title: CT-defined phenotype of pulmonary artery stenoses in Alagille syndrome.
abstract: BACKGROUND
  Alagille syndrome is a rare disorder commonly associated with pulmonary artery stenosis. Studies exist discussing the cardiovascular sequela but no consistent phenotype, or pattern of pulmonary artery stenosis, has been described.
  
  
  OBJECTIVE
  The objective of this study was to characterize the distribution and severity of pulmonary artery stenosis in patients with Alagille syndrome based on computed tomography angiography.
  
  
  METHODS
  A retrospective chart review identified patients with Alagille syndrome who had undergone CT angiography. Pulmonary trunk (MPA), left main pulmonary artery (LPA) and right main pulmonary artery (RPA) diameters in Alagille patients were compared with those from matched control subjects. Stenoses at lobar and segmental pulmonary arteries were categorized as: Grade 1 (<33% stenosis), Grade 2 (33-66% stenosis) or Grade 3 (>66% stenosis). Involvement among the different lung regions was then compared.
  
  
  RESULTS
  Fifteen patients ages 6 months to 17 years were identified; one had surgical augmentation of the central pulmonary arteries and was excluded from the central (main, right and left) pulmonary artery analysis. The proximal LPA and RPA, but not the MPA, were significantly smaller than those of the control subjects (P<0.01). The proximal LPA was significantly smaller than the proximal RPA (P<0.01) in the Alagille group (0.55 LPA:RPA ratio). Within the Alagille group, 75% of the lobar and segmental branches showed mild or no stenoses (Grade 1), 17% showed moderate stenosis (Grade 2) and 8% showed severe stenosis (Grade 3). While not statistically significant, the right lung demonstrated a greater percentage of Grades 2 and 3 stenoses (28%, right vs. 20% left, P=0.1). The right middle and lingula lobes of both lungs showed more Grade 2 and 3 stenoses (33% upper/middle vs. 18% lower, P<0.01).
  
  
  CONCLUSIONS
  We describe a common pattern pulmonary artery stenosis in Alagille patients consisting of severe proximal LPA stenosis, heavy involvement of the lobar and segmental branches (more often right than left), and a greater involvement of the upper lobes. Knowledge of this phenotypic pattern can help in the diagnosis of Alagille syndrome in patients presenting with pulmonary artery stenosis.
authors.affiliation: Department of Pediatrics (Cardiology), Packard Children's Hospital, Stanford University Medical Center, 750 Welch Road, Suite 305, Palo Alto, CA, 94304, USA.
authors.forename: Renee M
authors.initials: RM
authors.lastname: Rodriguez
authors.affiliation: Department of Pediatrics (Cardiology), Packard Children's Hospital, Stanford University Medical Center, 750 Welch Road, Suite 305, Palo Alto, CA, 94304, USA. jaf@stanford.edu.|Department of Bioengineering, Stanford University, Palo Alto, CA, USA. jaf@stanford.edu.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Feinstein
authors.affiliation: Department of Radiology, Stanford University, Palo Alto, CA, USA.
authors.forename: Frandics P
authors.initials: FP
authors.lastname: Chan
mesh_terms: D000293:Adolescent; D016738:Alagille Syndrome / Q000150:complications*; D002648:Child; D002675:Child, Preschool; D000072226:Computed Tomography Angiography / Q000379:methods*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010641:Phenotype; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D000071079:Stenosis, Pulmonary Artery / Q000150:complications* / Q000000981:diagnostic imaging*
keywords: Alagille syndrome; Children; Computed tomography angiography; Pediatric imaging; Pulmonary artery stenosis