Advanced multimodality neuroimaging of a giant, thrombosed MCA aneurysm complicated by an acute stroke in a pediatric patient

A 17-year-old boy presented to our quaternary hospital because of acute mental status changes following prolonged gastrointestinal illness resulting in dehydration. Neuroimaging studies with computed tomography and magnetic resonance imaging (MRI) revealed a giant thrombosed aneurysm of the left middle cerebral artery (MCA) with acute left MCA stroke. An ischemic penumbra was identified based upon the mismatch between diffusion weighted (DWI) and susceptibility weighted (SWI) MRI matching with the perfusion weighted imaging (PWI). On follow-up MRI, the core of ischemia as identified by DWI progressed into the ischemic penumbra identified by SWI. The patient had permanent moderate right hemiparesis and aphasia on last follow-up. In conclusion, thrombosis is a rare complication of a giant aneurysm in children. Advanced neuroimaging using the combination of DWI and noncontrast enhanced SWI is a valuable alternative or possibly adjunct to PWI to identify tissue at risk for progressing stroke.