18F-Fluorodeoxyglucose Positron Emission Tomography-Magnetic Resonance Monitoring of Brain Metabolic Changes in a Case of Arteriovenous Malformation–Related Steal Phenomenon Symptoms

Background Unruptured brain arteriovenous malformations (AVMs) represent a complex disease in young healthy adults. Most often AVMs are clinically silent but also can display a neurologic syndrome due to hypoperfusion/hypometabolism in perilesional brain tissue called steal phenomenon. Case Description A 34-year-old woman was admitted to a secondary neurologic center complaining of a right hemiparesis and secondarily generalized seizures. Computed tomography scan and magnetic resonance imaging of the brain showed a left prerolandic AVM without signs of acute or previous bleedings. Digital subtraction angiography confirmed a left juxta-central AVM, with a diffuse pattern, fed by hypertrophic rolandic branches from the left middle cerebral artery. An 18 F-fluorodeoxyglucose positron emission tomography-magnetic resonance imaging scan was performed 3 days after the critical episode. A significant hypometabolism in parenchymal regions ipsilaterally to the AVM was detected. Two embolization sessions were performed by means of N-butyl cyanoacrylate glue. At the end of the second procedure, a decrease of the shunt-flow and AVM size was observed. Six months later, 18 F-fluorodeoxyglucose positron emission tomography-magnetic resonance imaging scan showed persistent hypometabolism located in the AVM area, with a significant improvement of the cortical hemispheric hypometabolism. The patient was asymptomatic and was sent to stereotactic radiosurgery to complete the treatment. Conclusions In clinical practice, irritative symptoms in patients with unruptured AVMs could lead to erroneous evaluations. In case of fluctuating clinical syndromes, like our case, establishing that symptoms are related to a steal phenomenon is usually difficult.