title: Pulmonary arterial hypertension in children: diagnosis using ratio of main pulmonary artery to ascending aorta diameter as determined by multi-detector computed tomography.
abstract: BACKGROUND
  The ratio of the transverse diameter of the main pulmonary artery (MPA) to ascending aorta as determined at multi-detector CT is a tool that can be used to assess the pulmonary arterial size in cases of pulmonary arterial hypertension in children.
  
  
  OBJECTIVE
  To establish a ratio of MPA to ascending aorta diameter using multi-detector CT imaging suggestive of pulmonary arterial hypertension in children. We hypothesize that a defined ratio of MPA to ascending aorta is identifiable on multi-detector CT and that higher ratios can be used to reliably diagnose the presence of pulmonary arterial hypertension in children.
  
  
  METHODS
  We calculated the multi-detector CT ratio of MPA to ascending aorta diameter in 44 children with documented pulmonary arterial hypertension by right heart catheterization and in 44 age- and gender-matched control children with no predisposing factors for pulmonary arterial hypertension. We compared this multi-detector-CT-determined ratio with the MPA pressure in the study group, as well as with the ratio of MPA to ascending aorta in the control group. A threshold ratio value was calculated to accurately identify children with pulmonary arterial hypertension.
  
  
  RESULTS
  Children with documented primary pulmonary arterial hypertension have a significantly higher ratio of MPA to ascending aorta (1.46) than children without pulmonary arterial hypertension (1.11). A ratio of 1.3 carries a positive likelihood of 34 and a positive predictive value of 97% for the diagnosis of pulmonary arterial hypertension.
  
  
  CONCLUSIONS
  The pulmonary arteries were larger in children with pulmonary arterial hypertension than in a control group of normal children. A CT-measured ratio of MPA to ascending aorta of 1.3 should raise the suspicion of pulmonary arterial hypertension in children.
authors.affiliation: Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging, University of Toronto, 555 University Ave., Toronto, ON, M5G 1X8, Canada. pablo.caro-dominguez@sickkids.ca.
authors.forename: Pablo
authors.initials: P
authors.lastname: Caro-Domínguez
authors.affiliation: Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging, University of Toronto, 555 University Ave., Toronto, ON, M5G 1X8, Canada.|Epworth Medical Imaging, Epworth Hospital, Richmond, VIC, Australia.
authors.forename: Gregory
authors.initials: G
authors.lastname: Compton
authors.affiliation: Division of Cardiology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
authors.forename: Tilman
authors.initials: T
authors.lastname: Humpl
authors.affiliation: Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging, University of Toronto, 555 University Ave., Toronto, ON, M5G 1X8, Canada.
authors.forename: David E
authors.initials: DE
authors.lastname: Manson
mesh_terms: D000293:Adolescent; D001011:Aorta / Q000000981:diagnostic imaging*; D006328:Cardiac Catheterization; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011237:Predictive Value of Tests; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Ascending aorta; Children; Computed tomography; Main pulmonary artery; Pulmonary arterial hypertension; Ratio