title: Prevalence of acute pulmonary embolism in central and subsegmental pulmonary arteries and relation to probability interpretation of ventilation/perfusion lung scans.
abstract: OBJECTIVE
  The purpose of this investigation is to determine the prevalence of acute pulmonary embolism (PE) limited to subsegmental pulmonary arteries.
  
  
  BACKGROUND
  Contrast-enhanced helical (spiral) and electron-beam CT, in the hands of experienced radiologists who are skillful with this modality, are sensitive for the detection of acute PE in central pulmonary arteries, but have a low sensitivity for the detection of PE limited to subsegmental pulmonary arteries. The potential for CT to diagnose PE, therefore, is partially dependent on the prevalence of PE limited to subsegmental pulmonary arteries.
  
  
  METHODS
  Data are from the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED). The largest pulmonary arteries that showed PE, as interpreted by the PIOPED angiographic readers, were identified in 375 patients in PIOPED with angiographically diagnosed PE.
  
  
  RESULTS
  Among all patients with PE, 6% (95% confidence interval [CI], 4 to 9%) had PE limited to subsegmental branches of the pulmonary artery. Patients with high-probability ventilation/ perfusion (V/Q) scans had PE limited to subsegmental branches in only 1% (95% CI, 0 to 4%). Among patients with low-probability V/Q lung scans, 17% (95% CI, 8 to 29%) had PE limited to the subsegmental branches. Patients with low-probability V/Q scans and no prior cardiopulmonary disease had PE limited to the subsegmental pulmonary arteries in 30% (95% CI, 13 to 53%), whereas patients with low-probability V/Q scans who had prior cardiopulmonary disease had PE limited to subsegmental pulmonary arteries in 8% (95% CI, 2 to 22%) (p < 0.05).
  
  
  CONCLUSIONS
  Based on data from all patients with PE in PIOPED, the prevalence of PE limited to subsegmental pulmonary arteries is low, 6%. PE limited to subsegmental pulmonary arteries was most prevalent among patients with low-probability V/Q scans, particularly if they had no prior cardiopulmonary disease.
authors.affiliation: Henry Ford Heart and Vascular Institute, Detroit, MI 48202-3006, USA.
authors.forename: P D
authors.initials: PD
authors.lastname: Stein
authors.forename: J W
authors.initials: JW
authors.lastname: Henry
mesh_terms: D000208:Acute Disease; D000792:Angiography; D001158:Arteries; D003287:Contrast Media; D006331:Heart Diseases / Q000150:complications; D006801:Humans; D008168:Lung / Q000098:blood supply* / Q000000981:diagnostic imaging; D008171:Lung Diseases / Q000150:complications; D015995:Prevalence; D011336:Probability; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging / Q000209:etiology*; D011856:Radiographic Image Enhancement / Q000379:methods; D011877:Radionuclide Imaging; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods; D014692:Ventilation-Perfusion Ratio
chemical_list: D003287:Contrast Media