ABSTRACT
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 18F-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, 18F-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.
Subject(s)
Intracranial Arteriovenous Malformations/diagnostic imaging , Subclavian Steal Syndrome/diagnostic imaging , Adult , Embolization, Therapeutic , Female , Fluorodeoxyglucose F18 , Humans , Intracranial Arteriovenous Malformations/metabolism , Intracranial Arteriovenous Malformations/therapy , Magnetic Resonance Imaging , Positron-Emission Tomography , Subclavian Steal Syndrome/metabolism , Tomography, X-Ray Computed , Treatment OutcomeABSTRACT
BACKGROUND: Patients with severe cerebral ischemia may lose autoregulation to increase cerebral blood flow following neural activity. Although the steal phenomenon under conventional cerebral blood flow study has been known as a high-risk factor for stroke, the cerebral oxygen hemodynamics in ischemic patients during functional activation has not been thoroughly investigated. In this study, we present rare cases with intracortical steal phenomenon during motor tasks detected by multichannel functional near-infrared spectroscopy before and after surgery. METHODS: The relative concentration change of oxygenated, deoxygenated and total hemoglobin in and around the primary sensorimotor cortex during contralateral hand grasping was investigated in 11 patients with severe internal carotid artery stenosis. RESULTS: In 3 patients, the concentration of total hemoglobin around the primary sensorimotor cortex significantly decreased in response to motor stimulation and returned to baseline soon after termination of the motor task. This phenomenon partially disappeared postoperatively in all patients who underwent surgery. The remaining 8 patients showed no signs of total hemoglobin decrease in and around the sensorimotor cortex. In 9 patients, lack of decrease in deoxygenated hemoglobin in the center of the primary motor cortex during the motor task was observed and 3 of them showed significant increase in deoxygenated hemoglobin. CONCLUSIONS: We have demonstrated that in some patients with severe ischemia, an abnormal motor-related steal phenomenon can be observed. This phenomenon can be modulated by surgical intervention and might imply the severity of ischemia.
Subject(s)
Carotid Stenosis/diagnosis , Carotid Stenosis/physiopathology , Spectroscopy, Near-Infrared/methods , Subclavian Steal Syndrome/diagnosis , Subclavian Steal Syndrome/physiopathology , Aged , Brain Ischemia/diagnosis , Brain Ischemia/metabolism , Brain Ischemia/physiopathology , Carotid Artery, Internal , Carotid Stenosis/metabolism , Cerebrovascular Circulation , Female , Hemoglobins , Humans , Male , Motor Skills , Oxygen/metabolism , Severity of Illness Index , Spectroscopy, Near-Infrared/instrumentation , Subclavian Steal Syndrome/metabolism , Time FactorsABSTRACT
Cerebral blood flow (CBF) and cerebellar blood flow (CeBF) were measured and correlated with brain lactate, pyruvate and adenosine triphosphate concentrations from groups representing 3-week old suckling (n = 10), 18-22-week old adult (n = 9) and 70-week old aged (n = 7) Sprague-Dawley rats before and during bilateral carotid occlusion (BCO). The steal ratio, calculated as the ratio of %control CBF to %control CeBF, was 1.02 +/- 0.06 (mean +/- SEM) at 60 minutes of BCO in adult rats that exhibited normal levels of brain metabolites. By contrast, the ratios significantly decreased to 0.74 +/- 0.06 in suckling rats and 0.69 +/- 0.06 in aged rats with simultaneous increases by 2.4 to 2.9-fold of tissue lactate. Pyruvate and lactate/pyruvate ratio also increased by 1.4 to 1.8 times control in both suckling and aged rats. We conclude that there is age-related steal phenomenon occurring with blood flow during BCO. Ischemic derangement of the brain metabolism is in part related to poor blood supply from the posterior circulation in suckling and aged rats.
