Absence of Deep and Basal Veins Is Common and Clinically Relevant in Sturge-Weber Syndrome

Common intracranial vascular abnormalities in Sturge-Weber syndrome (SWS) include leptomeningeal venous malformations (LVMs) and enlarged deep veins. A few small studies have reported absent deep veins in some patients. We used susceptibility-weighted imaging (SWI), a magnetic resonance imaging (MRI) sequence sensitive to detecting small veins, to evaluate deep cerebral veins and the basal vein of Rosenthal (BVR) and assess the radiological correlates and clinical impact of their absence.

Fifty young subjects, including 30 patients with unilateral SWS and 20 healthy controls, underwent 3T brain MRI prospectively. The presence or absence of the internal cerebral vein (ICV), its two main tributaries, and the BVR were evaluated on SWI in all 50 subjects and correlated with other brain abnormalities and clinical symptoms in the SWS group.

Although deep veins and the BVR were identified bilaterally in all control subjects, absent veins were observed in 70% of patients with SWS: in the SWS-affected hemisphere, absent ICV in 15 (50%), thalamostriate vein in 11 (37%), septal vein in seven (23%), and BVR in nine (30%) patients. Absent contralateral veins were also observed. Absent veins were associated with enlarged and collateral veins. Absent BVR and ICV were associated with extensive LVM, brain atrophy, and worse motor functions (P < 0.05); absent BVR was also associated with stroke-like episodes.

Absence of deep and/or basal cerebral veins is common in SWS and is associated with venous vascular anomalies, parenchymal damage, and motor impairment. Absent BVR may also increase the risk for stroke-like episodes.