Question 1: The imaging demonstrates a case of bilateral moyamoya disease, with the axial FLAIR MRI revealing ivy sign (red arrows, a marker of slow cortical blood flow) and chronic left frontal infarction in a watershed distribution (blue arrow). The MRA shows marked attenuation of the internal carotid arteries bilaterally, left worse than right (red arrows), concordant with the more severe disease with infarction on the left. In addition, the vertebrobasilar system is normal (blue arrow), a common finding in moyamoya (although posterior cerebral artery disease has been reported in 10-30% of some series). The AP and lateral left ICA injections on the catheter angiogram support the diagnosis of moyamoya, with classic Suzuki III-IV findings of ICA narrowing and the “puff of smoke” collateral circulation (red arrows). The lateral vertebrobasilar injection confirms the absence of posterior circulation disease, while also highlighting evidence of posterior to anterior collateralization along the splenium and body of the corpus callosum (blue arrow).
Question 2: The diagnosis of symptomatic moyamoya, with transient ischemic attacks (TIAs) clinically and advanced radiographic disease including stroke, support surgical revascularization as a first-line treatment. While there is debate about specific surgical approaches, the young age in this case suggests that indirect bypass may be technically the most feasible option. In addition, recent data and guidelines support the preferential use of indirect bypass in the pediatric population. Outcomes are demonstrably better at high-volume centers, supporting referral of pediatric moyamoya patients to hospitals with established pediatric cerebrovascular programs.
Question 3: Mutations in the RNF213 gene are present in approximately 2/3 of familial cases of moyamoya in patients with Asian ancestry. The history of potential TIAs in the patient’s mother, the childhood stroke-related death of the mother’s sibling and the presentation of the patient suggest that a familial mutation may be present in this case. Referral to a geneticist for RNF213 testing and possible family screening may be indicated.
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Nexus Occlusive Vascular Cases