: Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Sanne M
authors.initials: SM
authors.lastname: Schreuder
authors.affiliation: Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Saskia
authors.initials: S
authors.lastname: Middeldorp
authors.affiliation: Department of Vascular Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Pieter W
authors.initials: PW
authors.lastname: Kamphuisen
authors.affiliation: Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands; Department of Internal Medicine, Slotervaart Hospital, Amsterdam, The Netherlands.
authors.forename: Victor E A
authors.initials: VEA
authors.lastname: Gerdes
authors.affiliation: Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Ludo F M
authors.initials: LFM
authors.lastname: Beenen
mesh_terms: D000328:Adult; D000368:Aged; D000792:Angiography / Q000379:methods*; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D033162:Incidental Findings; D008171:Lung Diseases / Q000000981:diagnostic imaging*; D008198:Lymph Nodes / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*