Quantitative Assessment Of Cerebrovascular Reactivity In Paediatric Moyamoya

Background: Moyamoya disease is a progressive steno-occlusive arteriopathy that causes recurrent ischaemic events and neurological decline. Cerebrovascular reactivity (CVR) is an indicator of tissue level perfusion impairment and stroke risk. Quantitative BOLD MRI using carbon dioxide as a vasoactive stimulus has been validated in adults and region of CVR abnormality shown to be concordant with angiographic region of abnormality. However the evidence in paediatric literature remains scarce and mainly refers to the use of targeted-controlled delivery of CO2 which has limited utility in the paediatric population. Objective: To examine whether hypercapnic challenge BOLD CVR using endogenous CO2 in the awake (breath-hold [BH]) and sleep (general anaesthetic [GA]) state in children is reliable and repeatable. We also sought to explore whether regional abnormalities of CVR using these techniques were concordant with angiographic regions of abnormality. Method: Consecutive children with angiographic confirmation of MM had BH or GA CVR studies. All repeat studies - conducted on the same day in the same MRI session - were assessed for reliability and repeatability of qualitative measures of CVR. Results: Thirty seven children (16 male; median age MM diagnosis 8.61 years, range 0.6 - 16.7; median age at CVR 10.7 years, range 1.08-17.7) had CVR studies. Children who had a CVR study under GA were significantly younger at diagnosis of MM (mean age 7.4 years, range .67-16.58) compared to those studied using BH (mean age 10.47 years, range .83-15.58). CVR region of abnormality was concordant with region of angiographic abnormality. Twenty nine had repeat studies (14 GA, 15 BH). Intraclass correlation was fair (0.783, 95% confidence interval .534-.899) to excellent (.910, 95% confidence interval .577-.908) and agreement between repeat measures good. Conclusion: Qualitative measures of CVR using general anaesthetic and breath-hold techniques are reliable, repeatable and interpretable for use in clinical practice. However standardization of protocols would allow more reliable application of these tools for assessment of ischaemic risk in childhood cerebrovascular disease.