title: MR venography in children with complex craniosynostosis.
abstract: OBJECTIVE
  Chronic venous hypertension due to jugular foramen stenosis has been proposed as an etiology for the hydrocephalus and tonsillar herniation seen in some patients with complex craniosynostosis. We report the use of MR venography (MRV) to evaluate venous outflow obstruction in this clinical setting.
  
  
  METHODS
  We studied 17 patients, (ages 4 months to 34 years; mean 7.3 years) with complex craniosynostosis; 8 patients with Crouzon's syndrome, 2 with Apert's, 1 with Pfeiffer's and 6 patients without an eponymous classification. MR imaging included routine imaging sequences and axial 2D TOF MRV. Patterns of venous drainage and the presence of hydrocephalus and tonsillar herniation were noted.
  
  
  RESULTS
  Jugular vein obstruction was seen in 12/17 patients; in 5/8 patients with Crouzon's, 1/2 with Apert's, the single patient with Pfeiffer's and 5/6 patients with nonsyndromic craniosynostosis. The predominant collateral drainage was via the posterior condylar veins. Nine of 12 (75%) of the patients with abnormal MRV had hydrocephalus; 3/8 patients with Crouzon's, 1/2 patients with Apert's, and 5/6 nonsyndromic patients. Two patients had hydrocephalus with normal MRV. Ten patients had tonsillar herniation, which was associated with shunted hydrocephalus in 7/10 patients, and hydrocephalus seen prior to shunt placement in 3/9. Nine of 10 patients with tonsillar herniation had an abnormal MRV, while 1 patient had a normal MRV. Venous pressures measured in 1 patient showed an 8-mm-Hg differential across the skull base.
  
  
  CONCLUSIONS
  The posterior condylar veins appear pivotal in maintaining venous drainage when the jugular bulbs are occluded. Although the association between venous outflow obstruction, hydrocephalus and tonsillar herniation is intriguing, evidence of venous outflow obstruction by MRV may not be indicative of significant intracranial venous hypertension.
authors.affiliation: Department of Radiology, University of Texas Southwestern Medical Center and Children's Medical Center, Dallas, Tex 75235, USA. nrolli@childmed.dallas.tx.us
authors.forename: N
authors.initials: N
authors.lastname: Rollins
authors.forename: T
authors.initials: T
authors.lastname: Booth
authors.forename: K
authors.initials: K
authors.lastname: Shapiro
mesh_terms: D000293:Adolescent; D000328:Adult; D002550:Cerebral Veins / Q000473:pathology*; D002560:Cerebrovascular Circulation; D002648:Child; D002675:Child, Preschool; D003251:Constriction, Pathologic; D003393:Cranial Sutures / Q000000981:diagnostic imaging / Q000473:pathology*; D003398:Craniosynostoses / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D007223:Infant; D019586:Intracranial Hypertension / Q000209:etiology; D007601:Jugular Veins / Q000473:pathology*; D018810:Magnetic Resonance Angiography; D008297:Male; D010690:Phlebography / Q000379:methods*; D012886:Skull / Q000000981:diagnostic imaging; D013577:Syndrome; D014690:Venous Pressure