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

Purpose: 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. Patients and methods: 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. Results: 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). Conclusion: A change in the postoperative Ivy sign can be an indicator of effective cerebral reperfusion in MMD. Keywords: Ivy sign score, FLAIR, Moyamoya, Post-operative, Pediatric, Revascularizatio