Circle of Willis abnormalities in children with neurofibromatosis type 1.

Background And Purpose: The aim of the study was to assess anatomical variants and abnormalities in cerebral arteries on magnetic resonance angiography in 67 children with neurofibromatosis type 1 (NF1).

Materials And Methods: The study included 67 children aged 9 months to 18 years (mean 6.6 years). Control group comprised 90 children aged 2-18 years (mean: 11.8 years). All patients were examined at 1.5T scanner.

Results: We found cerebral arteriopathy (moyamoya disease) in one child (1.5%) in the study group. No aneurysms were found. Twenty-nine NF1 children (43.3%) had arterial anatomical variants. In 13 of them, more than one variant was diagnosed (44.8% of group with variants, 19.4% of study group). In control group, 19 children (21.1%) had variants, including four children with more than one variant (21% of group with variants, 4.4% of control group). Arterial variants were more common in NF1 patients compared with control group (p=0.026, binomial test for two proportions). Percentage of multiple variants was higher in study group than in control group, but this difference was not significant. Variants were more frequent on left side than on the right one (significant difference in control group; p=0.022, McNemara test). In study group, the number of left-sided anomalies (25) was similar to that of right-sided ones (22). There was no correlation between gender and variants, unidentified bright objects and variants or between optic gliomas and variants.

Conclusions: Occurrence of arterial variants in NF1 patients was twofold higher than in control group. Multiple variants were more frequent in the study group although the difference did not reach statistical significance. Features of cerebral arteriopathy were found in one child with NF1.