The “ivy sign score” on FLAIR MR images: Clinical utility following revascularization in pediatric Moyamoya disease

The aim was to evaluate post-operative changes in the Ivy sign on unenhanced fluid-attenuated inversion-recovery (FLAIR) following surgical intervention in pediatric Moyamoya disease (MMD) and assess its clinical utility as an indicator of hemodynamic improvement. Fifteen pediatric patients with MMD were included in this retrospective study. Surgical revascularization had been done in all patients on the cerebral hemisphere with reduced cerebral vascular reserve (CVR); one of them had bilateral surgery (n = 16). FLAIR examinations were reviewed in each patient, pre and post-operative. We compared the pre and post-operative total Ivy score (TIS) for each of the 16 hemispheres and correlated them with the clinical status. FLAIR images depicted the Ivy sign pre-operatively in all 16 hemispheres and a strong positive correlation between the TIS and the grade of clinical hemispheric symptom (p < 0.00001). Following surgery, reduction of the TIS was seen in 13 (81.25%) out of the 16 hemispheres while the TIS remained unchanged in 3 (18.75%) hemispheres. All patients with reduced Ivy signs post-operatively showed improvement of pre-operative clinical symptoms with moderate positive correlation (p = 0.01). A change in the postoperative Ivy sign can be an indicator of effective cerebral reperfusion in MMD.