title: Patent foramen ovale: detection with nongated multidetector CT.
abstract: OBJECTIVE
  To evaluate nongated multidetector computed tomography (CT) in the detection of patent foramen ovale (PFO) and atrial septal aneurysm (ASA) in comparison with transesophageal echocardiography (TEE).
  
  
  METHODS
  The study was approved by the institutional review board, and informed consent was obtained from all patients. One hundred five patients (57 men, 48 women; mean age, 53 years) with a recent stroke underwent TEE and multidetector CT on the same day. After injection of a diluted iodinated contrast material, a series of 2.4-mm-thick transverse images centered on the fossa ovalis were acquired in conjunction with release of the Valsalva maneuver. Two independent radiologists considered PFO present if left atrial enhancement was detected visually before enhancement of the pulmonary veins or if an early peak of left atrial enhancement was found at time-attenuation curve analysis.
  
  
  RESULTS
  PFO was detected with 98% specificity (95% confidence interval [CI]: 0.91, 0.99). Overall sensitivity was 55% (95% CI: 0.38, 0.70), ranging from 28% for shunts classified as grade 1 at TEE to 91% for those classified as grade 4 at TEE. Interreader agreement was good (kappa = 0.81). Visual assessment was better than time-attenuation curve analysis, which enabled detection of only 15 of the 40 cases of PFO. Multidetector CT depicted only 22% of cases of ASA. The mean effective radiation dose was 2.3 mSv.
  
  
  CONCLUSIONS
  Nongated multidetector CT can be used to diagnose high-grade shunts through a PFO, with 91% sensitivity and 98% specificity. Thus, PFO detection, in addition to routine CT evaluation of the lungs, could be indicated in patients with unexplained hypoxemia.
authors.affiliation: Department of Radiology, Calmette Hospital, Centre Hospitalier Regional Universitaire de Lille, University of Lille-2, Boulevard Jules Leclercq, 59037 Lille, France.
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Revel
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Faivre
authors.forename: Thierry
authors.initials: T
authors.lastname: Letourneau
authors.forename: Hilde
authors.initials: H
authors.lastname: Henon
authors.forename: Didier
authors.initials: D
authors.lastname: Leys
authors.forename: Valérie
authors.initials: V
authors.lastname: Delannoy-Deken
authors.forename: Martine
authors.initials: M
authors.lastname: Remy-Jardin
authors.forename: Jacques
authors.initials: J
authors.lastname: Remy
mesh_terms: D054092:Foramen Ovale, Patent / Q000000981:diagnostic imaging*; D006801:Humans; D014057:Tomography, X-Ray Computed / Q000379:methods*