Early MRI diagnosis of Sturge Weber Syndrome type 1 in infants.

BACKGROUND: Patients with Sturge-Weber syndrome type 1 (SWS1) have a port-wine birthmark (PWB) as cutaneous hallmark. Up to 35% of neonates with a high risk PWB develop SWS1. Clinical manifestations are severe and often progressive. Especially early onset seizures are associated with worse neurocognitive outcome. Identification of pre-symptomatic SWS1 patients is hampered because brain MRI in the first months of life does not always show the for SWS1 characteristic leptomeningeal capillary malformation (LMC). OBJECTIVES: Identification of sensitive and specific MRI predictors for early SWS1 diagnosis. METHODS: In this retrospective single centre study, we included 24 SWS1 patients and 20 controls. We studied specificity and sensitivity for SWS1 diagnosis of LMC and indirect MRI signs such as choroid plexus (CP) size and thickness, abnormal white matter signal, lobar cerebral atrophy, ischemia and cortical calcifications. RESULTS: In SWS1 patients CP thickness and CP thickness ratio on non-contrast brain MRI was significantly increased. The optimal cut-off value of 5.6 mm on the affected side corresponded with a sensitivity of 91.7% and a specificity of 100% for confirmation of SWS1 diagnosis. In 21% of children aged ≤3 months with a later confirmed SWS1 diagnosis, LMC on initial MRI could not be discerned but CP thickness ≥5.6 mm on the affected side confirmed SWS1 diagnosis. CONCLUSIONS: In this study, CP size ratio and thickness were found to be sensitive and specific signs additional to earlier described criteria to support SWS1 diagnosis in neonates and infants which need to be confirmed in other series.