title: Amplatzer atrial septal defect occluder for pediatric patients: radiographic appearance.
abstract: OBJECTIVE
  To describe the chest radiographic appearance of the Amplatzer septal occluder (ASO) (AGA Medical Corporation, Golden Valley, Minn) for atrial septal defects (ASDs) in pediatric patients.
  
  
  METHODS
  Two radiologists independently reviewed frontal and lateral chest radiographs obtained in young patients 24 hours after transcatheter ASD closure with the ASO. The appearance (flat disks or dots) and location of the ASO were recorded. The location was related to that of a thoracic vertebral body on frontal and lateral chest radiographs and to a line drawn between the anterior margin of the right hilum and the posterior margin of the inferior vena cava (hilar-caval line) on lateral radiographs; this line corresponded to the expected position of the interatrial septum. The relationship between ASO appearance and patient age was assessed with logistic regression and cumulative probability plots.
  
  
  RESULTS
  Sixty-eight pediatric patients (age range, 1 month to 18 years; mean age, 4.2 years; 24 boys and 44 girls) were included. On frontal radiographs, the ASO center projected between T7 and T9, either to the right of or over the spinous processes of the vertebral body. On lateral radiographs, the ASO projected over (n = 66) or anterior to (n = 2) the hilar-caval line. On frontal radiographs, it appeared as one or two flat disks (n = 61) or as two metallic dots (n = 7). On lateral radiographs, it appeared as two flat disks (n = 54) or as two metallic dots (n = 14). The relationship between increasing patient age and the metallic dot appearance on frontal and lateral radiographs and on the combination of frontal and lateral radiographs was highly significant in each case (P < .001, likelihood ratio chi(2) test), with r(2) values of 0.35, 0.20, and 0.28, respectively. ASDs were successfully occluded with the ASO in all patients except one, in whom trivial shunting was seen at 12-month follow-up.
  
  
  CONCLUSIONS
  The ASO in pediatric patients has a characteristic radiographic appearance when properly positioned.
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, St Louis, MO 63110, USA.
authors.forename: Edward Y
authors.initials: EY
authors.lastname: Lee
authors.forename: Marilyn J
authors.initials: MJ
authors.lastname: Siegel
authors.forename: Celeste M
authors.initials: CM
authors.lastname: Chu
authors.forename: Fernando R
authors.initials: FR
authors.lastname: Gutierrez
authors.forename: Henry W
authors.initials: HW
authors.lastname: Kort
mesh_terms: D000293:Adolescent; D006328:Cardiac Catheterization; D002648:Child; D002675:Child, Preschool; D005260:Female; D006344:Heart Septal Defects, Atrial / Q000000981:diagnostic imaging* / Q000628:therapy*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D013902:Radiography, Thoracic; D016896:Treatment Outcome