MR venography in children with complex craniosynostosis

Purpose: Chronic venous hypertension due to jugular foramen stenosis has be en proposed as an etiology for the hydrocephalus and tonsillar herniation s een in some patients with complex craniosynostosis. We report the use of MR venography (MRV) to evaluate venous outflow obstruction in this clinical s etting. Materials and Methods: We studied 17 patients, (ages 4 months to 34 years; mean 7.3 years) with complex craniosynostosis; 8 patients with Crou zon's syndrome, 2 with Apert's, 1 with Pfeiffer's and 6 patients without an eponymous classification. NIR imaging included routine imaging sequences a nd axial 2D TOF MRV. Patterns of venous drainage and the presence of hydroc ephalus and tonsillar herniation were noted. Results: Jugular vein obstruct ion was seen in 12/17 patients; in 5/8 patients with Crouzon's, 1/2 with Ap ert's, the single patient with Pfeiffer's and 5/6 patients with nonsyndromi c craniosynostosis. The predominant collateral drainage was via the posteri or condylar veins. Nine of 12 (75%) of the patients with abnormal MRV had h ydrocephalus; 3/8 patients with Crouzon's, 1/2 patients with Apert's, and 5 /6 nonsyndromic patients. Two patients had hydrocephalus with normal MRV. T en patients had tonsillar herniation, which was associated with shunted hyd rocephalus in 7/10 patients, and hydrocephalus seen prior to shunt placemen t 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 post erior condylar veins appear pivotal in maintaining venous drainage when the jugular bulbs are occluded. Although the association between venous outflo w obstruction, hydrocephalus and tonsillar herniation is intriguing, eviden ce of venous outflow obstruction by MRV may not be indicative of significan t intracranial venous hypertension. Copyright (C) 2000 S. Karger AG. Basel.